DEPARTMENT OF THE INTERIOR 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, DIRECTOR 

PROFE~SIONAL PAP~R 90 

SI-IORTER ·CONTRIBUTIONS TO 

GENERAL GEOLOGY 

1914 

DAVID WHITE, CHIEF GEOLOGIST 

vV ASHINGTON 

GOVEH.Nl\IENT PRINTING OFFICE 

1915 

CONTENTS. 

Page. 

Geology of the pitchblende ores of Colorado, by Edson S. Bastin (published March 17, 1914).................. 1 

Erosion and sedimentation in Chesapeake Bay around the mouth of Choptauk River, by J. F .. Hunter (published 

~fay 23, 1914).......................................................................................... 7 

Dike rocks of the Apishapa quad:angle, Colorado, by Whitman Cross (published June 13, 1914)................ 17 

'l'he composition of crinoid skeletons, by F. W. Clarke and W. C. Wheeler (published June 16, 1914)............ 33 

Contributions to ti10 stratigraphy of southwestern Colorado, by vVhitman Cross and E. S. Larsen (published 

September 17, 1914) ..................................................... · ....................... ,....... 39 

A reconnaissance in the Canyon Range, west-central Utah, by G. F. Loughlin (published October 17, 1914) . . . . 51 

'fhe Montana group of northwestern Montana, by Eugene Stebinger (published October 14, 1914).............. 61 

A deep well at Charleston, S. C., by L. W. Stephenson, with a report on the mineraiogy of the water, by Chase 

Palmer (published December 31, 1914)............................. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69. 

The stratigraphy of ti1e Montana group, with special reference to the position and age of the Judith River formation in north-central Montana, by C. F. Bowen (publi.med February 12, 1915) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 

• >, 'l.'he Cretaceous-Eocene contact in the Atlantic and Gulf Coastal Plain, by L. W. Stephenson (published February 27, 1915) ........................................... ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155 

. " The history of a portion of Yampa River, Colo., and its possible bearing on that of Green River, by E. T. Hancock 

(published February 20, 1915) ........................ ~................................................. 183 

,. 'l.'he inorganic constituents of echinoderms, by F. W. Clarke and W. C. Wheeler (pt~blished February 27, 1915).. 191 

Index ........................................................ :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197 

ILLUSTRATIONS. 

Page. 

Pr.A'l'J~ I. A, B, Camera Iucida drawings of polished surface of pitchblende ore from the Wood mine, Quartz 

Hill, Gilpin County, Colo ........... ~......................................................... 4 

II. A, Camera Iucida drawing of polished surface of pitchblende ore from the Calhoun mine, Quartz Hill, 

Gilpin County, Colo.; B, Microphotograph of polished section of pitchblende ore from the Wood 

mine, Quartz Hill, Gilpin County, Colo........................................................ 5 

III. Map of the mouth of Choptank River, with Tilghman, Sharps, and James islands, showing different 

positions of tile shore lines at the time of the first, second, and third surveys and ~reas of erosion 

and sedimentation ................................................ ~.......................... 10 

IV. Relief map of south-central Colorado, showing relation of the Apishapa quadrangle to the Spanish 

Peaks center of eruption ....................................... '................................ 18 

V. Photomicrographs of analyzed augite vogesite: A, With one nicol; B, With crossed nicols........... 22 

VI. Photomicrographs of analyzed hornblende-augite vogesite: A, With one nicol; B, With crossed 

nicols........................................................................................ 24 

VII. Phot01nicrographs of analyzed plagioclase basalt: A, With one nic9l; B, with crossed ni.cols......... 26 

VIII. La Plata sandstone on schist of Uncompahgre formation on north bank of Piedra River, Colo........ 44 

IX .. Lake Bonneville beds at the mouth of Sevier Canyon, near Leamington, Utah . . . . . . . . . . . . . . . . . . . . . . 56 

X. Geologic map of area examined between Musselshell and Judith, Mont .................. . f!........ 104 

XI. Map showing approximately the trend of the Cretaceous-Eocene contact in the Atlantic and Gulf Coastal 

. Plain ...................................................................... , . . . . . . . . . . . . . . . . 156 

XII. A, B, Contact between the Selma chalk (Upper Cretaceous) and :Midway group (Eocene) at Old Canton 

Landing, Alabama River, Ala.................................................................. 1162 

XIII. A, Fault involving the Cretaceous-Eocene contact at Old Canton Landing, Alabama River, Ala.; B, 

Exposure exhibiting the Cretaceous-Eocene contact on Macon-De Kalb road, 7! miles south of Macon, 

Ala ............................................ •.............................................. 163 

XIV. A, Cretaceous-Eocene contact in cut of St. Louis & San Francisco Railroad 1 mile east of New 

Albany, Miss.; B, Potholes in basal limestone of the :Midway formation on the Rio Grande 1 mile 

below 'Vhite Bluff, Maverick County, Tex..................................................... 168 

XV. Map of Maverick County, Tex., showing the approximate trend of the Cretaceous-Eocene contact 

from the Rio Grande northward through the county .............................. ·.............. 170. 

III 
lV ILLUSTRATIONS. 

Pago. 

XVI. A, B, Cretaceous-Eocene contact on the Rio Grande at White Bluff, Maverick County, Tex......... 172 

XVII. A, Contact between the Midway formation and overlying sandstone of Midway or Wilcox age on the 

Rio Grande in Maverick County, Tex.; B, Sandstone of :Midway or Wilcox age in a prominent 

westward-facing bluff on the Rio Grande in Maverick County, Tex .... __________ . ______ ~ _______ . 173 

XVIII. A, Basal limestone of Midway formation on southeast side of Elm Creek 11 miles south of Sabinal, Tex.; 

B, Eocene sandstone in bed of Hondo Creek 3-t miles south of Elstone, Tex. ___ ..... ·.~ ___ ._ .. _____ 178 

XIX. ,A, Escondido formation in bed of Hondo Creek at Rock Crossing, Medina County, Tex.; B, Basal limestone of Midway formation on left bank of Hondo Creek in Medina.County, Tex __ . ______ . ___ .. _ _ 179 

XX. Map showing the course of Yampa River, in Moffat County, Colo., from Green River east to 107° 3(Y 

west longitude ........... _ .. _ . __ .. ____ . _. __ . ______ . _ . _ .. __ .. _ .... __ . __ ................. _. ___ . _ _ 184 

XXI. Jointing in sandstone of Mesaverde formation: A, At the "Transfer," T. 2 N., R. 92 W., Meeker 

quadrangle, Colo.; B, InT. 4 N., R. 91 W., Monument Butte quadrangle, Colo._ ........... _~ ___ . 188 

FIGURE l. Sketch map of Chesapeake Bay, showing the area studied and its relation to other parts of the ba,y. 8 

2. Drainage map of a part of the Piedra Valley, Colo .... _ ... ____ . ___ ._. ___ .. _ .. _______ . ___ . ___ . ___ . 42 

3. Diagrammatic section along northwest side·of Piedra Canyon, Colo __ .. _. __ .. ___ ...... __ . _ .. ___ . _. 45 

4. Reconnaissance-map of the Canyon Range, Utah, showing geologic formations .. _~ ............... ·.. 52 

5. View across North Fork of Yellowstone River, Canyon Range, Utah, looking northwest from Arbroath 

shaft ... _ .... · ................... __ ........ ______________ . _ . _______________ . _________ . . . . . . . 53 

6. Generalized section8 along north and south sides of Fool Creek canyon, Utah..................... 55 

7. Generalized section along north side of Oak Creek canyon, Utah .......... : . ........ ·.· .. ,....... 55 

8. Eocene conglomerate resting on upturned Mississippian (or older?) limestone at head of Yellow-

.stone Canyon, Utah ........................ _ .. _ ................ _ ............ ___ ...... _..... 56 

9. Diagram showing probable relations of the marine and continental sediments of the Montana group 

in the northern Great Plains region, the top of the Colorado group being taken as a datum plane. 67 

10. Diagram of well at Charleston, S. C., showing size of hole and length of casings inserted._.......... 70 

11. Diagram indicating the terms used to designate paleontologic zones and the relation of these zones 

to formation units in the Chattahoochee region and the Carolinas ........ _ .. _................... 87 

12. Diagram showing correlation· of Cretaceous. portion of the Charleston well section in terms of the 

faunal zones recognized in the Cretaceous deposits of the eastern Gulf region ..... _............. 88 

13.' Generalized section of the Upper Cretaceous and Eocene series in west-central Alabama and eastcentral Mississippi. ......... __ .. __ . __ .. ______ . _____ ._. ___ ...... __ . __ ......... __ .. -.- .... _ .. - 156 

14. Generalized section from Troy, Ala., northward to Conecuh River .. _ .............. _ .... - "....... 161 

15. Sketch showing position of Cretaceous-Eocene contact and faulting at Old Canton Landing, Alabama River, Ala. ___ ·.-_ .. _ ..... _._ ..... _._ .. __ ..... _ ............ __ ........... __ .-.--- ...... - 162 

16. Section showing Cretaceous-Eocene contact on Curls station road half a mile southwest of the courthouse at Livingston, Ala._.' ... ~ ____ . ~ .. _ .. _ ....... _ ......... _ ...................... -.... _ . . . 163 

17. Section showing Cretaceous-Eocene contact on Sucarnochee Creek 5 miles northwest of Livingston, 

Ala ................................... _ ... _ ................. _ ......... · .. __ .......... _ . _ . . . 164 

18. Section showing Cretaceous-Eocene contact half a mile west of Giles, Kemper County, Miss....... 165 

19. Profile section along the left bank of Rio Grande below White Bluff, Maverick County, Tex._..... 172 

20. Sketch map showing outcrop of Cretaceous-Eocene contact in portions of Uvalde and Medina 

counties, Tex. ____ .... _. ______ ........... _._ ......... _ ... _ ............... _ .......... _. ___ .. 178 
SHOll'rER OONTRIBU'riONS To· . GEN.ERAL GEOLOGY, 1914. 

GEOLOGY OF THE PITCHBLENDE ORES OF COLORADO. 

By EDSON s. BASTIN. 

The large amount of public interest that has recently been manifested ·in radium because 

of the apparent cures of cancer effected by certain of its emanations makes it desirable to place 

before the public as promptly as possible all available information in :~:egarcl to the occurrence 

of the minerals from which radium may be derived. The following account of the mode of 

occurrence of pitchblende at Quartz Hill, in Gilpin Comity, Colo., is therefore published-in ad~ 

vance of a much larger report on the same region in which many other types of ore deposits 

will be considered. The field studies were made in the fall of 1912. As the geologic relation·s · 

at Quartz I-Iill differ in important particulars from those at foreign localities, a summary of 

the genetically important features of the principal European occurrences is included for purposes of comparison. ~1y thanks are due to :Mr. Frank L. IIess, of the Geological Survey, for 

generously placing at my disposal additional specimens for study. 

SOURCES OF URANIUM.IN THE UNI.TED STATES. 

The quantity of uranium ore mined in the United States is exceedingly small and in 1913 

appears. to have been equivalent to about 38 short tons of uranium oxide (U30 8), or approxinlately 32 tons of metallic uranium.1 This is considerably larger than the production in 1912, 

which was equivalent to about 26 short tons of urariium oxide, or in 1911, which was equivalent 

to about 25 short tons. Practically the entire production of 1911 and 1912 and about half that 

of 1913 went to foreign countries. Of this tonnage nearly all came fron1 sandstones of the high 

plateau regions of southwestern Colorado and southeastern Utah, in which the uranium occurs 

d~sseminated as the canary-yellow mineral carnotite (2U03 .V20 5.IC20. xH20) or its calciumbearing equivalent tjuyamunite (2U03.V20 5.Ca0. xii20). The sinall rernaining portion of 

uranium ore mined in the United States, amounting in 1912 to only 275 pounds, was uraninite, 

or pitchblende, a complex uranate of variable con1position to which a definite chemical formula 

can not yet be assigned. This mineral occurs in two distinct w~ys-in small amounts in 

granite pegmatites, notably in North Carolina, and in int:iillate association with metallic 

sulphides in certain mineral veins of Quartz I-Iill, near Central City, Gilpin County, Colo. 

'rhe mines frorn which pitchblende has been obtained are all located on Quartz Hill and 

include the Calhoun, Wood, ICirk, German, Belcher, and Alps mines. For many years a small 

and sporadic production has corne from this group and has been used mainly for specimens and 

for experirnents. Quartz liill is not only the one irnportant locality in the United States where 

pitchblende occurs in mineral veins but one of the few in the world. 

PRINCIPAL FOREIGN OCCURRENCES OF PITCHBLENDE. 

In preparing the following smnmary of the principal foreign occurrences, the writer has so. 

fa.r as possible consulted original sources. The chief locaUties outside of the United States at 

which pitchblende has been found in mineral veins are the western part of the Erzgebirge, near 

the German-Austrian boundary, and the Cornwall district in Engl~ncl. A brief summary of the 

geologic occurrence of uranium rninerals is also given in a recent article by P. Kr~sch. 2 

1 Hess,]~. IJ., Preliminary statement of tho production of uranium and vanadium: U.S. Geol. Survey Press Bulletin, January, 1914. 

a Uber die nutzbaren Radiwn-Logerstiittcn und. die ·Zukunft des Radiwn-Marktes: Zeitscbr. prakt. Geologie, vol. 19, pp. 83-90, 1911. 

1 
2 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

THE ERZGEBIRGE. 

Types of deposits.-Muller 1 recognized in and near the granite batholiths of the western 

Erzgebirge in Bohemia and Saxony four types of ore deposits, which he classified as follows·: 

A. Older ore-forming period: 

1. Veins of the tin type. 

2. Veins of the pyritic lead-zinc type. 

B. Younger ore-forming period: 

3. Veins of the cobalt-silver type. 

4. Veins of the iron and manganese type. 

Deposits of type~ 1 and 2 are connected by transitions. - The tin ores are confined to the 

granite and its immediate vicinity, while the pyritic lead-zinc veins are a little farther removed 

from the granite batholiths. The veins of types 3 and 4 are later than tP.ose of types 1 and 2. 

At Joachimsthal, in Bohemia, and at Schneeberg, Annaberg, and Johanngeorgenstadt, 

across the border in Saxony, the veins of principal economic importance belong to :Muller's 

cobalt-silver type (No. 3). It is with the veins of this type that the pitchblende is characteristically and exclusively associated. 

· Joachimsthal, Bohemia.-According to Step and Becke 2 the ores of the .cobalt-silver type 

in the Joachimsthal district may be further subdivided into two classes-cobalt-nickel-arsenic 

ores and rich silver ores. In my opinion the ores of the first class represent the primary ore depo~ 

sition, and those of the second class are in all probability the result of sulphide enrichment 

acting on the primary ore. The pitchblende, with its accompanying gangue minerals, quartz 

and dolomite, has rarely been observed in actual contact either with the rich silver e>res or wlth 

the cobalt-nickel-arsenic ores. Usually the uranium and its gangue n1inerals have as metallic 

associates only variable amounts of pyrite and chalcopyrite, which appear to be in part earlier 

and in part later than the pitchblende. In a few places, however, the pitchblende, quartz, and 

dolomite coat ore containing cobalt or nickel minerals (smaltite, chloanthite, or niccolite), and 

therefore apparently are later than those minerals. The relation of the uranium ores to the 

rich silver ores can be inferred only from museum specimens in which rqby silver or proustite 

occurs in vugs in the pitchblende ore and in minute veinlets traversing it. It appears fairly 

well established, therefore, that the uranium ores of Joachimsthal were deposited somewhat 

later than the nickel-cobalt-arsenic ores but before the development of rich silver sulphides, 

which in these deposits were probably formed by enrichment· due to the action of meteoric 

waters. The deposits are now controlled by the Austrian Government. 

A.nnaberg, Saxony.-In the Annabetg region also the cobalt-silver type of ore is economically 

the most important, and its veins in many places cut or even materially displace the earlier tin, 

copper, and pyritic lead-zinc veins. According to Muller 3 the pitchblende is characteristically 

though nowhere abundantly associated with the cobalt-silver type of veins. It usually forms 

compact spherulitic or grapelike masses, some of which have shell-like or concentric structure, 

as a coating on siderite and fluorspar. Rarely it forms layers as much as 7 centimeters thick. 

The primary minerals of the cobalt-nickel veins are~ according to MUller, barite, fluorit~, 

quartz, siderite, rammelsbergite (NiAs2), niccolite, chloanthite, smaltite, native bismuth, tetrahedrite, stibnite, chalcopyrite, pyrite, reddish sphalerite, .and bertbierite (FeS.Sb2S3). The 

pitchblende, together with siderite, calcite, and some pyrite and chalcopyrite, is later than the 

cobalt-nickel group of minerals but earlier than the rich silver minerals wh,ose origin, in my 

opinion, may be attributed with much probability to downward enrichment. 

Johanngeorgenstadt, Saxony.-In the Johanngeorgenstadt district, which has been described 

by Viebig,4 the most valuable uranium ores also belong genetically with Muller's cobalt-silver 

type, but they are characterized by an unusual abundance of native bismuth and bismuth 

compounds and are valuable mainly as a source of that metal and only subordinately for the 

1 Muller, Hermann, Die Erzgange des Annaberger Bergrevieres, Erlauterungen zur Specialkarte des Konigreichs Sachsen, p. 66, Leipzig, 1894. 

2 Step, Josef, and Becke, F., Das Vo~kommen des Uranpecherzes zu St. Joachimsthal: K. Akad. Wiss. Sitzungsber., vol. 113, pp. 585-618, 

Wien, 1904. 

a Muller, Hermann, op. cit, pp. 94, 98-100. 

4 Viebig, W., Die Silber-Wismutgli.nge von Johanngeorgenstadt in Erzgebirge: Zeitschr. prakt. Geologie, vol. 13, pp. 89-115,1905. 
GEOLOGY OF THE PITCHBLENDE ORES OF COLORADO. 3 

nickel, cobalt, or silver they carry. The principal primary minerals-of these veins are arsenopyrite, cobaltite, chloanthite, native bismuth, quartz, dolomite, siderite, calcite, andrarely 

barite and fluorite. The pitchblende is invariably associated ·with the veins of this type. It 

is in part disseminated and in part in solid crusts or bands some of which reach a thickness 

of 6 to 8 centimeters. Kidney-shaped and concentric forms are common. Characteristic 

metullic associates are fme-grained galena and chalcopyrite and native bismuth, small masses 

of these minerals being l9cally inclosed in the pitchblende ore. The common gangue mineral 

is an iron-manganese carbonate. In other parts of the Erzgebirge the pitchblende is irregularly 

distributed in nests, but in the Gottes Segen Spat mine, in this region, it occurs in considerable 

quantities and ·with much regularity. 

Schneeberg, Saxony.-In. the Schneeberg district, according to M:iiller/ pitchblende is a 

characteristic though not an abundant accompaniment of the cobalt-silver type of veins. Its 

kidney-shaped or rounded shell-like masses are ordinarily associated with chalcopyrite, galena, 

and brown carqonate. Miiller regarded the pitchblende and ~ts accompanying minerals as of 

slightly later formation than the primary cobalt and ~ckel minerals and earlier than the rich 

silver minerals. 

CORNWALL DISTRICT, ENGLAND. 

In and near the granite batholiths of Cornwall occur not only tin and copper lodes but 

also, usually at a greater distance from the granite, younger lodes of two types-(1) those containing uranium and nickel ores and (2) iron-manganese lodes. 2 In the vicinity of Bodmin, 

for example, there occur certain lodes containing arsenic and copper minerals and smaller 

quantities of uranium, cobalt, and nickel ores. These lodes cross the tin and· copper lodes 

that are the main mineral resources of the district and are therefore somewhat younger, although 

it is believed that all the .lodes are geneticilly connected with the granitic intrusives of the 

region. 

In the St. Austle Consols mine, according to Williams,3 uranium minerals have been found 

in certain small veins that cross the main tin-copper lode. The associates of the uranium 

minerals in the cross veins are locally copper ores but more commonly ores of nickel and cobalt. 

The urani urn nunerals also occur on the sides of the veins. 

At Dolcoath~ according to Pearce/ pitchblende occurred "associated with native bismuth 

and arsenical cobalt in a matrix of red compact quartz. and purple fluorspar." At South 

Tresavean it occurs with "kupfer-nickel, native silver, and rich argentiferous galena." "I 

believe," says Pearce, "in all the loc8lities I have named, it was found in little veins crossing 

the lodes'~ (that is, the tin lodes). 

At the South Ten·as or Uranium mine, in Cornwall,5 "The uranium lode * * * is 

said to vary in width from 3 to 5 feet, but the uranium ore is confined to a leader a few inches 

in width, consisting partly of pitchblende arid calc and copper uranites with copper pyrites, 

mispickel, and galena, and small quantities of nickel, cobalt, and chromium ore in a veinstone 

of q u·artz and green garnet rock.'' 

PITCHBLENDE IN THE QUARTZ HILL DISTRICT, COLO. 

GENERAL GEOLOGIC RELATIONS. 

Tho predominant rocks of Quartz Hill and neighboring parts of Gilpin County are preCambrian igneous and sedimentary rocks and Tertiary intrusive rocks in the form of dikes and 

stocks. 

Tho oldest pre-Cambrian rocks are those of the Idaho Springs formation, predomina11;tly a 

quartz-mica s~hist, which is believed to be a metamorphosed sediment. This schist is intruded by 

I MUller, Hormann, Dor Erzdistrikt-von Schnooberg in Erzgebirgr., in B. von Cotta's Gangstudicn, vol. 3, pp. 129-138, 186!1. 

D Usshcr, W. A. E., Darrow, G., and MacAlistor, D. A., The geology of Bodmin and St. Austell: Geol. Survey England and Wales Mem., 

Expl. Sheet 347, p. 134, 100~1. 

o Williams, R. H., Notice of tho occurrence of nickel and cobalt at St. Austle Consols mine, ncar St. Austlc, Cornwull: Roy. Inst. Cornwall 

Thirty-ninth Ann. Ropt., pp. 32-34, 1857. 

4 l)ourco, Uicburd, Noto on pitchblende in Cornwall: Uoy. Geol. Soc. Cornwall Trans., vol. !l, pp. 103, 104, 1875. 

D Usshor, W. A. E., Bnrro,V", G., and MacAlister, D. A., op. cit., p. 157. 
4 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

pre-Cambrian granites of at least two ages-an older granite that has been dynamonletamorphosed to a granite gneiss and a younger granite that has not been notably dynamometamorphosed .and is commonly.massive. qranite pegm.atite offshoots from both these granites are 

nume~<:ms a11:d in places intrude the Idaho Springs. formation so intimately as to produce an 

injection gneiss. Where the Idaho Springs formation lies near or is inclosed by considerable 

bodies of granite. rock, it has commonly been contact-metamorphosed to a hornblende schist. 

All the pre-Cambrian rocks are intru.ded by dikes and stocks of monzonite porphyry and of 

bostonite porphyry (entirely orthoclase). These are believed to be of Tertiary age. 

The mineral·veins of the vicinity are the result of combined fissure filling and replacement 

along a series of fractures characterized by easterly to northeasterly strikes and commonly. 

by steep dips. The veins cut both the pre-Cambrian rocks and. the Tertiary intrusives. On 

the basis of mineral composition they can be divided into two types, which may be designated 

the pyritic type and the lead-zinc type. They have been worked principally for their preciousmetal content, though yielding also considerable amounts of copper and lead. 

The principaJ primary minerals of the. pyritic type are pyrite and quartz; chalcopyrite 

and tetrahedrite are almost inv~riably present in subordinate amounts, and enargite, fluorite,~ 

and rhodochrosite occur here and there. The primary minerals· commonly present in the 

veins of the lead-zinc type are galena, sphalerite, pyrite, chalcopyrite,_ quartz, and calcite. 

Some parts of the district are characterized solely by one or the other of these types of mineralization, but in many of the veins both types are present. In such veins it has been demonstrated 

by repeated exposures that the lead-zinc type is somewhat later than the pyritic type and that 

the minerals of the former commonly line vugs or fractures in those of the latter. It is believed, 

however, that the lead-zinc mineralization followed close upon the heels of the pyriti~ mineralization, and that the two types represent merely successive epochs in one great vein-forming 

period.· Although the mineral veins cut the monzonite prophyry dikes and stocks, it is believed 

that both came from a common deep-seated source, the ore-bearing solutions following the 

monzonite intrusion after a short interval. 

Sulphide enrichment in the upper portions ofmany veins of the lead-zinc type has developed 

secondary silver minerals in considerable abundance, and such veins are known as "silver · 

veins,". their principal value being in that· metal. 

PITCHBLENDE ORES. 

Although few opportunities were afforded for studying the richer pitchblende ores in place, 

because of suspension of mining at most of the mines, numerous specimens presented to the 

Survey by men interested in these mines were polished and studied under the reflecting n1icro~ 

scope and found·to show clearly the relations of the pitchblende to the sulphides which accompany it in the veins. 

In a number of· specimens it is evident that the pitchblende crystallized contemporaneously 

with chalcopyrite, pyrite, and probably gray quartz. A specimen from the Wood mine, obtained· 

through the courtesy of Mr. W. C. Denison, when polished and studied presented the appearance 

shown in Plate I. Some of the int~rgrown chalcopyrite and pitchblende show angular outlines, 

as indicated in Plate I, A·, but more con1monly the pitchblende areas are ringlike in cross section 

with chalcopyrite occupying the center of the ring and inclosing it, as indicated in Plate I, B. 

Pyrite and gray quartz, apparently contemporaneous. with the pitchblende and chalcopyrite, 

are present in small amounts. Specimens from the Wood and German mines in the. mineral 

collections at the State Capitol in Denver show chalcopyrite and pitchblende so intimately 

, intergrown as to leave little doubt of their contemporane<?us crystallization. In other specimens from the Wood mine botryoidal pitchblende has cores of pyrite and is in places fringed 

with pyrite, as shown in .Plate II, B. To summarize, the manne:r: in which the minerals are 

intergrown in several specimens shows conclusively that pitchblende crystallized contemporaneously with chalcopyrite and probably with minor amounts of pyrite and gray quartz. 

· In other specimens the relations ·between pitchblende and sulphides are entirely different. 

A specimen of rich ore from 'the Call1oun mine, obtained through the courtesy of ltfr. I-Iugh C. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PL ATE I 

·, · .. 

· . . ·::: 

. .· :·C _h_~~~-opyr ite. · · · · · . · .. · 

A. 

B. 

CAMERA LUCIDA DRAWINGS OF POLISHED SURFACE OF PITCHBLENDE ORE 

FROM THE WOOD MINE, QUARTZ HILL, GILPIN COUNTY, COLO. 

Show in g contempora neous growth of pitchbl ende, cha lcopyrite, and pyrite. In B, drawn 

from another part of the same spec imen as A, th e pitchb lende areas show round ed 

outlines. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE II 

A . CAMERA LUCIDA DRAWING OF POLISHED SURFACE OF PITCHBLENDE 

ORE FROM THE CALHOUN MINE, QUARTZ HILL, GILPIN COUNTY, COLO. 

Showing pitchblende trav ersed by later vein lets of spha lerite, pyrit e, and ga lena. 

B. MICROPHOTOGRAPH OF POLISHED SECTION OF PITCHBLENDE ORE 

FROM THE WOOD MINE, QUARTZ HILL, GILPIN COUNTY, COLO. 

Showing botryoid a l forms characteristic of mu ch of th e pitchblende. Py, lntergrow n pyrite. 
GEOLOGY OF THE PITCHBLENDE ORES OF COLORADO. 5 

Brown, consists principally of pitchblende, but this mineralls sharply cut by veinlets one-eighth 

inch or less in size, composPd of sphalerite, pyrite, and some galena. An enlarged viaw of some 

of the smaller veinlet3 as seen under the reflecting microscope is shown in Plate II, A.. Another 

specimen from this mine shows pitehblende in botryoidal forms fractured and tr:aversed by 

minute veinlets consisting predominantly of pyrite, chalcopyrite, and dark-gray quartz, but 

containiDg some galena and sphalerite. In the more shattered ·portions fragments of pitchblende lie in a matrix of these sulphides. A specimen from the Call1oun n1ine, obtained from 

:Mr. Percy R. Alsdorf, shows altered schist traverse-d across its .foliation by a l-inch to -A--inch 

veinlet of pitchblende. A polished section shows that the pitchblende has in places been 

shattered and that fragments of it lie in a n1atrLx of galena, sphalerite, chalcopyrite, and gray 

quartz, while other parts are traversed by minute veinlets of galena. It is clear, therefore, 

that there has been some sulphide mineralization subsequent to. the deposition of the pitchblende. 

The pitchblende ores of Quartz I-Iill are believed to represent merely a local and unusual 

variation in the main sulphide n1ineralization of this region--a variation of the same order as 

the occurrence of enargite in a neighboring group of veins near South Willis Gulch. I found 

no evid(:mc~ to support Rickard's opinion 1 that the pitchblende mineralization is genetically 

connected with the intrusion of .the granitic rocks, whose age is pre-:-Cambrian; on the contrary, I believe that, together with the sulphides that accompany them, they are genetically 

related to the Tertiary monzonite intrusives. 

The significance of the contrasting and apparently contradictory modes of association of 

the pitchblende with the sulphide nunerals becomes apparent when it is recalled that the 

Centrnl City district is in general characterized by two types of mineralization, an earlier 

pyritic mineralization and a later lead-?<inc mineralization. It is believed that the pitchblende 

was deposited during the. earlier or pyritic mineralization, that it was afterward fractured, 

and _that the fractures thus formed we~e filled by sulphides of the later or lead-zinc mineralization. 

The general geologie relations and the absence of c.haracteristic high-temperature minerals 

in the deposits of Qun,rtz I-Iill, as well as in ti1ose of Cornwall and t~1~ Erzgebirge, indicate that 

the pitchblende was deposited under conditions of moderate temperature and pressure. Unlike 

the European pitchblende, however, the pitchblende of Quartz Hill is not associated with 

nickel and cobalt minerals, which so far as known have never be.3n found in that region even in 

small quantities. The occurrance of pitchbknde in pegmatite a~ well as in n1ineral veins of · 

the type here described shows thn,t the mineral may also forn1 under conditions of high 

temperature and pressure. I ' I · 

J Hlckard, Forbes, Pitchblende from Quartz Hill, Gilpin County, Colo.: Min. and Sci. Press, June 7, 1913, pp. 851-856. 

EROSION AND SEDIMENTATION IN CHESAPEAKE BAY AROUND 

THE MOUTH OF CHOPTANK RIVER. 

By J. FRED. HuNTER. 

INTRODUCTION. 

With the unfolding of geologic knowledge during the last century the processes of denudation, 

transportation of sediments, and sedimentation have become better understood, and to some 

extent their relative effects in bringing about the present configuration of the earth's surface 

hav:e been deternrined. The nature of these processes has been studied in many parts of the 

globe, but owi11g to the large size of the units affected and the slowness of the processes there 

has been little opportunity to collect quantitative data. Indeed, the data available are very. 

largely conjectural, their degree of accuracy being only that of good guessing. IIowever, with 

the advent of accurate topographic and hydrographic surveys, the first steps toward actual 

measmements of some of the many interesting surficial changes that are in progress have been 

taken, and it only remains for time and additional observatio1:1s to afford opportunities for 

con1parison. Resurveys, particularly by the United States Coast and Geodetic Survey, of parts 

of the eastern coast of the United States at different intervals have. shown in many places marked 

changes of both shore line and sea bottom, as on Cape Cod, on Nantucket Island, and in Delaware Bay. Comparisons of this kind have so far. been incidental to work in engineering and 

coast surveying, so that there has been little opportunity for the selection of localities particularly adapted to studies of erosion and sedimentation. . 

Chesapeake Bay, which is really a large tidal river, is favorable for such investigations, in 

that it has ~ drainage basin of moderate size and retains a large. part of the sediments brough~ 

in from that basin by its tributary rivers. Moreover, this bay, since the memorable explorations 

of Capt. John •Smith in 1608, has been of much interest to explorers and map makers. The 

classic map n1ade by Smith was followed by many others of varied character, such as Herman's 

"Map of Virginia and Maryland" (1670) and Griffith's "Map of Maryland" (1794), both of which 

were the standard maps of their time and marked great advances in the cartographic knowledge 

of the bay.1 In the course of the general economic development of this region further data 

tts to the limits and character of Chesapeake Bay and its tributaries continued to accumulate as 

the result of the work both of governmen'tal bureaus and of private concerns until in the fourth 

decade of the last century the need began to b~ felt for a thorough topographic and hydrographic 

study of the bay. In 1845 the United States Coast and Geodetic Survey began such a study, 

and by 1848 had smveyed the entire bay and prepared charts on the scale of 1:20,000 showing , 

with accun.tcy the shore lines and the depths of water. In 1900 it was deemed necessary to make 

a silnilar study ·of the bay in connection with the work of the :Maryland Shell Fish Commission, 

and by 1903 a second set of charts had been completed by the Coast Survey, on the same scale 

and showing the same detail as the earlier charts. Both sets of charts are accurate and are 

unique in covering so well so large a.nd important an area at dates removed from each other 

1 :!<or an interesting detailed history of tho explomtions and surveys of Chesapeake Bay, see Mathews, E. B., The maps and map makers or 

Marylmul; Maryl!md Goo!. Survey. vol. 2, pt. 3, 1898. 

7 
8 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

by an interval of more than half a century. Even a cursory examination of the corresponding 

charts of the two periods shows important changes in the position of the shore line and of the 

bay bottom. 

FIGURE I.-Sketch map of Chesapeake Bay, sh-owing the area studied and its relation to other parts of the bay. 

Mr. Charles· Yates, of the United 

States Coast and Geodetic Survey, who 

has spent a,.number of years on Gov-

:ernment survey work in Chesapeake 

Bay and to whom the writer is indebted for· a nun1ber of facts used. in 

the preparation of this paper, has re-. 

peateclly urged a study of the processes 

of erosion and sedimen ta tio,n as brought· 

out by a comparison of these charts. 

Owing to the great mechanical labor 

and the long time necessary for such 

an investigation, the writer has contented himself with the study of a 

very small test · area on the eastern 

shore of the bay around the n1outh of 

Choptailk River, including Tilghn1an, 

Sharps, and James islands· and the 

adjacent mainland, with the purpose 

of ascertaining the advisability and 

possible results of a more elaborate 

study of the entire bay. (See fig. 1.) 

The test area, which is situated about 

midway of the length . of the bay, is 

representative of th~t portion of it 

which has suffered change sufficient 

to be noted by cursory examination 

of the two sets of charts. Moreover, 

it lies in an intermediate position, 

north of which the change in shore 

lines has been effected chiefly by erosion and south of· which there has 

been a very large amount of ·marsh 

building. This sn1all area affords an 

excellent opportunity to establish cer-

·tain local rates of erosion and sedimentation, but of course gives no data 

for many of the larger and Inore general conclusions that would be expected 

from a study of the entire bay. For 

example, the relation of sedimentation 

to land waste as studied by Humphreys and Abbot ip. the Mississippi 

River basin and by Mellard Reade, 

Elie de Beaumont, Archibald Geilde, 

and others in river basins of· Europe 

and elsewhere, suggests itself as a 

subject for an investigation that could 

hope to bear fruit only if pursued on 

the larger scale. 
EROSION AND SEDIMENTATION AROUND MOUTH OF CHOPTANK RIVER. 9 

. . SURVEYS OF THE AREA DISCUSSED. 

The earliest adequate sketch of the mouth of Choptank River is on Herman's "Map 

of Virginia and Maryland" (1670). Although the map shows much distortion, the chief land 

feo.tures of the arQo. here discussed are represented about as they exist to-day except that James 

Islo.nd (culled Jo.mes Point) had a broad cmmection with the mainland. Griffith's " Map of 

:Mo.ryland" (1794) shows the land features as they are.now, James Island, strange to say, being 

widely sepo.rated from the n1ainland, although a chart of the Coast Survey prepared in 1848 

shows a narrow isthn1us between the two. A singular though probably not very significant fact 

in view of the primitive methods of surveying and the moderate degree of accuracy of the 

two early maps is that on each of them Tilghman Island is represented as having an outline very 

different fr01u its present shape and as being separated from Sharps· Island by a considerable 

stretch of water. This fo.ct is interesting in view of the· current belief of the:inhabitants in 

a very recent land connection between the two islands. Although these maps are of interest in 

view of the changes tho.t are known· to be taking place, no reliance can be put on their accuracy. 

Besides the topographic and hydrographic surveys of 1847-48 and 1900-1901, a plane-table 

survey of the shore lines of James ·and Sharps islo.nds, the southern portion of Tilghman Island, 

o.nd Cook and I-Iills points was made by Mr. Yates and the writer in December, 1910, with the 

aid of. .the charts and triangulation stati9ns of the Coast and Geodetic Survey. The United 

States Geological Survey has published topographic and geologic maps covering the area/ 

which is located partly in the Chop tank and· partly in the St. Marys quadrangle. 

TOPOGRAPHY AND GEOLOGY. 

Two principal topographic and geologic features are represented in this area. One of 

these is the plain or terrace occupied by the Talbot formation, which is the lowermost and at the 

san1e tune the youngest of the Pleistocene Columbia group. Although elsewhere this terrace 

n1n.y rise to 40 feet above sea level, it does not reach more than 10 feet in the area under discussion. 

It is built up chiefly of clay marl and sand, with scattered patches of gravel, and in most places 

it is terminated by o. low scarp cut by the waves, though locally it slopes gently to the water's 

edge. The other prn1cipal feature is the tidal marshes which occupy the remaining but much 

sn1aller po.rt of the area not covered by the Talb<;>t formation. · They consist of low-lying, 

swo.n1py land which at high tide n1ay be largely submerged. They are composed mainly of the 

so.me n1aterials as the Talbot but cop.tain also an abundant growth of swampy sedge, or grass 

wh.ich o.ids in filling up the depressions by serving as obstructions 'that retain the mud and by 

furnishn1g a perennial accumulation of vegetable debris. The living and dead plants form a 

thick network through the clo.y marl and peat, which, thus reinforced at the water's edge, offer . 

greo.t resistance to the cutting of the waves. · 

CHANGES IN SIIORE LINE. 

JAMES ISLAND. 

Loss in a·rea.-James Island is the southernmost of the trio of islands (James, Sharp, and 

Tilghman islands) which stand in a line across the mouths of Choptank and Little Choptank 

rivers and front on the bay. It is crudely wedge-shaped and is nearly cut in two by an inlet 

that crosses it diagonally. It is next to Tilghman Island in size, being nearly' 2 miles ·long and 

three-quarters of a mile wide and having a present area of 490 acres. Although now deserted 

except for a few families the islo.nd had at one time a much larger population, as shown by the 

presence of n.bout 20 houses, a schoolhouse, and a church. · The land nowhere rises above 10 

feet in elevation, and the shore scarps in pl~ces attain 7 feet. 

A COlnparison of the maps of 1848 and1900 shows'some remarkable changes in this island. 

(See· Pl. III.) The narrow istl1mus, probably no more than a sand bar, which connected the 

island with the mainland in 1848 had disappeared in 1900, when 0.28 mile of water separated 

the two land bodies .. At the tin1e of the survey in 1900 the west shore had receded to ·a point 

• 1 Shnt.tuck, G. H., nnd 1\fillor, B. L., U.S. Geol. Survey Geol. Atlas, St. Marys folio (No. 136), 1906. Miller, B. L., U. S. Geol. Survey Geol. 

Atlns, Choptank folio (No. 182),.1912. 
10 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

500 yards beyond the head of the inlet of 1848. The inlet had been filled in and the sand bar 

separating it from the bay had shifted bodily eastward. In area the island had decreased 

from 975 acres in 1848 to 555 acres in 1901. It had thus suffered a loss of 420 acres, or 43 per 

cent, in 53 years, showing a mean annual loss of nearly 8 acres. During the succeeding 9 

years it ~as cut down to 490 acres, an average of over 7 acres being cut away each year, the 

total loss for the period being 65 acres, or 12 per cent. During the 62 years covered by the study, 

485 acres, or nearly half the island, had disappeared, an average of 7.8 acres, or about 0.8 per 

cent of the original area, being carried away each year. However, as the island becomes smaller 

and the coast line shorter, this average annual loss will be reduced. 

Linear cutting.-As in the other islands, almost the entire cutting has taken place on the 

northern and western shores, the eastern strand line remaining practically stationary during 

the entire period. The cutting of the outer shores is doubtless due to the strong bay currents 

and storm waves which sweep these shores, eroding and carrying away great quantities of 

sediment. However, the rate of cutting has differed notably in different parts of the shores, 

owing in large measure to unequal resistance of the land material. In general, where the land 

is comparatively high and where the shore material consists of the clays and marls of the Talbot 

formation, the cutting goes on most rapidly. In such places 'the low cliffs offer favorable 

conditions for erosion. The marly clay, being undercut by the waves, crumbles down in clods 

or lumps of various sizes. This process of breaking .down is helped and to some extent regulated 

by joints and narrow clay seams, probably formed by the percolation of water dashed back on 

shore. In many places the shore has numerous angular and rounded reentrants, in some of 

which are fashioned small caves that may extend to a distance of several feet. The presence 

of trees on the shore, especially 'Yhere it is high, may hasten the retreat of the strand line. As 

the waves cut away the e~rth from around their roots they fall over into the water, carrying a 

quantity of soil with them and loosening still more of it where they formerly stood. 

The low-lying marl land is much more resistant to erosion than the higher clay scarps. 

The salt marshes formed by this type of shore deposit support a dense growth of sedge and grass, 

whose roots are matted together in the clay and sand. This vegetation serves to hold the fine 

material blown and washed over it, and the marsh is thus built up. At the same time the waves 

are unable to cut this reinforced material rapidly. Out of these facts comes the explanation of 

a rather curious and interesting phenomenon. The map of 1901 showed that the only remains 

of the north end of the James Island of 1848 was a small island situated on the spot which 

was formerly an arm of the diagonal inlet but which was later filled with marsh material. That 

water in the midst of land in 1848 should become land in the midst of water in 1901 is a remark:. 

able result of the greater resistance of the marsh-built land. Similar phenomena have been 

noted elsewhere in the course of the study; in fact, wherever the shore has been of tide-marsh 

formation the erosion has been comparatively slight. 

Another interesting feature of the change in James Island is the shifting of the sand bar 

that separates the waters of the bay from the head of the inlet .. The waves probably add 

about as much sand as they carry away, the accretions being largely carried over into the inlet 

basin. Thus the bar seems to be moving ,slowly eastward. It is probable that in time the 

bar will be broken through, as was the bar between the island and the mainland. Once open 

the channel would be widened and the rate of erosion of the resulting two islands accelerated. 

No less striking than the loss in area suffered by th~ island during the last 62 years is the 

amount of linear advance of the bay. A comparison of the first two maps shows that the average 

amount of erosion on the north and west coasts of the island during the period from 1848 to 

1901 w~ nearly a quarter of a mile and the annual average was 24 feet. That the rate is fairly 

constant is shown by the fact that during the nin~ years succeeding 1901 the average annual 

rate was 23 feet. At this rate the island, whose maximum width is 0.66 mile, should disappear 

in about 150 years. This estimate is almost exactly the same as another reached by a consideration of the annual areal loss per mile of eroded shore line. Although this agreement is 

interesting, the result is little more than a guess, as numerous other factors may enter to. disturb 

the present conditions and rate of erosion. 
U.S.GEOLOGICAL SURVEY 

GEORGE OTIS .SMITH, DIRECTOR 

' ~ 

(I) 

LEGEND 

~ 

r;;J Areas of erosion 

D Areas of sedimentation 

Survey of 1847-1848,U.S.C.&G.S. 

Survey of 1900-1901, U.S.C.&G.S. 

Survey of 1910, J.F. Hunter 

r• 

I ~ 

I 

-" 

r 

f 

'? 

\ 

~ 

~ 

'f{ 

tl: 

/ 

~ 

tq 

tq 

~ 

(J 

Cha 

'!(~.,., 

~ ,,.._ ",. 

~ 

&· \ '.?.- \ 

-

' ... " "" 1 \; J 

~fAP OF THE ~fOUTH OF CHOPTANK RIVER,V\IlTH TILGHMAN, SHARPS,AND JAMES ISLANDS 

Showing positions of the shore line at the time of different surveys, together with areas of erosion and sedimentation 

Prepared by J. F. ltunter from charts of the U. S. Coa st and Geodetic Survey and original surveys 

Scale lf~ . 

o 1 2 Miles 

==EE===1::::::::::3:o~~~===============;,:===="============3'2=;;Kil;;;. "'om"""e~t"'er"'s3 

1914 
EROSION AND SEDIMENTATION AROUND MOUTH OF CHOPTANK RIVER. 11 

SHARPS ISLAND. 

Loss in area.-Sharps Island, the smallest of the three under discussion, stands directly 

at the mouth of Choptank River, unprotected on any side from the action of the waves. Less 

than a generation ago it was a srnnmer resort and supported a nutnber of people throughout 

the year. The north end was well wooded and the island was a favorite ground for hunting 

ducks and stnall game. The clays of its prosperity are now but a tnetnory, and the life of the 

. island is a thing of the past. The trees have disappeared save for a meager half dozen; the houses 

have been washed away except for the large hotel which stands alone in the center of the island, 

a crutnbling n1o.nu1nent to the activity of other days; the site of an artesian: well has been 

transgressed by the waves so that it now presents the unique feature of a well in the midst 

of tho waters of tho bay. The survivors of the piling that made up the long pier which formerly 

invited tho voyager only add to the melancholy of the deserted and dreary scene. 

Itnpressions and hearsay are not the only evidence of remarkable changes in the. island, 

for tho story told by c01nparison of the three maps of 1848, 1900, and 1910 is equally noteworthy. In 1848 the island contained 438 aeres; in 1900 the surprisingly sn1all area of 91 acres, 

or but 21 per cent, had survived. There had been an average annual loss of 6.7 acres, or 1.5 

per cent. Owing to tho decrease in tho length of shore line the amount of erosion annually 

during -tho period frotn 1900 to 1910 dropped to an average of 3.8 acres, which, however, was 

4 per cent of the total area of 1900. The area of the island in 1910 was 53 acres, showing a loss 

of 88 per cent in 62 years, an average annual loss of 6.2 acres, or 1.4 per cent. 

Linea.'J' cu.tting.-The maximum erosion on Sharps Island, as on James Island, has been on 

the west and north sides, the east and south sides having remained substantially unchanged. 

An interesting feature is the continuance of the sand spit on the south end Ul)til after 1900, 

when tho pier was washed away. Since then the spit has moved around to the southeast corner 

of the island, inclosing a stnall pond. The northern part of the island is made up of material 

of the Talbot formation and rises out of the water as much as 7 feet. Here the erosion has been 

enonuous, tho water adv-ancing 0.35 mile in 52 years and 0.57 n1ile in 62 years. · The average 

eucroaclnnent on the north and west coasts during the 52-year interval was 0.32 mile, or at the 

rate of 32 feet a year. During the 10 years between '1900 and 1910 the bay advanced 0.21 

mile on tho north shore, or at the remarkable rate of 110 feet a year. The loss Qn the west 

coast, however, was much less, averaging about 21 feet a year during the period. 

Tho marshland of the southern part ·of the island is withstanding the force of the waves 

much more effectively than the rest of the island and will doubtless be the· last to disappear. 

It Inay he interesting in this connection to venture a prediction, based on the facts at hand, 

as to the thne of final disappearance of the island. By platting the length of the island as 

ordinates against the time interval between surveys, it is evident that the rate of erosion has 

greatly increased in the last 10 years. If the' rate of that interval were to continue the island 

would disappear before 1930. However, it·is obvious from the general study that the erosion 

was unusually intense during this period and furthermore that when the marshland is reached 

the rate will decrease. On the basis of the rate of encroachment during the 52-year interval 

and the n1a..ximu1n width of 0.28 mile, the time .of disappearance would be put at 1947. From 

a consideration of tho annual areal loss per mile of shore line subject to erosion, one-half the 

rmnaining exposed shore. line being used as a basis, .the average annual loss will be 1.67 acres .. 

By this n1ethod the date of the island's entire submergence would be put at 1942. At the rate 

during the last 10 years on the west coast, the estimated date would be a littl·e later, probably 

about 1950 to 1955. · · 

Fr01n general considerations the writer feels that it is fairly safe to predict that Sharps 

Island will be entirely gone by 1950 and that it is not beyond the range of possibility that the 

island will disappear before 1940. ·The higher land to the north will doubtless be cut away 

ftrst, and in 15 years, if the average yearly rate persists, the house will be reached. In 20 years 

probably little will be left bu~ the low-lying n1arshland. 

37183°-15-2 
12 SHOllTER ·CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TILGHMAN .ISLAND .. 

Tilghman Island is the largest and most northerly of the three islands under discussion. 

It is over 3! miles long and has an area of n1ore than 3 square miles, providing homes for many 

prosperous farmers and fishern1en .. At its north end are located the towns of Tilghman and Ava- . 

Ion, with a population of sever~l hundred people. It is separated fron1 the mainland by a narrow 

strait called Knapp Narrows. 

·This island has suffered much less erosion in proportion to its area than either of the other 

two. The eastern coast, as in the other islands, ren1ained essentially unchanged during the 

63 years from 1847 to 1910. Extensive erosion has taken place along the western coast, except 

in the protected portion in Pawpaw Cove, a semicircular indentation n1idway of the island. 

During the 53 yearf? between 1847 and 1900 the area of Tilghn1an Island decreased from · 

2,015 to 1,686 acres, a total loss of 329 acres, or over 16;3 per cent. The maximum encroachInent of the sea has been on the southern cape (Blackwalnut Point), which has receded a quarter 

of a mile in 63 years. The average annual encroachment of the sea on the western shore during 

th~· 53-year period was 10 feet, the estimate excluding the shore of Pawpaw Cove, which has 

not changed. .This is a n1uch lower rate than those effective on the corresponding coasts of 

the other islands. Only the southern portion of the west coast was surveyed in 1910, but here 

the. erosion has been rather rapid, averaging 29 feet a year for the 10-year period beginning 

with 1900. 

That Tilghman Island will have a much longer life than the other two islands is 1nanifest. 

By considering as before the mean annual areal loss per n1ile of exposed shore line and using 

one-half the remaining westerly exposed shore line as a basis, it would seem that the i'3land 

will not disappear in its watery grave for at least 570 years. However, this estimate n1ust be 

regarded only as a very rough approximation. · 

Although the earliest maps show a large stretch of water between Tilghman and Sharps 

islands, many of the residents recount the tales told by their forbears of a generation or two 

ago concerning the proxin1ity and even the connection of the two islands. It may be interesting in this connection to point out the fact that during the 63 years from 1847 to 1910 the 

average annual widening of the intervening water area was 0.01 mile. As the islands in 1910 were 

3.38 miles apart, the time of their separation, if this rate of widening has prevailed continuously, 

would be about 340 years ago, or about 1570. This is a hundred years earlier than the date 

of the oldest map, that of Herman,. which shows a considerable stretch of intervening water. 

SHORES AROUND THE MOUTH OF THE CHOPTANK. 

This discussion so far has considered chiefly the shores exposed to the waves of Chesapeake 

Bay. It may be worth while for con1parison to note the changes that have taken place on 

points affected more particularly by the currents of Choptank and Little Choptank rivers. 

Cook Point, which lies almost clue east of Sharps Island, has been ren1arkably eroded. During 

the 53-year interval from 1847 to 1900 this point suffered a loss of 108 acres, or about 17 per 

cent of its area, thus losing about 2 acres each year. On the northwest coast of the point, 

where the erosion has been greatest, the water has encroached as much as 0.2 mile in 63 years, 

or at the rate of 16 feet a year. This rate, however, is a n1aximum-not an ayerage for the 

coast line~ · An interesting feature is the increase of the rate during the 10 years from 1900 to 

1910, when the ·maximum cutting amounted to 0.06 mile, or 32 feet a year. Except at the 

extreme end there has been comparatively little change on Cook Point. On the west side of 

the point a pond inclosed by a sand bar is filling up, and is a further example of strongly resisting 

marsh material. On Hills Point, south of Cook Point, there has been considerable erosion 

along the northwesterly exposeP. shores. The average rate here i.s about 15 feet annually, 

although· the point of n1aximun1 cutting may show nearly twice that nnlCh. The spit at the 

end of this point is ren1arkable for its persistence throughout the 62 years. · Farther south 
EROSION AND SEDIMENTATION AROUND MOUTH OF CHOPTANK RIVER. 13 

the west shore of Ragged Point was cut away to a distance of 0.14 nule in 52 years, or at the 

considerable rate of 14 feet a year. Nelson Point, on the north side of the Choptank and east 

of ~L'ilglnnan Island, suffered a very considerable loss in the 53-year interval before 1900. The 

fol'lner point receded nearly a quarter of a mile, while farther north the neck was cut through 

by the currents, leaving the former.southern part of the peninsula an island. 

In general the erosion inside the rivers has been less than on the shores exposed to 

the action of the bay, although at a few favorable points the cutting has been equally 

great. As n1jght be expected, the numerous inlets which in part 1na~e up· the devious shore 

line of this area showed but little change at the end of the 53-year period. Except at the 

localities already 1nentioned, the shore does not show any large losses, the 1naximun1 probably 

being 300 or 400 feet. :Moreover, nowhere in the area under discussion has any considerable 

amount of gain been made by the building up of land. I-Iowever, south of the area studied 

ln.rge delta deposits are constantly growing and will add a very intei·esting chapter to ~h~ hist9ry 

of the bay. 

CHANGES IN SEA ·BOTTOM. 

GENERAL STATEMENT. 

Co~nparison of the surveys of 1847-48 and 1900-1901 not only showed very, ~ppr~~i.abl~ changes in the position of the shore lines of the bay but also more or less shifting of ~lie ~~cUm~nts 

on the sea bott9n1, as indicated by the differences in soundings for the two periods. · :Ma.i1y of 

these differences are so slight as to come witlrin the limit of error and of the personal (1quatio~ 

of the hydrographers. At the ·sanle time, in the study of a large area such as the entire Chesapeake Bay, 1nany of these s1nall differences might rightly be taken into accovn.t,. for· any 

errors would probably tend to cmnpensate rather than to accumulate. However, ov~r ·a 

considerable area the results would without doubt be negative; that is, tl?.ey would show no 

change. The area here discusse.d is entirely too sn1all to o,btain any very substantial or impor~ 

tant conclusions. Nevertheless, a few facts n1ay be wor.thy of note and n1ay suggest further 

and better 1nethods for the study of the larger problem. 

The 1nethod here pursued was to draw, from the 9oast Survey charts, hydrographic contours 

representing depths of 6, 12, 18, and 30 feet below mean sea level for the two perioc~s. By 

suitably designating the two sets of contours, the areas of cut and'of fill could by a little inspection be distinguished. As an intermediate step the area over which a recent contot1r had 

shifted was hachured differently according as it had moved toward wh~t was higher ground, 

thus showing a scouring, or toward what was lower ground, thus showing a shoaling. This 

f,'l'eatly facilitated the Inapping of the areas subject to erosion and to sedimentation. 

AREAS OF EROSION. 

The largest and most iinportant area of scouring is that west of Tilglunan and Sharps islands. 

In fact, except for a small area directly north of the mouth of Choptank River and an area west 

of Jan1es Island, the slopes of the bay have experienced fairly uniform cutting. Almost everywhere, however, the erosion has been greatest near the shore, while at a depth of 30 feet the 

contours show but little change. In the vicinity of the 6 and 12 foot contours the difference in 

depth for the two dates very rarely re_aches 6 feet, while the average would probably be n1uch less. 

Another area of extensive erosion is that north and west of James Island, at the mouths of 

Choptank and Little Choptank rivers, where there has been a deepening of more than 6 feet 

near shore and unifor1nly less toward the deep channel. An interesting and rather unexpected 

area of scour is that west of Ragged Point and southeast of Hills Point, but the amount of change 

here is SOinewhat Slllaller than in the other areas lllentioned. Snlaller areas of scour are scattered 

with little regularity over the region, the exact causal relations in 1nany of them not being 

entirely evident. 
14 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

AREAS OF DEPOSITION. 

The areas of deposition are fewer and somewhat more interesting than the areas of erosion. 

They indicate local checking of the movements of the currents, which may have resulted from 

a variety of causes. Perhaps the most interesting example of shoaling is that between Tilghman 

and Sharps islands, where more than 6 feet of sediment has been laid down in places, the 

maximum amount being found between the 12 and 18 foot contours. Here Choptank River, 

flowing westward, probably meets, for a large part of the time at least, a strong inshore current 

from the bay .. The velocity of the river waters is thus diminished and deposition results. On 

the opposite (south) side of the channel scouring has taken place, thus indicating an acceleration 

of the river current on that side, except close to the shore, where, strange to say, the soundings 

show slight deposition. As the river flows on and reaches the broad stretch of water between 

Sharps !~land and the shores of Trippe Bay, its velocity is again decreased, owing to the 

increase in area of cross section, with the result that deposition occurs on both sides of the 

channel. 

North of the mouth of the river there is an area in which the movement of the water is 

modified, owing to the junction of the bay and river currents. Here there is, for this reason, a 

small area of deposition. The cause of the shoaling west o{ James Island is not immediately 

app·arent, although it may lie in the diversion of the strong river current in a southeasterly 

direction by the bay currents, a portion of the water being thus backed up against the island 

and east of the main channel. Other areas of deposition are those east of James Island and on 

the east side of the Little Choptank between Ragged Point and Hills Point. 

Approximately 34 per cent of th~ area covered by water in the territory under discussion 

has been affected by erosion or by sedimentation. Of this portion about 80 per cent, or approxi-

~ately 26 per cent of th,e total area under water, has been subjected to scouring during the 

52-year interval from 1848 to 1900. It appears from a study of profiles and contours that the 

vertical elements in the areas of erosion and in the, areas of sedimentation are approximately 

equal. Now, inasmuch as but 20 per cent of the area subject to change showed shoaling while 

80 per cent showed scouring, and 3t'3 the vertical element is approximately the same in each case, 

it becomes evident that the equivalent of at least 60 per cent of the sediments affected in -the 

area must have been carried farther down the bay. The areas subjected to erosion aggregate 

35·square miles and those subjected to sedimentation 9 square miles, making an excess of 26 

square miles eroded. By taking 1~ feet as a reasonable average for the amount of vertical 

change, the total quantity carried out of the area and do-\vn the bay would approximate 0.007 

cubic mile. Of course, no estimate is possible as to the amount transported through this area 

from points beyond its borders. However, it.is apparent that a study of the entire bay would 

yield interesting data on the amounts of material eroded and deposited in different portions of it. 

If to such data could be added an estimate of the amount of sediment carried past any point 

in the bay during the 52-year interval, an approximate estimate could be made of the total land 

waste of the basins drained by the tributary streams above t~is point. Such a result would· be 

of fundamental importance to geologists in the consideration of the phenomena of denudation. 
ElWSION AND SEDIMENTATION AROUND MOUTH OF CHOPTANK RIVER. 15 

SUMMARY. 

The quantitative results of the study can best be presented by the following table: 

Results of erosion at rnouth of Chop tank River. 

Jmncs Island .......................................................... { 

Sharps Island ............................ , .......................•.... { 

'l'ilghmru1 Island ........ : ............................................. { 

Coqlc Point <l •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• { 

Hllls Point ............................................................ { 

Rnggcd Point ......................................................... 

1

{ 

a North shore. I> West shore. 

Date of 

surveys. 

1848 

1901 

1910 

1848 

1900 

1910 

1847 

1900 

1910 

1847 

1900 

1910 

1848 

1910 

1848 

1900 

Average advance of water on eroded 

Interval Loss per coasts. Area between 

(acres). surveys year For the (years). (acres). 

rreriod Annually 

miles). (feet). 

~~~ · · ·······53· · · · · · · · · 1: 9· · · · · · · · o:24 · · · · · · · · · · · 24 490 9 7.3 .04 23 

~~ ••••••••• 52 ......... 6:7 ......... :32 ........... 32 

53 10 3. 8 { a. 21 a 110 b. 04 b 21 

i;g~~ ·········53·········5:2· ········:o9· ···········9 . . . . . . . . . . . . 10 . . . . . . . . . . . . c. 06 c 29 

::::: :~::::: ....... '"53' ........ 2' .. :::::::::::: :::::::::::: 

. . . . . . . . . . . . 10 ............ { ;: ~6 g~ 

:: ::: :: : :: :: · · · · · · · · · 62 · : ::: : : : : : : : : · · · · · · ··:is· · · · · · · · · · ·is 

:::::::::::: ......... 52. :::::::::::: ........ : i.i ........... i4 

c Onlr tho south end of Tilghman Island was surveyed in 1910. d Owmg to the shnpe of Cook Point the maximum linear cutting was measured rather than the average. e For 63 years. I For 10 years. 

The most interesting feature of the study is the rapid destruction of the three islands. 

Sharps Island is disappearing n1ost rapidly and will probably be entirely effaced before 1950. 

The ren1arkable rate of cutting during the last 10 years on the north end of this island, amounting to 110 feet a year, is worthy of note. Observation shows tl:lat practically all the erosion 

·has been on the west and north sides of the islands; that is, on the shores which· are most open 

to the attack of the southerly bay currents and the· westerly winds and their waves. In general 

the cutting has been greatest along the shores having low scarps made up of the clays and marls 

of the Talbot fonnation and least along those of the low-lying tidal marshes. For this reason 

the land now being forn1ed will in n1any places outlive the older and higher portions. Most of 

the projecting points within the entrance to the Choptank show considerable change, although 

n1uch less than the shores of the bay proper .. No building up of the land is going on within the 

area studied, although farther south extensive delta deposits are being laid down. 

A study o~ the submarine changes shows rather extensive scouring along t4e eastern· shore 

of the bay proper and less extensive though equally intensive shoaling at places within the 

river mouth. The equivalent of approximately 60 per cent of the total amount of the sediments 

subject to change in the area is carried farther down the bay. ·A very rough estimate of the 

quantity of material carried away fron1 the area is 0.007 cubic mile, but owing to the fact that 

this material con1es fron1 several different basins and that the amount of sediment transported 

through the area is unknown :no idea as to the rate of land waste could be obtained. 

In conclusion, while tl1e present work should be regarded only as a test investigation of 

the erosion and sedimentation in Chesapeake Bay, it is demonstrated by the comparison of the 

two surveys of 1848 and 1900 that very significant changes both in the topography and in the 

hydrography of the region have taken place. Although the data here set forth are chiefly of 

local importance, it is hoped that the study may suggest certain methods that are applicable to 

a c01nplete study of the bay. Such a study of the changes during an interval of over 50 years 

would present some idea as to the land connections and distribution not only of the past but 

likewise of the future. It would also give quantitative data on the rate of erosion and of sedimentation and, if carried 'far enough, should furnish new and significant qata on the rate of 

land waste in the surrounding basins. Finally, if the study of this small area shall lead to a 

n1ore extensive investigation as to the quantitative relations of these fundamental geologic 

processes, the purpose of the work will have been fulfilled. 

DIKE ROCKS OF THE APISHAPA QUA:QRANGLE, qoLORADO. 

By WHITMAN CROSS. 

INTRODUCTION. 

Location ancl fieul W01'k.-The Apishapa quadrangle, ·the geographic relations of which are 

shown by Pln.te IV, is situated on the plains south of Arkansas River, in Colorado, about 24 

miles east of the 1nountain front. The geology of the Pueblo, vValse~1burg, Spanish Peaks, and 

Elmoro quadrangles, adjoini~1g it on the northwest, west, southwest,· and south, ·respectively, 

has been described in folios of the Geologic Atlas.1 • G. K. Gilbert, assisted by F. P. Gulliver 

and G. W. Stose, took up the survey of the Apishapa area in 1894. The Apishapa folio was 

c01npleted by Stose and was issued in 1913. · The rocks to be described in this paper were collected by Gilbert and his assistants, the present writer never having visited the area. The 

following description of the occurrence of the rocks has been kindly furnished by J\1r. Stose. 

Occurrence of the rocks.-Forty-three dikes have been observed in the Apishapa quadrangle. 

They are n1ostly vertical in position and trend as a rule nearly west, or somewhat to the south 

of west. The greater nu1nber o.re frorn 4 to 10 feet wide, but o.· few reach a width of 20 feet or 

n1ore. , 

'rhe trend of the dikes o.nd the charQ.cter of the dike rocks dernonstrate clearly that they 

belong to the outer zone of the systen1 of dikes radiating from the Spanish Peaks center, to 

the southwest. Neo.r this center similar dikes cut the Eocene Huerfano forn1ation, and in the 

Apishapo. quo.dra~Jgle the latest Cretaceous formation present is penetrated by some· of the 

rocks here described. vVhile the dikes are therefore possibly of late Eocene age, they may be 

considero.bly younger. Fragrnents of t~e dike rocks are found in ·the earliest terrace deposits 

of the quadrangle. 

The dikes are 1nost nurnerous, naturally, i~1 the southwestern part of the quadrangle-the 

po.rt neo.rest to the Spanish Peaks. The n1ost thicldy intruded tract is a~1 elliptical upland 

area southeast of Bonita Cordova n1.nch, where 12 dikes occur within a strip about 1 mile wide. 

In a few places dikes 'vere observed to intersect o~1e another, but the relative ages were not 

deter1nined, though the identification of specilnens has shown that in n1ost of these places the 

intersecting dikes are 1nade up of different rocks. In Graston Butte, the dike hill east of North 

Rattlesnake Butte, a long branching dike of basalt is cut by a shorter one of augite vogesite. 

Where the dikes penetrate shale the shale has. been indurated, as a rule for several feet 

fr01n the contact, and erosion has left the dike and the indurated wall rock projecting above 

the surface of the soft shales. No noticeable 1nineral change has occur~red in the baked sho.le. 

A similar effect is locally found where dikes cut limestone. 

The n1ost conspicuous of these dike ridges are Mica Butt~ and Blue Hill. Graston Butte, 

east of North Rattlesnake Butte; and some others, unnamed, are nearly as large but are less 

conspicuous because they are less isola;ted. 

Where the dikes cut the Dakota sandstone or the Tim pas limestone (Cretaceous), they are 

generally attacked n1ore reo.dily by weathering and erosive agencies than the wall rocks and 

therefore are indicated by crevices or channels traversing the sedin1entary forn1ations .. 

t Gilbert, G. K., U.S., Geol. Survey Geol. Atlas, Pueblo folio (No. 36), 1897. Hills, R. C., idem, Elmoro folio (No. 58), 1899; Walsenburg 

folio (No. 68), 1900; Spanish Peaks folio (No. 71), 1901. 

17 
18 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Several dikes contain xenoliths of foreign rocks brought up from lower levels and derived 

partly from sediments traversed. by the dikes and partly from the pre-Cambrian complex below. 

The pre-Cambrian rocks are granites, gneisses, and schists, similar to those of the Greenhorn 

Mountains, to the west. No fusion or notable metamorphism of these xenoliths was observed. 

General character of the rocks.-All the Apishapa dike rocks are very dense a~1d dark in the 

un~ltered state. The rock most easily determinable in hand specimens is a minette. Two 

diabases are dar~ gray and with a hand lens one can recognize feldspar and pyroxene in them. 

The largest group is that of the homogeneous-appearing aphyric aphanites; these grade· into 

melaphyres (in the field meaning of the term) exhibiting more or less abundant and distinct 

small olivine and augite phenocrysts. Biotite tablets as much as 1 <:entimeter in diameter are 

sporadically developed in some rocks. 

A few specimens are characterized by round or irregular white grains of analcite. Although 

in two specimens these grains appear like phenocrysts, it is believed that they are the filling of 

small pores. In one rock a fibrous zeolite occurs beside analcite partly filling vesicles. Calcite 

and chlorite are associates of the analcite in some rocks. 

Microscopical study shows that the rocks belong to a series of lamprophyres ranging from 

minette to basalt. That the basalt is but one extreme of the series is shown by the gradation 

through several occurrences into alkali feldspar rocks carrying abundant biotite and brown 

hornblende, with augite and more or less olivine. The analyses to be presented confirm this 

characterization. The dikes of the adjacent quadrangl~s furnish many other lamprophyric 

varieties, according to Hills, making the gradation still more striking. 

The Apishapa dike rocks will be described under the names minette, ~ugite minette, 

tinguaite, olivine-bearing augite vogesite, augite-hornblende vogesite, sodic 'diabase, and olivineplagioclase basalt. 

PETROGRAPHY. 

MINETTE. 

Description.-The single dike of normal minette occurs west of the lower or north end of 

the canyon of Apishapa River. It trends east-west-and is 10 feet or more in average width. 

:Material from a point about 5 miles west of the river has a reddish or gray-brown color due to 

numerous leaves of glistening biotite, many of which are 2 or 3 millimeters across. A rude 

parallel arrangement of the biotite flakes causes a marked schistosity. The matrix is pale 

pinkish in tone, owing to the presence of minute biotite scales and limonite pigment. No 

phenocrysts of feldspar or augite can be detected. 

Under the microscope the rock is seen to be a mas~, of interlacing leaves of Iresh biotite, which 

form perhaps one-third of the whole, with a matrix consisting principally of clear alkali feldspar 

in blades, many of them arranged in sheaf-like bundles. Besides these· predominant constituents, apatite is notably abundant in colorless cross-jointed prisms, the smaller of which are 

included in the biotite. A prismatic mineral, presumably diopside, was once an abundant 

element but is now almost wholly decomposed, chlorite and calcite in a very fine. aggr~gate of 

indistinct outline taking its place. Magnetite is scattered through the rock in dustlike particles 

surrounded by limonitic stajn. The feldspar is principally orthoclase, with which is associated 

some soda-rich plagioclase, probably oligoclase-albite. 

Calcite occurs not only as one of the alteration products of the prismatic mineral but also 

in minute scales and irregular particles scattered through the mass. No calcite grains with 

distinct cleavage have been seen. The amount of calcite corresponding to the C02 found by 

analysis is much greater than the estimate from microscopical examipation. This discrepancy 

is explained by the presence of minute seams of calcite parallel to the schistosity, representing 

a deposit from circulating solutions. These seams do not appear in the thin sections. 
U. S. GEOLOGICAL SURVEY 

10 5 oScale1o 20 miles 

'"""'«.-,_. •::< 

PROFESSIONAL PAPER 90 PL ATE IV 

~>;-

..}''eft 

-~ 

"'~~(. e 

cr· 

RELIEF MAP OF SOUTH-CENTRAL COLORADO, SHOWING RELATION OF THE APISHAPA QUADRANGLE T O THE SPANISH PEAKS 

CENTER OF ERUPTION. 

T he Apishapa q uadrangle is outlined in whi t e. 
DIKE UOCKS Ol!"' THE APISHAPA QUADRANGLE, COLOUADO. 19 

Ohe~ical composition.-1'~..11 analysis of the_rock just described, made by George Steiger in 

the laboratory of the Geological Survey, is given in column.l below and is accompanied by 

analyses of s·i1nilar rocks: 

Analyses of minette .and related rocks. 

6 

--------1---1---------------

32.32 52.26 . 50.81 40.71 50.41 41.57 ,IU6 13. G6 15.13 19.46 12.30 !l.i5 9.46 2. i6 2. 40 7.46 5. 71 4.06 4.10 4. 45 3.52 6.83 3.06 4. 47 J 5. 97 8.21 10. 64' 6.21 8.69 8.65 12.60 7.06 4. 96 11.83 7.08 11.10 .69 2.80 1. 01 1. 80 .97 1.57 5.97 3. 87 7. 01 3. 26 7.53 6.10 4.09 1. 34 3.07 1.53 1. 80 2.30 1. 03 1.53 .............. .............. .46 1. 54 4.55 .58 1.71 """:74" 1. 47 2.36 6.30 . 49 ·Trace. ······:46' 1. 24 3. 78 .52 .62 ................. 4.05 . 26 "''''j4' ······:is· ...... :is· .13 'I' race. .25 . 36 .23 ............... ................ .23 . 44 . 24 ................. ............... .. .............. ................ .11 

10J. 01 100. 25 100. 88 100. 01 100. 42 a 99. 90 Loss 0.... ................. .................................... .... ............ .. . .13 

99.88 

a Incluc~ing Z~02 0.02, C~ 0.04, F 0 ... 23, Cr20a 0.04, NiO 0.02, V 2<?s 0.04, FeS2 0.06, and deducting 0.11 0 for F, Cl. 1. (Aug1to) mmotto Aplshapa quadrangle, Colo. George Steiger, analyst. . 2. Augite minetto, Shoop Crook, Little Bolt Mountains, ?.font. W. F, Hillebrand, analyst; rock described by L. V. Pirsson, U.S. Geol. Survey ~rwontioth Ann. H.ept., pt. 3, p. 531; 1900. 3. Augite minetto Plauonsche Grund near Dresden, Saxony. B. Doss, analyst; Min. pet. Mitt., vol. 11, p. 27, 1890. 4. Minetto, 1~rankhn :Furnace, N.J. i. G. Eakins analyst; described by J.P. Iddings U.S. Geol. Survey Bull. 150, p. 238,1898. 5. Syonitic lamprophyre, •rwo Buttes, Colo. W. F. Hillebrand, analyst; described by \v. Cross, Jour. Geology, vol. 14, p. 165 1906. 6. Apat;ito minetto, northwest bank Columbia River, opposite Northport, Wash. W. F. Hillebrand, analyst; described by F. L. H.anl)ome, 

Am. Jour. Sci., 4th sor., vol. 26, p. 337, 1908. 

Analysis No. 1 shows low silica and alumina, corresponding to the dominance of biotite; 

potash is strongly in excess over soda; and phosphoric acid is very high, in agreement with the 

abundm1ce of apatite. The decomposition of the pyroxene and especially the infiltration of 

calcite account for the high carbonic acid. It 1nust be assumed that the biotite is rich in 

magnesia, and probably a large part of the titanic acid is to be found in the mica, as no 

ilmenite or titanite has been detected. 

A c01nparison with other analyses of minette, after all due allowance has been made for 

the calcite present, shows the Apishapa rock to be unusually fernie. While good analyses of 

1ninette are rare, the few found in literature are of rocks much richer in silica, alumina, and 

1nagnesia. None of those cited is so comparatively rich in potash. The Colorado rock has 

also a larger amount of titanic acid than the others. It is exceeded in phosphoric acid contents only by the apatite-rich minette of Washington (No. 6). The Washington rock is also 

rich in titanic acid, and it seems not improbable that these two minettes were, when unaltered, 

closely allied rocks. . ' . 

In gene:ral mineral and chemical character this minette is about as closely related to the 

peculiar lamprophyric rock (prowersose) from Two Buttes, Colo. (No. 5)·, as it is to any of the 

analyzed minettes. That rock is richer in orthoclase and diopside and poorer in biotite than the 

1ninette. It has also much less normative apatite and ilmenite. ·The Two Buttes rock was 

described as "a syenitic lamprophyre allied to minette." · 

Olassijication.-The described characters of this rock clearly place it under minette in the 

qualitative system. It was no doubt originally an augite-bearing minette, though perhaps 

approaching the pure biotite variety. The rarity of minette free from augite or hornblende 

has been commented on by Rosenbusch. 1 

The position of this rock in the quantative system may be approximately determined in 

sp:ito of its high content of carbonic acid, for, as has been pointed out, the greater part of the 

1 n.osenbusch, H., Mikroskopische PhysioJ,rraphie der massigen Gesteine, 4th ed.; p. G6G, 1907. 
20 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

calcite is not due to decon1position of rock constituents. The norm and systematic position of ... 

the rock are as follows: 

Nonn and systematic position of minette from Apishapa quadrangle, Colo. 

or ....... _._. ab ..... _____ _ 

c.----------

en----- _____ _ fo ... _______ _ 

rot---------- hm _____ : __ _ 

il .. - -------- a.p ... - _._--.--

35. 58 

6. 29 

. 41 

1. 70 

9. 24 

. 23 

9.28 

8. 66 

9.07 

Sal 42.28 · Class: Fem = 38_

18=1.11, salfemane, III. 

Order: ~=41 87 =0, perfelic, gallare, 5. 

K20'+Na0' 76 . . Rang: CaO' 0 oo, peralkalic, 1, orenclase. 

80 46 S b · KzO' 64 · 

l . · u rang. N>l-o,=l2=5.33, dopotass1c, (1) 2 (unnamed). Ca c1te .. _.... 14. 30 ~.: 

H20, etc.... 5. 38 

Symbol: III.5.1.(1)2. 

100. 14 

Unless more soda has been removed than there is discernible reason to suppose this is one 

of the most distinctly potassic rocks known. But the degree of alteration, as well as the transitional position of. the rock shown by the ratio K20 :N a20, renders it inappropriate to name 

the subrang from this occurrence. The minette from Washington (No.6) contains both nephelite and leucite and a large amount of diopside in its norm. It seems evident that the Apishapa 

'rock may have contained so much pyroxene that normative lenads would have appeared if 

the analysis had been made on fresh material. 

AUGITE MINETTE AND TINGUAITE. 

Mica Butte, situated west of Apishapa River, in the southern portion of· the quadrangle, 

is traversed by ari. east-west dike, the single specimen of which at hand exhibits two distinct 

rocks, one cutting the other in very intricate fashion. No recorded observations give fur,ther 

data on the field relations. The specimen consists chiefly of a brown, fine-grained, plainly 

biotite-bearing rock, much 1>recciated, and penetrated by dull pale-green tongues of apparently 

crystalline character. A poikilitic fabric is indicated in both parts by the cleavage luster of 

large feldspar grains, sop1e nearly 1 centimeter across. The chadacrysts 1 are irregularly distributed through the orthoclase and all other primary constituents occur in this manner. 

From the name given to the butte where this dike occurs it may be inferred that biotite 

is developed in much of the rock in larger crystals than in the specimen. The green material, 

of tinguaitic character, is so different from the minet~e that_some considerable development 

must also be oassumed for it. . 

Under the microscope the minette part of the specimen is found to consist of biotite, augite, 

alkali feldspar, apatite, magnetite, and brown glass.. Fresh feldspar grains of various sizes 

inclose many augite and apatite needles of perfect crystal form and wholly irregular _orientation. 

Son1e of the augite prisms betray the presence of the regirite molecule by color and pleochroism 

but retain a large extinction angle. Smoky glass acts like the feldspar as matrix for the other 

n;1inerals in many spots. Titanite is present in a few large grains penetrated by apatite needles. 

This augite-bearing minette gives reason for the suppositon tha.t the altered prismatic 

nuneral of the other minette described was augite, but the latter rock is much richer in biotite 

than the specimen fron1l\1ica Butte. 

The tinguaitic material, injected in fine veinlets all through the minette, varies greatly in 

texture and in the degree to which it is mixed with the minette minerals, especially biotite. 

Some narrow arms are coarse grained and consist of alkali feldspar, regirite, apatite, titanite, 

n1agnetite, and glass. In such parts the regirite occurs· in irregular bunches or interstitial 

grains between the larger 11nd more abundant alkali feldspars . 

. 1 Chadacrysts are the crystals or grains inclosed in the oikocryst, or "host": Iddings, J.P., Igneous rocks, vol. 1, p. 202,1909. . 
DIKE HOCKS OJ!"' THE APISHAPA QUADRANGLE, COLORADO. 21 

In other tongues there is a felt of regirite needles in a fme granular mass of feldspar, and 

here augite of the smne habit is more or less mingled with regirite, as is also more or less biotite, 

in n1inute flakes. Sodalite or noselite in regular crystals is variably developed in some veinlets. 

"While this occurrence of tinguaitic character is worthy of note, the lack of observations as 

to its occurrence and the inadequate 1naterial at hand for its study make further description 

at this ti1ne undesirable. 

OLIVINE-BEARING AUGITE VOGESITE. · 

Description.-The 1nost abundant variety of these Apishapa dike rocks is made up principally of augite, olivine, 1nagnetite, apatite, and a colorless n1atrix, which in n1ost rocks consists 

1na:inly of alkali feldspar but in son1e is in part a glass. Biotite is a very con1mon and brow11 

hornblende an occasional constituent of small quantitative importance. All these rocks appear 

to be do~ma:fic1 in general character,- but the analysis of a typical rock of this group shows tha~ 

the salic n1olecules actually predonunate in the norm and they probably do so also in the n1ode. 

:Most of these vogesites are dopatic or perpatic nucrophyres, megaphenocrysts of olivine, 

augite, or biotite 9eing rare. Both olivine and biotite sporadically reach din1ensions of 1 centimeter or 1nore. Under the nucroscope it is seen that olivine is comn1only and augite occasionally developed in pronunent phenocrysts. But the porphyritic texture is locally·obscured by 

the seriate developn1ent of augite fro1n the largest to the minutest particles. In a few specilnens 

white grains of analcite_are conspicuous, but these are believed to be the filling of small vesicles, 

and though possibly fonned imn1ediately after the consolidation of the 1nagma, the' analcite is 

not properly a phenocryst. 

Augite is the 1nost ab11;ndant constituent of these rocks, possibly exceeding 35 per cent in 

son1e dikes. It is pale green in color, prisn1oid in for1n, and generally of euhedral or subhedral 

developn1ent. In size it ranges from 1nicrophenocrysts several nllllimeters long to n1inute 

particles requiring a high-power lens for their identification. It is aln1ost invariably unaltered. 

Olivine was probably present in all these rocks, and in many of then1 it is still fresh, but 

in a few it is entirely altered to a chloritic or pili tic aggregate. Biotite is seldom lacking among 

the minute particles of the groundmass, and here and there hornblende of similar brown color 

is associated ·with it. 

The brownish color of the base in some rocks is found by high Inag1n:fi.cation to be due 

mainly to .tninute scales of biotite or short prisms of hornblende, and in others it is caused by 

ferritic globulites. Both hon1blende and biotite may be developed in equant grains of shnilar 

appearance. :Magnetite occurs in n1any s1nall and nearly uniform grains, but is less abundant 

than nught be expected in such basic-looking rocks. Apatite is variable in an1ount but is 

unusually abundant in n1ost dikes. 

The felsic 2 elmnent of these rocks plays the part of a base holding the 1na:fi.c constituents. 

It is holocrystalline in a few rocks, partly crystalline in son1e, and almost or quite hyaline in 

others. In the 1nost distinctly crystalline forn1 it. is anhedral and granular and consists of 

apparent alkali feldspar having a refractive index always distinctly less than that of balsan1. 

:More con1n1only the base exhibits but faint polarization and has a pale-brow.nish color when 

exanu,1ed with low power. Under high 1nagnification the mass often appears fibrous, the 

fibers being outlined ~y pale-brownish globulites between thmn. 

The rock of this group, of which an analysis is given on page 22, is represented in Plate V. 

Plate V, A shows the appearance in ordinary light. Olivine i'1large crystals is represented by 

white areas having a rough surface. Augite is developed in clouded prisms corresponding to 

the olivines in size and also in n1any sn1all prismoids and grains. The wlute irregular base is 

l1lfa[tc applies to the whole group of fcrromagnesian minerals developed in rocks and to rocks in which such minerals dominate. It is distinct 

fromfcmic, which applies properly only to normative nonaluminous ferromagnesian molecules. Cross, Iddings, Pirsson, and "'ashington, Jour. 

Geology, vol. 20, p. 561, 1912. 

2Ji'clsfc, a term complementary to mafic, has been proposed for the group of modal feldspar, feldspathoids, and quartz, to which the normative 

term salic is often incorrectly applied. Cross, Iddings, Pirsson, and Washington, icem. 
22 SHORTER CONTRIBUTIONS TO GENERAL GEOLOG~,. 1914. 

alkali feldspar, some of the radiating and branching groups of needles being visible in the center 

of the figure. Biotite is here very sub01.:dinate and its small flakes can not be distinguished 

from magnetite in the photograph. 

Plato V, B brings out the rather prominent ,bundles of alkali feldspar needles and the 

irregularly granular, anisotropic character of the rest of the white base of Plate V, A. 

In a few of these augite vogesites there is some isotropic or very faintly polarizing substance 

that plays the same textural part as the feldspar aggregate of the rock illustrated by Plate V. 

Some alkali feldspar accompanies this· base, which is supposed to be glass. It is clouded by 

minute brownish particles. 

In several rocks there is also another isotropic substance, of dusty appearance and low 

refractive index, which is usually associated with chlorite and calcite and is believed to be 

secondary analcite. 

Indications of plagiocla!?e are entirely lacking in most of these olivine-bearing augite 

vogesites. Nephelite is possibly present in small amount in the very fine grained- base, which 

consists largely of alkali feldspar, but it nowhere assumes a distinctly recognizable form. 

Chemical composition.-An analysis of a fresh typical olivine-bearing augite vogesite is given 

in column 1 below, together with analyses of chemically analogous rocks, for comparison. 

Analyses of olivine-bearing augite vogesite and related rocks. 

3 6 7 

------------·----------1--------·-----·---------

Si02--·································································· AhOa ....... · ........................................................... . Fe20a ....................•.............................................. FeO ................................................................... . 

~;g_ ·:::: :: :::: :::::::: ::: ::: :: :: :::: :: :: :: :: : ::: :: :: ::: : : : : : :: :::: ::::: 

N3.20 .................................................................. . K20 ................................................................... . H20+ ...................................... 1. ••••••••••• ~ •••••••••••••• 

H20- ................................................................. . 

Ti02···································································· P2o •..................... : ............................................. . s ...................................................................... . MnO ........................................... ~ ....................... . BaO ................................................................... . SrO .................................................................... . 

44.31 

~ 14. 10 

4. 75 

6.02 

7.80 

9.66 

3. 74 2.83 

3.29 

.88 

2.10 

.53 

.10 

.18 

.10 

.10 

44. 39 44. 87 43. 64 42. 80 44. 66 44. 52 

13. 12 14. 05 13. 12 12. 49 12. 97 14. 28 

4. 19 2. 03 6. 40 4. 32 3. 84 6. 36 

7.38 7.79 5.52 6.06 7.55 5.39 

9.54 8.87 9.36 7.62 9.35 7.13 

9. 55 9. 76 9. 52 10. 43 8. 82 10. 20 

·4.17 4. 65 3. 89 4. 33 4. 24 3. 76 2. 22 2. 31 2. 18 2. 75 2. 78 2. 59 

1. 96 . 62 . t~ 4. 92 . ~~ } 3. 53 

. .... 2."4o······4:7i. 4:55 2.36 2:16 2.04 

. 93 . 27 . 74 1. 77 1.10 . 56 

.23 .................... ·········· ··········· .07 .......... .......... .20 ......... . 

:::::::::: :::::::::: ····--:o3· :::::::::: :::::::::::::::::::: 

100. 49 100.18 a 100. 23 99.60 99. 85 b·99. 71 100.36 Less 0 .................................................................. · .05 

100.44 

a Including Co2, 0.16. b Including Cr203, 0.01, and NiO, 0.26. 

1. Olivine-bearing augite vogesite, dike south-southeast of Dripping Spring, Apishapa quadrangle, Colo. Analyst, George Steiger. 

2. Feldspar basalt, Friedrichstolln, Der Meissner, .Allendorf, Hesse. Cited by F. Beyschlag, ErHi.uterungen zur geologischen Spczialk:arte von Preussen, Blatt Allendorf, p. 47, 1886. · 3. Essexite, Haselbach, Passau, Bayrischer Wald, Bavaria. Analyst, G. Vervuert. ~ascribed by A. Frentzel, Geogn. Jahresheften, vol. 24, p. 162, 1911. 

4. Nephelite basanite, La Garrinada, Olot, Spain. Analysis and description by H. S. Washington, Am. Jour. Sci., 4th ser., vol. 24, pp. 

233-240, 1907. 

5. Leucite basalt, Hertinghausen, Hesse-Nassau, Germa.riy. Analyst, Dittrich. Described by R. Bemges, Neues Jahrb., Bell. Band 31, p. 633, 1911. . 6. Basalt (tiachydolerite), Sverre1 Fjeld volcano, Bock Bay, Spitzenbergen. Analyst, Dittrich. Described by V. M., Goldschmidt, Videnskapsselsk. Skr.-naturv. Kl. 1911, No. 9. 7. Nephelite basanite. Jesserken Berg, Bohemian Mittelgebirge. Analyst, C. Fr. Eichleiter. Described by G. Irgang, Min. pet. Mitt., vol. 

28, pp. 55-57, 1909. 

·The agreement in ·chemical character among these rocks is notable, yet the names assigned 

to them show how. greatly the conditions of consolidation affect the mode. The seemingly 

small variations of the different oxides have in fact an ~mportant effect on the normative or 

potential mineral character of these magmas, as appears from the table of norms given below. 

Titanic acid is notably high. . · 

Classification.-The norms of the rocks whose analyses have been quoted will be found 

in the table below. Those for the cited rocks of this and succeeding tables have been calculated 

by I-I. S. Washington. 1 

1 Dr. Washington has kindly given me free acC!JSS to the extensive material he has compiled for a new edition of his invaluable tables of rock 

analyses, now nearly ready for publication. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PL ATE V 

A. 

B. 

PHOTOMICROGRAPH S OF ANALYZED AU GITE VOGESITE. 

A , With on e nico l ; B , w ith crossed ni co ls. Magn ified 51 di amet ers. 
DIKE ROCI\:S OF THE APISHAPA QUADRANGLE, COLORADO. 23 

Norms of olivine-bearing augite vogesite and related rocks. 

----------------------1---------------------

or ..... 0 ........................ 0 ...... 0 .... 0. 0.......................... 16. 68 120 79 13. 34 12. 79 16.12 16. 68 15. 57 ab ...................................... 0 ....... . : . ....... 0........ ... .. 7. 60 -10.74 7. 07 . 15. 58 7. 86 9. 96 100 48 l\11 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 13o 07 100 56 10o 84 11o 95 60 95 7. 51 14ol8 110 ....... ~ ......... .'.................................................... 13020 13.49 17.46 11o 08 150 34 130 92 11. 64 <11....................................................................... 25o32 24.12 28.23 230 76 26o 46 23o12 250 68 ol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. 08 13. 25 9. 78 So 68 6o 81 130 66 4o 93 Jnt...................................................................... 6.96 6.03 3o02 4o 64 6o 26 5o 57 9o 23 11 ................................................................ :...... 4.00 4.56 8.97 So 66 6. 38 5. 32 3o 95 11111 ............................................................. : .................................... . 3o 20 o••••····· ··•······· ......... . ap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. 24 2. 35 • 67 • 1. 68 4o 02 2. 69 1. 34 

The position of the Apishapa rock (No. 1) in the quantitative syste~ is determined by 

the following data: 

Class: l~~~ =~~:~~=1.11 =III, salfemane. 

]~ 13·

20 

Order: F=:n _ 0 376 6 

35= . = , portugare. 

K20'+Na201 91 1 hi Rang: CaO' 47 1.936=2 , monc quase. 

. K20' _ 2Q.. _,4 hi Subrang. Na20,- 61 =0.49 - , monc quose. 

The other rocks have the following symbob: 

2 .... III.6.2.4 ·4 .... III.6.2'.4 6 .... III.6.2.4 

3 .... III.6(7).2.4 5 .... III.6'.2.4 7 .... III.6.2(3)'.4 

The Apishap~ rock con1es well within the central parts of the salfemane class and its lendofelic order, portugare. It is don1alkalic but intermediate toward the alkalicalcic rang limburgase. 

As to subrang it is dosodic but intermediate toward the sodipotassic shonkinose. With regard 

to the fernie elements it is dopolic, prepyric, premiric, and premagnesic, and in these respects 

the rocks cmnpared with it are closely analogous. . 

In the 1nineralogic or· qualitative system the Apishapa rock must be called an oliVine.:. 

bearing .augite vogesite, for it has no plagioclase. Manifestly its feldspar is highly sodic and 

hence the rock is not a typical· vogesite. 

Bearing the name vogesite, the Apishapa rock parts company with its chemical analogues 

so far that no suggestion of close similarity with them is conveyed by their current names. 

Comparison of norm and mode.-In the vogesite from Colorado norm and mode do not agree 

at all closely in some important respects. Thatrock is purely of an alkali feldspar type, yet 

it has 1nore nonnative anorthite than· most of the chemically analogous rocks· containing plagioclase. It has a large amount of normative nephelite but little in the mode, while the reverse 

is true of augite and olivine. No doubt the augite contains much of the lime and alumina of 

the nol'lnative anorthite, and the abnorn1ative. amounts of olivine and augite release some 

silica, which presu1nably served to decrease the nephelite and increase the albite of the rock. 

It is interesting to note that the rocks compared with this vogesite also exhibit differences 

of JlOrnl and mode. The basalt of the :Meissner (No. 2) is a well-known rock cited by Rosenbusch, Zirkel, and others as typical of the doleritic basalts of intersertal texture, without mention 

of n:ephelite as a constituent. Beyschlag, however, notes that amo11g the petrographers who 

have studied the :Meissner basalt Senft and }t1ohl have reported nephelite, a determination which 

he regards as requiring confirmation. The quoted analysis of the :Meissner basalt se~ms clearly 

to be the 1nost reliable of those cited by Beyschlag, but he unfortunately gives no special descrip- · 

tion of the mat~rial analyzed. Alkali feldspar is present, though not in larg~ amount, in a 

section of rock f1~om the :Meissner given to me many years ago by Prof. Zirkel, but I have not 

been able to find nephelite in it. The norm of the }t1eissner basalt shows that it has potential 

nephelite, and if conditions in son1e parts of the n1ass were favorable to its development nephelite 

might ~ell assun1e locally an important rOle. · 
24 SHORTER CONTRIBUTIONS TO GENERAL. GEOLOGY, 1914. 

The essexite (No. 3) of the above table has abundant andesine, though its normative 

anorthite is less than that of the vogesite. In spite of the name essexite Frentzel does not 

mentionnephelite as a constituent, although 17.46 per cent isshown in the norm.· The nephelite 

basanite of La Garrinacla (No. 4) has abundant labradorite and son1e nephelite, but orthoclase 

is not mentioned by Washington. The leucite basalt (No. 5) has so n1uch glass that its halocrystalline n1ode can not be safely inferred, but its abnormative leucite is certainly not ·due to 

low silica or high potash contents. · 

The basalt of Bock Bay (No. 6) appears fron1 the full description of Goldschmidt to have 

nephelite in its groundmass, though in particles so minute that he regards the determination 

as questionable. Although containing practically the same potash and more soda than the 

vogesite, this basalt has no determinable alkali feldspar. With less li.n1e and much less normative 

anorthite than the vogesite, it has considerable plagioclase, richer in soda than in lime. 

The nephelite basanite of Jesser ken Berg (No.7) presents curious relations of norm and mode, 

particularly when compared with the vogesite (No. 1) and the basalt of Spitzbergen (No. 6). 

It is a sanidine-bearing nephelite-hauyne basanite with oligoclase as its lime-soda feldspar, yet 

it has nearly twice as much normatiye anorthite as the basalt from Spitzbergen and is riot so 

rich in the alkali molecules. It agrees closely with the vogesite in chemical composition but 

has both plagioclase and lenads much niore prominently developed. 

HORNBLENDE-AUGITE VOGESITE. 

Description.-A group of vogesites differing but little fron1 the group just described in 

n1egascopic appearance is characterized by an abundance of camptonitic brown hornblende, 

equaling or exceeding augite in amount, 'Yi.th_ biotite of the san1e brown color, and a variable 

development o.f plagioclase, which is always subordinate to alkali feldspar. Olivine is or was 

a constituent of less importance than in the other group, and it is con1n1only decomposed to a 

pilitic aggregate, while the other mafic silicates are fresh. Apati~e and magnetite are abundant. 

, Some of these vogesites are unevenly panautomorphic, granular except for the alkali 

feldspars, and so coarse that their texture can almost be recognized by the unaided eye. Others 

are microphyres, and in these hornblende and biotite are chiefly or wholly in the groundn1ass, 

while a part of the augite appears in distinct microphenocrysts along with olivine. 

The mafic silicates predonunate somewhat, but feldspa:rs are more abundant than they semn 

to be, because .of the occurrence of the alkali feldspars as the matrL'X. Plagioclase is n1ost con1-

monly developed in stout crystals of imperfect form and is labradorite or andesine. 

Analcite occurs in round phenocrystic grains and some of it seen1s as if it might be prilnary, 

but this is questioned because small pores of the san1e size containing chlorite, calcite, and 

sometimes analcite are present in the same rocks. 

Plate VI reproduces ph<;>tomicrographs of the hornblende-augite vogesite of which an 

analysis is submitte9. below. This rock came from a dike 3 miles west of the upper end of 

Apishapa Ca~yon and. east of Mica Butte. Plate VI, A, taken in with one nicol, shows the general 

texture very well. . The large prism to ~he left of the center and. nearly all other prisms and 

grains of the sa~e· shade of gray are augite. Many darker-gray crystals are brown hornblende, 

which is intergrown with augite at one end of the large prism and in many other crystals. Three 

decomposed olivine crystals appear near the center. Biotite is very subordinate in this rock. 

The black grains of Plate VI, A, are all magnetite, and several long needles of apatite appear in 

the left-hand portion. The feldspathic base is resolvable only in polarized light betw:een cr<;>ssecl 

nicols. Plate VI, B, brings out the multiple twinning (albite anq pericline laws) of a stout crystal 

near the upper border, and albite twinning appear~ in-a few other grains but is less easily distinguished in .the illustration. Some clear alkali feldspar needles, -\vhich are also visible in A, appear 

more sharply defined in B, lying in a fine aggregate of feldspathic character. · 

Chemical composition._:_The augite-hornblende vogesite of a dike 4 miles west of Apishapa 

Canyon has the composition given in column 1 on page 25, according to an analysis by George 

Steiger. Analyses of some of the most closely allied rocks are given for comparison. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE VI 

A. 

B. 

PHOTOMICROGRAPHS OF ANALYZED HORNBLENDE-AUGITE VOGESITE. 

A , With one nicol · B , with crossed nicols. Magnified 51 diameters 
,.• 

DIKE ROCH:S OF THE APISHAPA QUADRANGLE, COLORADO. 25 

Analyses of a-ugite-hornblende vogesite and related rocks . 

. ---------------~----------------------------------~------~-----.------~-----.------

-----------------------------1----------------

~~~~~::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :·:::::::: ::: g: ig n ~~ n ~g· t~: 5g 11:g~ }'c10 8 •••••••••••••••••••••••.•••••••••••.••••••....•••••••••.••••• :.......................... 5. 92 3. 40 2. 32 3. 19 4. 56 l?oO............ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5. 18 9. 13 7. 30 8. 41 7. 27 

~~~':':':':':':'::·::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :·:: ::::::::::::: 1gJ~ 1~: ~~ 1~: ~~ ~:~ ~Jg 1~20......................................................................................... 2. 53 2.13 3. 89 2. 35 2. 30 II20+....................................................................................... 3. 05 2. 40 . 45 . 76 . 30 1:120-... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. 86 . 47 . . . . . . . . . . . 12 . 05 COs ........................................................................................ · ................................................... . ~1'10 2 ................................. ,. • • • • • • • .. .. .. • • • • • • • • • • .. .. • • • • • • • • • • • • • • • • .. • • • • • • • • • 2.10 3. 32 . 30 4.10 4. 25 ]>20 5 •••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 75 .95 .39 .62 .67 

~i::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :·:::: :~:::: ...... : ~~. · · ·,i,~ace: · :::::::::: :::::::::: :::::::::: l<oes ...................... , ........................................................................................... -........................ . NiO.......................................................................................... .......... .......... .......... .14 ......... . 1\fnO ........................................ :................................................ .10 . .. . . . . . . . . 35 . 51 None. l3n0... ... .............. ................................ ..................................... .13 ......•................................. SrO. .. . . . . . . . . .. .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . .. .. .. . . . . . . .. . . . .. . . . . .. . . . .. . . .. .. . .12 ....................................... . 

100. 52 99.70 101.38 99.84 100.13 

t. Auglto-hornblendo vogosito, Apishapu quadrangle .. Colorado. .. 2. :t~lmhurgito, Woodond, Macedon, VIctoria, Australia. Skeats and Summers, Geol. Survey Victoria Bull. 24, p. 28, 1912. 3. Olivine monzonite. Smalingen, Fahlun, Sweden. Analyst, L. Schmelck. Described by W. -C. Brogger, Die Eruptivgesteine Kristiania- goblotos vol. 2 p. •Hi, 1895. 4. Nopbollte basanite, Cruzcat, south of Olot, Spain.· Analysis and description by H. S. Washington, Am. Jour. Sci., 4th ser., vol. 24, pp. 233-2•10, HJ07. • 5. Nepholltn basanite, Montsacopa, near Olot, Spain. Analysis and description by H. S. ·washington, Joe. cit. 

This type is 1nore basic than the vogesite described above, having less silica, alumina, and 

alkalies and1nore p1agnesia and lime, but these differences are not enough to obscure the general 

sin1ilarity of the two rocks. The cumulative effect of the differences is best appreciated by a 

con1parison of the norms of the two rocks~ 

Olassijication.-The norms of the hornblendic vogesite and the correlated rocks ·are as 

follows: 

Norms of augite-hon~blende ~:ogesite and relate~ rocks.a 

------------ or ........................................................................................... . 15.01 12.23 22.8 13.90 13.34 ab .......................................................................................... . 11.00 13.10 11.0 9.43 14.15 0.11 ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 16.40 15.29 18.3 14.73 15.01 no .......................................................................................... . 5.11 2.84 6.5 11.64 9.37 

<11. .......................................................................................... . 23.48 21.99 23.6 24.28 21.86 9.48 17. 79 13.1 11.11 9. 73 8.58 4. 87 3. 5 4.64 6. 73 ol. .............................................. , ................................ : .......... . 1111; ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 

il. ........................................................................................... . 3.95 6.38 .6 7. 75 8.06 np ................................................................................... .-...... . 1. 78 2.35 1.0 1. 34 1. 68 --------------- 94.79 96.84 100.4 98:82 99.93 5. 62 2. 87 .5 .88 .35 

100.41 99.71 100.!) 9.9. 70 1.00. 28 

a '.l'ho norms of Nos. 2 to 5 aro as calculated by Dr. Washington. Nos. 4 and 5 differ slightly from those originally published by him (loc. cit.).· 

The position of the vogesite in the qlJ.antitative systmn is indicated by these dat~: 

Sal 47. 52 I I Class: l!"'ero.=t17_ 27=1. += I , salfemane. 

Order: ~ = ~: ~i=o. 120+=5(6), portugare-gallare. 

0'+N~O' Hang: CaO' w=l. 66 2 1' 1 =3, camptonase- lmburgase. 

K 0' 27 Subrang: N~O' =:39=0. 69=3', ourose-kentallenose. 

The syn1bols of the analogous rocks n.re: 

2 .... III. 5'. 3 .. 3( 4). 4 .... III. 6.(2)3.4. 

3 .... III. 5(6). 3. 3. 5 .... III.'6.(2)3.4. 
26 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The Apishapa rock is near the center of the salfemanes and by its low nephelite falls in the 

perfelic order gallare, but it is transitional to portugare, in which ·the hornblende-free vogesite 

comes. Through low alumina and consequent lower anorthite this vogesite is alkalicalcic 

and through less preponderant soda it is sodipotassic. 

Kentallenose and ourose ht1Ve even' fewer known representatives than monchiquose and 

the Apishapa rock has few very close analogues, as the above table shows. 

The motex 1 of this rock places it in the mineralogic system as a lamprophyre 0f dominant 

alkali feldspar with hornblende, augite, and olivine as its mafic silicates. By the appearance 

of plagioclase the rock approaches the monzonit.ic series of lan1prophyres. 

Comparison of norm and mode.-In this rock, as in the olivine-bearing vogesite, the most 

notable discrepancy between norin and mode is in the lime feldspar. With 16.4 per cent norma-

. tive anorthite the rock has but little plagioclase, while its nearest chemical·analogues are characterized by plagioclase. 

OLIVINE-PLAGIOCLASE BASALT. 

Description.-The basalts of the Apishapa quadrangle are dark, dense rocks, differing 

from the vogesites because of their more distinctly crystalline appearance, due to the developJnent c-f feldspar. Yet these rocks are so fine graine_d that only a few crystals of olivine, augite, 

or plagioclase can be clearly recognized by the una,ided eye even in the coarsest specimens. 

The microscope shows that the olivine, augite, plagioclase, magnetite, and apatite have a 

development like that most commonly found in typical basalts of dense and nearly holocrystallin~ texture. Olivine exhibits a tendency to form small phenocrysts, while augite and 

plagioclase are less commonly prominent in this way. But a seriate gradation from largest 

to smallest grains diminishes or d~stroys the porphyritic appearance. The ophitic relation of 

plagioclase and augite is seldom pronounced. 

Biotite in small leaves is' sparingly present in some of these basalts. Brown hornblende 

has' not been noted. The interstitial ·feldspar is orthoclase or an alkali feldspar containing 

both potash and soda. In some dikes this alkali feldspar is almost lacking and in others it has 

a development similar in character though not in importance to that in the olivine-bearing 

augite vogesite. Glass is pnsent in some dikes in clear colorless ar~as penetrated by mineral 

grains or prisms, but does no~ assume· the role, common in basalts, of a base of smoky color 

and globulitic interpositions. 

Plate VII, A, represents the appearance of the basalt of which an analysis is given below, 

as seen in ordinary light. · The'l~rge phenocrysts of rough surface are olivine. Augite appears 

only in the prismoids and grains of much smaller size but forms a large part of the rock. The 

interstitial white. areas represent abundant plagioclase laths and irregular grains Qf plagioclase 

or alkali feldspar, which are not readily distinguished except when seen in polarized light. The 

greater part of the black areas represent dark~brown biotite and the remainder magnetite. 

Plate VII, B, represents .the same area as seen .in polarized light, the plagioclase laths 

being here much more distinct. 

Chemical composition.-The chemical analysis of the basalt is given in the subjoined table, 

together. with those of the nearest chemical analogues of which I have found mention: 

· 1 1lrotex is a convenient term by which to refer to the mode and texture of any rock. See H. S. Washington, Am. Jour. Sci., 4th ser., vol. 24, 

p. 230, 1907. 
U. S. GEOLOGICA L SUR VEY PROFESSIONAL PAPER 90 PLAT E VII 

A. 

B. 

PHOTOMICROGRAPHS OF ANALYZED PLAGIOCLASE BASALT. 

A, With one nico l; B , wit h crossed nicols. Magn ified 51 diamet ers. 
DIKE ROCKS OF THE APISHAPA QUADRANGLE, COLORADO. 27 

Analyses of olivine plagioclase basait and related rocks. 

----------------,...-------------1----!1--------------- 8102 ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 44. 64 44. 29 44. 78 45. 80 43. 76 

AbOu.............................................................................. 12. 82 12. 62 12. 76 13. 41 11. 58 

]?o30 8 •••••• •• • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 3. 64 3. 61 5. 42 6. 89 4. 39 

lfoO............................................................................... 8. 34 8. 84 8. 34 5. 69 7. 57 

~r;g,!::::::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ~8: 8~ 18:~ ~8: g 1~: g~ 1~:~! Nn20............................................................................... 3.39 3.25 3.56 3.57 3.03 ]{20 ......... : .. . . . .. . . . .. .. .. .. .. . . .. .. .. .. .. .. . .. . . . . . . . . . .. . .. . . . .. .. . . . . . . . . . . . 1. 76 1. 82 1. 81 1. 41 1. 84 

i::8~::: ::::::::::::::::::::::::::::::::::::::::::: :': ::::::::::::::::::::::::::::: 1:~~ :~ 1. 42 .47 

45.15 

12.93 

5.26 

6.88 

11.35 

9.97 

2.90 

1. 76 

.32 

.29 cou .. .. ....... ······:93· ::::::::::······:as· 

g&~~j j ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~;~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~.~ __ ::: ~~ ~~: 4J~ .... __ : ~~ _ ::::::: ~~: 3: n ____ .. ~:- ~~ ~~·~u:::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ...... :~~. :::::::::::::::::::: ······:is·:::::::::: 

NIO............................................................................... ........... .......... .......... .......... .......... .01 

1\t:nO.............................................................................. .16 (a) .......... .......... .......... .16 

Bl\0 ..................................................... ,......................... .14 .06 ........................................ . SrO... ... . . .. .. .. .. .. .. .. . . . . . . . . . ..... .. . . .. .. . . . . . . . . .. .. .. .. . . . . . . .. .. .. ... . . . . . 09 .04 ....................................... . I ' --------------------

99.57 99. 68 100. 59 99.96 99.78 100.36 

a Not determined. 

1. Ollvlno-plagloclaso basalt dike 8 miles cast-northeast of North Rattlesnake Butte, Apishapa quadrangle, Colorado. Analyst, George Steiger. 

2. Nophclito basanite, Las Planus, south of Olot, Catalonia, Spain. Analysis and descriptiOn by H. S. Washington, Am. Jour. Sci., 4th scr., vol. 24, p. 217, 1007. 

3. Basalt, lli.l11cnhorg, Blatt M:elsungen, Prussia. Analyst, Steffen. Described by F. Beyschlag, Erliiuterungen zur geologischen Spezialkartc von Prousson, Blat;t M:olsungon, p. 20, 1891. 

4. Basalt, Wostray, ncar Milloschau, Bohemia. Analyst, J. Hanamann. Cited by J. E. Hibsch, 1\fin. pet. 1\fitt., vol. 24, p. 274i1905. 5. Basnlt.L M:atavuno., flow of 1905-6, So.vaii, Samoan Islands. Analyst, Heuseler. Described by A. Klautsch, Preuss. geol. andesanstalt 

Jahrb., vol. 27 (1907) p. 174, 1910. • 6. Basalt, Mount '!'orang, Camperdown district, Victoria, Australia. Analyst, A. A. Tbpp. Rock described by H. J. Grayson, Geol. Survey Victoria Mmn. 9, p. 2Z, 1910. · 

The basalt of the Apishapa quadrangle has a composition similar to that of the' vogesites 

but is slightly richer in 1nagnesia aud richer in soda relative to potash. The total of the alkalies 

is high and the silica low for an average feldspar basalt. 

Olassi:fication.-The norms of the basalt of the Apishapa quadrangle and the analogous 

rocks are as follows: 

No~s of olivine-pl_agioclase basalt and related rocks. 

1 • 

---------------------------1------------------------

or .. ··········································'···································· 10.56 11.12 10.56 8.34 11.12 10.56 

ub ................................................................................ . 12.58 15.20 14.67 13.10 8. 91 14.67 

(\11 .......... : . .................................................................... . 14.18 14.18 13.62 16.12 12.79 16.96 110 ................................................................................ . 8.52 6.82 8.24 9.37 8.80 5.40 <11. ............................................................................... . 24.53 22.02 21.04 23.89 25.41 22.14 

01 ....................................................................... ,. ........ .. 16.24 14.10 18.62 18.16 17.78 15. 7S 1111:. ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 5.34 5.34 7.89 9.98 6.50 7.66 

il ................................................................................. . 3.80 9.42 .48 6.54 5.02 

np •..........•••.•..•.............................................................. 2.12 1.34 2.12 1.01 1. 01 1.68 ------------------ 97.87 99.54 97.24 99.97 98.86 99.84 

Hcst ................................................................. ·············· 1.56 .47 3 . .'i4 .00 1.14 .62 ------------------ 99.36 100.01 100.78 99.97 100.00 100.40 

The quantitative classification of No. 1 is shown by the ratios cited below: 

Cl Sal 45.84 I I I ass: li'em =52.

03=0.881= I , sa femane. 

0 d L 8·

52 r er: F= 0 228 '6 37 .

32= . = , portugare. 

R . K20'+N~O' 74 I I' 

ang. CaO' 51 1.45= 3, 1mburgase. 

Subrang: :~~=~=0.345=4, limburgose. 

The symbols of the rocks express the degree of normative resemblance between them. 

1. _:. III/6. '3.4. 3 .... III.'6.(2)3.4. 5 ... ~ III.6.(2)3.4. 

~- _. _ III.(5)6.'3.4. 4. _ .. III.6.3.4. 6. ___ III.5(6).3.4. 

37183°-15-3 
28 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The classification by motex places the Apishapa rock among the olivine-plagioclase basalts. 

That. it is not a typical feldspar. basalt is shown in the discussion of norm and mode. 

Comparison o.f norm and mode.-While the mode of the basalt of the Apishapa quadrangle 

is more nearly normative than those of the associated vogesites, in that anorthite is at least 

more fully developed in plagioclase, its norn1 contains a considerable an1o11nt of nephclite which 

probably does not appear in the mode. This nephelite shows the basalt to belong potentially 

with the nephelit~. basanites rather than with the common basalts falling in auvergnose or 

can1ptonose. The potential significance of this normative nephelite is fortunately illustrated 

in striking manner ·by the nephelite basanite of Las Planas (No.2 of table), which is very near 

to the basalt of the Apishapa quadrangle in chemical composition but has less normative 

nephelite. 

The basalts of Hiinenberg (No. 3) and Wostray (No. 4) are not described in detail in the 

publications cited, but presu~ably they contain no recognized nephelite. 

The lava of :Matavuna volcano (No. 5) is, according to Klautsch, largely vitreous, but it 

contains labradorite, both in small phenocrysts and in n1icrolites. · IGautsch points out a 

chemical shnilarity between this lava and the nephelinite of ICatzenbuckel and the. nephelite 

basanite of IIundeskopf. 

The basalt of Mount Terang (No. 6) is also largely glass, but shows some augite and feldspar .. 

SODIC DIABASE. 

Three dikes of the Apishapa quadrangle have a general diabasic character in that the 

specimens from them are largely augite-plagioclase rocks with ophitic texture more or less 

distinctly developed. They are of very simple nuneral composition, and their principal characteristic is the highly sodic ·character of the plagioclase. This appears to be oligoclase or 

oligoclase-albite, no andesine or labradorite having been noticed. 

The rock nearest to common diabase in texture forms a dike 7 miles south-southeast of 

Dripping Spring. It is a grayfine-grained ophitic rock in which the fabric is more evident to 

the· unaided eye than in any other dike of the quadrangle, yet few of its largest feldspar and 

augite crystals exceed 1 millimeter in length. The plagioclase crystals are more nearly euhedral 

than the augite crystals and often penetrate them, but the augite grains are not large enough to 

emphasize the ophitic fabric. , · 

Plagioclase predominates over augite, to which the other constituents, embracing biotite, 

titaniferous magnetite, apatite, and probably some monoclinic alkali feldspar, are all decidedly 

subordinate. Chlorite, calcite, and analcite 0) are the noteworthy secondary minerals. Of 

these, chlorite seems to represent, in part, a former prismatic constituent, of much less abundance 

than augite, which is tentatively thought to have been hypersthene, for augite does not undergo 

visible alteration to chlorite in these rocks, nor does the bro'Vn hornblende of other dike rocks 

of the region. Olivine is not present and the long prisms replaced by chlorite are of a form 

not assumed by olivine in the associated rocks. · 

Plagioclase, the principal constituent of the rock, occurs in tablets of multiple alibitic 

twinning, appearing very ''dusty" in ordinary light, but it is really not much decomposed. 

Its refractive index in most sections is near that of Canada balsam but is prevailingly lower, 

and the maximum extinction from the trace of albite twinning plane is about 7°. It seems 

probable that. oligoclase-albite is the term best expressing the composition. Some monoclinic 

alkali feldspar is probably present, but none was definitely identified. A colorless, isotropic 

mineral of low refraction occurs in small amount, in association especially with calcite and 

chlorite, and is referred to analcite. ' 

One of these diabasic rocks forms a dike running east from the mesa 5 miles 'Yest of Dripping 

Spring. It is similar in texture and grain to the rock just described and differs from it in composition mainly in the character of the plagioclase, which is more distinctly o).igoclase.· Biotite 

and hornblende of the same deep-brown color are equally abundant, but are far subordinate to 

pale-green augite. · 
DIKE BOOKS OF THE APISHAPA QUADRANGLE, COLORADO. 29 

REJ.:JATIONS OF THE APISHA.PA ROCKS TO THE SPANISH PEAKS. 

The dikes of the Apishapa quadrangle belong to a great system of radia!" dikes, with 

associated sills, which surround the Spanish Peaks, an eruptive center situated 25 miles southwest of the border of the quadrangle. (See Pl. IV.) The rocks of this center and of the dikes 

anct' sills, so far as they occur in the Spanish Peaks, Walsenburg, .and Ell\1oro quadrangles, have 

been described in a general way by R. C. flills, in the folios dealing with these areas. No 

chemical analyses accompanied the descriptions by Hills. The description of the Apishapa 

rocks and especially the four analyses present'ed in this paper indicate in some measure the 

interest attaching to the rocks of this remarkable center of associated differentiates. A summary of the data given by I-Iills will make this still clearer. 

At the Spanish Peaks there are three great stocks penetrating Eocene beds. The rocks of 

these 1nasses are called by flills granite porphyry, augite granite porphyry, and augite diorite. 

The granite porphyry -is described as containing abundant large phenocrysts of orthoclase and 

quartz and some plagioclase. The groundmass is rich in quartz, partly in niicrographic intergrowth with feldspar, presumably orthoclase. No mafic constituents are mentioned as present 

in this rock, but it grades within a narrow transition zone into the augite granite porphyry, 

which is characterized by both augite and biotite. Augite diorite is a collective name for somewhat different rocks variably rich in. augite, biotite, hypersthene, plagioclase, orthoclase, and 

quartz. 

On the n1ap of the Spanish Peaks quadrangle Hills represents 240 dikes. A ·large and 

perhaps equal nun1ber are said to occur in the unmapped area west of ~he center of eruption. 

At 10 or 15 miles from the peaks begins a zone marked by thin sills of rocks like those which 

. occur in dikes, and in several places dikes and sills are visibly connected. In the Walsenburg 

quadrangle 70 dikes and 20 sills were mapped, most of which belong to the Spanish Peaks 

systen1. Ten dikes and several sills occur iii the El Moro quadrangle, south of the Apishapa .. 

The dike and sill rocks are referred by llills to five principal groups, which at their intersections exhibit certain rather definite age relations. In the folio ·legends these groups are 

designated "early n1onzon,ite porphyry" (76 dikes), "early lamprophyre" (10 dikes), "late 

monzonite porphyry" (13 dikes), "late lamprophyre" (88 dikes), and "basalt" (34 dikes). 

The monzonite porphyries carry both ·plagioclase and alkali feldspar in large amount. In 

the earlier group the mafic constituent$ are augite and brown hornblende, while in the later 

group these ~ninerals ·are less prominent than biotite. Quartz is present in. the groundmass of 

some of the later porphyries. 

The lan1prophyres exhibit great variety in composition. both as to feldspars and as to 

mafic silicates. 'rhey range "from a near approach to the syenites, at one extremity, through 

the hornblende vogesites and monzonites, to the camptonitic varieties, at the other." · A 

basic variety of the earlier group, ''containing but little hornblende, shows an abundance of 

biotite, with more or less augite and olivine as phenocrysts, and magnetite in the groundmass." 

Some of the later lmnprophyres are ophitic in fabric. , 

Under "basalt" I-Iills groups various rock types, some of which he says are nearly related 

to certain lamprophyres through abundance of hornblende ana biotite and the presence of 

alkali feldspar. There are, however, some ''normal basalts," which constitute the only exceptions to "the general statement that alkali feldspars in varying proportions range through the 

Spanish Peaks rocks from one end to the other." No minette is mentioned by Hills as occurring in either one of the quadrangles surveyed by him. It is evident that the Spanish Peaks 

area is a rich field for detailed petrographic "\vork. 

DISCUSSION OF.RESULTS. 

It is clear that the chemical and mineral characters of the Apishapa dike rocks illustrate 

son1e of the n1ost puzzling and important problems of petrology. But while this is true, the 

great complex of associated rocks at and about the Spanish Peaks must be thoroug"bly studied, 
30 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

with adeq~ate chemical analyses of many types, before the significance of the facts observed in· 

this small number of rocks can be fully appreciated. 

The Apishap~ rocks have a considerable range in chemical composition,. but very n1uch less 

than is exhibited in the great series to which they belong. Those analyzed are all low in silica, 

but vary as to their bases from the potash-rich minette to a basalt with soda strongly dominant 

over potash. Lime and magnesia are very prominent, and titanic acid appears to be one of 

the notable chemical.features. · · 

The mafic silicates, augite and olivine, are abundant in nearly all the rock varieties; biotite 

is also common and is the leading constituent in the minette, and brown hornblende is strongly 

developea in several types.- Of the felsic silicates alkali feldspar is characteristic of the greater 

number of the rocks and plagioclase is quantitatively important ~n relatively few. 

The modal development of the rocks requires most of them to be classified in the current 

system >as alkali feldspar rocks. The vogesites are soda-rich, and .so apparently are the diabasic types. Even in some of the basalts alkali feldspar is abnormally developed. The persistence of alkali feldspars is probably the most notable. modal feature of the whole series of 

intrusive rocks about the Spanish Peaks. 

The prominence of the alkali feldspars must undoubtedly lead petrographers accustomed 

to refer all igneous rocks to either an alkalic or a calcic series to assign these rocks to the former 

category. But even the small group in the Apishapa quadrangle has some basalts with little 

alkali feldspar, and it seems altogether probable that the series ranges in fact from alkali-rfch 

rocks to those of normal basaltic character-that is, to rocks which are intrinsically equivalent 

to 'typical basalts of the calcic, subalkalic or "Pacific series." As has been pointed out in the 

preceding pages, there has been some prevalent condition in the Apishapa region which has 

brought the alkali feldspars into great prominence and obscured for most rocks their potential 

anorthite. It is true of many rocks of the Apishapa quadrangle, ·and presumably also of the 

large series ,about the Spanish Peaks, that they are not so strongly alkali-rich rocks as they 

seem to be from their mode. -

This brings us to the _problems of greatest general and theoretical interest presented by 

the rocks under discussion. It has been shown that the nearest known chemical analogues of 

the vogesites and the associated b~salt are for the most part rocks of notably different modes. 

This is most striking in the case of the olivine-b'earing augite vogesite. These rocks emphasiz~ 

anew the fact that for magmas of intermediate-chemical composition, containing all the common 

bases in considerable quantities, there is a great possible range in the minerals which·may develop 

on crystallization. Aside from the evident probl~ms of classification under these circumstances, 

there is the more fundamental question as to the genetic significance of the observed relations. 

Are these facts capable of interpretation as expressing other defillite n~tural relations, if not a 

dependence of mineral upon chemical characters~ Are the several mineral combinations possible 

from such magmas as those of the Apishapa district due to conditions attending their differentiation in various regions, or are they due to variable conditions of consolidation, or to both~ 

For the Apishapa rocks the point of most critical interest relates to the .conditions that 

prevented normative anorthite fron1 en~ering into plagioclase, as it more commonly does in 

rocks of similar chemical composition, and to the place at which these conditions were effective. 

In the olivine-bearing augi~e vogesite 13 per cent of normative anorthite has been taken into 

other minerals, most of it going undoubtedly into augite. Such entrance of anorthite molecule 

'into augite is common enough, but the conditions under which it takes place are not yet determined. 

In his study of the variation in mineral composition of the rocks of Y ogo Peak, Pirsson 1 shows 

that in a series of rocks ranging from granite porphyry to shonkinite, lime and alumina ente.r 

into augite apparently in proportion as magnesia acquires a molecular dominance over lime in 

the magmas. In a shonkinite, with 9.2 per cent MgO and 9.7 per cent CaO, there is but 10 per 

cent of plagioclase to 35 per cent of aluminous augite. 

l Pirsson, L. V., chapter on petrography in Geology of the Little Belt Mountains, Montana, by W. H. Weed: U.S .. Geol. Survey 'l'wentieth 

Ann. Rept., pt. 3, p. 567, 1900. 
DIKE ROCK~ OF THE APISHAPA QUADRANGLE, COLORADO. 31 

Such a control by n1agnesia does not exist in the Apishapa rocks, for it is in the olivineaugite vogesite with lowest actual and relative magnesia that the anorthite is entirely suppressed and in the basalt with highest actual and relative contents in magnesia that plagioclase 

is n1ost abundant. Nor is it a question of the amount of normative anorthite, for the hornblende-augite vogesite, with 16.40 anorthite, has little plagioclase,. while 'the plagioclase basalt 

has but 14.18 anorthite, only 1 per cent more than appears in the norm of the plagioclase-free 

vogesite. · 

Ignoring the disturbing effect of assimilation of 'foreign substances and assuming that the 

fonnation of a series of magn1atic differentiates in a given region is a result of certain forces, 

known or unknown, characteristic of that region, we n1ust also recognize that in the course of 

eruptio'n and crystallization these magmas come under the influence of pressure and temperature 

differing fr01n those of the site of deep-seated differentiation, causing more or less pronounced 

reactions. When we consider also the possibilities of the absorption by the magma of various 

potent substances while passing from one place to another, it seems scarcely overdrawn to say 

that a magmatic solution may become the plaything of conditions quite unrelated to those of 

the place of its origin, that these independent conditions may vary in one district from time to 

time, and that they surely must vary from one province to another, when magmas of the same 

chen1ical composition are involved. 

, When a large series of eruptions or intrusions of various differentiates has occurred in one 

province it is conceivable that the conditions attendant on consolidation, though independent 

of those regulating differentiation, may have been so constant as to permit the development 

of son1e highly characteristic mineral features of the rock series. But the fact that conditions 

of crystallization may vary in one region during a long series of eruptions and are not the 

smne, unless by fortuitous coincidence, in different regions where the magmas nlay have been 

sin1ilar must lead to caution in extending over the whole world the generalizations that apply 

to one area. 
) 
THE COMPOSITION OF CRINOID SKELETONS. 

By F. W. CLARKE and W. C. WHEELER. 

INTRODUCTION. 

That many rocks, now raised far above sea level, were once marine sediments and that living organisms contributed to their formation are among the .con1monplaces of geology. It is 

also lmown that radiolarians, diatoms, and sponges form siliceous deposits; that c~lcareous 

rocks are derived in part from corals and mollusks; and that crustacean and vertebrate remains 

are largely phosphatic. These facts are established in a broad, general way, but they need to 

be studied in greater detail, so that the function of each class of.organisms may be more exactly 

known. An investigation of this kind is reported in the following pages. The special problem 

covered by it was suggested by·:Mr. Austin H. Clark, of the United States National :Museum, who 

furnished tho specimens for analysis. · 

EXISTING CRINOIDS. 

In 1906 I-I. W. Nichols 1 published a number of analyses of marine invertebrates, and in 

one of them, a crinoid; J1etacrinus rotu11dus, from Japan, he found 11.72 per cent ofmagnesium 

carbonate. Tills analysis attracted :Mr. Clark's attention, and at his request two other analyses 

·of crinoids were made in tho l.aboratory of the United States Geological Survey by Chase Palmer, 

who nlso found that they contained abundant magnesia. These analyses, which were published 

and discussed by :Mr. Clark,2 will be considered in detail later. They at once suggested that 

crinoids generally might be highly magl'l:esian and so play an important part in the formation of 

1nagnesian lin.1estones. 

In order to settle this .question :Mr. Clark supplied us with 22 specimens of recent crinoids, 

representing 19 genera and covering a wide range of localities. These were analyzed by :Mr. 

Wheeler, and the analyses confirmed the original supposition. All the specimens contained 

magnesium carbonate in notable proportions but varying in a most remarkable manner. The 

data obtained are in detail as follows, beginning with the list of the specimen~ studied: 

1. Ptiloc1·imts pinnatus (A. H. Clark). Albatross station 3342, off the Queen Charlotte Islands, British Columbia. 

Latitude 52° 391 3011 N ., longitude 132° 381 W. Depth of water, 2,858 meters; temperature, 1.83° C. Mean of two 

analyses. 

2. Floronwtra asperrim,a (Clark). Albatross station 3070, off the coast of Washington. Latitude 47° 291 30// N ., 

longitude 125° 43' W. Depth, 1,145 meters; temperature, 3.28° C. . 

3. Psathyrometrafragilis (Clark). Albatross station 5032, Yezo Strait, Japan. Latitude 44° 051 N., longitude 145° 

30' E. Depth, 540-959 meters; temperature, 1.61° C. 

4. Pentametrocrinus japonicus (P. H. Carpenter). Albatross station 5083, 34.5 miles offOmai Saki Light, Japan. 

Ln.titude 34° 04' 2011 N., longitude 137° 571 30// E. Depth, 1,123 meters; temperature, 3.39° C. 

5. Ca]Jillaster multiradiata (Linne). Albatross station 5137, Philippine Islands near Jolo, 1.3 miles from Jolo Light. 

Latitude 6° 041 2511 N., longitude 120° 58' 3011 E. Depth, 36 meters; no temperature record. 

6 . .Pachylometra patula (Carpenter). Albatross station 5036, Philippine Islands, North Balabac. Strait, 15.5 miles 

frotn Balabac Light. Latitude 8° 061 4011 N., longitude 117° 18' 4511 E. Depth, 104 meters; no temperature record. 

7. Catoptontetra ophiura (Clark). Same locality as No.6. 

1 Field Columbian Mus. Ptl'). 111, p. 31. 2 U. S. Nat. Mus. Proc., vol. 39, p, 487, 1911. 

33 
34 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914: 

8. Hypalocrinus naresianus (Carpenter). Albatross station·5424, Philippine Islands, 3.4 miles off Cagayan Island, 

Jolo Sea. Latitude 9° 371 0511 N ., longitude 121° 12' 3711 E. Depth, 612 meters; temperature 10.22° C. 

9. Parametra granulata (Clark). Albatross station. 5536, Philippine Islands, between Negros and Siquijor, 11.8 

miles from Apo Island. Latitude 9° 15' 4511 N., longitude 123° 22' E. Depth, 502 meters; temperature, 11.95° C. 

10. Craspedometra anceps (Carpenter). Albatross station 5157, 3.3 miles from Tinakta Island, Tawi Tawi group, 

Sulu Archipelago. Latitude 5.0 12' 3011 N., longitude 119° 55' 5011 E. Depth, 32 meters; no temperature record. 

11. Ptilometra mulleri (Clark). Sydney Harbor, New South Wales, Australia. Latitude 33° 15' S., longitude 

151° 12' E., approximately. 

12. Hathrometra dentata (Say). 'Fish Hawk station 1033, off Marthas Vineyard, Mass. Latitude 39° 56' N ., longitude 69° 241 W. Depth, 329 meters; temperature about 7.8° C. · 

13. Bythocrinus robustus (Clark). Albatross station 2401, Gulf of Mexico, southeast of Pensacola. Latitude 28° 

38' 3011 N ., longitude 85° 52' 3011 W. Depth, 255 meters; no temperature record. 

14. Crinometra concinna (Clark). Albatross station. 2324, north of Cuba. Latitude 23° 10' 3511 N ., longitude 

82° 201 2411 W .. Depth, 59 meters; temperature, 26.17° C. 

- 15. ISocrinus decorus (Wyville Thomson), stem. Off Habana, Cuba, Latitude 24° N ., longitude 82° W., approximately. 

16. Same as No. 15, arms. 

17. Endoxocrinus parrc.e (Gervais), stem. Off Habana. 

18. Same as No. 17, arms. 

19. Tropiometra picta (Gay). Rio d~ Janeiro, Brazil. Latitude, 25° 54'S., longitude, 44° W., approximately. 

20. Promachocrinus kerguelensis (Carpenter). Shores of the Antarctic Continent in the vicinity of Gaussberg. 

Latitude 67° S., longitude 90° E., approximately. Depth, 350-400 meters; temperature, -1.85 ° C. Salinity of water, 

3.3 per cent. 

21. Anthometra adriani (Bell). Same locality as No. 20. Nos. 20 and 21 were collected by the German South Polar 

Expedition. 

In the following table the actual analyses are given. The symbol ''R20 3 " represents the 

sum of ferric oxide and alumina, and' 'Loss on ignition" covers carbon dioxide, water, and organic 

matter, the last being often very high. At the"foot of each column th~ 002 calculated to satisfy 

the bases is given. The de:fici(:mcies in summation are mainly due to inclosed or adherent salt, 

an inevitable impurity, as was proved in the analyses of two samples, Nos. 15 and 17.1 Analysis 

No. 1 is the mean of two concordant analyses of separate samples. 

Analyses of crinoids. 

2 6 8 9 10 11 

--------------------------- Si02 .......................... 1. 64 0.04 1.11 0.37 0.16 0.12 0.04 0.07 0.40 0.15 0.17 R20a .......................... 1. 07 .39 1. 01 .71 .62 .63 . 79 .09 .50 .19 .19 

MgO ....................... -... 3.08 3.60 3.12 3. 76 4. 77 4.94 4.64 4.44 4.48 5.13 4.17 CaO .......................... 40.65 40.37 34.20 38.50 38.12 41.34 40.75 45.86 41.79 42.77 38.91 

P2o ........................... .11 .21 Trace? .40 Trace. .43 . 33 Trace. Trace . .11 .17 Loss on ignition ............... 51.45 53.75 60.04 55.25 54.61 51.36 51.80 48.32 51.44 50.28 54.61 --------- --------------------- 98.00 98.36 99.48 98.99 98.28 98.82 98.35 98.78 98.61 . 98.6.'3 98.22 

C02 needed ......... · .......... 35.23 35.48 31.37 34.01 35.19 37.51 36.81 41.27 37.77 39.17 34.90 

12 13 14 15 16 17 18 19 20 21 

------------------------ ~--

Si02···----····--··············'···---- 3.17 0.40 0.04 0.03 0.09 0.04 0.15 0.02 0.02 0.23 R20a .................................... .31 .31 .25 .07 .19 .20 .26 .35 .45 .37 

~r.;g_-_-.-.-.-.-.-:~::::::::::::::::::::::::::: 2.49 4.56 4. 75 5.08 4. 70 5.09 5.04 4.51 3.02 3.27 26.12 47.08 41.78 45.67 42.77 45.42 43.41 39.57 40.68 42.49 

i~~;oi; ii~it-ion:.-.-.-_·:: :::::::::::::::::: . 23 Trace. Trace. Trace . Trace? Trace. Trace. . 10 Trace. Trace . 65.25 47.17 50.33 47.54 50.59 48.58 50.00 53.64 54.53 52.22 ------------------------------ C02needed .................... .' ......... 97.57 99.52 97.15 98.39 98.34 99.33 98.86 98.19 98.70 98.58 22.73 41.93 38.00 40.40 38.71 41.29 39.65 36.05 35.18 37.08 

In order to make these- analyses n1ore instructive it is necessary to recalculate them into 

such form as to show the composition of the true crinoid skeleton-that is, to eliminate the 

highly variable organic matter of the original specimens. On doing this and recalculating to 

100 per cent, 'Ye find that they assume the following form: · 

1 No. 15 contains 1.27 per cent of water-soluble salts and No. 17 contains 0.21 per cent. These raise the summations to 99.66 and 99.54 per cent, 

respectively. 
THE COMPOSITION OF CRINOID SKELETONS. 35 

Revised analyses of crinoids. 

8 10 11 

·--------------------------------- 810~ .••........................ 2. 01 0.05 1. 57 0.48 o. 21 0.14 0.05 0.08 o. 47 o. 24 0. 21 :R20o .......................... 1. 31 . 48 1. 41 . 91 . 78 . 74 .95 .10 .59 .22 .24 ?.{~COa .•...................... 7. 91 9.44 9. 25 10.15 12.69 12.20 11.68 10.16 11.08 12.34 11.13 CnCOo ...••.................... 88.48 89.45 87.77 87.34 86.32 85.81 86.46 89.66 87.86 86.93 87.94 

CO:JP,Oa ....................... .29 ' .58 Trace? 1.12 Trace. 1.11 .86 Trace. 'I' race. . 27 .48 

----------------------------------- 100.00 100.\JO 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

12 13 14 15 16 17 18 19 20 21 

-------------l----1~-----------~--------------

8102·················: ................... 5. 73 0.42 0.05 0.03 0.10 0.04 0.17 0.02 0.02 0.28 n20a .................................... .56 .33 .30 .08 . 21 . 21 . 29 .43 .57 .44 }.{~COo ..•............................... !1.36 10.09 11.69 11.69 11.42 11.62 11.96 11.77 7.86 8.23 Co.COo ............................. · ...... 83.47 89.16 87.96 88.20 88.27 88.13 87.58 87.51 91.55 91.05 Co P~Os ................................. . 88 Trace. Trace. Trace. Trace? Trace. Trace . . 27 Trace. Trace . 

------------------------------ 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

With these analyses the two n1ade by Mr. Palmer ·may. be advantageously compared, 

although they were not quite so elaborate. The data are as follows: 

22. I:lelio~wtra glapialis var. maxima. Iwanai Bay, northeastern part of the Sea of Japan, latitude 43° 01' 4011 N. 

Depth, 315 meters; temperature, surface 20.5° C., bottom 1.5° C. . 

23. },{etacrinus rotundus. Eastern Sea, off Kagoshima Gulf, southern Japan, latitude 30° 58' 30" N. Depth, 

278 meters; temperature, surface 27.8° C., bottom 13.3° C. 

In No. 22, which contained much organic matter, Mr. Palmer found 2.68 per cent MgO 

( = 5.61 l\1g003 ) and. 40.03 CaO ( = 71.48 Ca003). InN o. 23, with no organic matter, he found 

4.89 l\1g0 ( = 10.29 :Mg003 ) and 49.95 CaO ( = 89.19 CaC03 ). Assuming that the crinoid skeletons consist essentially of carbonates, and recalculating to 100 per ·cent, we have as the content 

of 1nagnesiun1 carbonate in these crinoidsNo. 22, 7.28 per cent. 

No. 23, 10.34 per cent. 

These figures fit in well with the others and even by themselves suggest a relation between 

tmnperature and the magnesia content of crinoids. In the following table the entire series is 

arranged in the order of ascending Mg003 , with the accessory data as to latitude and locality 

conveniently abbreviated. In this table the two analyses of Endoxocrinus are averaged together, 

and so also are the two of Isocrinus. 

No. 

22 

20 

1 

21 

3 

12 

2 

13 

4 

8 

23. 

9 

11 

15, 16 

7 

14 

19 

17,·1g 

6 

10 

5 

Magnesium carbonate in crinoid skeletons. 

Locality. 

Northern Japan ....................................... . Antarctic ..... ~ ....................................... . British Coltimbia ...................................... . Antarctic ........... ·' ................................. . 

~~~!~~h~:~~:~~: .·. ·_ ~: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : ~ : : ~~f~l~f ~i~~i~~--- .-::::: : :: : : :: :: : :: : : : : : :::::: ::::::: :::: 

!~~~~~-~~:;::··::::::::::::::::::::::::::::::::::::: Cuba ................................................. . 

~~~~!~~~}~~~--:::::::::::::::::::::: ·:::::::::::::::::: :): : 

Brazil. ................................................ . Cuba ................................................. . 

. ~~~i~~~~l~~~:. ·_ ·.:::: .- _·. ·. ·_:: : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 

..... do ................................................ . 

Latitude. 

43° N ........ . 67° S .......... . 52° 39' N ...... . 67° S ......... .. 44°N ........ . 39° 56' N ...... . 47°29'N ...... . 28° 38' N ..... .. 34° N ........ . 9° 37' N ....... . 30° 58' N ...... . 9°l5'N ...... .. 33° 15' S ...... . 24° N ........ . go N ......... . 23° 10' N ...... . 25° 54'S ...... . 24° N ........ . go N ........ .. 

5° 12' N ....... . 6° N ......... . 

Depth 

(meters). 

315 

375 

2,g58 

375 

(?) 

329 

1,145 

255 

1,123 

612 

27g 

502 

~H 104 

59 

H~ 104 

32 

36 

Temperature (°C.). 

1.5 

-1.8 

l. 8 

-J..g 

1. 6 

7.8 

3.3 

(?) 

3.4 

10.2 

13. 3 

12 

m 

26.2 

?) 

H 

H 

Percent 

MgCOa. 

7.28 

7.g6 

7.91 

g,23 

9.25 

9.36 

9.44 

10.09 

10.15 

10. 16 

10.34 

11.08 

11. 13 

11.56 

11.68 

11. 69 

11. 77 

ll. 79 

12.20 

12. 34 

12. 69 
36 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

From the foregoing table it is perfectly clear that the proportion of magnesium carbonate 

in crinoids is in some way dependent on temperature. ~Temperature, however, is not entirely 

dependent on latitude. Depth of water has also a distinct influence. The crinoids from relatively shallow depths in the Tropics are highest in -their magnesian content; those from the 

Antarctic and the far north are lowest. The proportion given for No. 12, from the coast of 

Massachusetts, is probably too low, for the speoimen as analyzed contained over 6 per cent of 

silica and sesquioxides-evident impurities, due to adherent mud from which the delicate structure could not be wholly freed. If these are rejected, the Mg003 is raised from 9.36 to 10 per 

cent, which gives the crinoid a better and more probable rating. 

So far as we are aware such a peeuliar relation between temperature and composition as 

is here recorded has not been previously observed. To recognize it is one thing; to account 

for it is not so easy. At first we supposed that it might possibly be due to a difference in the 

form of the more abundant carbonate-the less stable aragonite in the warm-water forms and 

calcite in the crinoids from colder regions. But tests by Meigen's rea,ction proved that the 

organisms were all calcitic, and so this supposition had to be abandoned. 

Mr. A. H. Clark, who is an authority on the crinoids, has stated to us that they are exceptionally we.1l suited to a study of the kind recorded here, ''for the skeleton is always entirely 

internal and :rrotected from the surrounding water by living tissue; so that whatever alteration it may undergo after its original deposition can not be influenced by the water in which 

it lives." He has also pointed out that the crinoids from warm regions have the most compact skeletons; the .compactness being in general proportional to the temperature and also to 

some extent dependent upon the size of the individual. Heliometra, for example, is the largest 

of the crinoids, its skeleton is one of the least compact, and its magnesian content is lowest 

among all the species examined. ·Structure as well as temperature seems to be correlated with 

the proportion of magnesia in the crinoids, but the chemical explanation of the facts is yet to 

be found. 

Only one other group of marine organisms, so far as is now definitely known, is conspicuous for its relative richness in magnesium carbonate, namely, the calcareous aJgre, as 

shown in an.investigation by Hogbom.1 In 11 analyses of algre belonging to the genus Lithothamnium he found magnesium carbonate in proportions varying from 3.76 to 13.19 per cent. 

No temperature relation, however, appeared in his series of analyses. The highest figure was 

obtained in a spec~en from the Arctic Ocean, the next highest in one from Bermuda, and the 

lowest in one from the Java Sea. Three analyses of fossil algre gave even lower magnesia than 

. was found .in the living forms. The average proportion was near that found among the crinoids. 

It is highly desirable that both groups of organisms should be studied more completely and 

with every precaution against error. Crinoids from European, especially Mediterranean waters, 

from the coasts of Africa and South America, and from the Indian Ocean might be analyzed 

to much ·advantage. One caution, however, is needed: only alcoholic material should be used. 

Specin1ens preserved in formalin, which tends to become acid, are of doubtful value in a research· 

of this kind. All the crinoids studied in the present investigation had been preserved in 

alcohol. 

FOSSIL CRINOIDS. 

In order to make this investigation n1ore systematic it seemed desirable to analyze a 

number of fossil crinoids, so as to determine whether any definite and regular changes could 

be traced in passing from the recent to the ancient organisms. · For the material studied we 

are indebted to the kindness of Mr. Frank Springer, who selected the material with great care 

so as to cover a range of horizons fro1n the Lower Ordovician up to the Eocene. The 10 crinoids 

chosen are described in the list on page 37, and the analyses which follow were made in the 

same way as those of the 1nodern sp.ecies . 

. f Neues Jahrb., 1894, vol. 1, p. 262. 
' 

THE COMPOSITION OF CRINOID SKELE'FONS. 37 

l. Pcntacrinus. dccadactylus (D'Orbigny), stem. Eocene, Vincenza, Italy. 

2. :Afillcricrinus mcspiliformis (Goldfuss), stem. Upper Jurassic, Kelheim, Bavaria. 

3. Pcntacrinus basaltifonnis (Miller), stem. Middle Lias (Lower Jurassic), Breitenbach, 'Vurttemberg, Germany. 

4. Encrinus l·iliiformis (Lamarck), stem. Tl"iassic, Braunschweig, Germany. 

5. Graphiocrinus nwgniflcus (Miller and Gurley), complete crown. Pennsylvanian (upper Carboniferous), Kansas 

.City, :Mo. 

6. Dorycrinus unicornis (Owen and Shumard), calyx and stem. Lower part of Burlington limestone, Mississippian 

(lower Carboniferous), Burlington, Iowa. 

7. Megistocrinus nodosus (Barris), plates. Middle Devonian, Alpena, Mich. 

8. Eucaly]Jtocrinus crassus, plates. Silurian, western Tennessee .. 

9. Crinoid sp. ?, stem. Trenton limestone, Middle Ordovician, Kirkfield, .Canada. 

10. Diaboloct-inus vesperalis~(White), plates and stem. Lower Ordovician, Tennessee. 

Analyses of fossil crinoids. 

2 3 4 6 8 9 

-------------1------------------------------

8102····································· 0. 99 2. 84 1. 55 0. 24 3. 07 6. 92 10. 39 29.11 2. 56 4. 17 H.20a ................................... . 2. 64 . 28 2. 59 . 43 2.18 . 64 . 87 1. 73 . 31 1. 95 

]?cO .................................... . 1. 36 None. None. 1. 32 None. 1. 19 . 27 None. . 88 

1\fnO ................................... . .13 None. Trace. . 15 Trace. · .16 . 04 Trace. . 04 . 78 . 38 . 84 9. 44 . 78 . 38 1. 21 . 58 . 91 . 79 ~~3::::::::::::::::::::::::::::::::::::: 51. 22 53. 68 51. 78 43. 40 50.10 51. 20 46. 57 37. 43 53. 87 50. 42 P200 •••••••••••••••••••••••••••••••• •••••• None. Trace. . 09 Trace. Trace. Trace. Trace. None. Trace. Trace. 

]~OSSOilignit.ion ......................... ~~~~~~~~~~~ 

99.92 100.11 100, 06 99. 46 99. 321 100.14 99. 59 99. 87 100.10 I 99. 68 

Revised analyses of fossil crinoids. 

2 3 4 6 8 9 10 

------------------ SlOg ..................................... 1.00 2.85 1. 57 0.24 3.11 6.94 10.48 29.30 2.55 4.10 It20s .................................... 2.66 .28 2.64 .44 2.22 .64 .88 1. 74 .30 1. 97 ]?cCOa ..................... --- ... · · · · · · · · 2.21 None. None. 2.16 None. 1. 94 .43 None. 1. 42 1\fnCOs .................................. . 21 None. Trace. .24 Trace. .26 • 06 Trace . .06 

~~3ga_._::::::::::::::::::::::::::::::::: 1. 66 .so 1. 79 20.23 1. 66 .so 2.56 1.23 1. 90 1.67 '92.26 96.07 93.80 79.09 90.61 91.62 83.88 67.24 95.25 90.78 

CoaP20a ................................. None. Trace. . 20 Trace. Trace. Trace . Trace. None. Trace. Trace. 

100. 00 100. 00 100. 00 100. 00 100. 00 100. 00 100. 00 100. 00 100. 00 100.00 

In some respects these analyses are unsatisfactory, for they show no regularities of any 

ku1.d. In only one of then1, No. 4, is there exhibited a concentration of magnesium carbonate; 

in the others the percentage of this constituent is very low. The reason for this falling off of 

Inag)lesia is by no means clear. It is conceivable that the ancient crinoids may have been 

deficient in n1agnesia, but it is .more probable that the loss is due to alteration, perhaps to the 

:infiltration of calcium carbonate. Such a change would obviously lower the apparent proportion of magnesium carbonate. Several of the crinoids contain noteworthy quantities of 

ferrous carbonate and manganese-constituents which did not appear in the analyses of the 

1noclern species. In No. 8 there is a very strong silicification, 29.11 per cent; but the matrix 

of the specimen contained only 7.55 per cent of silica. I-Iere again the infiltration of the impurity 

semns to be very clear. Son1e of the deficiencies in 1nagnesia may have been caused by solution 

and leaching, but calciun1 carbonate should then have been ren1oved to a greater extent. In 

short, the fossil crinoids differ widely in composition fron1 the still living species, and in a very 

irregular manner, and it is worth noting that in three analyses of fossil algre reported by Hogbom 1 

a similar falling off of magnesia appears. It would be easy to speculate on the significance 

of these differences, but the conclusions so reached would not be entitled to n1uch weight. That 

the recent crinoids are distinctly magnesian and that the proportion of n1agnesia is dependent 

in so1ne way on temperature are the two pqsitive results of this investigation. 

1 Loc.cit. 

CON'I'RIBlTTIONS TO THE STRATIGRAPHY OF SOUTH,VESTERN 

COLORADO. 

By WHITMAN CRoss and EsPER S. LARSEN. 1 

INTRODUCTION. 

In the course of field work of the United States Geological Survey in the San Juan region 

of Colorado observations have been made in the last three seasons that considerably extend our 

knowledge of the great stratigraphic break below the La Plata sandstone, which is currently 

assumed to be of Jurassic age. The new data pertain partly to the relations existing in the 

Gunnison Valley, north of the San Juan Mountains, where the'unconfor1nity n1arking this break 

was already known at certain places, and partly to the ~onditions in the Piedra Valley, on the 

south side of the mountain.'3, where the unconforn1ity had not before been noted. The Piedra 

Valley is of special interest, and it seems well to call attention to the relations observed even 

though they were examined only in a reconnaissance. The first part of this paper is devoted 

to the evidence of the overlap of the La Plata sandstone; the second to the stratigraphic relations 

in the Piedra Valley. 

The section of sedimentary formations in Piedra Canyon is of much interest because none 

of the pre-La Plata formations are known east of this locality on the south side of the San Juan 

Mountains. Most of these formations exhibit a notably different facies where they reappear 

from beneath the overlying beds at their nearest exposures in New Mexico, southeast of the 

Piedra Valley. It is believed that the character of the formations in the Piedra section should 

be recorded for the benefit of geologists who may be studying the Paleozoic and Mesozoic rocks 

of New Mexico, and accordingly the second part of the paper presents details of the structure 

and the stratig~·aphic section of,Piedra Valley. 

THE STitATIGRAPHIC BREAK BELOW THE LA PLATA SANDSTONE. 

GENERAL RESULTS OF THE HAYDEN SURVEY. 

The I-Iayden Geological Survey established the existence of great stratigraphic breaks in 

the central and western n1ountain regions of Colorado below both Triassic and Jurassic formations, and a corresponding overlap is also represented on the Hayden n1ap of western Colorado 

as occurring at the base of the Dakota Cretaceous. The map represents this break as being 

particularly prominent along the Gunnison Canyon, between the town of Gunnison and Vernal 

Mesa. The shales of Colorado age, belonging to the formation now distinguished in western 

Colorado as the Mancos shale, are also represented as overlying .the pre-Can1brian rocks east of 

Gunnison, on both sides of Toinichi Creek, and as abutting against the gneisses and schists of 

Vernal Mesa in prilnary contact. 

The overlap of the·Cretaceous fonnations upon the pre-Cambrian in this region, as shown on 

the I-Iayden n1ap, is in accord with the view expressed by A. C. Peale,2 that "The Archean 

area along the northern edge of the San Juan Mountains and south of the Gunnison River 

probably fonned a shore line in Cretaceous tin1es." · · 

F. M. Endlich was the geologist who visited the area within which the "Colorado" shales 

are represented by the Ifayden map as lying on granite, in the valley of T01nichi Creek, for a 

distance of about 15 1niles above Gunnison. As we shall explain n1ore fully later on, he found 

other sediments beneath the shales of this area, which are not shown on the map. 

t ~l'ho authors wish to ucknowlodgo tho otnciont assistance of J. Fred Hunter in the field work on which this paper is bused. 

21]\. S. Gool. ancl Goog. Survey 'L'orr. Ann. Ropt. for 1875, p. G9, 1877. 

39 
40 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The contact of Cretaceous shales and pre-Cambrian rocks on Verna] l\1esa, thought by 

Peale 1 to be of. primary origin, is now known to be a fault contact in a zone of cornplex folding 

andfraoturing, the details of which have been shown by the tunnel of the Uncon1pahgre irrigation 

project. 

THE OVERLAP IN THE GUNNISON VALLEY. 

The assumed overlap of the Dakota sandstone in the Gunnison V a1ley is unquestionably 

explained by the fact that Peale and other Hayden Survey geologists included in the Dakota 

several hundred feet of beds that belong in the Gunnison formation. (Jurassic n of Eldridge, 

embracing equivalents of the McELmo and La Plata formations of the San Juan region, a fact 

clearly sliown by Peale's section of the assumed Dakota occurring in Gunnison Canyon about a 

mile above Sapinero. 2 Th:ls section embraces 536 feet of strata, which. are described as predominantly sandstone, with some shaly beds and thin 'limestones. The upper n1mnber of 

Peale's section, 100 feet thick and described as "massive yellow siliceous sandstone," is all that, 

in our opinion, belongs in the Dakota. In mapping the Uncompahgre quadrangle we have 

examined this and many other sections of the Gunnison Canyon, and we assign to the Dakota a 

thickness of about 100 feet. It has the character common to it over large areas of western 

Colorado, which have been examined by several parties of the Geological Survey in 1:ecent years. 

A thin remnant of Mancos shale in som~ places lies between the Dakota and overlying volcanic 

rocks. 

The beds beneath the Dakota sandstone in the Gunnison Valley are largely sandy, as 

Peale has stated, but shaly beds of red, lilac, green, or yellowish colors are in ·many places well 

developed between the sandstones. At its base the sandstone is thicker and more n1assive, 

and this portion undoubtedly corresponds to the La Plata sandstone, as distinguished in the 

San Juan Mountains area and the adjacent portions of the plateau country to the west. The 

La Plata is also well developed in the Uncompahgre Plateau and the Uncompahgre Valley. 

In the wild lower canyon of the Gunnison, betwem1 Cimarron Creek and Smiths Fork, the 

Hayden map represents a thin Jurassic formation as appearing between the Dakota sandstone 

and the gneisses and schists, but farther down the canyon a thin Triassic formation appears in 

similar manner between the Jurassic and the crystalline rocks. This makes the section of the 

lower Gunnison Canyon correspond with that of the eastern flanks of the Uncompahgre Plateau, 

30 miles to the west. But though Peale 3 refers to his Jurassic forrnation as appearing beneath 

the Dakota at· a certain point and thickening toward the north, he was unable to examine the 

section in detail, and l.t seems reasonable to assume that if these beds are Jurassic they belong 

in the Gunnison formation with the greater part of the section above them, included by Pettle · 

in the Dakota. They may illustrate the progressive overlap of succeeding beds of the Gunnison 

on an uneven floor of crystalline rocks. . 

The age of the supposed Triassic. rocks ~f the lower Gunnison Canyon :bas not been determined by fossils or by close lithologic correlation with known Triassic rocks of similar position 

in the Uncompahgre Plateau, and it must be remembered that Eldridge found that the Gunnison formation in the southern Elk Mountains (=La Plata+McElmo) rests unconformably 

on red strata of the 1\iaroon conglomerate (Carboniferous), 4 and in the Uncompahgre Valley 

below Ouray both Triassic and Permian ( ~) beds occur between the La Plata and the Carboniferous.5 

Coming now to new data bearing on the character of the great overlap shown in the 

Gunnison Valley, we may say that our observations during the last few years have denlonstrated the presence. of ·the Gunnison formation between the Dakota and the pre-Cambrian all 

along the Gunnison Canyon and also in the valley of Cebolla Creek, the southern tributary of 

the Gunnison called "White Earth River" on the Hayden map. During the survey of the 

Uncompahgre quadrangle in 1911 it was found that the lower men1ber of that formation, now 

1 U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1874, p. 132 and Pl. VII; fig. 2, facing p. 97, 1876. 

2U. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1874, p. 131, 1876. The section is referred to as "beneath station 73"; the location is 

shown on the map facing p. 170 and the profile in fig. 1, Pl. XIV, facing p. 169. ' 

aU. S. Geol. and Geog. Survey Terr. Ann. Rept. for 1874, p. 126, 1876. 

4 U.S. Geol. Survey Geol. Atlas, Anthracite-Crested Butte folio (No.9), 1894. 

6 Idem, Ouray folio (No. 153), 1907. 

' . 
STRATIGRAPHY OF SOUTHWESTERN COLORADO. 41 

cuJJed the La Plata sandstone, extends for 16 miles up the ridge east of the Cebolla, overlying 

a variety of pre-Ca~nbrian rocks. In some places the :McElmo beds are preserved above it; 

in a few others there are also rmnnants of the Dakota sandstone. Tertiary volcanic rocks overlie 

all these sedin1e.nts. 

]~ast of Cebolla Creek the Gunnison beds probably exterid continuously underneath the 

volcanic rocks to the valley of Cochetopa Creek. They are exposed north of Agency Peak and 

on the ridge west of the Cochetopa, where the Hayden map represents the volcanic rocks. 

About 12 1niles south of Tomichi Creek the Gunnison beds cross the Cochetopa and pass under 

the Dakota sandstone on its eastern bank, in the area where the Hayden map represents Colorado 

shales as resting on granite. , The shales occur in this region but are restricted to the higher 

country several miles south of the Tomichi. 

In Ritzor Creek valley, next east of the Cochetopa, nearly 1,000 feet of :Mancos shale is 

locnlly preserved beneath the volcanic rocks. In an eastern branch of that strean1 not shown 

on the IIayden 1nap a fault brings up the Dakota, the Gunnison, and the underlying granite in 

a s1nall area nearly surrounded by volcanic rocks. 

In the extreme eastern part of this sedimentary area, which is traversed by Tomichi Creek, 

the Dakota and Gunnison formations are everywhere present beneath the l\1ancos shale. 

l\1oreover, these formations occupy a somewhat larger area than is assigned to· them on the 

Jiayden lnap, especially on the north and east. The bills and smooth-sloped ridges near the 

To1nichi are in most places formed of the soft McElmo strata, though rhyolitic tuff occurs 

in certain hills. The Dakota maintains its usual character and thickness, and fron~ its superior ii1duration it is everywhere the most prominent of these formations. On the northwest 

slope of Ton1icbi Don1e it has a measured thickness of 80 feet. 

Near Tmnichi Creek some low cliffs, which appear at about the horizon where the Dakota 

n1ight be expected, are of rhyolite. The volcanic rocks rest on a very uneven surface and are 

not readily recognizable at a distance. Moreover, the sediments are gently folded, and this 

adds to the difficulty of tracing formation boundaries in reconnaissance work. 

The Gunnison formation is rarely well exposed. The lower sandstones, which in the 

western part of the area are so prominent as to suggest a correlation with the La Plata sandstone, are thin or entirely absent in the eastern part. The forn1ation here exceeds 200 feet 

in thickness in but few places. Northwest of Torriichi Dome its thickness was found to be 150 

to 17 5 feet. It consists chiefly of reddish and greenish shales, sandstone being very subordinate. 

The decided thinning of the Gunnison formation eastward suggests that it may not have 

been everywhere present beneath the Dakota in the central mountain region of Colorado. The 

change in lithologic character here noted indicates that this thinning was due to nondeposition 

of the norn1al section in the area under discussion and n.ot to unconformity caused by erosion. 

As to the structure exhibited by the Mesozoic formations in the basin of Tomichi Creek it 

is sufficient to say that for about 20 miles east of Gunnison the creek flows in a syncline, the 

strata clipping at high angles toward it from the north and south. But the limitation of the 

fonnations on the east is due to a steep upturning of the beds. The Dakota and Gunnison 

beds assu1ne westerly clips of 80° or more and are in some places overturned. On the north 

side of Ton1ichi Creek the gradual change from a low southerly dip can be observed in the area 

northeast of Tomichi Dome, but on the S<?uth side of the creek the lower beds hold their steep 

dips until they clisappear beneath the volcanic .rocks. 

In regard to the Paleozoic sedin1ei1ts, the representation on the Hayden n1ap of Tomlcbi 

Dmne as "Lower Carboniferous" is incorrect, for the dome is n1ade up of a plug of rhyolite, about 

a mile across, intruding l\1ancos shale. 1\tioreo'ver, Paleozoic sedin1ents, not shown on the 

I-Iayden 1nap, form n1ost of the basin of Indian Creek, the fork of l\1arshall Creek which enters· 

frmn the north about 4 miles southeast of the town of Sargents. The Paleozoic beds are thus 

known within 5 miles of l\1arshall Pass. About 600 feet of these beds are exposed over the preCatnbrian in this area, and the section is similar to that of Fossil Ridge, where the Carboniferous is represented on .the I-Iayden map. The beds clip about 20° S. and on the east, west, 

and south are overlain by volcanic rocks, while on the north they overlie the pre-Cambrian 

rocks. 
42 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The error of the Hayden map in representing Color~do shales on pre-Cambrian· east of 

Cochetopa Creek is perhaps entirely cartographic. It is certainly not entirely due to incorrect 

observation, for the map does not· agree with Endlich's statements concerning the distribution 

of the Cretaceous formations in' Cochetopa and Tomichi valleys, nor with his profile sections 

through this region.1 · He repeatedly refers to quartzites under the shales as probably "Lower 

Cretaceous," but they were omitted from the map prepared some years later. The name 

Dakota does not appear to have been applied to these sandstones at the time of Endlich's report. 

SAN JUAN MOUNTAINS ARE,A.. 

The representation of the Hayden map by which Triassic, Jurassic, and Dakota Cretaceous 

beds are shown t0 overlap and in turn come in contact with the pre-Cambrian in canyon branches 

of Cimarro~ Creek, north of Uncompahgre Peak, is wholly hypothetical. There are no such 

exposures in these canyons, for the volcanic rocks d~scend to the streams. Yet an overlap of 

this general character for the La Plata sandstone must exist beneath the volcanic rocks between 

the Gunnison Canyon at the mouth of Blue Creek and the Uncompahgre Valley below Ouray. 

Endlich, who was responsible for this part of the Hayden map, understood the nature of 

the overlap existing beneath the volcanic 

rocks, but drew on his imagination for the 

exposures to express it. In the Ouray 

quadrangle the La Plata is found on the 

Dolores (Triassic) formation, and beneath 

the Dolores is the cpmplete known sedimentary section of the San Juan region 

from the Cutler formation (Permian~) to 

the Ignacio quartzite (Cambrian). The 

beginning of the overlap is near the Uncompahgre, however, for. on Cow Creek, one of 

its eastern tributaries, the La Plata rests 

with angular unconformity on Cutler beds, 

the Dolores and an unknown amount of the 

Cutler being missing. 

The sedimentary sections of the San 

o s •oMiles Juan Mountains district from the Uncom-

' FIGURE 2.-Drainage map of a part of the Piedra Valley, Colo. pahgre Valley, on the nor~h, around the 

western slopes and eastward on the southern side as far as Pine River agree in showing the La Plata sandstone resting on the Triassic red 

beds· (Dolores formation), the full Paleozoic sequence of the region occurring in most places. 

The details of these relations are described in the Ouray, Telluride, Rico, La Plata, and Engineer 

Mountain folios of the United States Geological Survey. At many localities, however, the 

sandstone of the Dolores formation beneath the La Plata has been much eroded, causing local 

unconformities. · . 

As stated in the Engineer Mountain and Needle.Mountain.3 folios, the great overlaps· shown 

on the Hayden map in the Animas Valley and east of it are not to be found as represented. 

Our recent work has shown, however, that about 25 miles east of the Animas, on the west side 

of Wiminuche Creek, both faulting and earlier overlap are plainly exhibited nearly on the 

northeast-southwest line where the Hayden map represents "Upper Dakota" beds in original 

contact with "Metamorphic granite." In the small portion of this area that nes in the San 

Cristobal quadrangle, north of 37° 30', the fault mentioned brings Dolores (Triassic), La Plata 

(Jurassic), and McElmo (Jurassic~) beds successively into vertical or steeply inclined position 

against pre-Cambrian rocks on the northwest~ A coarse granite is the chief of these older 

formations, but gneiss and Algonkian quartzite also appear in Wi1ninuche Valley near the point 

where the fault disappears under the later volcanics. The relations of Wiminuche Creek, Piedra 

Canyon, and other localities mentioned are shown in figure 2. 

I U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1873, Pl. XIV, pp. 341-342, 1874. 
STRATIGRAPHY OF SOUTHWESTERN. COLORADO. 43 

Farther southwest this fault is lost under glacial drift and a thick forest cover, but on the 

east and southeast slopes of Graha1n Peak, a granite mountain near by, which is unnamed on 

the I-Iayden n1ap but assigned an elevation of 12,836 feet, small remnants of quartzite and 

greenish shales rest on the granite northwest of the fault· line. T.hese beds dip gently to the 

southeast. Their character suggested to us that they belong to the La Plata and l\1cElmo 

formations, and the exposures of the Piedra Canyon, to b~ described, practically prove this 

correlation to be correct. The fault ·probably passes into a ·fold within the area shown in 

figure 2, but time was not available for an examination of the district where this change presump.bly occurs, ·nor were we able to examine the country southwest of Graham Peak, whe1:e the 

overlap of the La ]?lata sands'tone over the whole section of older sedimentary formations must 

apparently occur within a few miles. 

The I-Iayden map is also incorrect in its Te_presentation of the geology of Piedra Canyon 

and lower Wiminuche Valley and of the slope between Piedra River and the granite divide 

to the northwest, which is colored as entirely occupied by the "Upper Dakota.". Endlich, 

who mapped this di8trict, usually applied this term to the strata still called true Dakota _sandstone, and at 1nost a few hundred ·feet of lower beds. In the area referred to, however, the 

valleys and canyons on the dip slope have a depth of more than 1,000 ·feet, and as the true 

Dakota is less than 200 feet thick in this region lower formations are naturally exposed. lt 

is in the canyon sections that the ·overlap to be described is so clearly exhibited. 

A traverse down "\~Viminuche Creek to Piedra River ~nd down t~e c~nyon of the Piedra 

for 6 miles to the mouth of the second la:r:ge tributary from the nortiiwest, called "First Fork," 

revealed a most interesting structural and stratigraphic complexity, which is described in some 

detail on pages 44-46 of this paper .. · Within a few miles the river cuts across a monocline 

and two u.nticlinal uplifts, exposing three areas of pre-Cambrian rocks~ which .are 'overlain by 

somewhat different sections of the Paleozoic and Triassic formations, aB.d these in turn ar.e 

coveJ:ed in marked unconformity by the La Plata sandstone. Above this come the McElmo 

and Dakota formations, the Dakota forming the rim rock of a warped. and dissected plateau. 

The northeastern of these eroded uplifts reveals the La Plata Testing on granite or Algonlci.an schist; the middle one exposes the same pre-Cambrian formations but shows a varying 

Paleozoic section between them and the La Plata; the southwestern uplift was seen only from 

a distn.nce, but it also appears. to have a pre-Cambrian core in the rugged canyon below First 

Fork, and Paleozoic formations must be present, though perhaps in an incomplete section. 

RESUME. 

From the evidence here presented it appears that the ·overlap of the Gunnison formation 

on the pre-Cambrian rocks extends at least 50 miles farther up the valleys of the Gunnison 

and Tomichi thnn was represente~ for the Jurassic beds on the Hayden map. It takes the-place 

of the asSUJ?led transgressions of the Dakota sandstone and "Colorado" shale. Eldridge has, 

shown that the Gunnison extends northward through the Elk Mountains in marked unconformity with the Paleozoic forma.tions. 1 The relations in the Piedra Valley suggest that the 

La Plata sandstone overlapped earlier sediments and cnme into contact with the pre-Cambrian 

rocks along a general north and south line, crossing the San Juan Moui1tains area. Piedra 

Canyon is about 75 miles south of Gunnison River, and it seems not unlikely that the area of 

the La Plata overlap extended eastward through the present mountain district to the San Luis 

Valley. ·The suggestion has been .entertained that the strata known as the Gunnison formation on the western slope and the l\forrison formation on the eastern slope were once continuous 

deposits, having been connected across the area of the .Sawatch l\1ountains and perhaps also 

across the areas of the Sangre de Cristo, the Arkansas Valley, and the district south of South 

Park Although it is difficult to outline land areas in central and southern Colorado where 

the l\1orrison or Gunnison beds were not deposited, or to prove that there were any such areas, 

the thinning of the Gunnison formation eastward, as described on page 41, indicates that the 

two forn1ations 1nay never have .been .continuous. 

1 Eldridge, G. H., U. S. Gc_ol. Sunrcy Geol. Atlas, Anthracite-Crested Butte folio (No.9), 1894. 

37183°-15-4 
44 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

It is the current practice of the Geological Survey to refer the La Plata sandstone to the 

Jurassic because strata believed to be its equivalent occur in Utah beneath marine Jurassic beds. 

Tills reference does not require the assignment of the McElmo and :Morrison formations to the 

Jurassic: It seems, however, to .indicate that sedimentation may have·continued in Colorado, 

with no considerable interruption, from Jurassic through Lower Cretaceous tin1e. 

STRATIGRAPHIC RELATJONS IN THE PIEDRA VALLEY. 

STRUCTURE OF THE UPPER MESOZOIC FORMATIONS. 

The Mesozoic forn1ations exposed in the lowlands adjacent to the San Juan Mountains, in 

the area traversed by San Juan and Piedra rivers, exhibit many gentle folds and minor faults 

which can be grouped in no definite systems. These structural features are brought out by the 

Dakota sandstone in characteristic ledge outcrops on steep slopes and along the walls -of small 

canyons, or ~y undulations where it serves as the sustaining floor of many nearly level stretches 

between streams near the mountains. Such rolls and small faults are especially well shown 

near Pagosa Springs, where several small streams have cut through a thin n1antle of Mancos 

shale and revealed the underlying Dakota. 

The,McEln1o and La Plata formations must take part in these minor structures, but erosion 

has not revealed them, so far as known, in the valleys east of the Piedra. The structure shown 

immediately adjacent to Piedra Canyon is rudely expresse.d in. figure 3. It will be noted that 

the La Plata, and with it the overlying beds, has been warped by three low folds. The one best 

shown in the figure lies bet~een Sand Creek and First Fork. The fold southwest of First Fork 

. is probably still more striking, for it is plain that the La Plata, McElmo, and Dakota formations 

mvst all disappear beneath the Piedra, J:?y southwesterly dips or faulting, within 4 or 5 miles .of 

Fi.rst Fork. .These low folds of the La Plata are located, at least in a general way, above more 

pronounced folds of pre-Jurassic formations, to be described under the next heading. 

The structure of the underlying beds probably had much to do with the location of the later 

rrllnor folds of the La Plata along the Piedra, for many small faults in younger formations in the 

San Juan region represent renewed movement on fault planes along which older formations have 

been n1ore extensively dislocated at .some much ear\i_er period. It seems reasonable to suppose 

that the same is true of the folds, and the·gentle.flexures of the Piedra appear to be the results.of 

such repeated movement, but furtber stud_y is necessary to .~scertain definitely the relations of 

the folds in this region. . . 

:Mention has been made (p. 42) of a major fold-fault of southwest-northeast trend that 

crosses. the Wiminuche north of the area shown in figure 2. Whether this movement was synchronous with the minor flexures here referred to is not known. . 

THE 'U.NCONFORMITY BELOW THE LA PLATA SANDSTONE. 

The character of the unconformity may be n1ore clearly brought out by describing in some-

. what greater detail the relations so well exhibited in the Piedra Valley and its branches below 

the mouth. of Wiminuche Creek. The Piedra itself first cuis through the La Plata sandstone 

about a wle above the mouth of that creek. The La Plata there dips very slightly to the southeast and rests on steeply upturned shales, schlsts, and thin quartzites of the Uncompahgre 

(Algonkian) formation. These relations are brought out by the view given in Plate VIII. The 

schists are much decomposed and their appearance indicates that they had long been subjected 

to weathering before the deposition of the La Plata . 

. . In the angle between Piedra and Wiminuche Creek-the base of the La Plata lies about 200 

feet above the junction of the streams. It runs up the Wiminuche with nearly regular position, 

crossing it at about a quarter of a mile above Little Sand Creek, and in this distance it crosses 

an ill-exposed contact between the Uncompahgre strata and a great intrusive mass of coarsely 

porphyritic granite, regarded as a ·part of the Eolus granite, which occupies a large area in the 

Needle ~fountains. There n1ay be a fault contact at this point .. 

Q 
U. s." GEOLOGICAL SUR VEY PROFESSIONAL PAPE R 90 PL ATE VIII 

LA PLATA SANDSTONE ON SCHIST OF UNCOMPAHGRE FORMATION ON NORTH BANK OF 

PIEDRA RIVER, COLO. 
STEATIGRAPHY OF SOUTHWESTERN COLORADO. 45 

Below Wiminuche Creek the base of the La Plata descends gradually, with very gentle 

undulations, keeping from 100 to 200 feet above the river, to the point of the ridge east of 

Sand Creek. The Uncon1pahgre beds underlie the La Plata in the Piedra Canyon with a general 

northwestern dip of 43.0 -45°, to a point about a 1nile below the mouth of Wiminuche Creek, where 

they disappear beneath the lower Paleozoic formations, which dip about 11° SW .. These beds 

belong to the northeastern lhnb of a shallow syncline, the opposite side of which rises n1ore 

steeply beyond Sand Creek. 

Owing to this older structure the La Plata overlaps discordantly the formations fr01n the 

Elbert~ (Devonian~) to the Hennosa (Pennsylvanian), and at the point of the ridge east of Sand 

Creek it lies on I-Iernlosa beds several hundred feet above the base of the formation, with an 

angular unconformity rudely illustrated by figure 3. 

Sand Creek is nearly in the trough of the syncline just referred to, and it has cut below the 

La Plata for its entire length. The gradient of the stream is equal to the southeastern dip of 

the La Plata sandstone, about 4°, so that the base of the sandstorle keeps its position, from 

1.00 to 200 feet above the stream, for over 7 nules from the Piedra. The underlying I-Iermosa 

also persists until the great fold-fault alluded to on page .42 is approached. Where the lower 

beds turn up adjacent to that fold the creek cuts through then1 into granite. 

S01newhere in the region near Grahmn Peak the La Plata again overlaps the lower Paleozoic 

for1nations, but a heavy cover of forest and old glacial gravels obscure these relations and no · 

FIGURE 3.-Diagrammatic section along the northwest side of Piedra Canyon, Colo. 

exposures of the unconformity were found. Erosion may have re1noved the La Plata from 

the rather narrow zone in which it might otherwise be present. 

The divide at the head of Sand Creek and farther north is in the Eolus granite, and the base 

of the La Plata turns up sharply on" the higher slopes and swings around to the northeast where 

the fold n1erges into the Wiminuche fault. On some of the ridges of these upper slopes northwest of the fault remnants of the La Plata sandstone overlie the granite. 

Below the 1nouth of Sand Creek the La Plata sandstone assumes a northeastern dip and 

in a distance of less than a mile its base rises 1,000 feet above the bed of Piedra River. It 

then turns gently to the southwest and east of the mouth of First Fork, which is the next main 

strean1, it is again only a few hundred feet above the Piedra. As shown in figure 3, there is an: 

older and1nore pronounced fold in the pre-Jurassic strata between Sand Creek and First Fork 

and the La Plata truncates these older formations, the overlap being very plainly den1onstrated 

by the section displayed in Piedra Canyon and the valley of First Fork. . 

As the Piedra cuts across this anticline it first reveals the Eolus granite beneath the seclinumts, but on the southwest side a fault biings schists of the Uncompahgre formation once 

more to view. The river flows through these pre-Cambrian formations in a rugged canyon. 

The I-Iermosa and earlier Paleozoic formations are well exposed on the northwest side of the 

canyon .. 

First Fork also flows in a synclinal trough and for at least several miles above its 1nouth 

cuts below the La Plata. In the lower part of the valley bright-red sandstones are-prominent 

in the southwest bank and also appear on the southeast side of the Piedra. These beds and 

300 to 400 feet of variously colored grits, sandstones, shales, and nodular lin1estones which overlie them, clearly belong to the Permian ( ~) Cutler formation, for they are in turn overlain by 
46 SHORTER CONTRIBUTIONS TO GENEl,lAL GEOLOGY, 1914. 

the Triassic Dolores formation. The characteristic fine-grained "saurian conglomerate" of 

the Dolores, carrying fragme.nts of bones and teeth and made up mainly of small pebbles of gray 

limestone, is exposed on the northeast side of First Fork, halfway to the principal forks of the 

stream shown in figure 2, and also in th~ ridge between the forks. 

The white La Plata sandstone occurs 300 to 350 feet above the forks, being clearly shown 

in the mai~ ridge .to the northeast. It thus appears in First Fork in about the same position 

relative to the underlying section of Triassic and Paleozoic formations that it holds throughout 

the San Jua1i region, to the west, as described in the published folios. Except for a part of the 

Dolores formation the overlap from Triassic to pre-Cambrian rocks is complete between First 

Fork and Wiminuche Creek. 

Below the movth of First Fork the canyon of the Piedra has been seen only fron1 a distance. 

The canyon closes in and the walls are-high and rugged. The Paleozoic beds form a sharp anticline, with very steep dips on the southwest limb, and the pre-Cambrian rocks are probably 

again exposed in the canyon. The La Plata and overlying beds are also folded, but less sharply 

.than are -the underlying rocks, the conditions resembling those above First Fork. Within a 

few mil~s down the river all pre-Dakota formations disappear beneath the surface by southerly 

dips. 

The overlap of the La Plata has been def;)cribed with special reference to the exposures 

examined on the northwest side of the Piedra, but the same general relations are shown on the 

opposite side, as could be ~een fron1 many good points of view. But the structure exhibited 

by the older formation southeast of the Pie.dra is more complex than has been described. PreCambrian rocks rise about 1,000 feet above the river in an amphitheater nearly oppositE Sand 

Creek, and are there immediately overlain by the La Plata sandstone. A more detailed study 

than we could make is necessary in order to determine fully the structural relations of the formations in· this area. 

PRE-DAKOTA SECTION OF PIEDRA VALLEY. 

JURASSIC (?) SYSTEM. 

McELMO FORMATION. 

The McElmo strata, occurring between the Dakota and La Plata sandstones, are widely 

distributed in the Piedra and adjacent valleys, but owing to their soft, friable nature are well 

exposed at Jew plac~s. The only good section observed is in the little canyon of Wiminuche 

Creek, about 5! n1iles north of the area shown ·in figure 2, where the stream cuts across the 

st~ata adjacent to the fault mentioned on p~ge 42. In this canyon 470 feet of l\icEln1o strata 

are exposed in vertical position. 

At the base of this McElmo section is a dark-red marly shale, such as occurs at many 

places ·ln this position. It is succeeded by wavy friable sandstones, sandy shales, and clay 

shales, in beds tha·t are rarely more than a few feet thick, without marked change in character. 

·On slopes the harder sandstones form ribs separating shale depressions. The colors, especially 

·those of the shaly layers, exhibit the variegation characteristic of the formation, from red, 

through 1>ink, green, lilac, and yellow, to gray. 

It seems probable that this section does not show the true thickness of the formation, 

·owing to squeezing and shearing near the fault, and that the softer beds in particular are 

thinner than is normal. No fossils have been observed in the McElmo formation. 

JURASSIC SYSTEM. 

LA PLATA SANDSTONE. 

General character.-The La Plata of the Piedra Valley exhibits variations which are natural 

in a region o.f overlap upon an uneven topography. In other parts of the San Juan region 

the La Plata consists of two thick members of white massive cross-bedded quartzose sandstone, separated by a subordiuate and variable calcareous mmnber in places carrying some 

limestone but more generally consisting of calcareous sandstones and shales. In Piedra Canyon 

and its branches the lower. La Plata sandstone in many places has nearly its normal character 
STRATIGRAPHY OF SOUTHWESTERN COLORADO. 47· 

and above it come dark bituminous limestones, locally thin-bedded and brecciated. The 

upper La Plata sandstone is presumably present in less than the normal thickness, but owing 

to its soft and friable character it affords no good exposures. This character renders it possible, 

however, that these soft beds belong in fact to the :McElmo formation and that the La Plata 

here lacks its upper member. 

At the base of the La Plata a basal conglomerate, variably developed, is composecl1nainly 

of dense quartzite pebbles from the Algonkian Uncompahgre formation, a great thickness of 

which is shown in the adjacent Needle Mountains area. Such conglomerate was observed at 

several places near the mouth of Wiminuche Creek, where the La Plata rests on an irregular 

surface of Algonkian strata. 

Tho lower La Plata sandstone is variable in thickness and is very thin or wanting in some 

places, as on the east side of the Wiminuche about a mile above its mouth. A short distance . 

below this point conglomerate and some sandstone occur between the underlying granite and 

dark l.in1estone breccia. These variations are no doubt clue to the uneven surface on which. 

the sandstone was deposited. 

The limestone member of the La Plata in the Piedra' Valley presents very nearly the 

satne features that it does north of Ouray. Its total thickness is locally more than 30 feet, and 

usually a gray massive cavernous limestone lies in thin beds above and below it, but in some.· 

localitie~ almost the entire member is black breccia of thin limestone cemented by white calcite. 

In the thin shaly lin1estone layers below the 1nore massive part scanty fish remains were found. 

Dr. C. R. Eastman has examined these remains carefully but is unable to make any satisfactory 

determinations of the forms represented. . 

Section of La Plata sandstone.-On the northwest dele of the Piedra, about 1uidway between 

Sand and Wi1ninuche ereeks, the section given below was found. 

Section of La Plata sandstone on Piedra River between Sand and Wiminuche creeks. 

Top. Feet. 

1. Sandstone of the McElmo formation, reel, thin-bedded, argillaceous; poor exposures. 

2. No exposures.-; unexposed interval probably occupied by upper La Plata sandstone with some 

1\fcEhno beds. ___ ............ -._ .. _ .. -- ................... , ... __ ............ · ........ _ 70 

3. Limestone breccia, clark, made up of fragments like underlying limestone; contains open 

spaces, as the cementing material does not fill all the interstices; makes good ledge outcrops. _ .... ____ .......... _ ..... _ ... _ .. __ .... _ ............ ___ .. _ ........ _ . _ . _ ..... _ . _ _ 15 

4. Limestone, clark, in places nearly black; shaly; has a decided bituminous odor; carries fragments of small fish-------------------------<-------------------------··--··········· 10 

5. Quartzose sandstone, light yellowish gray, fine, even-textured; weathers with rounded, pitted 

forn1s. _. _ ...... _. ___ . _ ... __ ...... _. _. _ ... _. __ .. _ .. _ ................ _ ......... _....... 20 

6. Quaxtzose sandstone, white, even-grained, cross-bedded; makes rounded cliffs .. __ ._ .... _ .. _ 55 

This is tho normal section of the La Plata of this area, but tho two limestone members are 

rather variable and tho upper limestone breccia aione reaches a thickness of 30 feet just north 

of the 1nouth of Sand Creek, though at some other places it is much thinner. The heavy sandstone bed at the base is also somewhat variable in thickness. 

TRIASSIC SYSTEM. 

DOLORES FORMATION. 

The only known exposures of the Dolores formation· are adjacent to the fault in Wimin_uche 

Canyon and in the valley of First Fork. In neither locality were good sections seen, but it is 

clear that the formation here exhibits no marked change in character from that shown in the 

Animas Valley, as described in the Engineer ~fountain folio. There is the usual alternation 

of :fine linH)stone conglomerate and thin-beclcled sandstones and shales near the base,· followed 

above by intensely reel shales and more or less massive sandstones. The original thickness 

of this sandstone in this region is presumably nowhere preserved, owing to pre-La· Plata erosion, 

and it may have been much greater than at present.. Probably 350 to 400 feet is a n1axin1um 

measure of the Dolores forma:tiQ~ now occurrj.ng in the Piedra Valley. 
48 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Unless small isolated exposures of the Dolores occur in the San Juan, Navajo, or other 

valleys east of the Piedra, near the volcanic rocks of the mountains, these outcrops of Dolores 

beds of the Piedra are probably nearer than any others of Colorado to the long-known: fossiliferous beds of Rio Chama in New Mexico. No conglomerate like that of the Dolores has been 

reported from New ~1exico, but it is evident that if the worn particles of limestone were a little 

s1naller than they are in the conglomerate of First Fork and were mingled with sand grains the 

peculiar character of the ''saurian conglomerate'' would be lost. 

CARBONIFEROUS SYSTEM. 

PERMIAN ( ~) .SERIES. 

CUTLER FORMATION. 

The most complete section of the Cutler formation is in Dolores Valley below Rico, Colo.1 

The only observed outcrops of the Cutlar formation in the areaS here considered are those 

in First Fork, already mentioned, where, as noted, some of the sandstones and shales are very 

bright red, but the strata near the Dolores.formation have the character of the partial section 

given below, which occurs on the northeast side of First Fork about half a mile above the Piedra, 

where it is crossed by the Forest Bervice trail leading up First Fork. The top of the section 

is not rriore than 200 feet below the Dolores, but the intervening beds are poorly exposed. 

Section of Cutler formation about one-half mile above the Piedra. 

Top. Feet. 

1.. Arkose grit with subordinate red sandy shale; upper bed of arkose, 6 to 12 feet thick, varies 

locally inversely with red sandstone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

2. Arkose, cross-bedded, massive, pink; forms rounded outcrops ............................ 12-15 

3. Shale, calcareous, and nodular pink limestone.......................................... 8 

4. Sandstone, light gray, somewhat calcareous, weathering into rounded forms; tough fracture 6-7 

5. Limestone and shale; red nodular limestone with shaly matrix; crumbling .... ·............ 3 

6. Sandstone, gray, fine and even-grained ....................... ~......................... 3 

7. Shale, sandy.; dark red in upper part, grading below into dark-gree.::1 sandstone at base...... 12 

8. Sandstone; thin-bedded, greenish gray, dark at top and lighterbelow;strikeN.12°-1~ 0 E., 

dip 7°-8° YV ............. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

98 

Thi~ section is in general characteristh of the Outler of the southern San Juan region 

as to the variety of beds and their alternation, though no two sections agree in thickness or 

similar beds or in details of gradation. No exposures were. found in the zone between the 

Cutler beds and the typical Hermosa, so that it is uncertain whether the Rico formation (Permian ~) is present in the Piedra Valley or not. 

PENNSYLVANIAN SERIES. 

HERMOSA FORMATION. 

The lower part of the Hermosa !s exposed south ot Sand Creek and near the Piedra, in a 

diagonal section which is continuous for about 500 feet, the beds dipping 18° to 25° NE. Owing 

to a fault the actual base of the format~on is not shown in relation to this section, but probably 

there is a gap of less than 200 feet. The section is on the northeast limb of the antlcline shown 

in figure 3. 

Partial section of Hermosa/ormation near Piedra Canyon, south of Sand Creek. 

Top. Feet. 

1. Sandstone, yellowish green, argillaceous........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

2. Sandstone, pinkish, with a few thin variegated bands; slightly cross bedded, medium to 

coarse-grained .......................... :............................................ 16 

3. Shale, purplish ............. ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

4. Limestone, dark gray ...................................................... ·. . . . . . . . . . . . . 2 

5. Sandy shale, dark red to purplish........................................................ 20 

1 Cross, Whitman, and Howe, Ernest, Red beds of southwestern Colorado and their correlation: Geol. Soc. America Bull., vol. 16, p. 464, 1905. 
STRATIGRAPHY OF SOUTHWESTERN COLORADO. 

Feet. 

6. GTit, light gray....................................................... . . . . . . . . . . . . . . . . . . 6 

7. Limestone, nodular, with very fo::;siliferous shale layers.................................... 6 

8. Limestone, .nodular and fossiliferous, and shale; strike N. 65 ° W., dip -27 ° N E. 

9. Shale, reddish to purplish at base, drab at top ................. ·.· ......... ·............... 20 

10. Limestone, nodular and fossiliferous, with thin shale ............ _....... . . . . . . . . . . . . . . . . . . . 3 

ll. Shale, purplish ......................................................... ·................ 17 

12. Shaly limestone; fossils....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

l.3. Shale, sandy and reddish near base, calcareous and black near top......................... 6 

14. Sandstone, coarse, somewhat variegated, brown or red..................................... ~ 

15. Sandy shale........................................................................... 2 

16. Sandstone, soft, shaly, greenish, and somewhat' variegated................................. 5 

17. Grit and coarse sandstone ..... ·.......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

18. Limestone, very fossiliferous ........................................................... . 1 

19. Grit, light colored. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

20. Shale, reddish and calcareous at top..................................................... 23 

21. Grit, light colored ............. , ...................................................... . 

22. Limestone, dark gray; few shells .............. · .... ~ ......................... ~ ......... . 

23. Sandstone, thin-bedded, shaly, gray, and cross-bedded .................................... . 

24. Shale, forming flaky sandy clay, upper part dark gray, lower part reddish ................. . 

]7 

3 

9 

20. 

25. Limestone, sparingly fossiliferous; strike N. 356 W., dip 18° NE.......................... 4 

26. Shale, very fmc-grained, green and gray, orred; soft and poorly exposed (estimated thickness) 40 

27. Sandstone, arkosic, green with prominent red feldspar grains............................... 5 

28. Limestone; upper 5 feet nodular, gray, dense, rich in Productus, Spirifer, Terebratula, and 

'l'riticites; lower 7 feet earthy limestone grading downward; alternation of shales and lime-· 

stone in layer 3 to 4 inches thick; fossiliferous ........................................ . 

29. Shale, dark, calcareous ................................................. · ............... . 

30. Limestone, nodular; rich in Triticitcs sccalicus . ......................................... . 

31. Shale, soft, gray; poorly exposei ...................................................... . 

32. Sandstone, yellowish gray ............................................................. . 

12 

3 

2! 

20 

2 

33. Limestone, nodular in upper part, thinner bedded and sandy below; very fossiliferous...... 23 

34. Shale and shaly sandstone ......... :.................................................... 10 

35. Grit, arkosic, pink, gray, and mottled; cross-bedded, massive; much quartz................. 14 

36. Shale, red and gray.................................................................... 8 

37. Limestone, part lamina ted, part nodular; fossiliferous ......................... : . . . . . . . . . . 22 

38. Shale, red, with irregular nodules of limestone.............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

39. Limestone, massive, gray. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

40. Shale, red............................................................................. 4 

41. Limestone and red shale of irregular development; rich Triticites-bearing limestone layer.... 20 

42. Grit, gray, massive .................................. ·................................... 25 

43. Sandstone, dense, with dark-red shale partings to beds; pink and gray spots in sandstone.... 18 

490 

49 

Below this section is a zone, about 200 feet wide, in which the rocks are not exposed, and 

below that the Ouray lhnestone appears. On the south side of the fault which interrupts 

the continuity of the section the two lowest beds of the Hennosa are exposed. At the base 

is a gritty sandstone about 20 feet thick, and overlying it is a·nlore or less sandy fossiliferous 

li:nestone of wavy bedding, exhibiting an irregular alternation of pure dark-gray material 

with streaks of yellowish earthy limestone. This constitution is characteristic of the lowest 

lin1estone of the I-Iernlosa in the Anin1as Valley. 

MOLAS FORMATION. 

The descriptions of· the Molas fonnation in the Silverton, Needle Mountains, and Ouray 

fol~os show the persistent character of this thin and peculiar fonnation throughout the San 

Juan region. 

The Ouray limestone south of and adjacent to the fault that interrupts the Hern1osa section lies below reddish clay, shale, and calcareous beds that are typical of the :Molas formation. 

The full thickness of the MQlas forn1ation was not seen, but near the fault there are unusually 

good though not continuous exposures, 1naking it clear that the formation is at least 100 feet 

thick. It has the· usual character, consisting mainly of red calcareous shale. :Much of it is 

almost a red clay, but where the calcareous element is pronrinent the mass becon1es irregularly 
·so SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

nodular or lumpy. Layers or lenses of mottled limestone are rare. The largest extend several 

yards laterally. Some laye:rs of calcareous mud are twisted and are held by ordinary shale 

or clay. Near the top is a calcareous sandstone, apparently quartz-free, 1 to 2 feet thick. The 

upper 20 feet is not well enough exposed to show the character of the rock. 

CARBONIFEROUS AND DEVONIAN SYSTEMS. 

OURAY LIMESTONE. 

A massive light-gray crystalline limestone about 30 feet thick occurs below the Molas 

forn\ation in the section on the northeast limb of the anticline below Sand Creek. The upper 

surface of the limestone contains deep solution crevices filled by the reddish mud of the Molas, 

a condition common throughout the San Juan region. In the ~imestone were found cup coral 

and fragments of crinoid stems such as are common in the Carbonif~rous part of the Ouray 

limestones elsewhere. Chert' nodules occur in the upper part of the limestone. No Devonian 

fossils were found, and it may be that no part of the limestone here should be referred to that 

period. · · 

DEVONIAN SYSTEM (?). 

ELBERT FORMATION(l).l 

Below .the. Ouray limestone there are several quartzite beds, 4 to 5 feet thick in all, and 

some reddish or mottled crumbling sandstone. Green or reddish shale occurs below these 

sandstones ·but is poorly exposed .. No place for a section was found. It is estimated that there 

are 40 to 50 feet of sanely and shaly beds between the Ouray limestone and pre-Can1brian fornlations, and the re~erence of these to the Elbert rather than to the Upper. Cambrian (Ignacio 

quartzite) is based simply on probabilities. The Ignacio is absent on Pine River about 12 to 15 

miles west of the Piedra Canyon. 

ALGONKIAN SYSTEM. 

UNCOMPAHGRE FORMATION. 

As shoWn. in the profile section, there are in the Piedra Canyon two distinct exposures of 

quartzite and schist or shale belonging to the Uncompahgre formation. In the one at and near 

the mouth of Wiminuche Creek the strata have nearly the same character that they exhibit in 

the Needle Mountair1s. ·The quartzites are dense and hard ancl are bluish-gray in color. , They 

are in part coarse and in part fine grained. The shales have been somewhat metamorphosed 

and some b~ds. a~e. schistose through abundant mica, but in many places "they are soft and 

crumbling-~- Much of the decomposed appearance of these strata is probably due to weathering 

in a long period of exposure before the decomposition of the earliest Paleozoic sediments. 

·In the area of these Uncompahgre beds in the Piedra Canyon between Sand Creek and First 

Fork quar.tzite, accompanied by pronounced schists, is the principal rock, occurring in a band 

about 100 feet wide, adjoining the granite body. Brown t~urmaline and rudely developed 

chiastolite or anclalusite characterize the schists near the granite and indicate that the granite 

is intrusive. The Piedra Canyon, cut for a depth of 200 to 300 feet in these beds, is very rugged 

and has somber gray walls. 

The Uncompahgre strata beneath the La Plata sandstone of Plate VIII are locally contorted 

and crushed. Those of the canyon below Sand Creek strike nearly east and clip 60° or more to 

the north. · 

1 The Eibert formation was first described in 1904 (Cross, Whitman, A riew Devonian formation in Colorado: Am. Jour. Sci., 4th ser., vol. 18, 

p. 245). For further descriptions and map of type locality see U.-S. Geol. Survey Geol. Atlas, Engineer Mountain folio (No. 171), p. 5, 1910. 
A RECONNAISSANCE IN THE CANYON RANGE, WEST-CENTRAL 

UTAH. 

By G. F. LouGHLIN. 

INTRODUCTION. 

PREVIOUS STUDIES IN THE REGION. 

The Canyon Range, in west-central Utah, which derives its name fron1 the deep valley cut 

through its northern part,by Sevier River, has hitherto received no general geologic study, not 

even of a reconnaissance nature. The atlas of the Wheeler Survey,1 though showing the geology 

of the surrounding ranges, leaves the Canyon Range blank. Gilbert, in his study of Lake 

Bonneville/ exan1inecl the lake deposits in the valleys on the east and west sides of the range and 

in Sevier Canyon which connects them, but paid no special attention to the hard rocks of the 

range. Tower and Smith/ in their report on the Tintic district, north of the Canyon Range, 

n1ention the presence of folded Paleozoic strata, including Carboniferous limestone, along 

Sevier Canyon, and of Eocene conglomerate resting unconforn1ably upon the Paleozoic rocks. 

Their statmnent was based on observations made during a clay's drive from Juab to Leamington 

by Sn1ith, who noted the absence of volcanic material in the Eocene congloD?-erate and the 

abundance of it in the Pleistocene and recent alluvial deposits, and therefore concluded that 

the Tertiary volcanic rocks, which forn1 the southern part of the Tintic :Mountains, were postEocene. The latest geologic 1nap of North America 4 represents the Canyon Range as composed entirely of Cambrian and Lower Ordovician strata. 

FIELD WORK. 

The writer in 1912 5 1nade a trip through Sevier Canyon, noting the unconformity between 

the Eocene conglon1erate and the Paleozoic strata and also the presence of a bed of dark-colored 

volcanic rock, presun1ably andesite or latite, resting upon Eocene conglomerate, thus verifying 

Smith's c011clusions. The close resemblance of the Paleozoic quartzite in general li-thologic 

character to the Can1brian quartzite of the Tintic district, together with the age assigned to it 

on the geologic 1nap of North America (just cited), led the writer to describe the Tertiary conglonlerate as here resting on Cambrian quartzite. In June, 1913, however, while visiting the 

Lemnington 1nining district, he took the opportunity to 1nake a hasty reconnaissance of the 

range, spending half a day in the mountains north of Sevier Canyon and three days in trips up 

Wood, Yellowstone, .Fool Creek, and Oak Creek canyons and along the west base of the 

range. It was found that the quartzite, instead of being Can1brian, rested in apparent confonnity upon lower :Mississippian limestone. No careful measutements of the thicknesses of 

these fonnations were attempted, but interesting structural data were gathered, which, though 

. far· fron1 complete, are believed to be worthy of presentation. 

I U.S. Goog. Surveys W. lOOth Mer., atlas sheet 50. 

ll Gilbert, G. K., Lako Bonneville: U.S. Geol. Survey Mon. 1, pp. 104, 166, 192, and 193, 1890. 

a 'L'owor, G. W., and Smitll, G. 0., Geology and mining industry of the Tin tic district, Utah: U.S. Goo!. Survey Nineteenth Ann. Rept., pt. 3, 

pp. 617, 671, and 673, 1899. 

4 Wlllis, Bailey, Index to tho stratigraphy of North America: U. S. Geol. Survey Prof. Paper 71, Pl. I, 1912. 

~Loughlin, G. F., Reconnaissance in the southern Wasatch Mountains, Utah: Jour. Geology, vol. 21, p. 448,1913. 

51 
52' SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TOPOGRAPHY. 

The Canyon Range, as shown on the accompanying map (fig. 4), has the general featur~s of 

the maturely dissected basin ranges, but the transverse canyons on its west side are surprisingly 

broad in proportion to their 

15' 112.0 

4 

I 2. I y 1 0 ~ MILES 39 I •. 

15 

15' 112° 

LEGEND 

OUATERNARYt · TERTIARY ~ CARBONIFEROUS 

'Lake 

~~· ~ 

Bonneville~ :C:· Volcanic 

'/r;,\ 

+++++ 

Conglomerate~ 

~·~ ~ ~ Quartzite VCtl 

::.·.::.-::_,: 

Limestone 

~. ~ 

beds :::> rocks and sandstone:::s 

'(10" ¢ ~ 

faults Strik~ and dip Vertical dip. Anticlinal axis 

FIGURE 4.-Reconnaissance·map of the Canyon Range, Utah, showing geologic formations. 

lengths. · Those on the east 

side were not seen at close 

range. l\1ost of the lateral 

branches of the canyons on 

the west side are strike valleys separated by "hogback" 

ridges. (See fig. 5.) Some 

of these canyons are occ;upied by small creeks, the 

largest of which is Oak Creek, 

in the southern part of the 

range. 

The mqs t striking topographic feature is Sevier Canyon, in reality a rather wide 

valley with a flat bottom and 

gently sloping sides, which 

cuts completely across the 

range in a curved course at a 

very gentle gradient. Sevier 

River has terraced the unconsolidated lake deposits 

which constitute the canyon 

floor and follows a meandering course, interrupted at one 

or two places by gentle rapids, where it has uncovered 

buried ridges of quartzite. 

SETTLEMENTS. 

Two small agricultural 

towns are situated at the 

west base of the range at 

places where water for irrigation is available-Leamington, at the mouth of the 

canyon of Sevier River, and 

Oak Creek, or Oak City, at 

the mouth of Oak Creek canyon. A few ranches are located between these t w o 

towns, especially near the mouth of the canyon of Fool Creek, which supplies wa~er for 

irrigation. The San Pedro, Los Angeles & Salt Lake Railroad passes through Leanungton 

and Sevier Canyon. Oak Creek is reached by stage from Leamington. 
A RECONNAISSANCE IN THE ·CANYON RANGE, UTAH. 

GEOLOGY.· 

STRATIGRAPHY. 

GENERAL FEATURES. 

The Canyon Range is con1posed t"thnost entirely of seclilnentary rocks-Carboniferous linlestone and quartzite overlain unconformably by Eocene congl01nerate. Volcanic rocks have 

been reported fron1 the ·extre1ne northern and southwestern parts of the range, beyond the 

lin1its of the area visited. The valleys on either side of the range are floored with beds of 

Pleistocene age that were deposited in La.ke Bonneville and are known ~s Lake Bonneville 

beds, and locally with later alluvial deposits. 

SEDIMENTARY ROCKS. 

CARBONIFEROUS LIMESTONE. 

The limestone, as shown on the map (fig. 4), is the prevailing rock northwest of Sevier Canyon 

and forms the n1idclle western slope of the range south of Sevier Canyon as far as the south 

bound~y~Yellows~neCa~ ~~~~~~~~~~·~~~~~~~~~~~~~~~ 

yon. North of Sevier Canyon 

it has generally low dips, associated with gentle anticlinal 

and synclinal flexures, but 

locally its beds stand nearly 

vertical. South of Sevier 

Canyon the dip varies fron1 

steep westerly to vertical. 

The li1nestone on both sides 

of Sevier Canyon clips beneath 

quartzite. A sn1aller limestone area extends north and 

south across Oak Creek. Its 

beds show a monoclinal structure, clipping 70° W. beneath FIGURE 5.-Vicw across North Fork of Yellowstone River, Canyon Range, Utah, looking northl · d west from Arbroath shaft. t 1e quartz1te an are separated on the east from quartzite by a strike fault. Limestone is also said to be exposed in the 

narrow southern part of the range, near Scipio. A lens of lin1estone in quartzite ·was noted on 

the north side of Fool Creek. This lies well above the main li1nestone formation. 

The lithologic character of the limeatone varies somewhat in different places. The lowest 

strata seen, about 3 1niles northwest of Sevier Canyon, are thick ·to rather thin bedded, of mediunl to clark gray color, and fine to rather coarse grained in texture. Fossils are fairly abundant 

in certain beds. At a higher horizon, due north of Parley station, which is 5 n1iles northeast 

of Lea1nington, intercalated beds of s_hale are conspicuous. About a n1ile north of Parley 

station, on the east wall of a southward-sloping canyon, there is a pron1inent. bluff of vertical 

strata which consists largely of conglo1nerate c01nposed of li1nestone and chert pebbles and 

which lie within the zone of intercalated shale beds. The stratigraphic. significance of this 

conglon1erate can not be determined without detailed study, but fron1 the paleontologic evidence 

(seep. 54) it appears to be only a local variation within a single lin1estone formation. · 

The uppermost limestone beds vary in character at ciifferent places. On the west slope of 

the range, northwest of Sevier Canyon, they are very cherty, nodules. and continuous bands 

of chert comprising as 1nuch as 50 per cent of some beds. Perfect pseudon1orphs of brachiopod 

shells are conspicuous in 1nuch of the chert. Shale beds at this place are not conspicuous, and 

the gradation from limestone upward into quartzite appears to be n1arked by increase in chert. 

The exact relations of the chert to the quartzite were not ascertained. 
54 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

In vVoocl Canyon the uppermost beds are of light to n1ecliun1'gray color and are dolomitiC. 

~Iany of them are characterized by a concretionary or pisolitic structure, the concretions ranging 

up to an inch or more in diameter and offering greater resistance to weathering than the matrix. 

Above and intercalated with these strata are beds of striped shaly limestone, alternating with 

shale, and these in turn are overlain by a bed of brown ferruginous quartzite, which is followed 

by typical quartzite. 

At no place is the entire thickness of the lin1estone exposed. A rough estimate of the 

exposed thickness northwest of Sevier Canyon gives 1, 700 to 2,000 feet, but there are so many 

local variations in strike and clip that there are many chances for error in this estimate. The 

thickness of the limestone in Yellowstone Canyon is certainly much greater, but the entire 

exposed width was not studied, and the lower part of the limestone is concealed beneath thick 

bodies of Eocene conglomerate. In Oak Creek Canyon the exposed thickness is i"t,t least 3,500 

and may be over 4,000 feet. · 

Fossils collected from the upper cherty limestone beds on the west slope of the range, 

2! to 3 miles northeast of Leamington station, were determined by G. H. Girty, of the United 

States Geological Survey, as follows: 

Crinoid stems, large and numerous. 

Zaphrentis sp. 

Schuchertella chemungensis? 

Schizophoria swallowi? 

Spirifer centronatus. 

SpiPifer incertus? 

Syringothyris carteri. 

Cliothyridina aff. sublamellosa. 

Another lot, collected at a horizon much lower stratigraphically, in the saddle between the 

two main ridges of the range, about 2~ miles north of Parley station, contains Spirifer centronatus and Oomposita humilis. Mr. Girty states that the first lot "is clearly of lower Mississippian or :Madison facies," and that the sec'ond lot "is less diagnostic, since there are two 

Pennsylvanian speciea very similar to the only two comprised in the collection. but since the'' 

latter occurs below the first it must needs be Madison also." Fragments of fossils similar to' 

those listed above were noted in Yellowstone Canyon in the upper part of th~ limestone. 

The fossils prove the upper 1, 700 to 2,000 feet of the limestone to be of lower Mississippian 

or :Madison age. Lower portions may prove, on close study, to be older than ~1ississippian. 

In the Tintic district, 12 miles north of the Canyon Range, limestone of ~1ississippian age is 

2,000 to 2,250 feet thick and is underlain by 4,400 to 4,600 feet of Cambrian and Ordovician 

limestone. In the southern Wasatch Mountains similar conditions are found, but only 21400 or 

2,500 feet of the older limestones are present. These two sections are the basis for the suggestion that the lower part of the limestone in the Canyon Range may be -of pre-Mississippian age. 

QUARTZITE. 

The quartzite of the Canyon Range is exposed along the western half of Sevier Canvon 

~mel extends continuously southward well· beyond Oak Creek. South of the divide bet;een 

the Yellowstone and Fool Creek canyons the quartzite constitutes the summit and entire 

western slope .of the range, with the exception of the faulted band of limestone (p. 53) across 

Oak Creek. 

The quartzite as a rule is of fine, even grain and varies in color from nearly white to light 

and dark brown or reddish brown. Some of its beds are greenish. Its general appearance is 

very similar to that of the thick Cambrian quartzite exposed in the Tintic district and at severa] 

places along the Wasatch Range, thus accounting for the fact that the quartzite has heretofore 

been regarded as of Cambrian age. 

The quartzite contains a conspicuous and persistent dark-reddish finely banded membe.r, 

400 or 500 feet thick, ~hich is a convenient horizon marker and indicator of the geologic structure. (See figs. 6 and 7.) The northernmost exposure of this member is on the south side 

of Sevier Canyon, near its mouth, where it stands vertical in a pinched synclinal trough of 

southweaterly pitch. It was not traced southward across Wood and Yellowstone canyons. 
A RECON.NAISSANCE IN THE CANYON RANGE, UTAH. 55 

but is undoubtedly present in that part of tho range. South of Yellowstone Canyon the rod 

JUOlllber follows the ~vest edge of the range almost as far south as Fool Creek. It then swings 

southeast, crossing tho lower part of Fool.Creek canyon, and following an undulating course, 

probal?lY passing north and east of Fool Creek Peak, the highest peak of the range. South 

of Fool Creek canyon the red n1e1nber is probably present in the western part of the range, but 

was· soon only in the Yicinity of Oak Creek. North of Oak Creek canyon it is again prominent 

along tho west edge of the range and is exposed in a Yery gentle anticline for a considerable 

distance along both walls of the canyon, fro1u a point 11ear its mouth to thefit·st north branch. Hero 

a sudden steepening of the easterly dip carries it below the surface, but it reappears about a 

mile fn.rthor up the canyon a short distance west of the limestone band. It again appears in 

the. trough of a gentle syncline on the north. slope of the canyon near its head. It was not 

followed south of On.k Creek canyon·. 

Yz 

a 

b 

Approximate scale 

·o 2 ~iles 

~~--~--~~------------~--~------~ 

Elevation 

5,000 feet 

Elevation 

·s.OOOfeet 

FIGURE 6.-Goncro.lizod section along north (a) and south (b) sides of Fool Creek canyon, Uto.l1. 1, Tertiary conglomerate and sandstone; 2, Car· 

bonifcrous quartzite; 3, red member of the quartzite; 41 Carboniferous limestone; 5, limestone lentil in quartzite. 

FIGURE 7.-Gonero.lized section o.loug north side of Oak Creek canyon, .Utah. 1, Tertiary conglomerate and sandstone; 2, Carboniferous quartzite; 

3, red member of the quartzite; 4, Carboniferous limestone. 

One lens of gray limestone, mentioned on page 53, was noted on the north side of Fool 

Creek canyon. Detailed study may proYe the presence of several such lenses. 

The entire thickness of the quartzite was at no place exposed, owing to erosion of its upper 

portion. On the north side of Fool Creek canyon (fig. 6) the thickness of the exposed vertical 

strata on the east limb of the close antic1ine appears to be at least 5,000 feet. Elsewhere the 

variations in dip prevented a closer esti1nate. 

No fossils .were found in the quartzite, but its apparent conformable position aboYe limestone of Madison age suggests that its lower part at le.ast is J\1ississippian. Its upper part 

may be Pennsylvanian. A sin1ilar quartzite of . gre_aJ. thickness, containing some limestone 

.beds, forms the greater part of the West Tintic J\1ountains, the southern end of which is almost 

connected with the n~rthwest e1l.d· of the Canyon Range, and the writer has found upper Mississippian fossils in the limestone beds. Correlation, therefore, with this quartzite fixes the 

age .of ~he quartzite of the Canyon Range a;; upper J\1:ississippian. 
56 SHORTER CONTRIBUTIONS TO GENERAL· GEOLOGY, 1914. 

The upper Mississippian studied by the writer in the Tintic :Mountains north of the Canyon 

Range and east of the West Tin tic Range c·onsists of a thick series of alternating limestone, shale,· 

and sandstone or quartzite beds. The same series, 5,000 to 6,000 feet thick, is present in the 

southern part of the Oquirrh Range, 1 and is overlain by the thick Bingham quartzite, which 

has been referred by Girty to the Pennsylvanian series.2 In the Wasatch Mountai.lls the same 

intercalated series of limestones, shale, and sandstone is overlain by the Weber quartzite of 

Pennsylvanian age. These data indicate a transition northward and eastward from quartzite 

into strata composed largely of limestone and shale, and suggest that in late Mississippian and 

Pennsylvanian time the deposition of siliceous sediment was extended northward and eastward, 

overlapping the intercalated beds of limestone, shale, and sandstone. 

EOCENE CONGLOMERATE. 

The Eocene conglomerate is almost wholly confined to the east half of the range. A few 

small outliers were:noted on the higher spurs north of Fool Creek, and their approximate posi-

. tions are shown in figures. 4 

Mississippian and 6! A considerable area, 

li·mestone · · h' h h Mi~s·,ssippian In w IC t e rocks are very 

~'mie~$~~~n~e~~~~~~~~~~~~~~~~~~~~~~ poorly~pOM~W~~aV&Md 

FIGURE 8.---Eocene conglomerate resting on upturned Mississippian (or older) limestone, at 

head of Yellowstone Canyon, Utah. 

along the low foothills north 

of the town of Oak Creek. 

In the principal area the 

·Eocene consists of light-gray 

and red beds of conglomerate 

and sandstone, the conglomerate pebbles including limestone, quartzite, and chert. 

The western boundary of the 

principal area is exposed in 

Sevier Canyon near its northernmost point, where a coarse 

conglomerate rests unconformably on quartzite. On 

both sides of the canyon the boundary can easily be seen from a distance, owing to the 

n1arked contrast in color bet\veen the younger and older formations. South of the canyon 

the Eocene beds rest on the upturned lower Mississippian limestone and form the crest and 

upper west slope of the· range along the heads of Wood and Yellowstone <?anyons. (See fig. 8.) 

North of Fool Creek Peak the west boundary crosses the summit and extends along the eastern 

slope as far as the saddle at the head of Oak Creek canyon, where the contact is well exposed, 

the Eocene beds, with a dip of about 10° E., abutting against a steep erosion surface of quartzite. 

This relation of dip to contact indicates a very uneven pre-Eocene topography. 

· The Eocene_beds at the top of the saddle have disintegrated into l9ose cobbles and pebbles, 

with only scattered remnants of solid conglomerate. This disintegrated area lies b.etween 

quartzite summits and is further indication of the unevenness of the Eo.cene topography. 

The small outliers north and south of Fool Creek were recognized from a distance by their 

characteristic red color and by their rounded weathered surfaces, which sharply contrasted 

with the angular surfaces of the surrounding quartzite. The outliers occupied depressions 

between quartzite summits, suggesting that the basal portion of the Eocene conglomerate 

was deposited in strike valleys. (See fig. 6.) The existence of these pre-:Eocene strike valleys 

at the heads of present strike valleys suggests that the present drainage is essentially the same 

as in pre-Eocene time, and may thus account for the shapes of the canyons, which, as already 

remarked (p. 52), are unusually_ broad in comparison to their lengths .. 

1 Spurr, J. E., Economic geology of the Mercur mining district, Utah: U.S. Geol. Survey, Sixteenth Ann. Rept., pt. 2, p. 377,1896. 

2 Boutwell, J. M., Economic geology of the Bingham mining district, Utah: U. s: Geol. Survey Prof. Paper 38, appendix, p. 387, 1905. ~ 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE IX 

LAKE BONNEVILLE BEDS AT THE MOUTH OF SEVIER CANYON, NEAR LEAMINGTON, UTAH. 
A RECONNAISSANCE IN THE CANYON RANGE, UTAH. 57 

'l"'he rocks which form the low foothills north of Oak Creek ru:e almost completely reduced 

to a loose mass of lim.es.tone, quartzite, and chert cobbles, with a few ·remnants of consolidated 

conglo1uerate. These rmnnants fw·nish the clue to the origin of the foothills, which without 

thetu could not be explained, as the foothills are bounded on all sides by steep slopes and bear 

no direct relation whatever to the Quaternary alluvial deposits: The presence of the Eocene 

1naterial in these deposits is presumably clue to the sinking of a block dw·ing the faulting period 

when the Basin Ranges were developed. This occurrence extends the western boundary of 

Eocene deposition somewhat fartner westward than has heretofore been indicated. 

As only the eroded western edge of the Eocene beds was studied no idea of its thickness 

was gained. The beds are assigned to the Eocene by correlation with similar strata in the 

southern vVasatch l\1ountains- 1 and i1~ the ranges imn1ediately east of the Canyon Range. 2 

QUATERNARY DEPOSITS. 

The Quaternary deposits ii1clude the Lake Bonneville beds of clay and marl deposited in 

Pleistocene time and the overlying alluvial deposits at the mouths of the canyons. The Lake 

Bonneville beds are terraced by Sevier River and are well exposed at Leamington and along the 

.sides ofSevier Canyon, as shown in Plate IX. No special attention was given to these deposits 

by the writer, and the reader is referred for further information to Gilbert's monograph. 3 

VOLCANIC ROCKS. 

No volcanic rocks were seen at close range. From a distance a bed of dark columnar 

volcanic rock was seen overlying EoceJ.?,e beds northeast of the canyon, and its approximate 

location is shown in figure 6. Volcanic -i·ocks are said to be abundant in the extreme northern 

part of the range, and porphyry dikes are reported along Dry Canyon, south of Oak Creek.4 

STRUCTURE. 

The Carboniferous rocks are characterized by a few n1ajor folds with.steep dips, by several 

intervening minor folds with gentle dips, and by a prominent strike fault which appears to be 

coincident with a broken anticline. The northernmost major fold is the unsymmetrical syncline of southwesterly pitch, whose a.xial plane is nearly parallel with the western half of Sevier 

Canyon. Its northwestern lin1b has a moderate clip, 25° to 40°, which becon1es lower away 

from the a.."\:is, passing into an area of prevailingly monoclinal structure, though the general 

low and regular inclination of the beds is interrupted by several inconspicuous anticlines and 

synclines. The southeast limb is nearly or quite vertical along Sevier Canyon, but along vVoocl 

and Yellowstone canyons its prevailing dip is near 45°. · 

In Fool Creek canyon an anticline and syncline with north-south axes are exposed. (See 

fig. 6.) On the north side the details of the structure are not very clear. The moderate 

westerly dip of the quartzite changes eastward to vertical, the latter persisting for about 1! 

miles and then gradually changing to a moderate westerly dip, which continues eastward 

probably to the crest of the range. The only clue to the structure is given by the red quartzite n1ember, aided by c01npar:ison with the simpler structure on the south side of the canyon, 

which shows the strata to be folded into a close anticline of. vertical dip and an unsymmetrical 

syncline with vertical west l:il)lb ancln1oderately dipping east limb. Detailed study, however, 

may show the vertical strata to be more complexly folded than figure 6 ~ndicates. The struc- · 

ture Oli the south side of the canyon (fig. 6) needs no special con1ment. The lengths of these folds 

are not de:fi.nitely known, but the anticline may extend as far· no1:th as the rim of the south fork 

of Yellowstone Canyon, where the uppermost limestone beds stand nearly vertical. That the limestone is probably not far below the surface where the anticline crosses Fool Creek n1ay be inferred 

1 Loughlin, G. F., Jour. Geology, vol. 21, p. 448, 1913. 

2 U.S. Geog. Surveys W.lOOth Mer., atlas sheet 50. 

a Gilbert, G. K., Lake Bonneville: U.S. Geol. Survey Mon. 1, pp. 104, 166, 192, and 193,1890. 4 Oral information by James Overson, of Leamington, Utah. 
58 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 19~4. 

by the proximity of the red 1nember of the quartzite to the top of the liinestone in Sevier and 

Oak Creek canyons. 

Between Fool Creek and Oak Creek canyons several 1nii~or folds can be seen fron1 -the 

western foothills. In the lower part of Oak Creek canyon a gentle anticline with.lin1bs clipping 

about 10° is well exposed. About 2 miles above the mouth tlus passes into a synclille, both of 

whose limbs dip 60° to 70°. The syncline, however, is not sy1nmetrical. (See fig. 7.) The 

west limb is relatively sn1all, but the east limb is at least 1! n1iles in horizontal width and b1ings 

the limestone to the surface. The limestone is bounded on the east by the strike fault already 

mentioned, which separates it from quartzite of ge1itle easterly dip. ·The actual fault plane or 

zone is concealed, but the dips of the strata to either side of it north of the creek suggest a 

compression fault. (See fig. 7 .) The fault appears to die out both southward and northward. 

Northward it appears to pass into an anticline whose axis is in the limestmie; southward its 

relation to folding is not so clear, as the axes of the folds there swing southeastward and the 

trend of the fault is obscure. East of the fault the quartzite is folded into a rather gentle 

syncline and anticline, the anticlinal axis lying just east of the crest of the range. 

The character of the folds show that in the central and southern parts of the range the dominant c01npressive force was eastward, whereas in the northern part the prevailing force was 

northwestward. No expla1~ation of this difference in direction is warranted from so brief a 

study of this limited area. 

GEOLOGIC HISTORY. 

The geologic history of the Canyon Range may be summarized as follows: Deposition of 

limestone in early Mississippian and perhaps in still earlier time were followed by deposition of 

quartzite which continued during later Mississippian and possibly Pennsylvanian tin1e. The 

next recorded event was the folding of these sediments, which presumably took place during 

the post-Jurassic upheaval that affected a great part of the Cordilleran region. The period of 

fplding was followed by one of erosion, during which the rocks were dissected into ridges and 

valleys generally similar to those of to-day. The steep east slope along the southern part of 

the range, against which the Eocene strata are banked, was evidently forn1ed at this tin1e, and 

it is probable that a pronounced valley was developed in the Sevier Canyon syncline. Deposition during this erosion interval is represented by Cretaceous strata in t~e country to the south 

and east of the Canyon Range, and it is possible that the lowest beds called Eocene in the 

Canyon Range are Cretaceous. This deposition continued in the Eocene, during which the crest 

of the range was probably entirely covered by conglon1erate and sandstone. The volcanic rocks 

were erupted in late Eocene or post-Eocene time. 

The volcanic epoch was followed by the period of profound faulting in late Tertiary time 

which developed the Basin Ranges. One of these faults extends along the west base of the 

range, separating it from another block which moved downward and has left only its cap of 

disintegrated Eocene conglomerate above the present surface. A period of rapid erosion followed, during which all the Eocene strata were removed from the west side of the range save 

·a few remnants ·which occupied the heads of old north-south valleys. During this combined 

period of uplift and erosion, Sevier River eroded its channel through the soft Eocene rocks fast 

enough to maintain its course. After it had worn through the Eocene strata which formerly 

existed on the west side of tpe present range its course was guided _by the pronounced southwestpitching synqline, along which, as was just suggested, a valley may have existed in pre-Eocene 

time. , 

During a late stage in the erosion period, after the ·outline of the range was developed into 

virtually its pr~sent for-m, the surrounding lowlands were covered by the waters of Lake Bonneville, which at their highest (Bonneville) stage occupied Sevier Canyon and formed a landlocked ·bay on the east side of the range:- -It was in this stage that the fine material Dfthe 

lake beds was deposited. Later, during the Provo stage of the lake, the waters lowered until 

they receded from the canyon, and Sevier River resumed its cQurse, cutting its channelinto 

\ 
A RECONNAISSANCE IN THE CANYON RANGE, UTAH. 59 

the lake beds and building a low delta from Leamington southwestward to Deseret. Final 

· recession of the lake waters left the topography essentially as it is to-day. The only noteworth}r 

work of subsequent erosion was the further cuttjng of the .Sevier channel through the newly 

fonned delta. · ORE DEPOSITS. 

Ore deposits thus far worked or prospected in the Canyon Range comprise only a fe~v 

s1uall bodies of lead or lead-zinc ore in Wood and Yellowstone canyons and some quartz veins 

stained with copper carbonates near Fool Creek and Dry canyons. Only two properties, so 

far as the writer has learned, have shipped ore. 

LEAD AND ZINC. 

Yellowstone mine.-The Yellowstone n1ine is located in the south fork of Yellowstone Canyon, 

about 4 1niles southeast of Lea1nington. The workings include an inclined shaft 200 feet deep, 

following the dip of the lhnestone, abo;ut 60° W., and drifts at the 50, 100, and 170 foot levels. 

The country rock includes the uppermost beds of limestone. The ore forms small replacement 

bodies along the intersection of one of the limestone beds by fissures. On the 50-foot level small 

bodies were stoped along the intersection of the bed with a north-south strike fissure and one 

body where the bed was somewhat shattered at the intersection of the strike fissure and an 

east-west cross fissure. The 100-foot level was inaccessible. The 170-foot level follows the 

contact between a shale and lin1estone bed, along which there is a zone of veinlets, consisting 

chiefly of spar (dolomite and calcite), which are said to assay 3 to 4 per cent lead. 

The ore stoped consisted principally of galena and cerusite (lead carbonate) in a gangue 

of ferruginous -dolonrite .and calcite spar .. A little secondary aragonite was noted on a crust 

of fibrous calcite that lined a pocket along the strike fissure on the 50-foot level. Assays of the 

ore have run fr01n 30 to 65 per cent lead, the higher grade carrying 5 to 6 ounces of silver. A 

little gold has also been reported. The mine has been worked intermittently and has shipped 

only about 15 carloads of ore in over 20 years. No zinc has been found. 

Arbroath mine.-The Arbroath shaft is situated about an eighth. of a mile north of the 

Yellowstone, in a low spur which separates the south fork from the nor.th fork of Yellowstone 

Canyon. The writer did not gain access to the mine, which was idle, but the n1aterial on the 

dump showed the 1nineralization to be of the same type as that of the Yellowstone mine. The 

ore thus far found during assessn1ent work is reported to be of two grades, the higher carrying 

76 per cent lead and 9 ounces silver, and the lower 10 to 11 per cent lead and 1 ounce silver. 

Only a sn1all quantity of ore has been found thus far. 

Wood Oanyon grou1J.-The Wood Canyon group of claims is situated on the north side of 

Wood Canyon and includes the uppermost beds of the limestone formation. The mineralized 

outcrop is a brown, rust-stained dolomitic bed, contahring a large an1ount of ferruginous doloInite spar, white where fresh and brown where weathered, through 'vhich are scattered grains 

of galena and yellowish-brown zinc blende. The stained rock i.::; closely associated with two 

fiSsures, one tending no~·th-south and the other of S. 55° E., both of whose outcrops are marked 

by shallow gulches. Plans for dry conc~ntration of the ore were being considered in the summer 

of 1913. No assays, either of crude ore or concentrates, had been made.· 

COPPER PROSPECTS. 

A small copper prospect in quartzite is situated ·on the low ridge just north of 'the mouth of 

Fool Creek canyon. The mineralized material thus far found is white vein quartz with numerous minute fractures stained by.films of green and blue copper carbonates, with small spots and 

patches of clark brown iron oxide evidently derived through oxidation of pyrite and chalcopyrite. 

Other copper and lead prospects have been reported along Dry Canyon, south of Oak Creek, 

but the writer's attempts to get in touch with the owners were not successful, and he could learn 

nothing further in regard t<? the deposits. 

37183°-15-5 
60 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

COMPARISON WITH ORES OF OTHER DISTRICTS. 

The lead and lead-zinc ores above described are similar in mineralogy and mode of occurrence 

to certain ores in the North Tin tic, East Tin tic, Santaquin, and Mount N ebo districts. These 

ores, which as a rule occur rather remote from important bodies of intrusive igneous rock, consist essentially of galena, zinc blende, and· more or less pyrite, or oxidation products of these 

sulphides, with gangues of dolomite and calcite, and only minor amounts of quartz. Their 

silver content is low, averaging as a rule 3 to 5 ounces, but in some deposits rising as high as 

8 to 10 ounces per ton. The sizes and shapes of ore bodies vary according to conditions; strong 

fissures may contain continuous veins; permeable beds of pure limestone may be rather extensively replaced; but argillaceous and dolomitic beds have yie!ded only small bodies of high-grade 

sre and a few more extensive bodies of milling ore. The ore bodies of the Canyon Range are 

no exception to this rule. Those mined up to the present have replaced dolomitic limestone 

beds along their intersections with narrow fissures and are small or of low grade. The highergrade ore bodies when found may be mined at no great expense, but the cost of prospecting for 

riew bodies after old ones have become exhausted is likely to equal or exceed the net receiptsfrom ore sales. · 

In some of the districts above named there are small copper prospects near the lead and 

zinc ·mines. These, according to the "Writer's experience, are quartz veins containing chalcopyrite and pyrite or their oxidation products and are confined to the siliceous rocks-quartzite, 

schist, or granite. The copper prospects of the Canyon Range may, from the meager knowledge 

available, be classed with this type. Veins intermediate in composition between these arid the 

lead and zinc deposits have occasionally been found, and suggest that the two types were derived 

from a common source. None of these copper-bearing veins, to the writer's knowledge, have 

yielded steady shipments of ore. · 
THE. MONTANA GROUP OF NORTHWESTERN MONTANA. 

By EuGENE STEBINGER. 

INTRODUCTION. 

Recent field work has shown that the formations of the Montana group in and near the 

Blackfeet Indian Reservation of northwestern Montana are very different from those of the 

type area of the Judith River and associated formations on Missouri and Musselshell rivers, 

in the central part of the State, but similar to the formations in southern Alberta as described 

by Dawson. They seem to deserve special description not only because they present new 

e'-ridence regarding the relations of the Belly River forn1ation of Canada to the Judith River 

forrnation, but also because they indicate the varying geographic conditions that prevailed 

d1uing Cretaceous time in· this region. Furthermore, the stratigraphy. as interpreted affords 

an excellent example of variation in sedimentation fro~1 the seaward to the landward side of a 

zone of deposition. 

The Montana group, as here described, was first studied by the writer in the summer of 

1911, along Cut Bank Creek and ·Two Medicine River on the Blackfeet Indian Reservation, 

in company with Mr. T. W. Stanton, who has already briefly described some of the features 

of this region 1 and to whom the writer is much indebted for paleontologic determinations 

which, especially those for the marine formations encountered, were of great assistance in 

interpreting the· stratigraphy. During the next two seasons these formations were traced 

northward into the type area of the Belly River beds, described by G. M. Dawson 2 in 1885, 

·and eastward into an area of the Judith River forn1ation, as definitely determined by Stanton 

and I-Iatcher 8 in 1903. The interpretation of the field relations presented is therefore based 

primarily on the areal tracing of the formations, although every conclusion was substantiated 

by paleontologic evidence. 

FORMATIONS CONSTITUTING. THE MONTANA· GROUP. 

SECTION ON TWO MEDICINE. RIVER. 

A section showing the complete sequence of the formations of the Montana group in northwestern Mont_ana is exposed along the valley of Two Medicine River in the southern part of the 

Blackfeet Indian Reservation, and ~because ·of its completeness and of the excellence of the 

exposures is offered as a standa~d for the region. The section extends westward upstream 

fron1 the n1outh of the river, in T. 31 N., R. 5 W., to a point about 3 miles above the Holy 

Family Mission (Fan1ily post office), in T. 31 N., R. 9 W. Throughout this distance, about 35 

miles, the formations either lie nearly flat or dip slightly ·westward at an angle i:arely exceeding 

3°. As the river runs nearly at a right angle to the strike, it crosses the formations in succession 

fron1 yOlmger to older. On the whole the locality is almost ideal for a study ,.of the formations, 

the structure being sin1ple and easily determined and the rocks perfectly exposed throughout 

most .of the distance in the rninutely carved badlands along the sides of the valley. 

1 Sto.nton, '1'. W., Some vllriutions in Upper Cretaceous stratigraphy; presidential address before the Geological Society of Washington, 1912: 

Washington Acad. Sci. Jour., vol. 3, pp. 66-69, 1913. 

2 Report on tho region in the vicinity of the Bow and Be.lly rivers, Northwest Territory: Canada Geol. Survey Rept. Progress for 1882-1884, 

pp. 1-169c. 

a Stanton, '1'. W., ami Hatcher, J. B., Geology and paleontology oftheJudith Riverbeds, with a chapter on the fossil plants by F. ll. Knowlton: 

U. S. Geol. Survey Bull. 257, pp. 51-53, 1905. 

61 
62 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

From the to.p of the Colorado shale, which is readily recognized by its characteristic marine 

fauna and general appearance, the rock~ naturally group themselves in ascending order into 

four lithologic units-(1) a massive gray sandstone, chiefly marine; (2) a rudely bedded 111ass 

of clay and sandstone, chiefly a fresh-water deposit; (3) a dark n1arine clay shale; and (4) a 

massive gray sandstone, brackish and marine. Nos. 1 and 3 correspond to the Virgelle sandstone, as the lower sandstone men1ber of the Eagle sandstone has recently been designated, 1 

·and to the Bearpaw shale of the Missouri aud Musselshell river section in- central }.!fontana, 

whereas Nos. 2 and 4, formations hitherto not recognized, whose stratigraphic equivalents 

elsewhere are represented by formations having different limits and lithology, are here named 

the Two Medicine formation and Horsethief sandstone. The important details of the section 

are shown below. 

Formations of the jJ-fontana group of northwest )fontana exposed on Two Medicine River between its nwuth and Family 

post o.fjice. · 

'!'hickFormation. Lithology. Fossils. Topographic features. ness in 

feet. 

Gray to buff coarse-grained, much Mainly a brackish-water fauna cross-bedded, massive sandstone containing Ostrea1 Corbicula, Where the formation lies nearly in upper half. In lower half horizontal it may form a bold 

1Iorsethief sandstone. slabby gray sandstone, becom- Corbula,and Anomia. In places escarpment; where it is steeply 3GO 

ing shaly toward the base. In a marine littoral fauna yielding tilted it forms prominent hog- Tancredia americana, Cardium ~laces beds of heavy magnetite- speciosum, and Mactra. back ridges. caring sandstone. 

--- An abundant marine fauna Subdued and rounded topog- Dark-gray clay shale with a few ifierre) containing Baculites, Bearpaw shale. limestone concretions. lacenticeras~noceramus, A vic- raphy, gumbo soil, and few 490 

ula, and Scap ites. · exposures. 

An abundant reptilian fauna of I 

Judith. River types. At many 

Gray to greenish-gray clay and horizons a fresh-water fauna 

containing Unio, Viviparus and Eroded into extensive badlands soft irregular.sandstone which is Campeloma; at others brackish- along principal streams; else- Two Medicine formation. most abundant in the lower 250 1,950 feet. In places thin beds of red water forms, Ostrea, Corbula, "hereasmooth'rounded topogclay and nodular limestone. etc. One marine horizon yield- raphy. 

ing Tancredia americana, Cardium speciosum, Mactra, land 

plants, and much fossil wood. 

Gray to buff coarse-grained, much 'Vbere the formation lies nearly cross-bedded, massive sandstone horizontal it .forms a bold esVirgelle sandstone. with many ferruginous concre- Contains a poorly developed lit- carpment in many places; 220 tions in upper half. In lower toral marine fauna. .where it .is steeply tilted it 

half slabby gray sandstone, be- forms prominent hogback coming shaly toward the base. ridges. 

VIRGELLE SANDSTONE AND HORSETHIEF SANDSTONE. 

Both these formations are composed of massive gray to buff sandstone, and although they 

are 2,500 feet apart stratigraphically they are so nearly identical that they can best be described 

together. Each seems to be a sandy beach or near-shore deposit laid down in a retreating sea; 

the Virgelle representing a great recession of the Colorado sea at the close of Coiorado· tinte 

and the Horsethief representing an· even greater recession at the close of Pierre time. The two 

are therefore genetically identical, each being a sandstone laid do·wn on a marine shale in a 

retreating ~ea. Similar rocks are associated with both of these formations, each beil.1g overlain 

1 Unpublished report by C. F. Bowen entitled "The stratigraphy of the Montana group" (U.S. Geol. Survey Prof. Paper 9Q-I), from which 

the following definition is quoted: "The name Eagle sandstone was given by Weed (U.S. Geol. Survey Geol. Atlas, Fort Benton folio, No. 55) 

to the formation overlying the Colorado shale in north-central Montana and typically exposed on Missouri River at the mouth of Eagle Creek, 40 

miles below Fort Benton. In the type locality the formation as defined by Weed consists of three more or less distinct units, comprising an 

upper member of thin-bedded sandstone, a middle member of shale, and a lower member of massive ledge-making sandstone. This lower member is so persistent and characteristic over a large area in north-central Montana, even where the other divisions of the formation are not re~ognizable, that it seems desirable for purposes of description and correlation to give it a name. ·It is well exposed along Missouri River from 

the town of Virgelle, a few miles below Fort Benton, eastward, and the name Virgelle sandstone member of the Eagle sandstone has therefore 

been adopted by the United States Geological Survey for this division of the formation. The Virgelle sandstone member is the lower massive 

ledge-making sandstone of the Eagle sandstone as defined by Weed." In northwestern Mont!J.na the Virgelle sandstone is recognized as a distinct 

formation, and the overlying Two Medicine formation includes the equivalent of the remainder of the Eagle sandstone. · 
THE MONTANA GROUP OF NORTHWESTER-N MONTANA. 63 

by a thick n1ass of continentn,l deposits, apparently conforn1able and very si1nilar in cmnposition 

and appearance. 

In the section along Two :Medicine River the Virgelle sandstone rises in bold cliffs above 

the few feet of sanely shale that forn1 the uppern1ost beds of the Colorado group exposed 

at the n1outh of the river. Frmn this point .the sandstone, clipping very slightly westward, is 

continuously exposed upstrean1 for a distance of 8 nriles, fonning a narrow, steep-walled canyon 

several hundred feet deep, which is a little-known but picturesque feature of tlris part of ~1ontana. Similarly the IIorsethief sandstone, where it is cut through by Two ~1edicine River just 

above l'fa1nily post office, also stands <?Ut in bold cliffs over 300 feet high. 

The principal fossils found in· these sandstones are invertebrates, although in n1any places 

both the formations, especially the Virgelle, semn barren. The Horsethief sandstone (named 

for IIorsetlrief Ridge, in the Blackfoot qua.clrangle) has yielded both 1narine and brackish water 

forms. The brackish Witter forms are n1:1inly oysters, which are locally very abundant; the 

marine forms belong to the Fox Hills near-shore fauna, the dominant species being Tancredia 

americana and Oa?Ylium s1Jeciosum. On Two Medicine River the Virgelle sandstone is apparently unfossiliferous, but elsewhere it is known to contain a marine near-shore fauna. 

TWO MEDICINE FORMATION. 

The Two ~1edicine formation, wlrich lies immediately above the Virgelle sandstone, is a 

great n1w:;s of light-colored rocks about 2,000 feet thick, consisting mainly of typical continental deposits. Frmn the upper end of the canyon in the Virgelle sandstone, in T. 31 N., 

R. 5 W., neftrly all the forn1ation is excellently exposed in badlands that extend for 20 miles 

upstremn to the n1outh of Badger Creek, in T. 31 N., R. 8 W. It is composed principally of 

light-gray to greenish-grfLy clay and clay shale, so rudely bedded that it is impossible to follow 

a given stratmn for any greftt distance. In places the beds of clay are variegated, red and 

yellow stn1ta appearing. Thin nodular and nonpersistent li1nestone, apparently of freshwater origin, also occurs at irregular intervals. Probably 20 per cent of the total n1ass of the 

formation is _1nacle up of soft coftrse-grainecl sandstone in lenticular beds which, even where 20 

to 30 feet thick, can not be traced n1ore than 1 or 2 miles. At many localities these sandstones 

show the very irregular Cl'Oss-bedcling that is characteristic of eolian deposits. The lower. 200 

feet of the fonnation is n1ore sanely than the remainder; probably half of this part consisting of 

n1assive sandstone in irregular beds, the thickest measuring 50 feet. 

A well-developed vertebrate fauna, chiefly dinosaurs of Judith River types, occurs in this 

forn}ation. The abundance of fossil bones, especially in the upper 200 feet, is unusual. C. W. 

Gilmore/ of the United States National Museum, who spent the season of 1913 in collecting 

frmn these beds, noted parts of 13 different individuals of dinosaurs in the course of a single 

dity's field work. :Much of the n1aterial collected by hiln is new and will add greatly to our 

knowledge of the Cretn.ceous reptiles. Fragments of fossil wood and many complete sections of 

tree trunks are also very comn1on throughout the formation. All the plant remains collected 

were identified by F. II. ICnowlton ·as "Belly River or Judith River." 

The fossil shells f01.ul.d in the Two Medicine forn1ation also indicate that it is essentially of 

cont~nental origin, Unio, Viviparus, and other fresh-water genera bemg found at many horizons. 

In the lower, sandy part of the forn1ation, as well as at the top, there are loeal thin brackishwater beds with Ostrea, Corbula, and Corbicula. A fauna indicating a temporary mcursion of 

purely marine waters while the forn1ation was being deposited occurs in a sandstone about 200 

feet above its base and has already been characterized by ~1r. Stanton 2 as a Claggett-Fox !Iills 

fauna. It is ahnost identical with the fauna found at the top of the 1-Iorsethicf sandstone, a fact 

that shows that it existed in the shallow-water portions of the Pierre sea throughout nearly 

all ~1ontil.llil. time. 

1 Personal communication. 

2 Stanton, '1'. ,V., Some variations in Upper Cretaceous stratigraphy: Washington Acad. Sci. Jour., vol. 3, p. G6, 1913. 
64 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1.914. 

BEARPAW SHALE. 

The Bearpaw shale is a typical dark marine clay shale aver~ging 500 feet in thickness in 

this part of the State. The change in the character of the rocks from the Two J\1edicine formation to this one is very abrupt, there being practically no transition beds near the contact, and 

although shallow water must have existed for some time at this horl.zon while the ~earpaw sea 

was advancing, no trace of. the marine fauna· of Fox Hills facies, noted in the Two J\1edicine 

formation and above in the Horsethief sandstone, has yet been fo~d here. Invertebrate 

fossils are abundant in concretions throughout ~he shale and are of characteristic Pierre types, 

allowing fairly close and certain correlation with the Bearpaw shale of central Montana. 

RELATIONS OF THE MONTANA GROUP TO THE BELLY RIVER AND JUDITH 

RIVER FORMATIONS. 

The age of the Judith River formation and its correlation with the Belly River forn1ation 

of Canada )lave been under discussion, mainly by paleontologists, ever since the Judith River 

beds were first studied. Nearly every worker who during the last 40 years has been interested 

in the Cretaceous formations of the Rocky Mountain and Great Plains regions has taken part 

in this discussion, the extensive literature of w)lich has been thoroughly reviewed by Str..nton 

and Hatcher. 1 In 1902, .on the publication of Lambe and Osborn's report 2 on the vertebrate 

fauna ,of the Belly River formation, the controversy 3 w~s revived with renewed vigor. So 

great ·a difference of opinion was developed during the following winter that Stanton and 

H~tcher 'decided on a joint field investigation, which they made in the summer of 1903. The 

tesults of their work were published first in a preliminary note 4 and later-.in a detail report. 

They determined the succession of formations in the Montana group for the central Montana 

region, which has since been found to extend over a large area, and proved the Cretaceous 

age of the Judith River formation. Then, by means of practically continuous exposures, they 

traced the Judith River formation into the extreme southeastern part of the large area of 

Belly River beds, as originally mapped by G. M. Dawson. 5 This _le~ to their second important conclusion, namely, that the Belly River formation and the Judith River formation are 

of identical age. Their conclusions were generally accepted as having satisfactorily answered 

this much-discussed question in Cretaceous stratigraphy. There was no reason to suspect that 

the type section of the Belly River beds as described by Dawson, occurring on Belly River, 

was different from that in the locality into which they had traced the Judith River formation. That these sections are diff~rent appeared only when the section here described was 

ex~mined and compared both with Dawson's section and with the section of Stanton ·and 

Hatcher on Missouri River. 

In a recent paper 6 A. C. Peale again raises the question of the age of the Judith River 

formation. He does not deny the existence of the formations of the Montana group in central 

Montana in the successioD: ae ori¢nally described by Stanton and Hatcher, nor that they 

extend over a large area in central Montana, as proved by C. F. Bowen, R. W. Stone; and 

other workers, but contends that beds originally called Judith River in the type area on the 

Missouri near the mouth of Judith River are of Lance age and are not equivalent to the formations mapped as Judith River over a large part of Montana. Peale's contention thus raisea the 

question of the exact in~erpretation of the structure and stratigraphy in the small disturbed 

type area at the mouth of Judith River, and if his view is substantiated the name Judith River, 

as applied to the formation which has been so extensively mapped under that name, will be 

1 Stanton, T. W., and Hatcher, J. B., Geology and paleontology of the Judith River beds: U. S. Geol. Survey Bull. 257, pp. 14-3l, 1905. 

2 On vertebrate of the mid-Cretaceous of the Northwest Territory: Lambe, L. l\f., New genera and species from the Belly River series (midCretaceous); Osborn, H. F., Distinctive characters of the mid-Cretl!.ceous fauna: Canada Geol. Survey. Contr. Canadian Paleontology, vol. 3, pl.~. 

1902. 

s Science, new ~cr., vols. 16, 17, 18. 

4 Hatcher, J. B., and Stanton, T. W., The stratigraphic position of the Judith River beds and their correlation with the Belly River beds: 

Science, new ser., vol. 18, pp. 211-212, 1903. 

5 Canada Geol. Survey Rept. Progress for 1882-1884, pp. 1-169c. 

o Jour. Geology, vol. 20, pp. 530-549. 
THE MONTANA GROUP OF NORTHWESTERN MONTANA. 65 

invalidated. Therefore, without entering into the -question raised by Peale, it is important to 

inaist that the correlations made later in this paper refer to the formation mapped as Judith 

River over nearly all·of central :Montana. · 

In the course of their stratigraphic study in central :Montana, Stanton and I-Iatcher established the succession shown in the following table: "

0 

.... 

Formnt;ion. 

R~~mlalll~!~~~ro;.;l;litiol.:::::::: Claggett formation.' ........... . 

Eagle so.ndstono ................ . 

Colomdo shale ................ . 

Sect·ion of Cretaceous rocks in cent~al Monta?w. 

ThickCharacter of rocks and fossils. ness in 

feet. 

Dark clay shale with marine fatma.................................................................... 750? 

Variable shale and soft so.ndstone with dinosaurs and other reptiles and fresh and brackish watershells.. 500 

Dark clay shale with several beds of sandstone, especially in tho upper part; marine fossils throughout, 400± 

those of tho sandstone including many Fox Hills species. White, gray,and yellowish massive sandstone in lower and shale, coal, and thin sandstone in upper part. 200-300 

Contains marine shells, land plants, and dinosaurs. 

Dark nu~rino shale .................................................................................. ~. 800+ 

On comparing this section with that on Two ~1edicine River, the Colorado shale, which 

can be traced continuously fro1n its outcrops on Missouri River to those at the mouth of the 

Two ~1edicine and is also easily recognized because of its characteristic marine fauna and 

appearance, affords a safe stratigraphic datu1n plane on which to base comparative sections. 

First of all, the identification of the sandstone lying above the Colorado shale in the Two Medicine 

section as the lower or Virgelle sandstone n1en1ber of the Eagle is n1ade fairly certain by both 

its position and the fact that it also can be traced on the outcrop over the greater part of the 

distance fron1 the exposures on: Two Medicine River to those on the ~1issouri at the type locality, 

though its li1ni.ts 1uay vary slightly fron1 point to point. The outcrop of this sandstone can be 

traced without interruption in bold cliff exposures frmn the mouth of Two Medicine River to 

the Sweetgrass llills. Fro1n this locality to ·the outcrops of the Eagle, near Virgelle, on the 

~1issouri, the bedrock for1nations are con1pletely covered with drift, but the continuity of the 

sandstone over all of this distance is suggested by its presence in a well· boring in T. 34 N., R. 8 E. 

The for1nation recognized as Bearpaw on Two Medicine River can not be traced to ~1issouri 

River in the sa1ne manner because.it has been eroded away between these localities, but fortunately a characteristic niarine fauna is found in the shale, which, together with the lithologic 

appearance, thickness, and relative position of the formation above the Colorado shale, makes 

its correlation with the Bearpaw shale of the ~1issouri River section about as certain as· a correlation of this sort can be. This leaves the Two ~1edicine formation occupying the entire interval 

between the Virgelle sandstone and the Bearpaw, and it is therefore equivaient to all the sb:ata 

on ~1issouri RiYer that 1nake up the Judith River formation, the Claggett formation, and the 

coal-bearing shale and sandstone forming the upper member of the Eagle sandstone. 

In his report on the region in the vicinity of the Bow and Belly rivers Dawson 1 established 

the following section for the Cretaceous rocks occurring there: 

}<ormation. 

Fox Hills sandstone .......... . 

Pierro shales .................. . 

Bolly Hivorseries ............ . 

Lower dark shales ............ . 

Section of Cretaceous rocks near Bow and Belly rivers, Canada. 

Character of rocks. 

In some parts of the district well defmed as a massive yellowish sandstone, but inconstant and appar- ently often represented by a series of brackish-water transition beds between the Laramie and Pterre. 

Neutral gray or brownish to nearly black shales, include a zone of pale soft sandstone in the north- eastern part of district and fre9uent intercalations of harder sandstones near the mountains. Marine. 

Composed or an upper or "pale 'and lower or "yellowish" portions, and consisting of alternations of 

sandstones, sandy clays, shales, and clays. 

Gray to nearly black shales, in places including arenaceous shales ..................................... . 

'I.' hickness in 

feet. 

so 

750 

910 

800 

This section was compared with the section on Two Medicine River and it was fortunately 

found possible to· trace all the n1en1bers of the Two Medicine section clue north to the equivalent 

parts of the section in Alberta without interruption in the outcrops. The Colorado shale 

t Canada Geol. Survey Rept. Progress for 1882-1884, p. 112-c. 
66 SHORTER CONTRIBUTIONS TO GENERAL GEOL09-Y, 1914, 

exposed at the mouth of Two Medicine River can be traced directly into an area near the international boundary mapped by Dawson as Lower dark shales. The Bearpaw shale can be traced · 

with equal facility into the shale 1napped by Dawson as Pierre, and the Horsethief sandstone 

into Dawson's Fox Hills sandstone. The strata designated by Dawson the Belly River series 

comprise all the rocks between his Lower dark shales and Pierre shales, so that if his Lower 

clark shales are Colorado shale, and his Pierre shale is Bearpaw, it becomes evident that his Belly 

River series, lying between these ·two marine shales, is equivalent to the Virgelle sandstone 

and Two Medicine formation taken together, for they lie between the san1e two n1arine shales 

and the formations are entirely conform.able; or, carrying the correlations to Stanton and 

Hatcher's section on Missouri River, it is apparent, fron1 the correlation between the section on 

Two Medicine River and that on the :Missouri, already made, that the Belly River formation 

of Canada is equivalent to the Eagle, Claggett, and Judith River forn1ations con1binecl. 

The correlations made by Stanton and Hatcher in 1903, by tracing the ~uclith River fornlation up Milk River into Canada to beds mapped as Belly River by Dawson, leading them to the 

conclusion that the Belly River and Judith River formations were identical, are correct as far as 

they had gone, as can be understood by reference 'to the diagran1 (fig 9). . Starting fron1 the section in central Montana, they traveled northwestward, following the wedge of the Judith River 

formation t·o a point on :Milk River near Pakowki Lake in Alberta, where the section is as at 

'A in the accompanying diagram and th~re found Claggett shale beneath the Judith River 1 

formation. But Dawson had already mapped the beds found in this locality as Belly River, 

so that Stanton and Hatcher were justified in assuming the identity of the Belly River and 

Judith River formations. Dawson had also seen and described the dark marine shale of the 

Claggett near Pakowki Lake, but had erroneously correlated it with his Lower dark shales . 

(Colorado shale) of the area he mapped farther west, so that the formation he h'ad mapped as 

Belly River in the vicinity of Pakowki Lake included only a part of the Belly River formation 

as he had defined it in his type area along BellyRiver. 

·Dawson's error in correlating beds in different parts of the area originally mapped as Belly 

River, although suspected by Stanton and Hatcher, 1 has apparently never been recognized by 

Canadian geologists,for since the publication of Stanton and Hatcher's report they have assun1ed 

that the section of the Montana group occurring on the :Missouri in central Montana was applicable to all the area of southern Alberta up to the base of the Rockies. This seems evident from 

a report by D. D. Cairnes, of the Canadian Geological Survey, on the :Moose :Mountain district/ 

a 'tract lying adjacent to the mountain front in the "disturbed belt" on the west edge of the 

large area originally mapped by Dawson. Cairnes has described Claggett shale from this 

district, but, reasoning from our present understanding of the relations between the Judith 

River and Claggett formations to the beds mapped by Dawson as Belly River, it seems highly 

improbable that a lithologic unit equivalent to the Claggett shale exists at any point in the 

western part of the area originally mapped by Dawson. Cairnes, because of the intricate structure of the foothill belt near the mountains, has p~obably nlistaken areas of 13earpaw shale for 

the Claggett, to which it is very similar both lithologically and in fossil content. 

RELATIONS OF THE CONTINENTAL TO THE MARINE SEDIMENTS I:N THE 

MONTANA GROUP. 

The formations at the locality on Two Medicine River described in this paper lie near the 

western edge of the Cretaceous interior basin. (See index map on fig. 9, showing the Cretaceous 

deposits of the interior basin of North An1erica.) No areas west of this locality afford exposures 

of the Montana group belonging to this basin, so that by comparing sections of the Montana 

from the Black Hills region, the central Montana region, and the section on Two Medicine River, 

all of which lie approxin1ately on a straight line, we are able to present correlations ofthis part 

of the Cretaceous from a point near the center of the Cretaceous basin to a point on the western 

1 Stanton, T. W., and Hatcher, J. B., Geology and paleontology of the Judith River beds: U. S. Geol. Survey Bull. 257, pp. 24-25, 1905. 

2 Moose Mountain district of southern Alberta: Canada Geol. Survey Bull. 968, pp. 26-29, 1907. · 
THE MONTANA GROUP OF NORTHWESTERN· MONTANA. 

edge of the strata as they now reInain. In other words, we can show 

the relations, definitely in son1e areas 

and with probability in others, of 

the sedituents that must have been 

deposited near the center of this 

:Montana sea to those along its western n1m·gin. . 

These relations are illustrated 

in the diagratn forming figure 9. 

The section at each of the localities 

given is built up on the top of the 

Colorado group as a datum plane, 

the rock units being all conformable 

and the thicknesses drawn to scale, 

so that the relative thickening or 

thinning of these units is properly 

indicated. The sedin1ents that are 

1nainly continental are indicated by 

open lining, those that are mainly 

1narine are shown in closer lining, 

and the three in1portant sandstone 

units of the group are shown in a stippled pattern. The general thickening 

of the strata on the landward side 

of the basin, due to the increase in 

the supply of material, is evident at 

a glance. The rec01:d from the top 

of the Colorado shale, a horizon that 

probably marks the period of maximum extent of the Upper Cretaceous 

sea in tluc; region, shows a series of 

advances and retreats of the sea on 

the westward or landward side of 

tlll.s basin, while 1narine conditions 

to the east or seaward side remained 

undisturbed. These were, as indicated by arrows on the diagram, 

first, a n1arked recession of the sea 

during wlrich the Virgelle sandstone 

was laid down, followed immediately by the, piling up of continental sedhnen ts which in the section on the Two :Medicine are represented by the strata at the base of 

the Two Medicine formation; next 

an advance of the sea which did 

not reach so far as Two Medicine 

River except in probably only one 

brief epoch, during which the wedge 

of the 1narine Claggett shale was 

deposited; next a second recession, 

during which again a shore sandX 

---+~~~~~~r--, 

~- ~ :s: -,-~~.....,...,........,.-rh~~.__- ~ ~- a 

c: 0> 

(JI 

0 

~ J 

OOl 

--P~...,_,._,~o...>.HI--- ~ ~ g.,.-

Q) :I: 

lv.---::--m:~~~f..:+-- ~ ~ 

'< - 0 

3 

:;· 

00. 

:l.~ 

67 
68 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

the upper part of the Claggett-was laid down. This recession was immediately followed by 

a period of continental deposition, in which was formed the wedge of the Judith River 

formation; then a. second advance-the Bearpaw-much more extensive than the Claggett, 

which, like the former advance, did not result in the deposition of any great amount of sand; 

and, lastly, a third and very extensive recession, probably the final one for the western part 

of the region considered, during which again a persistent and easily identifiable sandstone was 

laid down, this deposition being followed immediately by the piling up of continental sedin1ents. 

The deposition of a sand upon each retr-eat of the sea in contrast to the practical absence of such 

a sand on each advance is a notable phenomenon in this sedimentary record, and seems to indicate that each retreat of the sea was accompanied by land uplift with an increase in strea1n 

gradients and consequent coarsening of sediments and each advance by the opposite conditions. 

The close similarity between these three sandy formations is further brought out by the fact 

that they contain littoral marine faunas, those of the Fox Hills and Horsethief sandstones and 

the sandstone at the top of the Claggett being practically identical and that of the Virgelle being 

a direct forerunner of later faunas. 

Above the Horsethief sandstone in the section on Two Medicine River there are light-

. colored soft clayey and sandy strata, already referred to as of continental origin, that are identical 

in appearance with the Belly River and Judith River strata. Although these rocks are younger 

than Montana in age, they deserve mention here because they seem to complete for a third 

time a cycle of sedimentation proceeding from purely marine to fresh-water or continental conditions. The first of these cycles is from the ma~ine Colorado shale, through Virgelle sandstone, 

to the strata of continental origin in the lower part of the Two Medicine formation; the second 

is from the marine· shale of the Claggett, through the sandstone in its upper part to strata, 

also of continental origin, comprising the Judith River formation; and the third is fron1 the 

marine Bearpaw, through the Horsethief sandstone, to the continental deposits above that 

sandstone .. The relations in each cycle between the continental deposits and the underlying 

sandstone seen1 to be identical. The strata are apparently perfectly conformable and the 

impression is very strong that the same conditions ruled in each trm~sition fron1 marine to land 

conditions, or, in other words, the strata above the Horsethief sandstone are physically as closely. 

related to the Bearpaw shale as the Judith River formation is to the Claggett or the Two :Medicine formation to the Colorado shale. . Now, these strata of continental origin above the Horsethief sandstone constitute the St. ]\1ary River beds of Dawson, which occupy the sa1ne position 

in the geologic column as the Edn1onton formation of central All;?erta and approx:jmately that 

. of the Lance formation of Wyoming. The age of this formation is therefore involved in the 

·Lance-Laramie problem of North American geology, and in the opinion of the writer the fact 

that iri this part of the interior basin this formation, which seems to be equivalent to the Lance, 

.appears to be as intimately related stratigraphically to Cretaceous marine shale below it as are 

siinilar continental deposits well down in the Cretaceous se~tion to a corresponding 1narine shale 

should receive considerable weight in the consideration of that problem. 

Lastly, the sedimentary record that has been described seems noteworthy because it shows 

three successive marked recessions of a sea which are not known to have produced unconformity 

or other hiatus in the stratigraphy-conditions commonly attendant on such recessions-but, on 

the contrary, seem to have been followed immediately by sedimentation at an increased rate, 

the strata deposited bearing conformable relations to the underlying rocks. The proper concept 

seems to be that each recession of the Upper Cretaceous sea in the northern interior region of 

North America was accompanied in extensive areas of lowlands on its margins not by uplift and 

erosion but by uplift and an increased rate of sedimentation. 
A DEEP 'VELL AT CHARLESTON, SOUTH CAROLINA. 

By LLOl~ Wn .. LIAM STEPHENSON. 

INTRODUCTION. 

A deep well at Charleston, S.C., completed in May, 1911, has furnished valuable information in regard to the stratigraphy of the· Cretaceous and younger deposi~s underlying. that .city. 

The well is owned by the Cl~arleston Consolidated Railway & Lighting Co. and is at the company's gas works at the foot of Charlotte Street, near the shore of Cooper River. The well 

satnples and the well log fron1 'vhich· the geologic data contained in this report were optained 

were sent toT. Wayland Vaughan, of the United States Geological Survey, by I. N. Knapp, 

engineer in charge. The driller was H. 0. Hendricks. Drilling was begun January 31, 1911, 

and the well was completed May 15, 1911. The total depth of the well is 2,001 feet (2,007 feet 

below the top of the casing). 

METHOD EMPLOYED IN DRILLING. 

• The well was drilled by the hydraulic rotary: method/ by which a drill pipe with a drill or 

bit belonging to one of several types attached at~ the lower end is rotated by machinery and 

at the san1e tin1e water is forced down on the inside of the drill pipe to the botton1 of the well 

·and up again to the surface between the outside of this pipe and the wall of the hole. The 

n1aterials loosened ~y the rotating bit are carried in susp·ension to the surface by the forced 

current of circulating water. When the bi~ is penetrating loose, caving sands, the water, 

before it is introduced into the· drill pipe, is n1ixed ·with clay until it forms a rather thick slush. 

The pressure of tlu3 column of muddy water as it is being raised· to the surface on the outside of 

the drill pipe forces the slush into the interstices of the sands that form the wall of the boring, 

thus plastering the wall and producing a sort of ·mud casing, which usually prevents serious 

caving. It is expected that the material loosened by the bit and carried to the surface by the 

ascending current will be mixed with the material used to form the slush and also with such 

1nn.terial as, in spite of the n1ud casing, may chance to cave from the walls of the boring. Samples of the n1i...~ture thus formed are obtained by passing the emerging stream through a series 

of screens, or by catching the slush in a vessel and washing out the suspended materials. In 

this manner fossils and fragments of the h11rder strata penetrated n1ay be obtained. The 

softer s·ands, cl~ys, and marls invariably have their character cha.nged and more or less obscured 

by the 1n:ixing proce~s. As the bit is rotated Clay or limy mud frequently adheres to it; and 

in this material fragn1ents of rock or fossil ren1ains are sometimes caught and when the drill 

pipe is drawn fr01n the well for the purpose of sharpen.ing or renewing the bit samples of the 

adhering n1ud and its contents may be procured. 

Fossils obtained from a well drilled by this process, even if the n1aterial containing then1 

is a 1nixture derived from several geologic horizons, may still have definite value in correlation, 

for l1 fossil must have c01ne either from the depth at which it was taken or from some higher 

level; it could not have come from a lower level. Therefore, if fossils characteristic of a certain zone are taken at a given depth the zone must have been penetrated at that depth or at 

a higher level. 

In the samples from the· Charleston well there is evidence of considerable mixing clue to 

caving, but many of the san1ples contain fragments of roc}( which appear to reveal accurately 

the character of the harder strata penetrated at the depths indicated, and many of them contain 

fossils which appear to have come from approximately the depths indicated by their lahels 

1 A moro dotaUod description of this method is given by Isaiah Bowman in U.S. Gcol. Survey Water-Supply Paper 257, pp. 70-75, 1911. 

69 . 
70 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

and which are sufficiently well preserved to permit their identification. Many of the samples 

~~ .. , gro"'r1 1001 

I 

I 

I 

zool I 

I 

I 

J 3001 

I 

I 

I 

«J01 I 

I 

I 

sooj 

I 

I 

eoo) 

I 

I 

I 

70~ I 

~ 

I 

I 

6001 I 

I 

I 

'I 

900~ I 

I 

I 

I 

1000: I 

I 

I 

I 

11001 I 

I 

I 

! 

12001 I 

I 

I 

I 

13001 I 

I 

I 

\ 

1400~ I 

I 

I 

I 

15001 I 

I 

I 

I 

160o1 I 

I 

I 

I 

170o1 

I 

I 

I. 

r· of='"" s' •bo~ '"'~ 

1 ~~om of IS" hole and 14"casing I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

I 

II 

I 

I 

I 

749 Bottom of 10" hole 

contain a mi...~ture of she~ls of Pliocene or Pleistocene age, 

originally derived from strata penetrated in the first 85 · 

feet of the boring, the mixing having been effected in part 

through the slush used to form the mud casing and in part 

by the caving of the walls of the well. The nature of the 

fossils and their condition of preservation are such that most 

of them are easily distinguishable from the older fossils, 

obtained at greater depths, and for th1s reason they do not 

interfere seriously with the interpretation of the ren1ainder 

of the section. 

The di~meter of the hole to various depths and the 

size and length of casings inse:r_:ted are indicated diagram-. 

matically in figure 10. The well was completed in 90 

working days of 10 hours each, the time including that 

required for inserting casing, fishing for lost tools, and 

making all.necessary repairs. · 

PRACTICAL RESULTS. 

QUANTITY AND TEMPERATURE OF THE WATER. 

The results of the undertaking are given in the following statement, which is quoted in substance from the 

original log furnished by I. N. Knapp, engineer in charge: 

On May 16, the day after drilling was discontinued, clear water was 

pumped into the well in the same manner that the slush was pumped 

. during the process of drilling. The temperature of the water emerging as 

a result of the forced overflow thus procured was 66 ° F. A natural flow 

soon started, and by evening the temperature of the water had increased 

to 85° F. and it was flowing at the rate of 100 to 150 gallons a minute. · 

On May 17 the flow increased, as did also the temperature, and 

fragments of shale and micaceous sand were brought up in suspension. 

On May 18 the flow was irregular, varying with the amount of shale 

and sand brought up in suspension. 

On May 19 the water was flowing from the well at a rate sufficient 

to fill a 50-gallon barrel in 15 seconds. The water was muddy and at 

times c·arried much sand and shale in suspension. 

On June 3 the temperature of the water as it emerged from the well 

was 99.75° F. The flow of the water, which rose to a height of 11 feet 

above mean low-water level, was sufficient to fill a 50-gallon barrel in 7 

seconds, or at the rate of 617,143 gallons a day. The water would rise in 

a pipe and flow a small stream at a height of 75 feet above mean lowwater level. The water was still somewhat muddy. 

ECONOMIC VALUE OF THE WATER. I 

16001 : 1 . : According to R. B. Dole, of the United States Geo1167sBottomof6'Ys"casingshoe logical Survey, the analysis indicates an extremely soft 19od'f r887Bottomof8Y:"hole water, softer than the waters from the Chisholm mill well 

~ '! 197SBottom of 6o/s"hole (depth, 425 feet) and the old Wentworth Street well (depth, 2000t__]zooiBottomof5Ys'hote 1,260 feet). (See analyses in table on p. 93.) The water 

FrGuRE 10.-DiagramorwenatCharleston, s. c., show- would deposit no. scale in boilers and under ordinary coning size of hole and length of casings inserted. All ditions would cause no corrosion; if too strongly concenthe measurements of depths were made from the top 

of. the rotary jaws, which stood 6 feet above the sur· trated by continuous evaporation it might cause foaming, 

faceoftheground. but this could be obviated by regular blowing off. Nothing in the analysis indicates that the water would be harmfuJ for drinking, though-it doubtless 

has a slight mineral taste. 
A DEEP WELL AT CHARLESTON, S. C. 71 

The object in drilling the well was to obtain water for a boiler supply at the gas works and, 

according to :Mr. l(napp, a practical test has shown that the water is satisfactory for this 

purpose. SCIENTIFIC RESULTS. 

THE WELL RECORD. 

A record of the well, compiled from a set of well samples and a well log furnished by :Mr. 

ICnri.pp, tl:ie engineer in charge, is given below. The fourth column gives the source of the 

samples as recorded by the engineer and additional information furnished by him concerning 

the character of the strata f~·om which some of the samples were taken; the fifth column con ... 

tains the writer's description of 'the samples; the sixth, seventh, and eighth columns constitute 

the well log, which was prepared by l\1r. Knapp as the drilling progressed and which records his 

itnpression of the character of the materials penetrated. 

The 1naterials penetrated in the well a;re of. marine origin and consist of sands, clays, n1arls, 

and lin1estones. The sands are either soft, incoherent beds or layers in various stages of induration, the hardest being a quartzite-like rock. They are in greater or less degree calcareous. 

:Many of the san1ples are glauconitic and some are micaceous. The clays are likewise either soft 

unconsolidated beds or layers in various stages of compactness, the hardest being aln1ost shaly. 

They are more or less calcareous and usually contain smne mica. The liillestones occur chiefly 

in the Eocene portion of the section. Smne of the layers appear to be fairly pure, but the rock 

in 1nost of the samples contains n1ore or less sand. The drill penetrated many beds of shell marl. 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas works of the company, foot 

of Charlotte Street, near Cooper River, Charleston, S. C. - - -

[Engineer in charge, I. N. Knapp; driller, IT. 0. Hendricks. Drilling begun Jan. 31, 1911; well completed M:ay 15, 1911.] 

Depth (in Method of obtaining Log of well furnished by engineer in chargo.a 

foot} at samples and other Ago and Sample WhiCh information f u r - .Author's description of samples. formation. No. sample nishod by. engineer Thick- Depth to was in charge. Material.- ness in base 

obtained. feet. in foot. 

---

Dark-gray, finely arenaceous Length of casing protruding 6 6 

above surface of around. 

1 40 From overflow .b _and micaceous clay, with a Cindeys, bricks, an tar ..... 10 16 

few shells and fragments of Layers of spongy material, 44 60 lignite. blue clay,-and shells, with 

i Q) roots and bits of wood. l:l --- ~ Very coarse quartz sand with 

~ 2 62 From overflow. numerous fragments of shells An abundance of broken 2 62 

~ 'Cil and a few well-preserved shells with sand. 

p:; shells. r:::i --- Chiefly fra~ments of shells 

but con tams numerous well3 73-75 From overflow. preserved shells. Includes a small percentage of coarse quartz sand. 

------ Same as samrte No.3 but con- OCI:> 

82-83 Concentrated from· tains smal chunks· of green- · 

~~ 4 overflow. ish-yellow sand and small 

black phosphatic pebbles. 

I Chunks of greenish-gray soft, 

ci slightl:y sandy and argillaIa I ceous limestone or marl with 

8 5 86 ' Mud from bit. Foraminifera and nodules 

of dark -gray calcareous phos-

~ ~ phatic sandstone. (See list 

-~ 0. of Foraminifera in table on 

1:= 8~ pp. 79-80.) 

Cll a:>S 8 m ... I Same as sample No. 5. (See L~1~:1Js ~vill~rl n~d~le~ ~~ 88 150 8~ 6 102 Mud from bit. list of Foraminifera in table 

~8 on pp. 79-80.) phosphate rock. 

~0 I Greenish-~ray calcareous sand 

~ resemblm5 Nos. 5 and 6 in 

A. 7 200 Mud or cuttings from color, wit 1 some Forami- A. overflow. nifera and some shells. (See 

t:> list of Foraminifera in table on pp. 79-80.) --- a All tho mcasmomonts given in thi> record wcro mado from tho t.op or the rotaqr jaws as a datum plane. As the top or the rotary jaws was 6 root nbovo tlto smfaco or tho ground tho exact depth of the well below the surface IS 2,001 feet ins toad of 2 007 feet. The top of the rotary jaws was 14t root above moan low water level. · · ·· ' · b 'Iho torm overflow, as usod in this well rooord, means tho flow or water emerging from tho mouth of the well during the process or drilling aCtor its l'a~sago under pressure from tho pumps, down tho interior of the drill pipe, and up again to the surfaoo between the outside of the drill 

plpo anc tho wall of tl1o bolo. 
72 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas worlcs of the company, foot 

of Charlotte Street, near Cooper River, Charleston, S. C.-Continued. 

Age and 

formation. 

Depth(in 

feet) at which 

sample 

Method of obtaining samples and other 

Log of well furnished by engineer in charge. 

Sample 

No. 

8 

9 

10 

11 

12 

was obtained. 

information f u r - Author's description of samples. nished by engineer in charge. 

220 Mud from bit. 

Concentrated from 262-263 overflow; hard lime- stone rock. 

Same as samples Nos. 5 and 6; 

contains Foraminifera and a 

~~''Fo~:~~fl~~;·in (fa~le ~~ pp. 79-80.) 

(From this depth to the bot- tom ofthewellnearly all the 

samples contain a few Recent, Pleistocene, or Plio- cene shells, which doubtless 

represent mixtures resulting from the caving of the walls 

in the upper 85 feet of the 

well.) 

Fragments of gray, rather soft 

limestone or marl; contains 

Nodosaria cf. raphinistrum; 

Cristellaria I, 2, 6, 7, and 9. 

Mud from bit; hard Chunks of gray limy mud, 270 drilling, about 6 derived from limestone. inches per hour. 

from 

Fragments of rather soft lime- stone or marl with a few 

echinoid spines; contains 

also Nodosaria .3 and Cristellaria 10. 

Material. 

Layers of marl with streaks 

of shells. 

Very hard whitish lime- stone. 

Alternate layers of lime- stone and marl; hard to medium drilling. Hardrock ................. . ----1----1----------1-------------1 Very soft materiaL ......... ~ 

13 348-350 

14 361 

15 

16 362 

17 365 

Concentrated 

overflow. 

Mud from bit; very hard. 

Sample missing. 

Mud from bit; hard 

drilling, about 1 inch 

per hour. 

Concentrated from 

overflow. 

Chunks of bluish-gray calca- reous, argillaceous, and 

sandy mud, with chunks of 

dark calcareous sandstone, 

probably derived from 

sandy limestone. 

Apparently a sandy limestone 

ground to a fine white mud 

by the bit. . 

Fragments of light-gray sandy limestone with a few echinoid spines and fragments of 

ll!arl. ..............•........ Hard rock .•...•............ 

Medium hard rock ...•...... 

Excessively hard rock; 

drilled 1 inch per hour 

with fishtail bit. 

~~:~lsi I cfntains also No.do- Hard r()('k and flint ...•..... 

----1---'---l----------l-------------l Excessively hard rock ..... . 

18 

19 

20 

375 Mud from bit. 

395 Mud from overflow. 

395 Concentrate d from 

overflow. 

Apparently a sandy limestone 

ground to a fine gray mud 

by the bit. 

Chunks of gray porous calca- reous sandy mud, apparent- ly a sandy limestone ground and mixed by the bit. 

Hard white limestone ..•.•.. 

Fragments oflight-gray sandy limestone with fragments of Layers of marl; easy drilling. 

shells. ----1----1----------1-------------1 Very soft material ......... - Hard dark-gray rock .....•.. 

21 

22 

23" 

Fragments of selected 

427-433 clay or shale from 

overflow. 

435 

439-444 

Concentrated from 

overflow. 

Coneent r ate d from 

overflow; bed of 

shells. 

Fragments of gray calcareous, 

micaceous shaly clay. 

Fragments of light-gray sandy limestone with numerous fragments of shells. 

Marl .....................•.. Very hard material. ........ . Soft material with sand and 

shells. 

Very hard material ......•.. Soft dark clay .......•••.... 

Fragments of light-gray sandy limestone with numerous Coarse-cutting rock, with 

fragments of echinoid spines, shells. 

bryozoans, and shells; con- Shells and rock ..•..•....•.. tams Nodosaria 5. 

Thickness in 

feet. 

109 

1 

68 

5 

4 

11 

6 

9 

1 

20 

19. 

2 

3 

5 

1 

3 

1 

7 

6 

5 

Depth to base 

in feet. 

259 

260 

328 

333 

337 

348 

354 

361 

371 

372 

392 

411 

413 

416 

421 

422 

425 

426 

433 

439 

444 
A DEEP WELL AT CHARLESTON, S. C. 73 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas works of the company, foot 

of Charlotte Street, near Cooper River, Charleston, S. C.-Continued. 

Dopth(in Method of obtaining Log of well furnished by engineer in charge. 

Ago and Sample foot~ at samples and other WhiCh information f u r- Author's description of samples. formation. No. sample nishcd by engineer Thick- Depth to was Material. DOSS in base 

obtained. in charge. foot. in feet. 

---- ---- .g Mixture or fragments or light-

.s ~rak sandy limestone and 

§ < ar or-gray, finelh arenaceConcentrated from ous calcareous s allJ clay, 

od' od~ 24 447 overflow. with numerous she I frag- a> mr.nts and some fragments ::I a>..-.. 

::IC'-· of Bryozoa; contains Nodo- :§ :§§ saria 2 cr. raphinistruml' 

= Nodosaria 5. 

~ l=lo 8cn Chunks of dark-gra~, finely J,~ I i J:l"' arenaceous and mwaceous, 8c:s calcareous clav; contains 

!il o8 Textularia b cf. sagittula, 

E-< ril~ 25 454 I Mud nnd lmgments of Vemeuilina a cf. propinqua, 0 rock from bit. Uvigerina a cf. canariensis. iil Globi~erina b cf. requilate- § ralis, runcatulinafcf.Zoba0 tula, Polystomella, Massi- Dark clay or shale .. ; ....... 24 468 ::a lin a. Hard rock; required 2hours 1 469 

------ to drill with fishtail bit. 

Chunks of lighter-gray, finely Soft material with shells .... 4 473 arenaceous and micaceous, 

calcareous clay; contains 

Textularia b cf. sagittula, 

26 478 Mud from bit. Cassidulina cr. subglobosa, 

Lagena b cf. sulcata, Uvige- Black shale or clay; no shells. 21 494 rina P11gmrea,. TruncatuUna I cf. lobatula, Polysto- molla. 

----27 500 Mud from overflow. 

Chunks of greenish-gray 

porous sandy calcareous 

clay. 

Con centra to d from Fragments of gray calcareous 

28 500 overflow. shaly clay with some admix- ture of quartz sand. 

Variable streaks or yellow 7 501 

Loose dark-green, highly sand and marl. 

glauconitic sand; the grains of quartz are clear and angu- lar; contains Textularia b 

29 504 Sand from overflow. cf. sagittula Polymorphina d{ Sphreroidina cf. bulloides, Layers of black sand with 9 510 

'1 runcatulina 1 cf. lobatula streaks of marl. 

Truncatulina 

mella. h, Polys toi ao I Concentrated from Fragments of gray sbal~ calca515 overflow. reous clay mixed wit green- ish-gray calcareous mud. - E-< Fragments of gray shaly, finely 15 Concentrated from arenaceous, mwaceous, calg overnow; Earts of careous clait and chunks of Alternating streaks of marl 26.5 536.5 soft greenis -gray limestone 

M .... 31 525-540 several samp es taken . or marl which srobably fell and clay, some yellow, .._, from between 525 and down from the ooper marl; some dark gray . a> 540 feet; all much the Very bard rock .............. .5 537 c!3 same, clay and marls. also loose sand; contains 

8. Foraminifera. (See list in 

table, pp. 79-80.) Po 

p 

321 

Mud from bit, medium Chunks of dark-gray argilla- 544 hard, black when ceous, glauconitic, calcareous wet. sand. Not described .. _ ........... _ ·8 545 ----

I 

Fragments of gray sbaly, finely Hard rock .... , .............. 1 546 

Concentrated from ~:g;~o~Y r:~ac~~~k~~f 

33 550-570 overflow; average of soft greenish-gray limestone or marl which srobably fell several samples. down from the ooper marl; 

also loose sand; contains 

Cristellaria 11 cf. clypeilormis. 

Fragments of gray sbaly, finely arenaceous micaceous,· calConcentrated careous clay and chunks of 

34 585 from soft greenish-gray limestone 

overflow. or marl which srobably fell 

down from the ooper marl; 

also loose sand; contains Alternating layers of black 41 587 Nodosaria 2 cf. raphinistrum. 

---- and dark-gray shale, me-

·Fragments of grad shaly cal- dium to hard; no shells. 

careous clah an chtmks of Soft material ...•............ 2 589 

35 600 Concentrated from soft greenis -y;ay limestone 

overflow. or marl wbic srobably fell 

down from the ooper marl, 

with some sand. 
74 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas works of the company, foot 

of Charlotte Street, near Cooper River, Charleston, S. C.-Continued. 

Depth(in 

feet) at which 

sample 

Method of obtainmg samples and other 

Log of well furnished by engineer in charge. 

Age and 

formation. Sample No. 

36 

was obtained. 

608 

information f u r - Author's description of samples. nished by engineer in charge. Material. 

Chunks of gray, finely arena- Alternatinglayers of medium ceous and micaceous, cal- hard dark-colored marls 

~~r;:n~~~~~~th~~f~~~ ~~ J~a}~~t s:d,~ecf~\~~ probably fell down from the in mud. 

Cooper marl. Very hard material.. ....... . 

Mud from bit. 

-------l--------1-----------------l----------------------l 

37 630-660 

Concentrated from 

overflow. Averageof several samples; formation variable, thin 

strata, hard to soft, 

in color yellowish, light gray, dark gray, black. 

Fragments of gray shaly, finely arenaceous, micaceous, cal- careous clay and chunks of 

soft greenish-gray limestone or marl which probably fell 

down from the Cooper marl; 

also loose sand; contains 

Foraminifera. (See list in 

table, pp. 79-80.) 

-------:-------1--------~-------1------

38 

39 

40 

41 

42 

661 Mud from bit. 

680-685 Concentrated 

overflow. 

from 

Mud from bit; very 702 hard dark-blue lime- stone. 

725 

74:l 

Concentrated 

overflow. 

from 

Mud from bit; dark 

gray, almost black 

when wet; very hard.' 

Chunks of grar, finely arena- ceous and miCaceous, calca- reous clay. 

Fragments of gra;v shaly, finely arenaceous, miCaceous, cal- careous clay and chunks of 

soft greenish-gray limestone or marl which probably fell 

down from the Cooper marl; 

also loose sand; contains 

Nodosaria 15. 

Chunks of gray caJ&areous clay with wh1te streaks of lime; 

contains Nodosaria 15 and 

Cristellaria 11 cf. clypeiformis. 

Fragments of gray shaly, finely arenaceous, miCaceous, cal- careous clay and chunks of . soft greenish-gray limestone or marl which probably fell 

down from the Cooper marl, 

also loose sand; contains 

Cristellaria 11 cf. clypeiformis. 

Chunks of gray calcareous 

clay with white streaks of 

lime; contains Nodosaria 15 and Cristellaria 11 cf. clypei- formis. 

Thin layers of light-colored marl and limestone, me- dium hard to hard. 

Very hard blue limestone .... 

Variable layers of light-col- ored clay or marl._ ...... . Soft grayish-white clay in 

overflow. 

Not described .........•..... 

Very hard material; re- quired 10 hours continu- ous drilling with fishtail 

bit. 

-------1-----1--------1----------1 

43 

44 

45 

47 

48 

750 Mud from overflow. 

Sandrock cuttings, 805-808 concentrated from 

overflow. 

810 

855-S60 

870-890 

Mud from overflow; in 

hard rock. 

Cuttings concentrated 

from-overflow. 

Selected from overflow; 

average. 

Gray calcareous, slightly ar- gillaceous, glauconitic sand; 

contains Clavulina cf. angu- laris, Nodosaria 2 cf. raphinistrum ?, Nodosaria 14, Nodosaria 15, Cristellaria 11 cf. 

clypei[ormis, Vaginulina. 

Very coarse quartz sand with 

fragments of gray glauco- nitic sandstone and numer- ous small black phosphatic pebbles. 

Gray porous calcareous clay w1th some sand; contains 

Clavulina cf. angularis, Nodosaria 14, Cristellaria 11 cf. 

clypeiformis, Vaginulina. 

Gray shaly, finely arenaceous clay with numerous small 

black phosphatic pebbles and some sand; contains 

Clavulina cf. angularis, Crlstellaria 11 cf. clypeiformis. 

Same as sample No. 46, ex- cept that black pebbles are not numerous; contains Clavulina cr. angnlaris, N odosaria 14, Cristellaria 11 cf. 

clypeiformis. 

Same as sample No. 47; con- tains Clavulina cf. angularis, 

Nodosaria 14, Nodosaria 15, 

Cristellaria 11 cf. clypei- formis. 

Hard material; medium to hard drilling. 

Hard rock ...•.............. Alternating thin layers of 

medium to hard rock. 

Soft material, possibly sand. 

Marl. ...................... . White sandy material. ..... . 

Layers of light-gray to black 

marl; easy drilling; variable materials. 

Thickness in 

feet. 

36 

75 

1. 5 

31.5 

2 

5 

3 

18 

5 

24 

2 

12 

3 

110 

Depth to base 

in feet. 

625 

626 

701 

702.5 

734 

736 

-741 

744 

762 

767 

791 

793 

805 

808 

918 
A DEEP WELL AT CHARLESTON, S. C. 75 

Record of Charleston Consolidated RaUway & Lighting Co.'s well, drilled in 1911 at the gas works of the comzJany, foot 

of Charlotte. Street, near Cooper River, Charleston, S. C.-Continued. 

Depth (in Method of obtaining Log of well furnished by engineer in charge. 

Smnplo foot) at samples and other Ago and WhiCh information f u r - .Author's description of samples. formation. No. sample nished by engineer Thick- I Dopth to was Material. ness in base 

obtained. in charge. feet. in feet. 

I Gray calcareous, slightly ar- I gillaceous sand; contains 

49 920 Mud from overflow. Clavulina cf. angularis, Nodosaria 15, Cristellaria 11 cf. 

clypci[ormis. 

Gray shaly calcareoush finely I arenaceous clay wit some 

Same as sample No. 49 sand; contains Clavulina cf. 

angularis, Ostrea sp. (young 50 920 with mud washed Greenish shale ....•......... individual), fragments of 4 922 out. Anomia argentaria Morton, 

and tooth of Corax [alcatus Agassiz. · 

----51 950 Mud from overflow. Gray calcareous, argillaceous sand. 

-------- Gray shaly, finely arenaceous clay with a few small black 

sa,~~~s :~t~J!~h:J phosphatic pebbles and Uniformly hard material, 33 960 52 950 some sand; contains Nodo- probably sandy lime- out. saria 16 cr. inflcxa, Ostrea stone. ~- (young individual), and Marl; easy drilling .......... 14 974 nomia argentaria Morton. Hard limestone .. · ........... 4 978 --- Marl. ....................... 14 992 

Probably cemented shells; 2 994 

1,000 Mud from overflow. Gray calcareous, slightly argil- rough drilling. 53 laceous sand. 

---- Coarse. sand with numerous 

Concentrated from fragments of gray shaly cal- :Marl. ...........•........... 6 1,000 

54 1,000 mud; same as sample careous clay; contains Os- trea sp. (young individual), 'i No. 53. and tooth of Corax falcatus ::s .Agassiz? .E 

= Gray shaly calcareous, finely 

~ od arenaceous clay with sand 

; and sandstone fragments; 

Q) 55 1,015- Concentrated from contains Ostrca falcata .Morg Q) Sandrock ................... 15 1,015 1,030 overflow. ton, Ostrea plumosa Morton, '0 

~ Q) Anomia argcntaria Morton, Q) and tooth of Corax falcatus Po. Agassiz? 

---- '"' Loose light~gray calcareous !. 'l'hin layers of shale, sand- 20 1,035 Po 56 1,035- Concentrated from sand with scattered grains of rock, and marl. 

probably I:> 1,045 overflow. glauconite; contains Ostrea Hard material, 4 1,039 falcata Morton. sand rock. 

1,055- Mud from O\rerflow. 

Chunks of gray calcareous, ar- 57 gillaceous, slightly glauco- 1,058 nitic sand. 

Fragments of gray shaly cal- careous, finely arenaceous 

Concentrated clay, with considerable fine, 

58 1,055- from 

1,058 overflow. ~~~~t~d f~~~~~~l b~~k phosphatic pebbles; con- tains Anomia argcntaria Morton (fragment). 

Concentrated from Fine. light-gray, slightly glau- Laf:ers of light to dark gray 61 1,100 59 1,090- overflow; uniformly conitic sand with small c ay with thin layers or 1,100 hard, sandy clay. fragments of gray calcareous sand rock. shaly clay. 

Concentrated from 

overflow; easy drill· Same as sample No. 59; con- 60 1,130- ing; uniform mate· tains Lima reticulata Forbes 1,140 rial, consisting of (fragment). sandy clay, with some shells. 

Gray shaly, finely arenaceous and micaceo.us, calcareous 

1,150- Selected from concan- clay, with a few chunks of Dark-gray and blue sandy 83 1,183 61 greenish - gray ·calcareous 1,200 trates. clay and some sand; con- shale; good drilling. 

tains B elemnitclla americana (Morton)? (fragment). ----·----
76 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas works of the Company, foot 

of Charlotte Street, near Cooper River, Charleston, S. C.-Continued. 

Age and 

formation. 

Sample 

No. 

Depth (in 

feet) at which 

sample 

was obtained. 

Method of obtaining samples and other 

information fur- Author's description of samples. 

nished by engineer in charge. 

Log of well furnished by engineer in charge. 

Material. 

Thickness in 

feet. 

Depth to base 

in feet. 

-----.-----I------------1----------------[-----~~------------J----------------------------

62 

63 

1,230-

1,250 

Concentrated and se- lected; fossils, py- rites, and _marls. 

Same as sample No. 61, with 

chunks of greenish-gray marl which probably fell 

down from the Cooper marl; 

contains the coral 'l'rochocy- athus sp. (aff. T. woolmani Vaughan), identified by T. 

Wayland Vaughan. 

Mud from bit; black Chunks of dark-gray, finely 

Sandy marl with reddish 

fossil shells. 

Hard rock .... ___ ... _ ...... _ 

1,259 and grayish when arenaceous and micaceous wet. ·clay with some sand. Not described_ ........... __ _ ----------------1------------1 

64 1• 262- Mud from overflow. 1,275 

Gray sandy, slightly argilla- ceous, calcareous sand. 

Same as sample No. 

64 bn t washed and 

concentrated. 

Gray coarse, slightly glauco- Medium-hard rock ...... ___ _ nitic sand and gray shaly, Soft sandrocJ.:. _ ..... ___ .... . 65 

66 

67 

68 

1,262-

1,275 

1,306 Mud from bit. 

1, 300-

1,306 

1, 310-

1,320 

Washed from overflow 

and selected. 

Concentrated from 

overflow. 

finely arenaceous and mi- caceous clay. 

Chunks of gray, finely arena- ceous and micaceous clay. 

Fragments of gray calcareous 

shaly clay and gray calcare- ous sandstone with a few 

small black phosphatic peb- bles. 

Gray calcareous sand and frag- ments of sandstone with 

fragments of gray shaly cal- careous clay. 

1.340- 68a · i,360 

Mud from ove~flo~v; medium-hard sandy rock; good drilling. 

Loose gr_ay calcareous, slightly glauconitic and micaceous 

sand, with chunks of slightly indurated sand. 

69 

70 

1,340-

1,360 

1,375-

1,400 

Washed and selected 

from overflow; same as sample No. 68. 

Concentrated and se- lected; shells 1,375-to 

1,381 feet. 

Chunks of gray calcareous, 

slightly glauconitic sandstone, and fragments of gray shaly calcareous clay; con- tains Ostrea sp. (youn_g individual) and Exogyra sp. 

(fragments of the small 

valve). 

Coarse gray sand and frag-' ments of calcareous sand- stone with a few fragments of gray shaly calcareous 

clay; fragments of shells nu- merous; contains Ostrea· 

plumosa Morton; Ostrea sp. (young individuals){ Exogyra sp. (fragments), and 

tooth of Lamna ?; shells 

from 1,375 to 1)381 feet. -------1---------·1------------1 

i1 

72 

73 

1 i :~go C~~g~~J~~~~ ~~~flo~~~ Same as sample No. 70. 

1, 440-

1, 450 

Concentrated and se- lected from overflow; 

shells. 

· Same as samples Nos. 70 and 

il; contains Ostrea plumosa 

Morton, Exogyra sp. (fral!- ments), Anomia argentaria 

Morton, and a small shark 

tooth. 

1, 460- Concentrated and se- Similar to samples Nos. 70-72 

1, 470 lected from overflow. but contains more loose sand. 

-----------------1------------1 

74 1,480-

1, 490 

Concentrated and se- lected from overflow. 

Fragments of gray, finely are- naceous and micaceous, calf:g:g~~ ;~~~~~~e~ay ar_gil-

-----------------1------------1 

75 1, 500- Concentrated and se- 1, 510 lected from overflow. Same as sample No. 74. 

----------1---------·1------------1 

76 1,514 Mud from bit; very hard material. 

Chunks of dark-gray, finely arenaceous and micaceous 

Clay with some sand. o 

Soft to medium-hard layers 

of marl and sandstone. 

Hard rock . __ .. ___ ......... . Variable layers of shale and 

sanely shaleh with som'e 

shells and fis teeth. 

Medium-hard sandy rock; 

uniform drilling. Hard rock. _ .... _ .. _ ........ . 

Soft material with broken 

shells. 

Probably sanely marl; good drilling. 

Hard rock ... _ ..... _ ....... . 

Not described .. __ ... _ ..... __ Very hard rock .. __ ...... _ . _ 

Layers of soft black stick-y clay with medium to hard 

shales and sandstones in 

thin layers. 

57 

19 

2 

14 

30 

'2 

28 

36 

3 

6 

35 

2 

12 

1 

88 

1,240 

1, 241 

1,260 

1,262 

1, 276 

1,306 

1,308 

1,336 

1,372 

1,375 

1, 381 

1, 416 

1, 418 

1, 430 

1, 431 

1,519 
A DEEP WELL AT CHARLESTON, S. 0. 77 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas works of the company,joot 

of Charlotte Street, near Cooper River, Charleston, S. C.-Continued. 

--------~----~--------------------~----------------~------------------------------

Depth (in 

foot) at winch 

sample 

Method of obtaining samples and other 

Log of well furnished by engineer in charge. 

Ago and 

formation. Sample No. 

77 

was obtained. 

information fur· Author's description of samples. 

nished by engineer in charge. Material. 

Gray shaly, fitiely arenaceous Uniformly hurd shale ...... . and micaceous clay and 

fragments of soft gray cal- careous, argillaceous, slightly Very stick"Y shale ........... . glauconitic sundstone; con- Rock ..... : ................ . tains Pecten venustus Morton. 

1, 5<10- cuttings selected from 

1,550 overflow. 

--------------1-----------1------------

78 

70 

so 

1 Shale and bits of py- '5'50- rites selected from Same as sample No. 77. 1

' 560 overflow. 

1,560- Selected from overflow. Same as samples Nos. 77 and 

1, 570 78. 

Cuttings from overflow. Same as samples Nos. 77-79 but contajns some sund. 

Layers 'or medium to hard 

shales with iron pyrites and layers of black shales; 

required frequent spud- ding. 

1,500-

1,600 ----~----1·----------1------------1 Very hard rock ............. . 

St 

82 

1,620- Cuttings from overflow. Similar to samples Nos. 77-80 . Variably thin strata of dark 

1,630 but contains much sund. shale . 

1,640-

1, 642 1\Iud from overflow. 

. ,. ·" " . ,. . . -Same .as samples Nos. 77-79; 

contains some fragments of Broken shells .............. . shel-ls. · 1\Iarl ....................... . 

----l·----l·-.,,---------l--""'-,.._,-,. ________ 1 Very hard rock ............ .. 

Same.-as: samples Nos. 77-79; 

contains Ostrea sp. (yotmg individual) und two teeth of 

fish. 

83 

84 

85 

86 

87 

88 

89 

90 

01 

92 

1,660-

1,670 

1,660-

1,670 

Selected from overflow. 

Mud from overflow; 

soft; easy drilling. 

Loose gray calcareous sund 

with numerous fragments of 

gray shaly calcareous clay. 

1, 700-

1, 705 Selected from overflow. Same as samples Nos. 77-7.9. 

1, 720- Concentrated from 

1, 723 overflow; very hard. 

1, 720-

1, 723 

1, 725-

1,730 

1\Iud from overflow; same as sample No. 

86. 

Mud from overflow; 

hurd to very hard, 

with one soft streak. 

1, 736 1\Iud from bit. 

1, 763-

1,767 

Concentrated from 

overflow; very hard, 

with one soft streak. 

Gray shaly, finely arenaceous und micaceous clay, with 

fragments of gray calcareous 

sandstone; contains a shark 

tooth. 

Loo~a light-gray glauconitic, calcareous sand, with frag- ments of gray sha~y clay. 

S(lme as sample No. 87; con-

~1t~:a No~~~:~:: 6 }~~r~o:!? (young individual), and 

fragments of Pecten quinque- costatus (Sowerby). 

Chu!lks of gray argillaceous, miCaceous, r.alcareous sand; 

contains Crassatellites sp. (cast). 

Loose gray calcareous, slight- ly glauconitic sand, with 

fragments of gray calcare- ous shaly clay. 

--1-,7-9_0-_I-F-•r_o_In--o,-,e-rfi_o_w_;_h-ar-d-l-------------------l 

1,800 rock. Same as sample No. 90-

1,800-

1, 812 

Selected from overflow Loosecoarsequartzsand,with 

fragments of gray calcareous 

shaly clay; contains Bryo- zoa?, Ostrea cretacea Morton, 

and a coprolite. 

(from 1,802 to 1,804 

feet lost water; prob- ubly water sand, 

sandrock and thin 

streaks of marl). , 

-------~-------1-------------~-:.-----------------------1 

Shales in layers; easy drilling. 

Hard rock, probably lime- stone. 

Probably limestone und flint; 

Y-ery hard und rough drilling. 

Layers of hard rock; rough drilling. 

Soft, stick"Y whitish clay .. .' .. 

Thin layers of hard rock 

'(rough drilling) with thin 

streaks of soft material. 

The layers are a few inches to 2 feet thick. 

Whitish clays and shales{ with hard lumps anc layers. 

Soft white shales ........... . 

Hard black marl, with nodules und lumps; rough drilling. · Sands and shales; lost water 'in drilling. 

']'hickness in 

feet. 

12 

16 

5 

63 

2 

23 

2 

3 

3 

46 

13 

4 

13 

30 

15 

25 

Depth to base 

in feet. 

1,531 

1, 547 

1,552 

1,615 

1,617 

1,640 

1,642 

1, 645 

1,648 

1,694 

1, 707 

1, 711 

1, 724 

1, 729 

1, 759 

1, 774 

1, 776 

1, 801 

1, 803 
78 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Record of Charleston Consolidated Ra·ilway & Lighting Co.'s well, drilled in 1911 at the gas works of the company, foot 

of Charlotte Street, near Cooper J}.iver, Charleston, S. C.-Continued. · 

Depth (in Method of obtaining Log of well furnished by engineer in charge. 

feet) at samples and other Age and Sample which information f u r - Author's description of samples. formation. No. sarriple nished by engineer Thick- Depth to ·was Material. ness in base 

obtained. in, charge. feet. in feet. 

--------

Mud ·from bit. 

Chimks of gray calcareous, 

93 1,813 finely arenaceous and mi- caceous clay. 

Chunks of soft greenish-gray limestone or marl which Layers of excessively hard 12 1,815 

94 1, 815- Selected from overflow. grobably fell down from the limestone with thin layers 1,818 ooger marl, and chunks of of sand, black shale, py- bar gray glauconitic sand- ~!~e:d. shells, and fossil stone. ---- Chunk of hard gray, slightly 

Soft yellow sandrock ......... 3 '1,818 

94a .1,830? Questionably from this calcareous sandstone or Not described ............... 12 1,830 depth. quartzite. ---- Chunks of finely arenaceous and micaceous calcareous 

95 1,832 Mud from bit. clay, with white streaks of Hard white limestone ....... 2 1,832 lime; contains fra1fent of 

Exogyra ponderosa oemer? 

96 1,835 

Mud from bit; very hard conglomeratic rock. 

Same as sample No. 95. 

Chunk of hard gray calcareous ' 

97 1,835 Taken from mud on sandstone or quartziteilwith bit. poo_rly preserved she re- mams. 

Loose: coarse sand with 

Concentrated from chunks of hard gray s'illdmud on bit; very stone, a few small water- worn pebbles and chunks of 98 1,839 hard; slow drilling; gay sandstone; contains knots or lumps in strea sp. (fragment), and materiaL t<?oth of Coraxfalcatu! Agas- rd SlZ. 

rd ~ ---- CD .a From mud on bit; Chunk of hard gray calcare- ::l 

.E ti 99 1,_839 same as sample No. · ous, m!caceous sandst_one or 

§ 0 98. quartzite. 0 

0 ~ Coarse sand with chunks of Layer of shale, con~mer- 15 1,847 ! i gray calcareous sandstone, ate, limestone, san tone; ::l gray calcareous shaly clay, 0 excessively hard, thin CD a few quartz pebbles uE to 0 layers of pyrites; some Concentrated from .;., inch in length, and ag- .s .s 100 1,841 mud on bit. ments of shells; contains layers of pyntes drilled at 2:! ~ rate of 1 inch per hour 0 Q) Hamulus onyx Morton, Os- CD with Sharp & Hughes bit ... trea cretacea Morton, and ~ in good order. CD undetermined pelecypod p. 

p. ~ cast. p 0 Very hard sandy limestone; 14 1,861 .$ ---- good drilling. ~ 101 1,862 Mud from bit. Gray calcareous, finely arena- ceous and micaceous clay. ---- Very coarse sand with chunks 

of .gray calcareous sandstone, chunks of gray calcaConcentrated from reous shalh clay, a few Very hard rock .............. 6 1,867 102 1,862 mud on bit; same as quartz peb les up to l inch 

sample No. 101. in length, and shell fragments; contains Ostrea ere- tacea Morton, Gryphrea ~-

(small), and Exogyra pon e- rosa Roemer? ----

103 1,887 Concentrated from Same as sample No. 102; con- mud on }?it. tains Ostrea sp. ---- Mud from bit; same as Chunks. of dark-gray, finely 104 1,887 sample No. 103. arenaceous and micaceous 

clay. ---- Hard shales which produce 39 1,906 

1,940- Loose grafc, slightly glauco- a sticky mud. 

I 105 Sand from overflow. nitic, ca careous sand; con- Very soft material ........... 3 1,909 1,960 tains Cristellaria 12. Medium-hard shales with 38 1,947 - thind soft layers, probablh san ; easy drilling wit 

1,950- Concentrated from Loose, coarse sand with nu- fishtail bit. 

106 merous small fragments of Medium-hard rock .......•.. 4 1,951 1,960 overflow. shells. Soft to medium-hard layers 23 1,974 of shale and sand; some sand and shell breccia in 

overflow. 

Mud fro!p bit. 

Chunks of gray calcareous, 

107 1,975 finely arenaceous and mica- Very h'ard sandrock; fish- 3 1,97'i 

ceousclay. tail bit would not make 1 ' inch per hour.' 
A DEEP WELL AT CHARLESTON, S. C. 79 

Record of Charleston Consolidated Railway & Lighting Co.'s well, drilled in 1911 at the gas 'works of the company,joot 

of Charlotte Street, near Cooper River, Charleston, S. C.-Continued. 

.Depth (in Method of obtaining Log of well furnished by engineer in charge . 

Sample feet) at samples and other Ago and WhiCh information f u r - Author's description of samples. Thick- Depth to formation. No. sample 

was nished by engineer Material. ness in base 

in charge. feet. in feet. obtained. 

---

22000- Concentrated from Loose, coarse light-gray sand 

108 with numerous small shell Sandrock with much muck; 28 2,005 ,005 overUow. fragments. fair drilling. --- Average of material Loose, medium-grained mica109 12974- brought to surface ceous, calcareou<:; sand with 

,007 by natural flow. bits of lignite. 

--- 12974- Fossil wood brought 110 to surface by natural Lignite. 

.g ,007 flow . 

rei ::I Chunks of gray laminated § :§ Brought to surface by micaceous1 slightly calcare- :§ !5 Ill 1,974- ous clay with fine sand partl l 2,007 naturalilow. ings; contains comminuted 

vegetable fragments. 

Chunks of light-gray micaj -~ ceous, calcareous sandstone or quartzite; chunks of gray .s calcareous shaly clayj one Blue clay or shale ........... 2 2,007 

~ ~ concretion of sandy ime- ~ stone; concretions of iron .. 

~ () pyrites; small -waterworn §: ,!4 pebble, lignite, and numer-

.M p ous shells and fragments of 

jl:l 1, 974- Brought to surface by shells. Recognized trag- 1L2 2,007 natural flow. mont of small coral, Bryo- zoa (incrusting), Ostrea sp. nov. a, Ostrea sp. nov. b, Ostrea cretacea Morton, Exogyra upatoiensis s te(shenson, Anomia sp. nov. same as . new species from Snow Hil~ 

N. C.), and undetermine 

fragments of Ostreidre. 

FOSSILS OBTAINED FROM THE WELL SAMPLES. 

PROTOZOA. 

The subkingdmn Protozoa is represented in the well section by numerous specimens of 

Foratninifera, which were referred to Joseph A. Cushman for identification. The.species recognized by him and their distribution in the well are indicated in the .. accompanying table. All 

measurements of depth indicated in this table and on the following pages were made from the 

top of the rotary jaws, which stood 6 feet above the surface of the ground: 

Foraminijerafrom well of Charleston Consolidated Railway & Lighting Co., Charleston, S. C. 

Uppermost 

Eocene or Oligocene. 

Cooper 

marl. 

Eocene. 

Motlllt Hope marl of 

Sloan(?). 

Eocene or Upper Cretaceous. 

Upper Cretaceous. 

Peedee sand(?). Peedee c~!~c~r- sand. mation. 

No. 

Depth ofsamplo................... ln foot.................... 86 

5 6 

102 200 71 220 8 9 262-290 11 365 

171 439-447 23 24 25 26 454 478 504 29 525- 31 33 55Q- 585 34 39 68Q- 702 40 725 742 753 41 42 40 810 45 46 84Q- 855- 47 87Q- 48 49 920 920 50 950 52~ 1725-194Q- 263 444 540 570 685 850 860 890 1730 1960 

------------1--------------------------------

Textulariidw. 

'l'o:<tularia a. . .. . .. .. .. .. .. .. . .. X ................................................................................ · .. · ...... · .... · 

~~!:SE~i~~.::~;;~~:::: ::: :~: ::: ~- :::::::::::::::::::::::? :::: :::::::::::::::::::: :;: ::::::::::::::: ::::::::: :::::::::: Dollvlnaa ...................... X ................................... X ....................................................... .. b ............................ X X ... X ...................................................................................... . d ••.•......•..................•• X ..•..••••.••.••.•.....•..•.••..•.••.....•...•....•..•..•..•..•.....•.• ·••· •·• ··• ··• ••••• ••••• e .............................. X .......................................... : ................................................. . /cf. rotlculata ............... X X X X .......................... X ........................................................ . 

Dulk~~=~~~~:::::::::::::::: :x: :~: :~: ;: :::::::::::::: j::: :::::: :~: :::::::,::::,::::::::::::::::::::::::::::::::::::::::: ;:::: 
80 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Foraminijerajrom well of Charleston Consolidated Railway & Lighting Co., Charleston, S. C.-Continued. 

Uppermost 

Eocene or Oligocene. 

Cooper 

marl. 

Eocene. 

M:ount Hope marl of 

Sloan(?). 

Eocene or Upper Cretaceous. 

Upper Cretaceous. 

Peedee sand(?). Pee dee 

sand. 

Black 

Creek for· 

mation. 

No. of sample................... 5 6 7 8 9 11 17. 23 24 25 26 29 31 33 34 39 40 41\42 43 45 46 471 48 49 50 52 88 105 Depth in feet. . . . . . . . . . . . . . . . . . . 86 102 200 220 262- 290 365 439-447 454 478 504 525- 55o- 585 68o- 702 725 742 750 810 840-85.1-870-920 920 950 1725-194Q263 444 540 570 685 850 860 890 1730 1960 

------------1------~-------------------------

Gaug::.~~~-:::::::::::::::::::: ::: ~ ::: ::: :::: :::::: :::: ::: ::: :·:: ::: :::: :::: ::: :::: ::: ::: ::: ::: ::: :::: :::: :::: ::: ::: ::: ::::: ::::: c ............................ X X ............................................... ··· ...... ··• ··• ................................ . 

2~$~1~~~~~~:::: :~: ~: :~: :~: :::: :::::::::: :;: ::: ~: ::::::::::: :::::::::::::::: :~: :~: :~: :~.: :~: :~: :~: :::::::: ::::: 

Chilostomellidre. 

Chilostomellaovoidea .............. .......... X ................................................................................................................... -.-· -~- ... 1 ... ..... . 

Lagenidre. 

Lagt~~-asufcata::::::::::::::::: ~ ··x: ·x· -~- :::: ::: ::: :::: ::: ::: x· ::: :::: :::: ::: :::: ::: ::: ::: ::: ::: :::: :::: :::: ::: :~: ::: ::::: ::::: c ....... · ........................... X .......................................................................... -•· ..•..•....••• 

Nod~~~l~~~~~::::::: :~: ~: ~: ::: :~: :~: ::::::: :;: ::::::::: :~: :::::::X:::::::::::::;:::::::::::::::::~:::::::::::::: 4 ............................... X ... X .......................... X ................................. : ........ , ............. . 5 ............................... X ................ X X ............................................................... ~ ....•.• G ..................... · .......... X ...................................... : ............................................ X .•••• 7 ............................... X ........................................................... .' ................................ . 8 cf. lrevigata. . . . . . . .. .. .. . .. .. . X ..................................................................... ; ............... • ...... . 9 cf. communis ................. X ................................ X ............................................... .. : .• ..... 10 •..................................• X .•....•..••.•.•.•..•.••..•.•...••...•......•..•.••..•..•..•......•....•..•..•..•....••• 11. ................................... X ....... ? ............................................ ; ................................ . 12 •..................................• X .••...•..•....•.•.••.....•....•.....•..••.••..•.••..• -•·· ..•...•..••...•..•..........•.. 13 cf. hirsuta................ .. . X ............................................................ , .......................... · ...... . 14........................... .. • .. . .. • .. . .. .. .. . . . • .. .. .. . . . . .. • .. . .. .. .. .. .. • . . .. .. . .. . . . • X X .. .. X X X ........... : .•.• 15........................... .. • .. • . . . . . . .. .. . . • .. • .. . . .. • .. • . .. . .. .. . . .. .. • .. X X ... X X .. . .. .. .. .. X ..... · ...•..•..•...• 16 cf. infiexa................. .. . . . . .. . .. . .. .. .. . .. . .. .. .. • .. . . . . .. . .. .. .. .. . .. . . . . .. . .. . .. . . . . . . . .. .. .. .. .. . . . . . .. . X ........ .. 17 .................................................................................................................... X ... .. Cristellaria 1. . . . . . . . . . . . . . . . . . . . X . . . . . • . . . X .....•............•..•.................•.....•................ -...• -.•.....•....•.• 2 •............................• X ..•..• X ..•..•............•..• X ......•.........•........•....................•..•....•.• 3 cf. latifrons.. . . . . . . . . . . . . . . . . X ..•..•......•..•......•........•..........•.•....•..•..•..•..•..........•...• -.•.....•... -.. . 4 cf. italica .................... X ............................................................................................ .. 5 cf. converge:1s ............... X ............................................................................................ . 6 .............................. X ... X X .................................................................................. . 7 .............................. X ... X X .................................................................................. . 8 .............................. X ... X .................... . : • ................................................................ 9 ....................................... X .................................................................................. . 10 ........................................... X .................... X ....... .. : . ........................................... .. 11 cf. clypeiformis .................. ,. .................................. X ....... X X X X X X X X X ............... . 12 ........................... . : . ........................................................................................... X Frondicularia a. . . . . . . . . . . . . . . . . . . . X X X .........•......•........•.........•................................................... 

;if~~~~~'~l[[ii! ~]J :~ :::; :::l:;: !iii iii :X: :X! :X: :i: ::;: ::: :::: ::: ::; !i!itl [Xl :;:: !li! :::: !l! ::: !l! ::::: ::::: 

Glo~ig?_r!:ttil~te~~~i-~:::::::::: ~ ~ ~ ~ :::: :::1::::::: ::: ·x· ::: ::: :::: :::: ::: :::: ::: ::: ::: ::: ::: :::: :::: :::: ::: ::: ::: ::::: ::::: 

Sphreroidina cf. bulloides... . . . . . X X X X . . . . . . . . . . . . . . . . • . . • . . . X X ........................................................ . 

Rotalidm. 

Pulvinulina cf. oblonga. . . .. . .. . X X .......................................... - ............... - ..... · · ........... · .. · .. ----- .... · 

~~~~~!i~1iita·~:::::::::::::::::: ~ B -~- :~: :::: ::: ::: :::: ::: ::: ::: ::: :~: :::::::: :::: ::: ::: ::: ::: ::: :::: :::: :::: ::: ::: ::: ::::: ::::: 

J;;:~;.~.:HE-E ~ g ~-~- ~- ::: ::~ ::~ :::~ :::) ~: ) :~: :J::: :~~: ::: :::::: ::~ ::: :::t:: ::::::: ::: ::: ::::: ::::: g .................................. X X .................................. ·•· ................................................. . h ................................. X x ....................... x ............................................................ . 

Numwulitidre. 

Polystomella .................... X X X X ................. X X X X ........................................................ . Nonionina cf. umbilicatula ..... : X X X .................................... - ... · · ........ · .... · .. · ...... -- -- .... - -- · ·-- · .... · .. --

.Miliolidre. l 

Massilina ........................ X X X X 1 ................. X ---~--- X ---- 1--- ....... ·--

1

--· --·~·-- ........ •••• ••• ............... . 
A DEEP WELL AT CHARLESTON, S. C. 81 

In regard to the Foraminifera listed in the table, Dr. Cushm·an says: 

Tho Poraminifera of the deeJ) well at Charleston have been examined carefully down to station 50 (depth 920 feet), 

where tho known Cretaceous begins, in order to determine, if possible, the limits of the Cretaceous in the questionable 

sections above. 'l'he samples of the Cooper marl, Nos. 5, 6, 7, and 8, were fust carefully studied. These samples 

contain a very rich foraminiferal fatma, as will be seen by the accompanying chart of distribution. Of the 81 species 

recorded from the well 71 occur in these four samples. .Sample 6 waa much the richest·in species, containing 50 of the 

71 Cooper marl species. In general it is such an assemblage as may have occurred in water ranging in depth from 

100 to 200 fathoms. It is m'ost marked by the practical absence of the Miliolidre, only one species being present and 

that allied to the forms found in the deeper water of present oceans. 

A study of the washed material from stations 25 to 50, the questionable section, soon showed that material from 

several horizons had been mixed. . As noted by those who had previously examined the Itthology of this material, the 

Cooper tnarl had dropped down in the boring and had. been mixed nearly throughout the samples taken below, so 

that it became necessary to eliminate the Cooper marl speCies from each sample. 'rhe occurrence of these specie~:~ 

was noted and is charted for samples 25, 26, 29, and 31, but it was soon seen that these species represented merely the 

material which had accidentally dropped from above, so that the charting was not continued. These species occur 

similarly in the samples down to 50, where the known Cretaceous begins. t • 

It became apparent that the upper part of the section was of slight interest as far as the Foraminifera were concemed, but in sample 39 other species were found. These, however, are too few and poor to afford very definite informa-· 

tion, but when sample 43 was reached a marked.changE~ was shown in both the physical character of the test and in 

ti1e species. At' this level there were specimens of the genus Vitrewebbina attached to specimens of Cristellaria and 

Nodosaria. This genus is recorded from the Cretaceous'of New Jersey by Bagg. These and certain other forms occurring at·ti1is level seem to show that the Cretaceous strata here lie as high as the 750-foot level. The same species characterize the samples taken immediate~y below. 

Many of ti1e forms, especially those of the Cooper marl, have been referred to known species, but the whole series 

s).1ows marked differences from allied known fatmas and the material must be carefully studied in ·conjunction with 

that from other localities for final determination. Meanwhile the data showing the distribution of the fossils in the well 

sample~ are available for use. 

C<ELE,NTERATA. 

A coral identified by Vaughan as Troc:Q.ocyathus sp. aft·T. woolmani Vaughan was found 

in satnple 62, depth 1,230-1,250 feet, and a frag1nent of an unidentified coral was found in 

sample 112, depth 1,974-2,007 feet. 

ECHINODERMA:r"A. 

The spines of unidentified echinoderms were found in four of the samples as follows: Sample 

11, depth 290 feet; sample 13, depth 348-350 feet; sample 17, depth 365 feet; sample 23, depth 

439-444 feet. 

· VE:RMES. 

Ha·'ll(bulus onyx Morton, a species regarded as belonging to the subkingdom Vermes, was 

found in sample 100, depth 1,841 feet. 

MOLLUSCOIDEA. 

, The subki.ngdon1 Mo Uuscoidea is represented in the well by Bryozoa, fragments of whlch 

were contained in satnples 22, 23, and 24. In these samples R. S. Bassler has recognized the 

following species: 

Sample 22, depth 435 feet, contains Entalophora cf. macrostoma. 

San1ple 23, depth 439 to 444 feet, contaim; Heteropora sp. nov., Escharinella (cf. altimuralis 

U. and B. of the Rancocas formation, but has smaller pores), Amphiblestrum (cf. heteropora 

G. and I-I. of the Rancocas formation), Lichenopora (cf. grignonensis :Milne-Edwards). 

San1ple 24, depth 447 feet, contains Heteropora sp. nov., Escharinella (cf. altim'ltralis 

U. ttnd B. of the Rancocas formation, but ha:; smaller pores). 

'MOI.LUSCA. 

MOLL USXS FROM THE ~:LEISTOCENE AND PLIOCENE. 

Fossil mollusks were found in samples 1 to 4, as follows: 

Sample 1, depth 40 feet, contained a few shells. . 

Sample 2, depth 62 feet, contained numerous fragments of shells and a few well-preserved 

shells. 
82 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Sample 3, depth 73-75 feet, consisted chiefly of fragments of shells with numerous wellpreserved shells. 

Sample 4, depth 82-83 feet, consisted chiefly of fragments of shells, with numerous wellpreserved shells. 

The fossils from samples 1 to 3 are of Pleistocene age and those from sample 4 are of Pliocene 

age. (See pp. 71, 85.) 

- Ma;ny of the samples taken between the depth of 86 feet and the bottom of the well contained 

a few Pleistocene or Pliocene shells, which doubtless represented mixtures resulting from the 

caving of the walls in the upper 86 feet of the well. Most of these fossils were easily distinguishable from the older Eocene and Cretaceous fossils, and since their mention would serve only 

to confuse the reader they have been disregarded in all that follows. 

MOLLUSKS FROM THE EOCENE. 

The samples from the strata of uppermost Eocene or Oligocene age between the depths of 

86 and 220 feet (samples 5 to 8, inclusive) and the samples from strata of undoubted Eocene 

age penetrated in the well between the depths of 262 and 447 feet (samples 9 to 24, inclusive) 

contained a few fragments of unidentified mollusks in addition to numerous shells which were 

obviously present as a mechanical mixture from the upper 86 feet of the boring. 

MOLLUSKS FROM THE CRETACEOUS. 

Exclusive of the shells which were obviously present as a mechanical mixture from the 

upper 86 feet of the section, samples 50 to 112, representing depths from 920 to 2,007 feet, 

contained the species of fossil mollusks listed in the following table: 

Cretaceous mollusks from the deep well of the Charleston Consolidated Railway & Lighting Co., Charleston, S. C. 

No. ofsample ...................................... . Depth in feet ........................ _ .............. . 50 

920 52 950 54 1,000 55 1,015-

1,030 

56 

1,035-

1,045 

58 1,055-

1,058 

60 1,130-

1,140 

61 69 70 1, 150- 1, 340- 1, 375- 1, 200 1, 360 1, 400 

72 1,440-

1,450 

--------'---------1·----------------------

Ostrea falcata Morton ...................................... _ . . . . . . . . . . . . . . . . X X ............................................... . plumosa Morton .... ~ .............................. _ .... _ . . . . . . . . . . . . . . . . X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X X cretacea Morton ........................................................................................................................ . 

r:~J~~~~~~~~~=-~f~~~~:):::::::::::::::::::·::::: :::~::: :::~::: :::~::: :::::::: :::::::::::::::: :::::::: :::::::: :::~::: :::~::: :::::::: 

(fragments) ................................................................... ~ ........................................................ . Gryphrea sp .......................................................................................................................... -...... . 

Exo~~~~li~~~:st:P~~~~~r:.~::::::::::::::::::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: Peci!~~:e~ttJsM:~i-t~n.".":::::::::::::::::::::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: ·--~--- ·--~--- ·--~·-· 

Lim1~~~~~~~~t~rsb~~~~~-~::::::::::::::::::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: ···x··· :::::::: :::::::: :::::::: :::::::: 

.Anomia argentaria Morton. . . . . . . . . . . . . . . . . . . . . . . . . . X X . . . . . . . . X . . . . . . . . X . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 

cras~~i!Wue~~~(c~~~f:.~~~:.f~~~-~~-~~-~~·-~:~."~: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::~:::: :::::::: ::.:::::: :::::::: Undetermined casts of pelecypods .......................................................................................................... . Belemnitella americana (Morton)? ...................................... -.......................... , . . . . . .. . . . X ....................... . 

'No. of sample....................................... 77 83 Depth in feet ........................................ 1,540- 1,660-

1, 550 1, G70 

88 I, 725-

1, 730 

89 

1, 736 92 1,800-

1,812 

95 

1,832 

98 

1,839 100 

1,841 102 1,862 103 1,887 112 1,974-

2,007 

----------------1----1---1--------------.-----

Ostrfla falcata Morton ........................ , ............................................................................................. . 

Ei~Fac eS:tf~it~:::.-::: :::::::::::::::::::::::::::: :::::::: :::::::: .... i ... :::::::: ... x ... :::::::: :::::::: ... x , ..... x ... :::::::: ... x .. . 

~:~J~~~~i~~g~~~)~~~~~::::::::::::::::::::::: :::::;:: :::~::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: ··-~·-· (fragments)..................................... . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X . . . . . . . . . . . . . . . . X X 

~7o~~r~!~s~~i-~:~~~~~~~:-~::::::::::::::::::::::: :::::::::::::::::::::::: :::::::::::::::: ::::~::: :::::::: :::::::: ·--~--- :::::::: :::~::: Pecf!~a~~~sM:~i-i~D"."::::::::::::::::::::::::::: ···x··· :::::::: :::::::: :::~:::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: Lim1~~~~~~~~;tWgr~~~~~~~~::::::::::::::::::::::: :::::::: :::'::::: ... ~ ... :::::::-: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: 

~:Si~~~ge1~~f:~if~~~:~~~~:~~~'~:~~~~:?:-~: :::::::: :::::::: :::·::::: :::~::: :::::::: :::::::: :::::::: :::::::: :::::::: :::::::: :::~::: ~~~~~W!hi~~~~~f(i:grro~gs?:::::::::::::::::: :::::::: :::·::::: ::::::::1:::::::: 1

:::::::: :::::::: :::::::: ·--~--- :::::::: :::::::: :::::::: 
A. DEEP WELL AT CHARLESTON, S. C. 83 

ARTHROPODA. 

The subl\:ingdon1. Arthropoda is represented among the fossils from the well by specimens of 

Ostracoda. A species of Cytheridea, closely related to 0. perarcuata Ulrich, was obtained from 

sample 25, depth 454 feet; a few Ostracoda were found in samples 26-48, depths 478 to 890 

feet; and a few specin1ens of unidentified Ostracoda were also found in some of the samples 

taken between depths of 920 and 2,007 feet. · 

VERTEBRATA. 

A :few remains of fossil vertebrates were obtained from samples. representing the Cretaceous portion of the section, as. follows: 

Samples 50, 54, 55, taken at depths of 920, 1,000, and 1,015-1,030 feet, respectively, Oorax 

falcatus Agassiz (a shark); sample 70, 1,375-1,400" feet, Lamna ~; samples 72, 83, 86, from 

depths of 1,440-1,450, 1,660-1,670, and 1,72Q-1,723 feet, respectively, shark teeth; sample 

92, 1,80Q-1,812 feet, coprolite; sample 98, 1,839 feet, Ooraxfalcatus Agaf3siz; sample 100, 1,841 

feet, Ptychodus ~ (fragment· of tooth). 

PLANTS. 

. The only plant remains found :in the·samples were a few fragments of lignite :in sample 1, 

depth 40 feet; numerous fragments of lignite from f3amples 109, 110, and 112, depth 1,974-

2,007 feet; and numerous comminuted vegetable fragments in sample 111, depth 1,974-2,007 

feet. 

RECORD OF ANOTHER WELL AT CHARLESTON. 

The record of a well1, 980 feet deep, drilled under the auspices of the city council of Charles-.. 

ton between the years 1876 and 1879 by Mr. F. Spangler, is inserted here for purpo~es of comparison. The well is known as the Citadel Green well and is at the southwest corner of the 

South CaJ.·olina Miljtary Academy grounds, near the corner of King and Calhoun streets. A 

scientific committee was appointed by the city council to cooperate with the city civil engineer 

''in devising and employing the best means of preserving, recording, and classifying the stratifications of the new well and publishing a statement of the 'York when done." 1 

This committee sent a set of borings from the well to Prof. James Hall, whose report to the 

chairman of the committee is here quoted in full. 2 

Right Rev. P. N. LYNCH, Bishop of Charleston: 

NEw YoRK STATE MusEUM OF NATURAL HrsTORY, 

Albany, Jtme 21, 18~0. 

I very much regret that it was not in my power to give prompt attention to the collection of specimens from the 

artesian well at Charleston which you placed in my hands, but you already know why I was not able to do so. 

I herewith hand you some memoranda regarding the collection as it came into my hands and as indicated by marks 

showing the number of feet in depth. The,se depths are sometimes specifically marked, and in other cases the specimens in the box or parcel are marked as extending over many feet. Some of the specimens of fossils can be readily 

identified, but most of them are too fragmentary to give the means of satisfactory specific determination, and I have 

indicated only their generic relations. 

'l'he species described by Capt. Vogdes, 3 with a single exception, do not appear in the collection in a condition to 

be satisfactorily determined. 

The higher beds are clearly of the modus Tertiary. There is nothing in the collection that indicates the presence 

)f Cretaceous strata at any point above 600 feet. The parcel marked 600 to 1,300 feet contains Cretaceous forms, and 

the specimens marked respectively 654-767 and 700-720 feet have all the aspect of Cretaceou~ marl or green sand but 

are without fossils. At 900 feet there occur teeth of Ptychodus mortoni Leidy, a characteristic Cretaceous fossil. 

1 Artosian wells: 'l'he reportofthe scientific committee appointed by the city council on July 5, 1876, consisting ofthe Rev. P. N. Lynch, D. D., 

Prof. C. U. Shepard, jr., and J. F. M. Geddings, M.D., embracing a historical sketch of the several attempts, from 1823 to the present time, to 

bore artesian wells in this city; also an elaborate analytical investigation of the waters and the strata penetrated in the artesian wells and other 

nnolyscs of cistern waters and of waters from many of the large fire wells of this city: Municipal report of the city of Charleston, S.C., 1881, 61 pp. 

Charleston, 1882. · 

2 Idem, pp. 21-24. 

sAm. Jour. Sci., 3d ser., vol. 10, pp. 09, 70, 1878. 
84 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The lowest depth of any marked specimens of fossils is 1,955 feet, and' the parcel cont~ns characteristic Cretaceous 

forms. The specimens indicated as 1,94o-1,980 are of greenish clay, without fossils. 

Regarding the Tertiary as terminating at the depth of about 600 feet this will give nearly 1,400 feet (1,980-600= 

1,380) of the Cretaceous formation in vertical thickness. 

The lowest marked specimens of fossils are of characteristic Cretaceous forms and present no remarkable change 

from those several hundred feet higher in the series. From the character of these fossils we should be warranted in the 

inference that there·may be a considerable thickness of Cretaceous beds below that horizon. 

The clay indicated by the numbers 1,94o-1,980 feet has the character of the lower clays of the Cretaceous formation in some localities, but it would be imprudent to draw any positive inference without further knowledge. 

Truly yours, 

JAMES HALL, 

State Geologist and Director State M'useum Natura(His.tory. 

Notes on samples of borings ft.om different depths of the artesian well at Charleston, S. C. 

Depths. 

65--100. Pliocene, Tertiary, Tellina, Area, etc.~ 

8o-100. Tertiary, Venus, T~llina, shark's tooth, phosphatic nodules. 

35o-430. Tertiary; phosphatic nodules, oyster-shell"breccia. [600 feet noted by Capt. Vogdes as containing Chama. No specimens.] 

680. Shell marl, concretions. Nothing indicating geological position. 

60o-1,300. Cretaceous, Exogyra foliacea, iion pyrites nodules, soft limestone of calc~reous rock with phosphate. · Specimens marked as abov.e; no indication of specific depth. 

654. Cretaceous, marl with fragments of shells. 

767. Cretaceous, marl with green sand, Anomia? sp. (fragmentary). 

778. Cretaceous, phosphatic concretions, green sand, iron pyrites. 

70o-720. Cretaceous, compact marl, oolitic and micaceous shells which are indetermin::tble. 

900. Cretaceous, Ptychodus mortoni Leidy (a characteristic Cretaceous fossil). 

1,090. Cretaceous, calcareous marl with fragments of shells. 

1,345. Cretaceous, Ostrea sp. ?, G,Yph::ea vomer. 

1,345-1,350. Cretaceous, Exogyra costata, Gryph::ea vomer, charred wood. 

1,349. Cretaceous, marl with sand, green sand, siliceous concretions. 

1,369. Cretaceous, marl with sand, Exogyrafoliacea. 

1,400-1,403. Cretaceous, concretions of sand ill a greenish marl. 

1,472. Cretaceous, concretions of sand in a greenish marl with shell breccia. 

1,520. Cretaceous, argillaceous marl. 

1,533-1,538. Cretaceous, sand with shells, c~sts of shells, and shells of Ostrea, Exogyra, Anomia? sp., Neithea 

mortoni D'Orb. 

1,553. Cretaceous, breccia of shells and bryozoans, Ostrea, fragments of bones, Serpula, lignite. 

1,570. Cretaceous, green sand, Exogyra costata. · 

1,575. Cretaceous, green san(J., siliceous concretions, Ostrea. 

1,580. Cretaceous, green sand, argillaceous. 

1,588. Cretaceous, green sand and marl, without shells. 

1,558-1,560. Cretaceous, sand, concretions, micaceous, Exogyrafoliacea, Inoceramus (fibrous portion of shell), 

Exogyra, fragments, Ostrea, casts of indeterminable fossils in green sand. 

1,558. Cretaceous, valve of Exogyrafoliacea. 

1,600. Cretaceous, Inoceramus (fibrous portion of shell), Exogyra costata, Dentalium. 

1,600-;-1,610. Cretaceous, green sand with Exogyra, Teredo. 

1,61o-1,620. Cretaceous, green sand with Exogyra. 

1,625--1,650. Cretaceous, g:reen sand with Exogyra, Ostrea. 

1,65o-1,675. Cretaceous, green sand with Exogyra, Gryph::ea vomer, Exogyra costata. 

1,690. Cretaceous, green sand with Exogyra. 

1,69o-1, 705. Cretaceous, green sand with casts of fossils and fragments of Exogyra. 

1,692-1,700. Cretaceous, green sand and marl. 

1,700-1,725. Cretaceous, green sand and marl, Ostrea, Gryphrea. 

1, 710. Cretaceous, green sand, ~iliceous. 

1, 728. Cretaceous, green sand, siliceous. 

1, 73o-1, 75Q. Cretaceous, green sand, Exogyra. 

1, 745. Cretaceous, green sand, siliceous. 

1, 765. Cretaceous, green sand, siliceous, fragments of Exogyra, Ostrea, upper valve of Exogyra costata. 

1, 790. Cretaceous, green sand. 

1,831. Cretaceous; Exogyra costata. 

1,835. Cretaceous, fragments of bones and Exogyra, two forms of Bryozoa, undetennined siliceous aggre- , 

gations. 
A DEEP WELL AT CHA~·LESTON, S. C. 

Dopths. 

1,845. Cretaceous, Exogyra, shell, breccia. 

1,840. Cretaceous, Exogyra, Ostrea, young of Gryphma convexa. 

1,840. Cretaceous, echinoderm (Bucleolites?). 

1,850. Cretaceous, fragments of bone, siliceous pebble. 

85 

1,835-1,840. Cretaceous, Exogyra, Gryphrea, sand, pyrite, Dentalium, bones, shark's teeth of the genera 

Ptychodus and Lamna, echinoderms, Nucleoletes ( Catophygus) lynchi1 Vogdes. 

1,844-1,845. Cretaceous, shells of Gryphma vomer?, Exogyra costata. 

1,840-1,845. Cretaceous, sandstone with fragments of shells, shell breccia, Exogyra costata (young), Gryphma 

pitcheri. 

1,845. Sand pump, Cretaceous, Gryphma pitcheri, Gryphma vomer, .sand concretions. 

1,835-1,840. Cretaceous, concretions of coarse sand, shells, Ostrea, Gryphma shephardi, .Exogyra. 

1,840. Cretac-eous, shark's teeth. 

1,840-1,940. Cretaceous, fish bone, Inoceramus sp.? 

1,900(?)~ Cretaceous, sand, Ostrea. 

1,900(?). Cretaceous, shark's .tooth, pebble, sand. 

1,932. Cretaceous, green sand, casts of fossils, pebbles, lignite, iron pyrite, Gryphrea. 

1, 930 .. Cretaceous, clay. 

1,930. Cretaceous, micaceous sandstone. 

1,900. Cretaceous, sandstone, iron pyrite, green sand, fine laminated clay. 

1,900. Cretaceous, Inoceramus, wood. 

1,900. Cretaceous, exterior shell of Inoceramus. 

1,900. Cretaceous, Teredo. 

1,923. Cretaceous, green sand, casts of Gastropoda, Inoceramus, Ostrea. 

1,940. Cretaceous, phosphatic nodule with iron pyrite, sand aggregation with mica. 

1,943. Cretaceous, lignite, red hematite. 

·1,950. Cretaceous, wood opal, iron pyrite. 

1,949-1,980. Cretaceous, clay. 

1,955. Cretaceous, lignite, iron pyrite. 

1,955. Cretaceous, shell breccia, Nucula, Turritella. 

1,955. Cretaceous, shell breccia, siliceous, Ostrea. 

1,955. Cretaceous, oyster perforated by sponge, green sand, iron pyrites, Inoceramus. 

According to Prof. Hall's interpretation 'the Cretaceous was reached in this well at a depth 

of 600 feet, although no characteristic Cretaceous fossils are recorded from a definitely determined depth less than 900 fee.t. Prof. Hall's report contains two proposed specific names of 

fossils, nan1ely, Exogyrajoliacea and Gry1Jhcea shephardi, which were not subsequently' described 

and which are therefore invalid. 

The present writer has, not been able to learn what disposition was made of the fossils 

fr01n this old well. 

CpRRELATION OF THE STRATA P~NETRATED. 

STRAT,A OF PLEISTOCENE AND PLIOCENE AGE. 

The fossil1nollusks in sa1nples Nos. 1 to 4 were submitted to Dr. Paul Bartsch, of the United 

States National :Museum, who regards those obtained from samples 1. to 3, representing depths 

frmn 40 to 75 feet, as of probable Pleistocene age and those from sample 4, depth 82-83 feet, as 

certainly of Pliocene age. 

STRATA OF UPPERMOST EOCENE OR OLIGOCENE AGE. 

Sa1nples 5 to 8, representing depths from 86 to 220 feet, contain a rich foraminiferal fauna, 

the species of which have been identified by Joseph A. Cushman. The names of the species and 

their distribution in the well are given in the table on pages 79-80 and the fauna is discus~Sed in 

the quotation that follows the table. The lithology of the samples shows that they belong to the 

Cooper 1narl, which outcrops in the vicinity of Charleston and which is referable to either the 

uppern1ost Eocene or the Oligocene. R. S. Bassler states that he has recognized ostracodes in 

the Cooper 1narl which appear to indicate that it is of Vicksburg age. On the other hand, the 

formu.tion has yielded n1ollusks and the vertebrate genus Basilosaurus, which Vaughan and 

others have regarded as indicating its Jackson age. 
86 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1~14. 

STRATA OF EOCENE AGE. 

A part of the samples iunnbered from 9 to 24, representing depths ranging from 262 to 447 

feet, were obtained as concentrates from the overflow. These consist largely of fragme~ts of 

limestone, fragments of shells, echinoid spines, and Bryozoa. Samples 9, 11, and 13, depths 

262 to 350 feet, were derived from layers of rather soft limestone or marl, but they yielded no 

determinable fossils. Samples 17, 20, 22, 23, and 24, depths 363 to 447 feet, are made up chiefly 

of Jragments of hard gray sandy limestone containing numerous indeterminable fragments of 

mollusks and a few fragments of echinoids and Bryozoa. These samples appear to be esse-ntially 

alike lithologically and probably represent one geologic formation." From samples 22 to 24, 

depths 435 to 447 feet, R. S. Bassler has identified the species of Bryozoa listed ·on page 81. · 

. ~ He reports that the fauna is closely related to the bryozoan fauna in the Castle Hayne 

limestone/ of Jackson (Eocene) age, exposed riear Wilmington, N. C., and to a similar fauna in 

the Mount Hope marl of Sloan, 2 exposed near .Eutawville (Eutaw Springs), 70 miles north of 

Charlesto11-, S. C. 

Vaughan, 3 because of the presence of Ostrea sellreformis Conrad, has correlated the Mount 

Hope 1narl of Sloan with the Claiborne group, but evidence afforded by the Bryozoa indicates 

that it may be of Jackson age. 

Although the stratigraphic and age relations of the upper Eocene and Oligocene deposits 

of this area have not been definitely determined, the fact that normally the strata dip coastward 

and the evidence afforded by the fossil bryozoans seem to support the view that the limestones 

and marls penetrated in the Charleston well between depths of 262 and 447 feet represent 

the buried coastward extension of the Mount Hope marl of Sloan. However, the evidence 

cited on page 85, which appears to indicate the Jackson age of the Cooper marl, necessitates 

questioning the correlations here suggested. 

Sample 25, depth 454 feet, contains ostracodes belonging to the genus Cytheridea and closely 

related to the species 0. perarcuata, which occurs in the Eocene of l\faryland in both the Aquia 

and Nanjemoy formations. 

STRATA OF EOCENE OR UPPER CRETACEOUS AGE. 

Samples 26 to 42, representing depths between 478 and 742 feet, yielded no fossils of sufficient diagnostic value to permit the determination of the age of the beds. A few specimens of 

Ostracoda and Foraminifera were oqtained, but it was not certain. that they belonged in place 

at the levels from which they were taken; indeed, it seemed highly probable that they fell from 

higher levels. Lithologically, the samples present no features of value for correlation. The 

upper part of the thickness represented (264 feet) is probably -Eocene and the lower part Cretaceous, but without more exact data the point of contact can not be determined. The samples 

obtained as concentrates consist chiefly of gray shaly, finely arenaceous, micaceous, calcareous clay containing more or less loose sand. One sample (No. 29, depth 504 feet) is a highly ' 

glauconitic loose sand. The san1ples obtained as mud from the bit consist of gray calcareous, 

more or less sandy clays. The lithology of these samples indicates that they may belong to either 

the Eocene or Cretaceous. The basal beds of the Eocene that outcrop in the Coastal Plain of 

South Carolina along the borders of the Cretaceous areas north and northwest of Cha-rleston 

· consist in part of dark shaly clays, the buried extension of which some. of these samples might 

well represent. The glauconitic sand (sample 29, depth 504 feet) may perhaps represent the 

glauconite-bearing Warley Hill marl of Sloan (part of Claiborne. group). l\fany of the samples 

below the glauconitic layer are not essentially different from those above it. 

STRATA OF UPPER CRETACEOUS AGE. 

The first definite paleontologic evidence of strata of Cretaceous age was afforded by species 

of Foraminifera found in sample 43, depth 7 50 feet. Dr. Cushman has discussed this evidence 

in the quotation give~ on page 81. From this depth to a depth of 920 feet the samples indicate 

1 Miller, B. L., The Coastal Plain of North Carolina; the Tertiary formations: North Carolina Geol. and Econ. Survey, vol. 3, pp. 185-197, 1912. 

2 Sloan, Earle, Catalogue of the mineral localities of South Carolina: South Carolina Geol. Survey Bull. 2, ser. 4, p. 462, 1908. 

a Vaughan, T. W., in Willis, Bailey, Index to the stratigraphy of North America: U.S. Geol. Survey Pr~f. Paper 71, p. 737, 1912. 
A DEEP WELL AT CHARLESTON, S. C. 87 

that the drill encountered sands and clays, more or less calcareous and glauconitic, containing 

sn1all black phosphatic pebbles. Son1e hard layers were penetrated, as is shown by frag1nents 

of sandstone in the samples. 

The fu·st identifiable n1ollusk of undoubted Cretaceous age, Anomia argentaria :Morton, was 

found in sample 50, taken at a depth of 920 feet. The strata penetrated from 920 feet to the 

bottmn of the well, as represented by the samples, are typical n1arine Upper Cretaceous materials, 

consisting of marls, n1ore or less calcareous and glauconitic, sands, and shaly clays, with 

indurated layers at intervals: These samples yielded the identifiable fossils listed on preceding 

pages. 

· The writer has heretofore attempted 1 to explain the lithologic variations and age relations 

of the Cretaceous deposits of the eastern Gulf region and to correlate them with the Cretaceous 

deposits of the North At- · · CHATTAHOOCHEE 

}antic region. Figure 11, CAROLINAS -------- REGION - which indicates the terms 

en1ployed in that report to 

designate the paleontologic 

} 

Liopistha protexta 

subzone 

zones recognized and the re- Peedee sand >- Exogyra costata zone >

Exogyra costata zone 

lations of these zones to formation units, is introduced 

in order that the Charleston 

well section may be compared with the Chattahoochee and Carolina sections. 

In figure 12 the correlation 

of the Cretaceous portion of 

the Charleston well sections, 

in tern1s of the faunal zones 

recognized in these regions, 

is indicated diagrammatically. 

The following fossils 

were identified specific!LllY 

in samples taken between 

Black Creek 

formation < 

Ripley < formation 

-----

>E xog'l}ra ponderosa 

zone > Exogyra ponderosa 

zone 

~ 

Un 

. Tombigbee } Mortomceras · sand subzone member --------

Eutaw < formation 

\ Fauna of the basal beds iJ of the Eutaw formation 

'4-----.......r 

Unconformity 

depths of 920 and 1,550 feet: Lower < 

conformity 0-. 

Lower 

Cretaceous . .Mollw~ca: Ostrea larva Cretaceous 

Lamarck, Ostrea plumosa 

:Morton, Pecten venustus 

Morton, Lima reticulata 

Forbes~' and Belemnitella 

americana (Morton) ~. 

Vertebrata: Oorax jalcatus Agassiz (a shark). 

FIGURE H.-Diagram indicating the terms used to designate paleontologic zones an<}. the relation' of 

these zones to formation units in the Chattahoochee region and the Carolinas. Horizontal 

dashed lines indicate age equivalencies within the Upper Cretaceous. -Not drawn to scale, 

and relative thiclmesses of formations not indicated accurately. The Ripley formation· of the 

Chattahoochee region is approximately the time equival.ent of the Selma chalk of western Alabama and east-central Mississippi and of the combined Ripley formation, Selma chalk, and 

upper part of the Eutaw formation of northern Mississippi. 

Of the fossils listed, Ostrea plumosa :Morton and Lima reticulata Forbes range through 

both the zone of Exogyra costata and the zone of Exogyra ponderosa, and Ostrea p~umosa Morton 

has been questionably identified from the basal beds of the Eutaw formation; Ostrea larva 

Lamarck ranges f:rom the zone of Exogyra costata downward into the upper part of the zone of 

Exogyra ponderosa. Oorax falcatus Agassiz is a wide-ranging species in the Upper Cretaceous. 

In known sections Pecten venustus :Morton and Belemnitella americana (Morton) are restricted 

to the zone of Exogyra costata, and upon the evidence of these fossils this portion of the section 

is con·elated with that zone. Heretofore the species Pecten venustus l\1o:rton has not been 

found below the horizon of Belemnitellq americana (Morton). As it was found here 300 feet 

below the level at which the fragment of Belemnitella was obtained, it is considerecl probable 

that it fell to that position from some higher level. In terms of the formation units recog1 Stephenson, L. W., Cretaceous deposits of the eastern Gulf region and species of Exogyra from the eastern Gulf region and the Carolinas: u.s. 

Geol. Survey Prof. Paper 81, 1914. 
88 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

nized in the Upper Cretaceous deposits of the Carolinas this portion of the section (depth 920-

1,550 feet) is correlated with the Peedee sand. 

Between the depths of 1, 725 and 1,862 feet the following fossils were identified specifically: 

Vermes: Hamulus onyx ~1orton. 

:Mollusca: Ostrea cretacea :Morton, Exogyra ponderosa Roemer~' and Pecten quinquecostatus 

(Sower by). 

Vertebrata : Oorax jalcatus Agassi.z (a shark). 

Of these fossils, Flamulus onyx Morton and Pecten quinquecostatus (Sower by) range throughout both the zone of Exogyra ponderosa and the zone of Exogyra costata but are not found in the 

basal beds of theEutawformation; Ostrea 

cretacea :Morton ranges from the basal 

beds of the Eutaw formation upward 

in to the lower half of the zone of Exogyra 

ponderosa)· Oorax falcatus Agassiz has a 

CHARLESTON WELL 

Pleistocene 

Pliocene 

Uppermost Eocene or Oligocene (Cooper marl) 

wide vertical range in . the U ppe;r OreEocene (Mt. Hope marl of Sloan ?) taceous; and. Exogyra ponderosa Roemer 

is restricted to the zone that bears its 

name. On the evidence afforded by the 

750' 

Exogyra costata zone 

Eiogyra ponderosa 

zone 

? 

Fauna of the basal beds}l~?il of the Eutaw formation 200"7"-1...- v 

Upper Cretaceous or Eocene 

Upper Cretaceous 

FIGURE 12.-Diagram showing correlation of Cretaceous portion of the Charleston 

well section in terms of the fatmal zones recognized in the Cretaceous deposits 

of the eastern Gtilf region. All measurements were made from the top of the 

rotary jaws, which was 6 feet above the surface of the ground. 

range of these fossils. this part of the 

section is correlated with the zone of 

Exogyra ponderosa of the Chattahoochee 

and Carolina regions. . 

The best specimens obtained from 

the Cretaceous strata penetrated by the 

boring we;re those brought to the smface 

by the natural fi@W of water from depth~ 

between 1,974 and 2,007 feet. The fossils identified specifically from this horizon are the following: 

Mollusca:. Ostrea sp. nov. a (four 

fairly good specimens and other fragments), Ostrea sp. nov. b, Ostrea cretacea 

Morton, Exogyra upatoiensis Stephenson 1 (threefairlygoodspecimens andseveralfragments), Anomia sp. nov. (same as 

sp. nov. from Snow Hill, N. 0.). 

Of the species listed, Ostrea sp. nov. 

a and b are new to science, and their 

value in correlation has not been determined. Ostrea cretacea ~1orton ranges 

upward into the lower half of the 

zone of Exogyra ponderosa)· Exogyra 

upatoiensis Stephenson has been found 

heretofore only in the basal beds of 

the Eutaw formation in the Chattahoochee region; Anomia sp. nov. (same 

as a new species from Snow Hill, N. 0.) 

ranges upward into the zone of Exogyra ponderosa. The particular localities at which Exogyra 

upatoiensis Stephenson have been found are the following: Broken Arrow Bend, Chattahoochee 

River 10~ miles below Columbus, Ga.; Chattahoochee River, one-half mile below Broken Arrow 

Bend; and a bluff on Upatoi0reek7milessoutheastof0olumbus, Ga., belowtheCussetaroad bridge. 

On the evidence of Exogyra upatoiensis Stephenson this horizon is correlated with the basal 

beds of the Eutaw formation in the Chattahoochee region. Exposures of these beds occur in 

I This species was described by the writer in u.s·. Geol. Survey Prof. Paper 81, p. 46, pl. 13, figs. 1-4, 1914. 
A DEEP ... wELL AT CHAE.LESTON, S. C. 89 

bluffs on Upatoi Creek, which forms the boundary between ~1uscogee and Chattahoochee 

counties, Ga., and on Chattahoochee River from a place a short distance below the mouth of 

Upatoi Creek, 9 miles below Columbus, Ga., nearly to the mouth of Euchee Creek .. about 16 miles 

below Columbus. 

In terms of the formation units recognized in the Carolinas, that portion of the section 

between a depth of 1,550 feet and the bottom of the well represents a part-perhaps the greater 

part-of the Black Creek formation. 

ORIGIN AND GEOLOGIC HISTORY OF THE WATER. 

Thu strata underlying the Atlantic Coastal Plain in the Carolinas consist of a series of. 

sands, clays, and marls, largely unconsolidated, and subordinately of impure limestones. These 

rest unconformably upon a basement complex of ancient crystalline rocks of pre-Cambrian age 

and locally upon Triassic sedimentary strata which occupy depressions in the crystalline rocks. 

These older rocks outcrop in the Piedmont Plateau, along the eastern border of which their 

upper eroded surface dips slightly southeastward and passes beneath the deposits of the 

Coastal Plain, becoming deeper toward the coast. 

At Fort Caswell, N.C., which is on the coast at the mouth of Cape Fear River, the crystalline basmnent rocks lie about 1,535 feet below sea level, as is shown by a well boring. ·At 

Charleston they lie more than 2,000 feet below sea level, for the deep wells there have failed to 

reach the basement. 

The formations above the basement rocks in South Carolina in the longitude of Charleston 

mnbrace deposits comprising in ascending order Lower Cretaceous, Upper Cretaceous, Eo.cene, 

Oligocene ( ~), Pliocene, and Pleistocene. The· strata composing the formations dip coastward 

at the rate of 40 feet or less to the mile. The younger formations in general lie flatter than 

the older, the youngest, the Pleistocene terrace deposits, having an·inclination of less than 5 

feet to the mile. 

The materials composing the sands, clays, and marls of the formations of the Coastal Plain 

were deriv-ed primarily from the predominantly feldspathic rocks of the Piedmont Plateau, with 

the exception of the matter, chiefly calcium carbonate, that was extracted by organisms or 

chemically precipitated from the sea water in which the deposits were for the most part laid 

down. The more. easily soluble minerals of the crystalline rocks of the Piedmont were in 

part leached out and carried to the sea in solution by the streams, but some of the feldspathic 1natter was transported coastward as detrital material in different stages of decay 

and became incorporated in varying proportions in the formations of the Coastal Plain. The 

capacity of the different strata of the Coastal Plain for admitting water and their efficiency as 

channels for circulation differ greatly. Some of the beds are compact and almost impervious 

to water; son1e are porous and where the structural conditions are favorable permit the free 

circulation of water. 

, The. underground waters in the deposits of the Coastal Plain have been derived from several 

sources, including water entering from the adjacent Piedmont Plateau, rainfall on the Coastal 

Plain, and originally included sea water. 

The greater part of the run-off from the Piedmont Plateau flows to the ocean in stream'3 

which, though they cross the Coastal Plain, probably do not contribute materially to the underground supply. The mass of underground water in the deeply weathered surficial rocks of 

the Piedmont, however, tends by gravity· to drift coastward, some of it doubtless passing into 

the deposits of the Coastal Plain. Of the land-derived underground water rainfall on the 

Coastal Plain itself is doubtless· the chief original source of supply. Water from either source 

COUleS into contact with feldspathic minerals, either in the rocks of the Piedmont Plateau itself 

or in the formations of the Coastal Plain which were derived from the crystalline rocks of the 

Piedmont Plateau, and from these minerals have been derived the characters which distinguish 

the underground waters of the area. 

The more deeply buried beds also contain water composed of a mixture of originally 

included sea water and subsequently included alkaline land water, both of which may properly 

be classed as fossil waters. The character of the fossil waters in. the v-icinity of Charleston is 

discussed by Chase Palmer on pages 90-94 of this paper. ' 
90 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The strata penetrated in the Charleston wells are all of ma~ine origin, and probably the 

greater part of the Cretaceous deposits and the lower part of the Eocene deposits have never 

been above sea level since their formation, so that no opportunity has been afforded for draining 

these anci~nt waters from them. During subsequent geologic time land-derived waters have 

moved downward along the gently dipping strata and have become mixed with the originally 

included sea waters in varying proportions in the different beds and at different places. The 

composition of the waters has been further changed by the solution of mineral matter from the 

deposits in which the waters have stood and by the precipitation of mineral matter from solution.· 

The conditions and principles governing the origin, storage, and circulation of underground 

waters in North Carolina, which are equally applicable in South Carolina, have been discussed 

by Stephenson i!ond J ohnson. 1 • 

RESUME. 

1. The first 75 feet of strata penetrated in the Charleston well is probably of Pleistocene age. 

2. Chara~teristic Pliocene fossils were found in a sample taken at a depth of 82-83 feet. 

3. Sands and clays bearing Foraminifera, which have been studied by Joseph A. Cushman, 

were penetrated at depths of 86 to 220 feet. On the grounds of lithologic similarity these sam-

·ples are referred to the Cooper marl. 

4. Strata of Eocene age (the Mount Hope marl 0) of Sloan) were penetrated from depths 

of 262 to 454 feet. 

5. The strata between depths of 454 and 750 feet yielded no determinable fossils. Their 

age is Upper Cretaceous or Eocene. 

6. From a depth of 750 feet to the· bottom of the well only strata of Upper Cretaceous age-, 

were encountered. 

7. At a depth of 750 feet Foraminifera were found which are regarded by Dr. Cushman as 

characteristic Cretaceous species. 

8. Between depths of 920 and 1,550 feet fossils characteristic of the zone of Exogyra costata 

of the eastern Gulf region and the Carolinas were obtained. 

9. Between depths of 1, 725 and 1,862 feet fossils characteristic of the zone of Exogyra 

ponderosa of the eastern Gulf region and the CBrolinas were obtained. 

10. Between depths of 1,974 and 2,007 feet fossils characteristic of the fauna of the basal 

beds of the Eutaw formation in the Chattahoochee region were brought to the surface by the 

natural flow of water immediately after the well was completed. 

11. In view of the fact that at the lower limits of this boring, which reached a depth of 

nearly 2,000 feet below sea. level, no Lower Cretaceous beds had been reached, it is inte~esting 

to note that at Wilmington, N.C., and at the mouth of Cape Fear River, N.C., borings which 

_ reached basement crystalline rocks at 1,100 feet and approximately 1,535 feet, respectively, 

below sea level, .failed to .encounter strata older than Upper Cretaceous. 

MINERALOGY OF WATERS FROM ARTESIAN WELLS AT CHARLESTON, S. C. 

By CHASE PALMER. 

PRIMARY ALKALINE FOSSIL WATERS. 

The writer made a complete analysis of ~he water from the new well at the power plant of 

the Charleston Consolidated Railway & Lighting Co. at the foot of Charlotte Street and a parallel 

analysis of the water from the old artesian well at the corner of Meeting and Wentworth 

streets, Charleston, with two objects in view--first, to compare the quality of the water of the 

old well (1,260 feet deep) with that of the new well (2,007 feet deep), and, second, to determine 

what changes, if any, might have taken place in the quality of the water of the old well since 

1868, the date of its first rec~rded analysis. It may· be stated here that no material change is 

shown either in the chemical character of the solution or in its concentration 44 years af~er it 

was analyzed by Charles U. Shepard, who, in 1882, published many analyses of waters of wells 

1 Stephenson, L. W., and Johnson, B. L., Water resources of the Coastal Plain of North Carolina: North Carolina Geol. and Econ. Survey 

vol. 3, pt. 2, pp. 342-348, 1912. 
A DEEP WELL AT CHARLESTON, S. C. 91 

in and near Charleston.1 The mineralogy of these artesian waters is here briefly outlined ai.1d is 

cOinpared with that of one other well water underneath Charleston and with that of the water 

of surface streams of the Piedmont Plateau. · 

On Citadel Green, in Charleston, in 1876, a well was sunk to a depth of 1,980 feet, and a 

fairly complete analysis of the water con1ing from that depth was then made· by S. T. Robinson, jr. The Citadel Green well evidently reached the same underground water that supplies 

the new 2,007-foot well of the Consolidated Railway'-~ Lighting Co., for the waters of the two 

'wells exhibit a close resemblance in mineralization. This resen1blance is not· confined to the 

degree of concenti·ation of mineral substances but extends to tho chmnical qualities of the two 

solutions, for the reaction properties of the water of the 2,007-foot 'vell are proportionally. the 

smne as those of the water of the 1,980-foot well, which was analyzed 35 years ago. 

The waters at the 1,260-foot level and at the 1,980-foot level under Charlest.on differ 

markedly in .the proportions of their reaction properties. This fact, taken in connection with 

the fact that the character of each solution remains practically unchanged after an interval of 

sev-eral decades, leads directly to the conclusion that these two artesian waters are fr01n independent wate{courses. On the other hand, they hav-e in comn1on certain peculiarities which 

might be expected if the natural conditions governing their original sources and their present 

e1n;ironment were recognized. 

By reason of its higher position and the impervious underlying granite the Piedmont 

Plateau is naturally one source of the water contained in the sands that are buried under material deriv-ed from the upland. It is therefore desirable to know, first, the quality of surface 

waters now flowing in the Piedmont area· and of the surficial waters of the upper Coastal Plain 

before they enter the ground water of the Coastal Plain, and, second, the quality of the underground waters near the coast, as indicated by the waters of tlrree artesian wells under the city of 

.Charleston, S. C. In order to show the character of the surface waters the waters of Peedee and 

Wateree rivers are chosen, .because they typify the river waters of the Piedmont Plateau and 

upper Coastal Plain of the southern Atlantic coast. The qualities of the series of surface waters 

from the James in Virginia to the Ocmulgee in Georgia. are tabulated in a recent publication of 

the United States Geologitml Surv-ey. 2 

The analysis of an artesian water coming from a depth of 425 feet, to be used in a cotnparatlve study of the waters fro1n the two lower lev-els, is obtained from the records of the municipal 

report of Charleston on artesian wells, already cited. 

INTERPRETATION OF ANALYSES. 

As the interpretation of water analyses adopted in this report .is new, its· novelty warrants 

a prelin1inary statement of the principle on which it is based and justifies definitions of the 

ter1ns used in its application. This chemical interpretation is based, not on the amounts of 

the constituents found by the analyst, but on their reaction capacities, and thus is opened a 

way leading directly to a consistent nomenclature of water qualities and a consistent classification of waters, as has been shown by the writer elsewhere.3 

In recent years the geologist has relied on the statement of the results of a water analysis 

for information concerning the quality of the water analyzed. A mere statement of the amounts 

of radicles, which are only parts of substances dissolved 'in a water, has no chemical significance, 

for it tells nothing of the qualities of the solution, the characteriza.tion of which is the chief 

object of the analysis. 

Fortunately the chemist is able to measure quantitatively four qualities of the water 

solution without resort to a complete analysis. The qualities capable of direct measurement 

are acidity, per1nanent hardness, ten1porary hardness (temporary alkalinity), and permanent 

alkalinity. A fifth quality of water, namely, saltness, caused by strong acid salts of the alkalies, 

cannot be so easily detertnined. ·This quality may be found, however, by balancing the reacting 

• Municipal report of the city of Charleston, S. C., for 1881. 

2 Palmer, Chose, 'l'he geochemical interpretation of water analyses: U.S. Geol. Survey Bull. 4i9, Table 2, opp. p. 16, 1911. 

a Palmer, Chose, op. cit. 

37183°-15-7 
92 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. . . 

values of the positive and negative radicles found by an~lysis after deduct-ing the reacting values 

of all the radicles that go to make up the other qualities directly measurable in the water solution. 

By proportionating this quality with the other qualities found in a water a rational statement 

of the chemical character of the water solution may be obtained. 

FORMULA OF THE SOLUTION. 

The reaction capacities of the radicles of the salts dissolved in water are the quotients 

obtained by dividing the weight of each radicle by its corresponding equivalent combining 

weight. The quotients thus obtained have been called the "reacting values" 1 of the radicles. 

Owing to the differences in the concentration of waters the application of the reacting 

values to the character of water is necessarily restricted to the water under examination. If, 

however; the reacting :values are expressed in percentages of their sum they may be used in 

the comparative study of different waters.· T~is expression of the reacting values of the 

radicles in percentages is called .the formula for the mixture of salts dissolved in a water, and 

on this formula rests the comparative study of waters in this report. -

PROPERTmS OF NATURAL WATERS. 

Nearly all natural waters have two general properties-salinity and alkalinity-on whose 

relative proportions their fundamental characters depend. All the radicles of the alkalies and 

alkaline earths tend to form alkaline solutions, but only the strong acid radicles (sulphate, 

chloride, nitrate) can overcome this tendency and render an alkaline solution neutral or saline. 

The sum of the reacting values of the strong acid radicles is therefore a measure of the salinity 

(saltness) of a natural water which is a solution of salts of strong and weak acids. The sum· 

of the reacting values of the metallic radicles in excess of the values of the strong acids is a 

measure of the alkalinity of a water. . 

In the qualities of waters included in this report only two kinds of salinity and two kinds 

of alkalinity will be considered. In accordance with the prevalence of the reacting values of 

the alkali group (sodium, potassium) and the alkaline earths group (calciun1, n1agnesium) 

four special properties are possible, namely: 

1. Primary salinity (alkali salinity)-that is, saltness such as would be caused by sulphates 

and· chlorides of the alkalies. 

2. Secondary salinity (permanent hardness)-that is, saltness such as would be caused by 

sulphates and chlori_des of calcium and magnesium. 

3. Primary alkalinity (permanent alkalinity)-that is, alkalinity such as would be caused 

by hydroxides, carbonates, and bicarbonates of the alkalies. 

4. Secondary alkalinity (temporary hardness)-that is, alkalinity such as would be caused 

by weak acid salts of calcium and magnesium. 

Secondary salinity and prin1ary alkalinity are incompatible, so that both of these qualities 

are not found in the same water. The waters considered in this report are represented by 

three qualities; for instance, an assemblage of 1, 3, j:,' or an assemblage of 1, 2, 4, exemplified 

by ocean wat~r. 

COMPARISON OF WATERS. 

The analyses of the waters of Peedee and Wateree rivers (columns 1 and 2 in the accompanying table, p. 93) show that they are very dilute solutions having practically the same 

concentration. Moreover, these two waters are almost _identical in composition, as may be 

seen by comparing the amounts of the radicles in column 1 with the amounts of the radicles in 

column 2. This close similarity in composition of two surface waters in different river basins 

at points 70 miles apart cross-country is noteworthy and is in marked contrast with the evident 

difference in composition of the th;ree underground waters (columns 3, 4, 5) at Charleston, at 

levels separated by vertical distances of only a few hundred feet. 

. 1 Stabler, Herman, The mineral analysis of water for industrial purposes and its interpretation by the engineer: Eng. News, vol. 60, p. 356, 

1908; also, chapter on industrial application of water analyses in U. S. Geol. Survey Water-Supply Paper 274, pp. 161-181,1911. 
A DEEP WELL AT CHARLESTON, S. C. 

TABLE 1.-Analyses and formulas of surface and artesian waters and of ocean water. 

[Analyses in parts per million; formulas in percentages of reacting values.) 

River waters of Piedmont 

Plateau. Artesian waters at Charleston, S. C. 

93 

Ocean 

water 1-----,..------1---------:--------1 (forConstituent. Analyses. Formulas. Analyses. Formulas. mula). 

2 1a 2a 4a. 5a. 

----------------1·----------------------

Sodium (Na)........................................ 7.4 7.2 . 19.3 19.1 1,154 1,014 421 43.6 47.4 49.1 

ff~~~~r3~~~~~~~~:::::::::::::::::::::::::::::::::::: t! t~ ~:: ~r:~ i~ tt3 ::: :J :~ :t 38.5 .8 

1.8 

8.9 

Iron(n.luminum)(Fo)(Al).......................... .6 .1 1.2 .1 'l'r. 1.0 ...........•..•. .1 

Sulphato(SO.)...................................... 4 4.2 5.2 5.5 271 'l'r. 7.2 4.8 0 .5 4.6 Chlorido(Cl) ........................................ 2.1 2.2 3.8 4 1,483 944 92 36.4 27.1 6.7 45.2 

M/!~~t~~~~~~li:tb~;j: ::::::::::::::::::::::::::::::: ·--~~: · ·--~~: · ... ~~} ·--~~}: ::(~)::: i;ii~~r.'. ""87~~r.'. :: :(~)::: · .. i~~r~· ... a~~i· ::::::: ~ Carbonate (COs).................................... 0 0 0 0 303 41 54 8. 8 3.1 4. 7 .1 Silica (Si02)......................................... 28 27 . . . . . . . . . . . . . . . . 40 36 32 .............................. .. 

===~=--=====-==:======= 

'l'otal solids......................................... 72.2 69.8 100 100 3,449 2,655 1,051 100 '100 100 100 

a Condition in solution unknown. C03 estimated in residue. 

1. Poedee River at Peedee, N.C. Average of 10 analyses made at U.S. Geological Survey in 1908. 2. Wateree :River at Camden S. C. Average of 15 analyses made at U. S. Geological Survey in 1908. 3 . .Artesian well at Chisholm's mill1 Charleston, S.C. Depth, 425 feet. Analyzed in 1879 by William Robertson. 

4. Old m·tesian well at comer l\feetmg and Wentworth streets, Charleston, S. C.; 1,260 feet deep. Analyzed in 1912 by Chase Palmer. 

5. Now artesian well at Charleston Consolidated Hallway & Lighting Co.'s station, Charleston, S.C.; 2,007 feet deep. Sunk in 1911. Analyzed in 1912 by Chase Palmer. · · G. Ocean water. Values obtained from average results of 77 analyses of sea water given in Challenger report. 'l'he average concentration of sea water is 35,000 parts per million. · 

'fABLE 2.-Reaction ]Jroperties of P;iedmont surface waters, of 'Waters of artesian wells, and of ocean water. 

2 6 

--------------- 19 20 82 57 14 78.6 0 0 0 0 0 21.1 25 23 12 40 85 0 . 56 57 6 3 1 .3 ------------------ 100 100 100 100 100 100.0 

Aside frotn such obse;rvations as these there is little to be gained by considering the amounts 

of the constituents found in a water, but in the formulas derived from the ;reacting values of 

the constituents the relative reaction capacities of all the constituents can be seen at a glance. 

For instance, the :relative reaction capacity of the alkalies and alkaline earths in surface waters 

flowing in areas of crystalline rocks is illustrated in column 1a. The su.m of the reacting V!).lues 

of the alkalies (Na, K) is 22.1 and the sum of the reacting values of the alkaline earths (Ca, Mg) 

is 26.7 .. Thus the aggregate values of the, alkaline earths exceed the aggregate values of the 

alkalies by 4.6 per cent, although the alkaline earths weigh less than the alkalies (column 1). 

Again, the cqmbined weights of the sulphates and chlp:ricles (column 1) is exactly eql,.lal to the 

weight of calcium (6.1)·, yet their capacity of neutralizing calcium is n<,:>tably deficient because 

the sum of the reacting values of chlorides and sulphates (column 1a) is 9 and the reacting 

value of calcium is 18. · 

In general, calcium and magnesium are potent factors of quality in surface streams, and 

thei;l.' importance in this respect is clue largely to their relatively high reaction capacities, which 

must be considered if the full chemical value of 'these two constituents is to be appreciated. 

Unfortunately, writers on the geochemistry of waters have :fixed their attention on the absolute 

weights of the dissolved constituents, so that they have failed to observe important facts concerning the chemical character of waters, especially facts relating to geology. Too much stress can 

not be laid on the consideration of the reaction capacity of every constituent that contributes 

to the quality or character of the water solution, for it is by their measurable qualities that 

solutions as well as other homogeneous substances are characterized. It is surprising that, 

in their attempts to characterize and classify waters, hydrologists have ·failed to apply this 

basic principle of chemical science. 
94 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The summaries of reaction properties of the three artesian waters (Table 2) show remark-

. able regularity in the variations in the proportions of all their properties. They_ are all primary alkaline solutions and h~nce are referable to a common origin, namely, the Piedmont 

Pla.teau, whose surface streams are uniformly characterized by primary alkafuity. Again, the 

progressive decline in the proportion of salinity (from 82 per cent to 14 per cent) an1ong the 

properties ·of these waters in connection with constantly increased dilution of the solutions suggests at once that at increasing distances from the su!'face these waters are less and less affected 

by still stronger saline solutions found in the Coastal Plain. 

The formulas of these· three artesian waters (Table 1) present ·a picture showing in 

detail the differences in the relative values of all the constituents. The preponderance of 

sodium in these underground waters as compared with its value in the Piedmont Plateau surface 

waters is noteworthy. The low values of calcium and magnesium are no less striking than the 

changes that appea;r in their relative prominence. In the water of the 425-foot well magnesium exceeds calcium. This relation is not known to exist in any of the surface waters of the 

Piedmont Plateau from Virginia to Georgia or in the Coastal Plain river waters entering the 

eastern Gulf of Mexico. In all these river waters calcium exceeds magnesium by a wide margin. 1 

The excess of magnesium over calcium in the water of the 425-foot well, taken in connection with the high proportional values of chlorides and sulphates, points directly to the presence 

of ocean water (column 6), in which the relations of all these constituents are si1nilar. Although 

magnesium does not prevail over calcium in the wate;rs at the two lower levels, nevertheless 

in the waters of the 1,260-foot and 2,007-foot wells traces of bromides have been found. 

Additional evidence is thus presented that water of marine origin has been retained in minimal 

amounts even by these deep-seated landward waters. The beds in which these waters occur 

were deposited in sea water, and doubtless sea water was entrapped in the rocks. In consideration of the ;restricted circulation underground it does ·not seem unreasonable to conclude that 

even at 1,260-foot and 2,007-foot levels mixtures of fossil primary alkaline waters with. fossil 

sea water-that is, water of the secondary saline type-may be found. 

The water of the 2,007-Joot well. as it emerges at the surface contains a slimy precipitate 

the. composition of which is shown in the following analysis: 

Analysis of sZ.imefrom water of a well2,007 feet ,ieep at Charleston, S. C. 

[Analysis reported Sept. 3, 1912.] 

Si02 ••••••••••••• ·· ••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 55.79 

Al20 3 •••.•••.•.••••••..•••••••.••.....•••..•.•••. : . . . . • • • • . . . . • • • . . • • • • • . . . • . • . • • • • • • • . 23. 80 

Fe20 3 •••••••••••• _............................................................. •.• • • • • • • • 4. 50 

FeO ............... · ................................................................ ·.... 1. 41 

CaO .................................................................................... ~-43 

MgO ....... · .................................................................... ~ ...... , . . 1. 87 

K20 ................. · ............................................ ·....................... 2. 45 

Na20 ....................... ·............................................. ... . . . . . . . . . . . . . 1.18 

}.1no.-........... __ .- __ ... -..... -.- ......... -... · .... -................................. _.. . 02 

H20 ............ --. --. --- -. ----. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6. 50 

99.95 

Slimes of this kind are said to be present in the waters of newly drilled deep wells in this 

vicinity. After the waters haye flowed for longer or shorter periods they gradually clarify. 

The consideration of fossil waters has hitherto been restricted to solutions of the secondary 

saline type. A brine obtained from a well more than 5,000 feet deep in West Virginia 'has 

recently been examined by the writer. This is evidently a fossil water, a relic of a Devonian sea . 

. Its secondary salinity represents 45 per cent of its properties, a proportion of secondary salinity 

more than twice as high as that of modern sea water. · 

It is just as reasonable to suppose that waters of the primary alkaline type are capable of 

fossilization as it is to suppose that secondary saline waters are fossil. -

1 U.S. Geol. Survey Bull. 479, Tables 2 and 3, 1911. 
THE STRATIGRAPHY OF THE MONTANA GROUP, WITH SPECIAL 

REFERENCE TO THE POSITION AND AGE OF THE JUDITH 

RIVER FORMATION IN NORTH-CENTRAL MONTANA. 

By C. F. BowEN. 

INTRODUCTION. 

The differences of opinion which have arisen regarding the stratigraphic position, and age 

of the Judith River fonnation led the w1:iter to undertake a study of the Montana group in order 

to determine, if possible, the stratigraphic relation of this formation. Stanton and Hatcher 

had previously announced that the Judith River formation is of Cretaceous age. Although at 

first this conclusion was generally a·ccepted, doubt has since arisen as to its correctness. The 

investigations of the writer were therefore begun in an area where the formations are well exposed 

ancl where the stratigraphic succession can be established beyond doubt. · From this area the 

forn1ations were traced northward to Missouri River in the type locality of the Judith River 

forn1ation. ':rhis study has demonstrated the correctness of Stanton and I-Iatcher's views and 

forms the basis of the present paper. 

'l'he area here discussed lies east of the Big Snowy and Judith mountains and extends from 

11usselsheli, on 11usselshell River, to Judith, on Missouri River, Mont. The geographic location 

of the area is shown by the key map on Plate X. 

The investigation, which was of a reconnaissance character, was undertaken to ascertain the 

coal resources of this area and to make a special study of the stratigraphy of the formations of 

11ontana age which are exposed in this part of the State. In this work the writer was assisted 

by I-Iarvey Bassler, T. K. Harnsberger, and J. R. Jaquet. The economic results of the investigation have already been published. 1 

In the preparation of this paper the writer has made free usc of all previously published infonnation, for which credit is given in the proper places. He is especially indebted to Messrs. 

C. W. Giln1ore, J. W. Gidley, 0. P. Hay, F. H. Knowlton, and T. W. Stanton for assistance 

rendered in the preparation and arrangen1ent of the paleontologic data. Inasmuch as the 

writer is not a paleontologist, it is proper to state here that the remarks regarding the synonymy 

and the validity of the determination of certain of the species of vertebrates have been extracted 

largely from the writings of E. D. Cope, J. B. Hatcher, 0. P. Hay, L. M. Lambe, R. S. Lull, 

and I-I. F. Osborn and have been approved by C. Y'f· Gilmore. 

PREVIOUS WORK. 

Since 1853, when I-Iayden did his first work on the upper part of :Missouri River, many 

observers have contributed to the discussion of the stratigraphic position of the Judith River 

and underlying forn1ations. :Most of these early observers, including Hayden, Meek, Cope, 

C. A. White, and Peale, studied the section along 11issouri River but did not attempt detailed 

mapping of the individual formations. In recent years more d«;}tailed work has been done in 

this and adjacent areas by Stanton and Hatcher,2 -Calvert,3 and Lupton. 4 

1 Bowen, C. F., Coal discovered inn rooonnnissnnoe survey between Musselshell and Judith, Montana: U. S. Geol. Survey Bull. 541, pp. 329-

337,1914. 

2 Stanton, T. W., and Hatcher, J. B., Geology and paleontology of tbe Judith River beds: U. S. Geol: Survey Bull, 257, 1905. 

a Calvert, W. R., Geology of tbe Lewistown coal field, Montana: U. S. Geol. Survey Bull. 390 .• 1909. 

t Lupton, C. T., Tho eastern part of tho Bull Mountain coal field, Montana: U. S. Goo!. Survey Bull. 431, pp. 163-189, 1911. 

95 
96 SHORTER ·cONTRIBUTiONS TO GENERAL GEOLOGY, 1914. 

BASE MAP AND. FIELD METHOD. 

The United States Geological Survey is preparing a map of the Unit~d States for publication 

on a scale of about 16 miles to the inch. Part of this map was enlarged to a scale of 4 miles 

to the inch and used as the base for the geologic map (Pl. X). The land lines and the drainage on this map are fairly accurate. The slight discrepancies which occur are so small that 

they do not appreciably affect the accuracy of the map on the scale on which it is here published, and therefore no adjustments were made. 

Horizontal control for the geologic mapping was based on township surveys of the General 

Land Office .. A main stadia traverse tied to land corners, generally not less than once in each 

township, was carried throughout the area, this part of the work being done with a Joh11son 

plane table and a Gale telescopic alidade. Side lines, tied to the main traverse and to land 

corners, ·were made by horse pacing and by triangulation, with a 15-inch plane table and an 

open-sight alidade. By these methods the structure was platted and the boundaries of the 

fo~mations were mapped. On the n1ap thus prepared (Pl. X) the portions of the boundaries 

that were located with considerable accuracy are represented by solid l~nes and the portions 

that .were located only approximately are represented by broken lines. 

STRATIGRAPHY. 

GENERAL SEQTION. 

The formations represented in the area here considered are the Colorado shale, Eagle sandstone, Claggett formation, Judith River formation, and Bearpa~ shale, of Upper Cretaceous 

age, and the Lance formation, of Tert.iary ( n age. The geologic age and stratigraphic relations 

of the Eagle, Claggett, Judith River, and Bearpaw formations in north-central Montai1a were 

worked· out by Stanton and Hatcher 1 in 1903, but Peale 2 in a recent ~rticle dissents from the 

conclusions they reached. The sequence, thickness, and characteristics of these formations, as 

determined by the studies of the writer in this field, are shown in the following generalized 

section: 

Generalized section of the sedimentary rocks in the area between Judith and Mussels.hell, Jfont . 

.. 

Systel!l and Group. Formation. Characteristics. Thickness senes. (feet). 

Tertiary(?),Eo- Lance forma- Alternating gray sandstone and clay shale, with thin beds of coal near the top.a 700-800 cene(?). tion. 

Be a.r paw shale. 

Marine shale, dark gray to black in up~er part-but with greenish tinge in lower 

part in southern portion of the :tiel ; contains numerous calcareous concre- tions which yield Baculites ovatus, Baculites compressus, Scaphites nodosus, 

Inoceramus barabini, and other species characteristic of the Pierre shale. 

1,100± 

Alternating beds of sandstone, clay, and shale, including carbonaceous mem- bers, mainly of brackish or fresh water origin. In the northern part of the 

Judith River area a more or less persistent coal bed occurs near the top of the formation 250-500 · formation. and is in most places overlain by a bed of marl or breccia, containinf great numbers of Ostrea subtrigonalis. The formation also contains bones o verteCretaceous (Up- brates, fragments of leaves and stems, and much silicified wood. 

per Cretace- Montana. 

ous). An upper division consisting of alternating beds of sandstone and shale, becoming predominantly sandstone at toK Marine fossils occur in these sandstones 

along Missouri and Judith rivers ut have not yet been found in the south- 200± ern part of the area. The common forms are Tancredia americana, Cardium · speciosum, M actra formosa, M actra alta, and other species formerly considered 

Claggett for- as characteristic of the Fox Hills sandstone. 

mation. 

A lower division of dark marine shale which can not be easily distinguished lithologically or paleontologically from the Bearpaw shale. The most com- mon 500± fossils are Baculites ovatus, Baculites compressus, Gervillia borealis, Ino- ceramus barabini, and Leda evansi-species characteristic of the Pierre shale. 

a Lupton, C. T., The eastern part of the Bull Mountain coal field, Montana: U.S. Geol. Survey Bull. 431, pp. 169-170, 1911. 

1 Op. cit., p. 6.1. 

2 Peale, A. C., On the· stratigraphic position and age of the Judith River formation: Jour. Geology, vol. 20, pp. 530-549,640--652,738-757,1912. 
STRATIGRAPHY OF THE MONTANA GROUP. 97 

Generalized section of the sedimentary rocks in. the area between Judith and Musselshell, .ilfont.-Continued. 

System and Group. 

I 

]<~ormation. I Characteristics. Thickness 

series. (feet). 

In the northern part of the field the upper member of the Eagle sandstone con- sists of thin-bedded sandstone with some interbedded shale, and the middle 

member consists principally of dark-colored shale in which there are a few lOG-180 thin beds of carbonaceous shale, coal, and sandstone. In the southern part of the field the middle member consists of thin-bedded shaly sandstone and 

Montana-Con- Eagle sand- contains no coal or carbonaceous beds. 

tinned. stone. 

Cretaceous Virgelle sandstone member, a massive to heavy bedded sandstone which is 

(Upper Cre- highly cross-bedded in some places. In the northern part of the field it is 

prevailingly of a white color and contains numerous small rusty concretions. lOQ-120 taceous)- n the southern part of the field the color is gray to light brown. It forms Continued. conspicuous ledges or hogback ridges wherever e:x-posed. 

In its upper part the Colorado is a black marine shale, alternating with thin 

beds of sandy shale and sandstone. At one locality examined a calcareous 

Colorado fossiliferous sandstone occurs in the up8er ~art of the formation. 'l'he lower Not measured. 

shale. part of the formation was not studie . aculites sp., Dosinia orbiculata, 

Gyrodes conradi, Inoceramus deformis, Inoceramuslabiatus, Scaphites ventriI cosus, and other forms were obtained from this formation. 

CRETACEOUS SYSTEM. 

COLORADO SHALE. 

Position and chm·acter..-Conformably beneath the Montana group lies black laminated 

shale in which are thin beds of ~renaceous 1naterial. The shale at several localities has yielded 

fossils which T. W. Stanton has pronounced of Colorado age. 

Distribution and topog1·aphic ex1J1'ession.-The Colorado shale is somewhat widely distributed to the west and south of the area mapped, where it is exposed around the anticline of 

the Big Snowy Mountains. From Willow Creek, in the southern par·t of this field, to the North 

Moccasin Mountains the shale is well exposed inunediately beneath the Montana group, .and 

at tw·o localities it occurs as an inlier, brought up by subordinate folds, within the area occupied 

by the younger rocks. Because of its slightly resistant character the shale is easily eroded and 

occupies valleys bordered by the n1ore resistant beds of overlying sandstone. 

Relation to overlying jo1·mations.-The Colorado shale lies conforn1ably beneath the Eagle 

sandstone and is separated fr01n the typical sandstone by a transitional zone of sandy shale. 

rrhe boundary between the two form.ations was drawn at the top of the transitional zone, 

because this horizon 1narka the most abrupt lithologic change and is 1nost easily recognized in 

the field. 

EAGLE SANDSTONE. 

Definition.-The nan1e Eagle sandstone 'vas given by Weed 1 to the formation overlying 

the Colorado shale in north-central Montana and typically exposed on Missouri River at the 

tuou.th of Eagle Creek, 40 miles below Fort Benton. In the type locality the formation as 

defined by Weed consists of three more or less distinct units, comprising an upper member of 

thin-bedded sandstone, a nriddle Inmnber of shale, and a lower member of massive ledge-making 

sandstone. rrhis lower member is so persistent and characteristic over a large area in northcentral Montana, even where the other divisions of the formation are not recognizable, that it 

seems desirable for purposes of description and correlation to give it a name. It is well exposed 

along Missouri River from the town of Virgelle, a few miles below Fort Benton, eastward, and 

the nmne Virgelle sandstone n1ember of the Eagle sandstone has therefore been adopted by the 

United States Geological Survey for this division of the formation. The Virgelle sandstone 

n1ember is the lower massive ledge-making sandstone of the Eagle sandstone as defined by Weed. 

According to· Stanton and IIatcher, the Eagle sandstone constitutes the lowest formation 

of the Montana group, and the fossils collected from it by the writer have been determined by 

Mr. Stanton to be of Montana age. 

1 Weed, W. H., U.S. Geol. Survey Geol. Atlas, Fort Benton folio (No. 55), 1899. 
98 SHORT:ER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Character and thickness.-In the southern part of the field the Virgelle sandstone member 

of the Eagle consists of a dull-gray to brownish massive, ledge-inaking sandstone about 100 feet 

thick; the middle division of the Eagle is a thin-bedded shaly sandstone; and the upper division 

is a thick-bedded, resistant sandstone in which large rusty-brown concretions are locally very 

numerous. As the formation is traced northward a change in the lithologic character may 

be noted about 12 miles east of Black Butte, where carbonaceous beds and thin streaks of coal 

begin to appear in the middle division of the formation. From Black Butte westw~rd thin beds 

of carbonaceous shale and coal occur in this part of the formation at several places, and near 

Deerfield (about 8 miles southwest of the area mapped on Pl. X) coal is being mined from a bed 

which, according to descriptions given by residents, overlies the Virgelle sandstone member. 

On Missouri River the _formation shows still further changes in lithology; the Virgelle sandstone 

member is glistening white to dull white in color, the middle division of the formation has 

changed to dark shale containjng several thin beds of coal, and the upper division consists of 

thin-bedded sandstone and sandy shale. 

The total thickness of the Eagle sandstone ranges from 200 feet in the southern part of the 

field to 250 or 300 feet on Missouri River. . 

Distrj,bution and topographic expression.-The Eagle sandstone occupies a narrow belt overlying the Colorado shale from Willow Creek to the North Moccasin Mountains. West of these 

mountains (beyond the area mapped) it is more widespread, because of the decrease in the dip 

·of the beds. The formation is also exposed at several places on Judith and Missouri rivers north 

of Fullerton. In these places it has been brought up by faulting. 

From Willow Creek north to Boxelder Creek the Eagle sandstone forms ledges 25 to 100 

feet high. Throughout the rest of the area the beds are inclined at angles of 20° to 70° and the 

formation produces narrow ridges with sandstone ribs- along their crests. A ~haracteristic 

topographic feature of the Eagle is a double ridge, formed by the sandstones of the upper and· 

lower divisions of the formation, separated by a shallow depression that is occupied by the 

more "easily eroded beds of the middle division. 

Because of its ledge-making habit, the Eagle sandstone is well exposed and easily traced 

throughout the area, except on the north side of the Judith and North Moccasin mountains, 

where it is partly obscured by gravel washed down from the mountains. 

Relation to Claggett formation and correlation.-The Eagle is conformable with the overlying 

Claggett formation, from which it is distinguished by its lithologic character. The co~relation 

of the Eagle on Missouri River with that mapped from the North Moccasin Mountains to the 

south side of the field is rendered certain because of its stratigraphic position, between the 

Colorado shale below and the shale of the Claggett formation above. 

CLAGGETT FORMATION. 

The name Claggett was given by Stanton and Hatcher 1 to the formation overlying the 

Eagle sandstone because the formation is well exposed in the neighborhood of Judith (old Fort 

Claggett), on Missouri River, which therefore becomes the type locality. As originally defined, 

the Claggett is separable into·two divisions-a lower one of shale and an upper one consisting 

predominantly ofsandstone. This definition will be followed in the present paper, though the 

writer believes that the upper divisiqn belongs more naturally to the Judith River formation. 

Character and thickness.~ The lower division of the Claggett consists of dark marine shale 

similar both lithologically and paleontologically to the Bearpaw shale, which will be described 

later. It is about 750 feet thick in the southern part of the field, as determined by stadia 

measurement. Just north of Fullerton, on Judith River, an aneroid measurement gave a 

thickness of about 500 feet, and at this locality the upper division is ab9ut 120 feet -thick. 

The upper division consists of alternating beds of sandstone and shale, becqming predominantly sandstone in the upper part.· At the top there is a bed of massive rusty-brown 

sandstone ranging.from 1 foot to 20 feet in thickness. These beds were included iri the Claggett 

by Stanton and Hatcher because they contain a marine fauna. 

I Stanton, T. W., and Hatcher, J. B., Geology and paleontology of the Judith River beds: U. S. ·Geol. Survey Bull. 257, p. 13, 1905. 
STRATIGRAPHY OF THE MONTANA GROUP. 99. 

The dark shale constituting the lower division of the Claggett contains Baculites ovatus, 

Bac'l.tlites compressus, Inoceramus barabini, Leda evansi, and other forms characteristic of the 

Pierre shale, most of which also occur in the Bearpaw shale. At the type locality of the 

Claggett its upper division contains Cardium speciosum, Mactra alta, J.1actra formosa, Tancredia 

.amm·iccwia, and some other forms, all marine types, many of which occur in the Fox Hills sandstone. This fauna led the earlier geologists to assign the beds to the Fox Hills. 

Dist1-ibution ancl topog1·aphic expression.-The surface distribution of the Claggett is shown 

on the accompanying map (Pl. X). Along the southern margin of the field and also along the 

north side nearly as far west as Black Butt~ the outcrop of the formation is very narrow, because · 

the dip of the beds is· steep. West of Black Butte the dip gradually decreases and the width of 

outcrop increases, so that north of the North Moccasin Mountains the formation is very widespread. Its western botmdary was not mapped in this part of the field, but a complete section 

of the formation is exposed in the valley of Judith River between a point a few miles north of 

Deerfield and Missouri River. · 

The soft shale of the lower division of the Claggett is easily eroded and. generally occupies 

a depression between the ridges formed by t~e underlying Eagle sandstone and the overlying 

sandstone of the upper division of the Claggett and the Judith River. The formation is in 

general well exposed throughout the area described, but along the north side of the Judith and 

North :Moccasin mountains the exposures are not so good, the formation being covered in places 

by gravel washed down from the mountains. There is also a n_arrow gap in the outcrop north 

of Boxelder Creek, where the Claggett has been eroded from the axis of the Cat Creek anticline. 

The lower division of the Claggett is easily recognized and traced in the field, because of 

its lithologic character and its· effect on the topography. The upp.er division is less readily 

recognized and traced, because of its resemblance to the Judith River formation, which it 

immediately underlies, but north of the North Moccasin Mountains it is very prominent in the 

upper part of the bluffs of the Judith River valley and is identified by the marine fossils which 

it contains. East of the North Moccasin Mountains no fossils were found_in this division of the 

formation, but it was recognized in many places, notably south of Flat Willow Creek, by its 

rusty-brown color and its resistance to erosion, because of which it forms a cap protecting the 

underlying softer rocks .. 

Relation to other formations.-The gradual transition· from the marine Claggett to the overlying fresh-water Judith River formation is adequately expressed by the following quotation 

from Stanton and Hatcher.1 Describing the exposures on Dog Creek, they say: 

For considerable distances the Judith River beds are nearly or quite horizontal and conformably overlie the 

Claggett formation in such a manner that it is difficult to determine where one formation ends and the other begins, 

although in the field a bed of yellowish-brown sandstone varying in thickness from 1 foot to 20 feet or more was regarded 

as the upper limit of the Claggett formation. * * * From the persistence of this sandstone and ·from the fact that 

it marked the beginning of a decided change in the lithology of the underlying and overlying beds, it would certainly 

form a convenient delimitation between the two series of deposits and should perhaps be considered as the uppermost member of the Claggett formation, notwithstanding that in a number of instances typically marine fossils extended 

for some distance above in the basal members of those lighter-colored sandstones and shales usually referred to the 

Judith River beds and generally .considered as entirely of fresh or brackish water origin. 

Cope's observations also agree with those of Stanton and Hatcher. He says: 2 

From what has preceded the general conclusion is reached that the series of beds from the lowest of the Fort 

Pierre epoch to the summit of the Judith River is continuous and uninterrupted by any nonconformity or hiatus. 

They appem· to have been deposited in regular sequence, and without any other disturbance than that oscillation of 

the bed of the sea which causes change in the character of the sediment. 

On the other hand, . Peale -

3 says that there is ·a suggestion of an unconformity between 

the upper diV'ision of the Claggett (called Fox Hills by him) and the Judith River beds in the 

v·alley of Judith River below Fullerton. . 

• Stanton, T. W., and Hatcher, J. B., op. cit., p. 36. 3 Copo, E. D., Iteport on tho geology of the region of the Judith River, Montana, and on vertebrate fossils obtained on or near the Missouri 

River: U.S. Gool. and Goog. Survey Terr. Bull. 3, p. 574, l877. ' 

8 Poale, A. C., On the stratigraphic position and age of the Judith River formation: Jour. Geology, vol. 20, p. 543, 1912. 
100 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

The writer's observations agree with those of Stanto;n and Hatcher and those of Cope. 

He was unable to detect any evidence of unconformity either between the Claggett and Judith 

River formations or at any other horizon in the section from the Colorado shale up to and 

including the Lance formation. He is of the opinion, however, that the upper di~tision of 

the Claggett more properly belongs with the Judith River formation. Stanton and Hatcher 

incll.lded this upper division in the Claggett formation because it contains a marine fauna, but 

the preceding quotation from them shows that there is no sharp line of demarkation either in 

lithology or paleontology between it and the overlying fresh-water beds. On the other hand, 

there is a rather marked lithologic change between the upper and lower divisions of the 

Claggett. · Furthermore, in the southern part of this field no marine fossils have been found 

in the upper division of the Claggett formation, and therefore the distinction between Claggett 

and Judith River as at present defined is even less marked here than o;n Missouri River. In 

fact, in the southern part of the field it is not practicable to separate the sandstone that has 

been included in the Claggett formation from the Judith River formation. Similarly, 35 miles 

northwest of the mouth of Judith River, in the Big Sandy coal field, where the same formations 

are involved, no marine fossils occur in the sandstone immediately overlYing the shale of the 

Claggett formation. Instead of containing marine fossils the sandstones, which there seem to 

be the equivalent of the upper division of the Claggett at the mouth of Judith River, contain 

carbonace0us beds and fresh or brackish water shells and are, therefore, of fresh or brackish 

. water origin. Inasmuch as the occurrence of marine fossils in the uppe~ division of the Claggett 

seems to be a local phenomenon, i;nasmuch as these marine fossils are not limited strictly to 

the Claggett as now defined but in some places extend up into the overlying Judith ,River formation, and inasmuch as the most striking lithologic change in the beds is at the base of the 

upper division- of the Claggett, it seems to the writer that this is the most logical horizon to 

.designate as the boundary between the Claggett and Judith River formations. It also constitutes a horizon that n1ay be readily recognized in the field because of the striking differe;nce 

between the dark fossiliferous marine shale and the overlying lighter-c9lored sandstone. It is 

true, however, 'that· these marine strata were excluded from the Judith River formation in all 

the early descriptions of the type area, and this fact doubtless influ~nced· Stanton and Hatcher 

in fixing the upper boundary of the Claggett formation when they described it in the same area. 

Prior to the work of Stanton and Hatcher the .upper division of the Claggett was called 

Fox Hills, and that assignment has recently been reiterated by Peale. 1 This correlation is 

based on the fact that many of the fossils occurring in the upper division of the Claggett at the 

mouth of Judith River are identical with those that occur elsewhere in the typical Fox Hills. 

The relations of this fauna are discussed more fully in the paleontologic part of this paper 

(pp. 114-115), and it will suffice here to point out that this so-called Fox Hills sandstone has been 

traced by means of its fauna from Missouri River southward as far ·as the North Moccasin 

:Mountains and has been recognized by its color and lit~ology at other places as far south. as 

Flat Willow Creek and that it is positively k;nown to be overlain at these places by thG Judith 

River formation and a marine ~hale (the Bearpi).w) which has. a Pierre faun:a. The sandstone 

therefore does not occupy the stratigraphic position of the Fox Hills sandstone at the type 

locality. · JUDITH BIVER FORMATION. 

The Judith River formation is chiefly of fresh or brackish water origin and lies between 

two marine shales. The formation was named by Hayden in 1871,2 but at that time its stratigraphic position was not understood. In 1903 Stanton and Hatcher 3 determined that the formation is a member of the Montana group and is the time equivalent of a part of the Pierre shale. 

Oharader and thickness.-The Judith River formation consists of alternating beds of lightcolored sandstone and clay, in which occur thin beds of carbo~1aceous shale. In the northern 

1 Peale, A. C., On the stratigraphic position and age of the Judith River formation: Jour. Geology, vol. 20, pp. 755-756, 1912. 

2 Hayden, F. v., Geology of the Missouri Valley: U.S. Geol. Survey Terr. [Fourth Ann.] Prel. Rept., p. 97, 1871. 

a Op. cit., p. 257. 
STRATIGRAPHY OF THE MONTANA GROUP. 101 

part of the are.a the fonnation contains some coal but is not known to be coal bearing east of 

Arn1ells Creek. It yields fresh and brackish water inV'ertebrates and locally some of marine 

origin. At maJlY places there is near the top of the formation a be~ ranging from less than 1 

foot to several feet in thickness that is n1ade up almost wholly of shells of Ostrea subtrigonalis 

and is therefore called the Ostrea marl or breccia. The formation also contains bones of vertebrates, much silicified wood, and stems and fragments of plants, though well-preserved leaves are 

exceedingly rare. 

The thickness of the formation on Willow Creek in the southern part. of the area, as determined by stadia measurements, is 250 to 275 feet. It seems gradually to thicken northward, 

and in the northern part of the area it is about 500 feet thick. 

Dist?'ibution and to1Jographic expression.-The surface distribution of the Judith River 

formation from the south side o~ the fie~d toT. 20 N. is shown on the accompanying map (Pl. X). 

North of T. 20 N. its upper boundary was not mapped. The variations in the width of the 

outcrop of the formation coincide in a general way with those of the underlying Claggett 

formation. 

Where the beds are nearly flat-lying, as in the areas south of Flat Willow Creek and northwest of Roy, the Judith River weathers into badland forms, but where the beds dip steeply 

the formation gives rise to narrow ridges with,sandstone ribs along their crests, very similar to 

the ridges formed by the Eagle sandstone. The Judith River is well exposed and its outcrop 

is easily traced because of its position between the shaly Claggett and the Bem·paw shale, both 

of which occupy low ground. The formation was traced from the southern border of the field 

northward nearly to Boxelder Creek, where jt passes beyond the eastern limit of the area mapped. 

It reenters the area in T. 15 N., R. 29 E. There is llO doubt that if followed farther east the 

formn.tion could be traced continuously around ·this gap 1 and that all the formations exposed 

south of Boxelder Creek could be connected directly with those on the north border of the 

field. The sequence, character, and fauna of the formations are identical in these two areas. 

From T. 15 N., R. 29 E., the Judith RiV'er formation was traced continuously to the mouth of 

Judith Ri,1'er and was there found to be identical with the Judith RiV'er formation of Hayden, 

this locality being in the western part of his original area. As far west as Roy tho formation, 

because of its highly inclined attitude, makes a hogback ridge and may be traced almost as readily 

as a turnpike. West of Roy it is well exposed along the main drainage lines, such as Boxelder 

Creek, Armells Creek, and Dog Creek, though it is con1monly not well exposed on the dhtides. 

West of Dog Creek the exposures are continuous along the east side of the :valley. of Judith Riv·or 

and its tributaries from the North Moccasin Mountains north to Judith. The tracing of the 

formation across the field is therefore rendered very certain. 

As the possibility of mistaken identification of formations in the faulted area north of Fullerton may be urged and doubt therefore cast on the above statem~nts, it may be well to poillt 

out again that the correlations in this part of the field do not rest on the tracing of the Judith 

River formation alone, but that the underlying Claggett formation, con1posed of two distinct 

men1bers (the Pierre and Fox Hills of Peale and many of the earlier geologists), e.ach containing 

a characteristic fauna, can be traced with equal certainty. (See quotation from Peale, p. 111.) 

On page 104 it is stated that the maxin1um displacement due to the fa.ults north of Fullerton is 

probably about 650 feet; and that therefore the key rocks-the two members of the Claggett 

fonnation-are in no place lost to sight. In view of these conditions it seems to the writer that 

no valid objection can be raised as to the correlation of the forrrmtions across this faulted zone. 

Relation to otherfm·mations.-The relation of. the Judith River to the Claggett is considered 

on pages 99-100. The formation lies beneath the Bearpaw shale, with which it shows conformable relations throughout this field. The evidences of the stratigraphic position and age of 

the Judith River fonnation aro considered more in detail ih another part of this paper. 

1 Since this paper wns prepared tho writer hns traced tho Judith River formation around this gap and has thus positively proved its 

continuity throughout this field. 
102 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

BEARPAW SHALE. 

The Bearpaw shalf:} overlies the' Judith River formation and is equivalent to the upper part 

of the Pierre shale. The formation was named and. its stratigraphic relations were determined 

by Stanton and Hatcher 1 in 1903. 

Character and thickness.-The Bearpaw is a dark marine shale of the same lithologic character as the Claggett of this field and the Pierre shale of other localities. It contains numerous 

calcareous concretions from which Baculites ovatus, Baculites compressus, Scaphites nodosus, 

Leda evansi, and other fossils characteristic of the Pierre rure obtained. The formation has a 

thickness of 1,150 feet south of Willow Creek, and this thickness seems to be fairly constant 

throughout the field so far as the entire formation was studied. 

Distribution and topographic expression.-The Bearpaw has a similar distribution to that 

of the Judith River. The upper boundary of the formation was mapped as far west as R. 24 E., 

and the lower bQundary to about the·center ofT. 20 N., R. 19 E.; at that point the outcrop 

bears off to the east, and a few miles beyond it becomes involved in extensive faults. 

The Bearpaw weathers easily and its outcrop generally occupies a depression between the· 

Judith River and Lance formations, but this feature becomes less distinctive as the width of 

the outcrop increases. The formation is well exposed througl!out most of the area in which 

it was mapped, but, like the Judith River, the Bearpaw passes beyond the eastern margin of 

the field and therefore was not traced continuously throughout the area. 

Relation to other formations.-The Bearpaw is similar in lithology and paleontology to the 

Pierre shale of other localities and to the shale of the Claggett formation in ~his field. Because 

of this similarity the Bearpaw and Claggett were confused by the early geologists who visited 

this. region and both were called Pierre shale. The following differences have been observed 

between the Bearpaw and the Claggett: (1) The Bearpaw is much thicker, as shown by the 

table on page 96. (2) The Bearpaw is more fossiliferous and contains a more diversified fauna. 

(3) In many places in this field a bed consisting almost wholly of brackish-water shells, largely 

Ostrea subtrigonalis, lies immediately beneath the Bearpaw. In this field no shells of this kind 

are found immediately beneath the Claggett. 

The similarity in the fauna of the Bearpaw and the shale of the Claggett is· shown by the 

following list of fossils: 

TABLE 1.-Invertebratejossilsjrom the shale of the Claggett formation and the Bearpaw shale. \ 

N6TE.-Species marked "I" were collected by Stanton and Hatcher. Species marked "2" are those collected by the writer and his assistants 

in 1912 which are not included in Stanton's list. 

Claggett. I Bearpaw. Claggett. Bearpaw. 

------------------~~-------1 

Acm::ea occidentalis M. and H ... ·................. . . . . . . . . . . X I 

Anchura americana (E. and S.)................... . . .. . . . . . . . X I 

Anisomyon centrale Meek ................. :....... . . . . .. . . . . X I 

Anisomyon alveolus M. and H.................... . . . . . . . . . . X 1 

A vicula linguiformis E. and S..................... . . . . . . . . . . X I 

Aviculanebrascana E. and S.... .... ...... .. .. ... X 2 X 1 

Nucula cancellata M. and H...................... x 1 x 1 

Nucula planimarginata M . .and H................. . . . . . . . . . . X 1 

~~~:r~:\r!~~~=~~!:~:::::::::::::::::::~ :::::::::: z ~ Placenticeras intercalare M. and H................ .. . . . . . . . . x 1 

Baculites compressus Say......................... X 1 X I 

Baculites ovatus Say..... . .. . . . . .. .. . . . . . . . . . . . .. . X 1 X 1 

Cinulia concinna M. and H. . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . X 1 

Cuspidaria ventricosa M. and H................... .. . . . . . . . . X I 

Haminea subcylindrica M. and H................. . . . . .. .. . . X I 

Inoceramus barabini Morton... . . . . . . . . . . . . . . . . . . . X 1 X I 

Inoceramus sagensis Owen... . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . X 2 

Leda (Yoldia) evansi M. and H................... X 1 X 1 

Liopistha (Cymella) undata M. and H............ X 1 X I 

Lucina subundata H. and M .............. :. . . . . . . . . . . . . . .. . . X 1 

Lunatia occidentalis M. and EL................... X I X 1 ? 

Placenticeras sp .....................................................•• Placenticeras whitfieldi Hyatt.................... X 1 X 1 

Protocardia rara E. and S ................................. ·'· X 1 

Protocardia subquadrata E. and S............ ... . ... . . . .. . . X 2 

Scaphites nodosus Owen.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 1 

Scaphites subglobos\is Whiteaves................. . . . . . . . . . . X 1 

Syncyclonema rigida M. and H. :. . . . . . . . . . . .. . . . . . . . . . . . . . . X · ThetiS? circularis M. and H....................... . . . . . . . . . . X 1 

~~~?:oa;;~~~~a ·M: iillci 'ii. ·. ~::::::::::::::::::: :::::::::: ~ ~ Gervillea borealis Whiteaves... . . . . . . . . . . . . . . . . . . . X 1 X 1 

An inspection of this table shows that all the species folind in the shale of the Claggett formation are also represented in the Bearpaw, but that the fauna of the latter is more varied than 

that of the former. This coincides with the field observations that fossils are more numerous' 

i~ th~ Bearpaw than in the Claggett. 

1 Op. cit., p. 13. 
STRATIGRAPHY OF THE MONTANA GROUP. 103 

TERTIAR~ (?) SYSTEM. 

LANCE FORMATION. 

No detn,ilcd study was n1ade of the Lance forn1ation, though its lower boundn,ry was traced 

nen,rly hn,lfway ·n,cross the a1;ea 1napped. The following statement concerning it is· taken from 

the report by C. T. Lupton on the en,stern part of the Bull :Mountain coal field/ which adjoins 

this a~·en, on the south: · 

It consists of 700 to 800 feet of yellowish-gray sandstone, clay of various colors, and grayish sandy shale. Sandy 

material predominates. 'l'he lower part is noticeably micaceous; the upper part contains thin beds of coal. W~ere 

the formation dips steeply it makes hogbacks with narrow valleys between, and where it is nearly level it makes a. series 

of scarps. Few fossils have been found in this formation. 

Two detn,iled sections were measured south of Willow Creek for the purpose of showing the 

transition from the Bearpaw to the Lance. One .of these is given below. -

Section of transitional beds between typical Bearpaw shale and typical Lance formation, T. 29 N., R. 9 E., Montana. 

Typical Lance. Feet. 

Sandstone·, buff to 1·usty, slightly cross-bedded............................................... 8 

Shale, drab................................................................................. 6 

Shale, sandy ............. ·....................................... . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Shale, cru·bonaceous; contains fragments of stems of plants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Sandstone, yellow, massive ................... ~.............................................. 20 

Shale, with carbonaceous member near middle ................. _.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Sandstone, white, friable.................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

Shale, black, carbonaceous at top .............. .-................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

Shale, drab ....................... · .............. _ ............................................ 15 

Sandstone, shaly, ferruginous ................................................ -............... 1 

Shale, black ............................ ~ ........ : .................... : .. :.................. 2 

Sandstone, yellow to brown......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

Shale, drab . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 

Shale, with intercalated shaly sandstone members ............... ~............................. 8 

Shale, typical Bearpaw~ drab, concretionary, containing Baculites and other forms. 

- 139 

STRUCTURE. 

FOLDS AND DOMES. 

The dominant structure in the eastern part of the area is a broad symmetrical fold-the 

Big Snowy anticline-on which are superin1posed several sn1aller folds, thus producing the type 

of fold known as an anticlinorium. The axis of the Big Snowy anticline trends northwest and 

pitches to the southen,st. Out on the plains the strata on opposite limbs of this fold dip at angles 

ranging fron1 20° to 70°. Toward the mountains the dips decrease in amount and from Black 

Butte westward along the north base of the Judith and :Moccasin mountains they do not exceed 

45 ° and the anticline loses its distinctive character. 

The minor folds, consisting of the Devils Basin, Flat Willow, and Cat Creek anticlines with 

intervening synclines, are also open symmetrical folds whose axes pitch to the southeast and 

trend roughly northwest but are somewhat sinuous in outline. The dips on opposite limbs of 

these folds as a rule range from 2° to 6° and rarely exceed 10°. 

A dome structure has been produced by the laccoliths which have given rise to Black Butte 

and the North Moccasin 1\1ountains. So far as traced, the beds dip steeply away from these 

uplifts, except at the southeast side of Black Butte, where they dip steeply toward the butte, 

probn,bly n,s the result of faulting. 

Out on the plains north of the Judith and North Moccasin mountains the strata dip at a. 

low n,ngle to the north or northeast. 

1 U. S. Geol. Survey Bull. 431, p. 170, 1911. 
104 SHOR.TER CONTRIBUTIONS TO GENERAL GEOLOGYj 1914. 

FAULTS. 

In this region faults are important structural features only in the area north of T. 20 N. 

Two minor faults on the- north side of the Judith Mountains are shown on the map (Pl. X), 

and, as already pointed out, there is probably a small fault at the southeast side of Black Butte. 

Between Fullerton and Missouri River three prominent faults and some minor ones, striking a 

little west of north, cross the valley of Judith River. These faults all appear to be of the normal 

type. At the first and second faults north of Fullerton the beds dip steeply to the north near 

the fault plane but are nearly flat a short distance away. At the fault nearest Missouri River 

they dip to the f?Outh, and there is evidence of some minor faults, the details of which were not 

worked out. The northernmost fault exhibits the maximum throw observed, and at that place 

the white massive Virgelle sandstone member at the base of the Eagle is brought into juxtaposition with the sandstone beds constituting the upper part of the Claggett formation. If a 

thickness of 150 feet is allowed for that part of the Eagle above the white massive Virgelle. 

sandstone and 500 feet for the lower or shaly portion of the Claggett, the throw of the fault 

would be about 650 feet. 

Fault lines were seen also on the east side of Dog Creek, in T. 21 N., R. 19 E., where the 

structure seems more complicated than on Judith River.· The maximum disturbance is probably shown along Mi.ssouri River between Armells Creek and Dog Creek. Speaking of this 

area Hayden 1 says: · ' · 

It presents perhaps the most rugged scenery on the Missouri River, the denudation and erosion having been much 

greater than at the badlands of White River. But the most remarkable feature of this basin is the wonderful disturbance of the strata. So much are the beds disturbed and blended together by forces acting from beneath that it 

seems almost hopeless to obtain a section showing with perfect accuracy the order of superposition of the differrnt strata. 

STRATIGRAPHIC POSITION AND AGE OF THE JUDITH RIVER FORMATION. 

SCOPE OF DISCUSSION. 

In the foregoing pages the discussion has been confined chiefly to the stratigraphy of the 

formations in the area represented by the shaded portion of the accompanying map (Pl. X). In 

presenting the evidence now at hand bearing on the position and age· of the Judith River formation it is necessary to give a brief review of previous opinions as to the age of these beds and 

the stratigraphic succession in the type area of the Judith River formation, to correlate the 

formations in the type ~rea with those in the area herein considered, and to present the paleontologic evidence as to the age of the Judith "River and associated formations. 

HISTORICAL SUMMARY. 

The literature bearing on the stratigraphic position and age of the Judith River formation 

has been fully and carefully reviewed by Stanton and Hatcher. 2 For that reason only a brief 

synopsis, sufficient to give the reader an understanding of the various opinions held, is presented here. 

NAME. 

The name Judith River group was first given to this formation by Hayden 3 in 1871. After 

discussing the Fort Union" group," he says: 

There is another basin near the sources of the Missouri River which has already yielded many fossils of great interest 

but which seems to be isolated from the others. This is whatihavecalled theJudithBasin, and inasmuch as it seems to 

be one of the ancient lake deposits, and characterized by a peculiar group of organic remains, I will designate the strata 

as the Judith group. The sediments do not differ materially from those of the Fort Union group and they contain 

impure beds of lignite, fresh-water Mollusca, and a few leaves of deciduous trees. But the most remarkable feature of 

1 Hayden, F. V., Notes explanatory of a map and section illustrating the geological structure of the country bordering on the Missouri River 

from the mouth of the Platte River to Fort Benton: Acad. Nat. Sci. Philadelphia Proc., vol. 9, pp. 115-117, 1857. 

2Stanton, T. W.; and Hatcher, J. B., op. cit., pp. 14-31. 

a Hayden, F. V., Oeology of the Missouri Valley: U. S. Geol. Survey Terr. [Fourth Ann.] Prel. Rept., p. 97, 1871. 
U. S. GEOLOGICAL SURVEY 

GEORGE OTIS SMITH. DIRECTOR 

INDEX MAP 

1 

Scale soo,ooo 

Mauland 

# 

19 

14 

13 

9 N 

PROFESSIONAL PAPER 90 PLATE X 

LEGEND 

~ ~ Lance formation 

(lower part) 

~ Bearpaw shale 

• Judith River rormation (J) 

~~Claggett f'ormation 

[. :~ I Eagle sandstone 

[11S]Fault 

0 Strike and dip 

:J 

0 

lJJ 

u 

~ w 

a:: 

u 

GEOLOGIC MAP OF AREA EXAMINED, BETWEEN MUSSELSHELL AND JUDITH, MONTANA 

By C. F. Bowen 
STRATIGRAPHY OF ·THE MONTANA GROUP. 105 

this group is the number and variety of the curious reptilian remains, of which ·we have only yet caught a glimpse. 

There is probably no portion of the West that fmnishes such a harvest of fossil remains and instructive geological facts 

as the country bordering the Missomi River from the mouth of the Yellowstone to the foot of the mountains above 

the Great Falls of the Missomi; and as this country is reserved for examination the coming season I will leave the 

obscurity which now invests it to be cleared in the next annual report. 

Prior to that time the term Judith River beds had been used in a general way 1 to include 

all the formations exposed near the mouth of Judith River. Since the strata were named by 

liayden the terms Judith River beds and Judith River formation have been used as synonymous 

with I-Iayden's term Judith River group, which has finally been supplanted by the term Judith 

River formation. 

ORIGINAL AREA AND TYPE LOOALITY. 

No exaqt locality was designated by Hayden as representing the type of this formatio~. 

It is evident, however, as the following quotation 2 will show, that the area in which his Judith 

River group occurs lies along MissouriRiver between Judith River on the west and the mouth of 

1\fusselshell River on the east. 

Near the mouth of the Judith River,.not far from the sources of the Missouri, in latitude 47° 30', longitude 109° 30', 

is a wild, desolate, and mgged region, which I have called the "Badlands of the Judith," in. contradistinction to those 

of White Rive1·. * * * 

The area occupied by this peculiar basin I could not determine with precision, but have estimated it _at about 40 

miles from east to west and from 15 to 30 from north to south, and it is separated into two nearly equal portions by the 

1\:Ussouri. The Judith River rises in the Judith MOlmtains, pmsues a course nearly due north, for the most part through 

Cretaceous strata, and empties into the Missouri in latitude 48°, longitude 106° [about 110°]. The Judith River forms 

the north [western] boundary of this basin. The Muscle Shell River also rises near the Judith Mountains but takes a 

course a little east of north, flows through Cretaceous formation No. 4, and empties into the Missouri near latitude 

47° 301 and longitude 108°. That portion of the "Badlands" which is formed of the estuary deposit under consideration lies between these two streams. 

PREVIOUS OPINIONS OF STRATIGRAPHIC POSITION A~D AGE. 

In 1856' Meek and IIayden 8 correlated the marine formation immediately underlying the 

Judith River formation at the mouth of Judith River with the base of the Cretaceous. This 

correlation was b~sed on the lithologic similarity of this formation to formation No. 1 (Dakota) 

and on the fossil evidence, especially that of the vertebrates, as determined by Leidy. In 

another paper 4 in the same volume Meek and Hayden suggest that this marine sandstone 

probably represents the older members of the Cretaceous but that it may be as old as Jurassic. 

In 1857 I-Iayden 5 described and mapped the badlands of Judith River as occupying a Tertiary 

basin. Later in the same year Meek and Hayden, 6 on the basis of the invertebrate fauna, 

again assigned the Judith River formation to the Tertiary but said that the saurian and fish 

rmnains ally it to the Wealden. In 1858 Hayden/ after studying a fresh-water fauna at the 

base of the Cretaceous in the Black Hills region, assigned the Judith River to the Cretaceous, 

· thus reversing his forn1er opinion, and said that· it may be the American representative of the 

Wealden. After a reexamination of the invertebrates of the Judith River formation and a 

comparison of these fossils with the forms from the Black Hills, Meek and Hayden referred the 

1 Mock, F. B., m1d Haydon, F. V., Descriptions of now fossil species of Mollusca collected by Dr. F. V. Hayden in Nebraska Territory, together 

with a complete oatllloguo of all remains of Im·ertobrata hitherto described m1d identified from tho Cretaceous and Tertiary formations of that 

region: Acad. Nat. Sci. Philadelphia Proc., vol. 8, pp. 265-286, 18.56. 

~Haydon, 1<~. V., Goologiclll sketch of tho estuary and fresh-water deposit of the badlm1ds of the Judith, with some remarks upon the surrounding formations: Am. Philos. Soc. Trm1s., new ser., vol. 11, p. 12_;3, 1860. 

sl\fook, 1<~. B., and Haydon, F. V., Some genom! remarks on tho geology of the country about the sources of the Missouri River: Acad. Nat. 

Sci. Philadolpltia Proc., vol. 8, p. 114, 1856. 

~ Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 267, 1856. 

G Haydon, 1<~. V., Notes explanatory of a map m1d section illustrating tho geologiclll structure of tho country bordering on tho Missouri River 

from tho mouth of tho Platte River to Fort Benton: Acad. Nat. Sci. Philadelphia Proc., vol. 9, pp. 109-116, map, 1857. 

o Mock, F. B., and Hllydon, F. V., Descriptions of nc;-.v species and genera of fossils collected by Dr. F. V. Hllyden in Nobraskll Territory, 

under t.ho direction of Lieut. G. K. Warren, U. S. 'l'opograp.hical Engineer: Idem, pp. 117-148. 

7 Haydon, 1<~. V., Explffillltions of a second edition of a geological map of Nebraska m1d Kansa.'l: Acad. Nat. Sci. Philadelphia Proe., vol. 10, 

pp. 13D-15S, map, 1858. 
106 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Judith River back to the· Tertiary. Speaking of the fresh-water Jurassic of the Black I-Iills, 

they said: 1 

At the time we published these facts [concerning the fresh-water Jurassic of the Black Hills] we were led by the 

discovery here of fresh-water shells, in such a position, to think that some estuary deposits of doubtful age, near the 

mouth of Judith River, on the Missouri, from which Dr. Leidy had described some saurian remains resembling Wealden 

types, might be older than the Tertiary. Laoor examinations, however, have demonstrated that the Judith beds 

contain an entirely different group of fossils from those found in the rock under consideration, and that they are really 

of Tertiary age and hold a position at the base of the great lignite series of the Northwest. 

In another paper published in the same year, 2 after classifying the Tertiary basins of the 

Northwest, Ha)7 den referred the Judith River formation to the Tertiary, as follows: 

The estuary deposits, of which the Judith basin may be regarded as the type, are quite remarkable and of a most 

interesting character. Opinions of a somewhat conflicting nature have been entertained in regard to them, owing to 

the peculiar tharacter of the organic remains, but recent observations have convinced me that they are all of Tertiary 

age, and that they are quite widely distributed throughout the far \Vest. 

In 1875 both ·Meek 3 and Hayden 4 announced independently that the n1arine sandstone 

immediately underlying the Judith River formation near the mouth of Judith River had been 

definitely correlated with the Fox Hills, but in 1876, in his last writings on the subject, 1\1eek 5 

referred the Judith River to the Cretaceous, as follows: 

We have long regarded the Judith River beds as forming a distinct group older than the Fort Union deposits. 

* * * That these older beds (the Judith River brackish and fresh water deposits and their equivalents elsewhere) 

are Cretaceous is certainly highly probable, as has been suggested by the author on former occasions; yet this can scarcely 

be properly regarded as an established f~ct. 

In 1856 Leidy 6 published his first determinations of the vertebrate collection n1ade by 

Hayden· in the Judith River basin, and allied the vertebrates of the Judith River formation 

with those of the Wealden of Europe. 

In 1860 Leidy 7 made the following statement:· 

The association of the remains of Trachodon, Deinodon, Crocodilus, and Lepidotus, corresponding with the association of the remains of the closely allied Iguanodon, Megalosaurus, Crocodilus, and Lepidotus of the Wealden 

formation of England, led the author to suspect the Judith River formation was of cotemporary age, though he was" 

fully aware of the fact that totally dissimilar animals have OCGUpied different portions of the earth at the same period. 

In 1871 Cope 8 referred the Judith River fossils to the Upper Jurassic. In 1873 he placed 

the Judith River formation in the Cretaceous on the basis of the fossil remains,9 and in the following year (1874) he assigned it to the top of the Cretaceous. 10 In 1877 he assigned the black 

shale "No. 4" (now called Claggett) to the Pierre, and the overlying marine sandstone, which 

marks the transition to the Judith River, to the Fox Hills sandstone.U He also said: 12 "The 

positive age of the Judith River fauna is Cretaceous, with some Tertia·ry affinities." 

1 Meek, F. B., and Hayden, F. V., Descriptions of new lower Silurian (Primordial), Jurassic, Cretaceous, anp. Tertiary fossils collected in 

Nebraska, by the exploring expedition under the command of Lieut. G. K. Warren, with some remarks on the rocks from which they were 

obtained: Acad. Nat. Sci. Philadelphia Proc., vol. 13, pp. 41!)-447, 1861. 

2 Hayden, F. V., Sketch of the geology of the country about the headwaters of the Missouri and Yellowstone rivers: Am. Jour. Sci., 2d ser., 

vol. 31, pp. 229-245, 1861. 

a Meek, F. B., Note on some fossils from ncar the eastern base of the Rocky Mountains, west or Greeley and Evans, Colo., and others from about 

200 miles farther eastward, with descriptions of a few new species: U. S. Geol. and Geog. Survey Terr. Bull., vol. 1, 2d ser., p. 39, 1875. 

4 Hayden, F. V., Notes on the lignitic group of eastern Colorado and portions of Wyoming: Idem, p. 403, 1876 . 

. 5 Meek, F. B., A report on the invertebrate Cretaceous and Tertiary fossils of the upper Missouri country: U.S. Geol. Survey Terr. Repts., 

vol. 9, pp. xlvii, 1, 1876. . 

a Leidy, Joseph, Notices of the remains of extinct reptiles and fishes discovered by Dr. F. V. Hayden in the badlands of the Judith River, 

Nebraska [Montana) Territory: Acad. Nat. Sci. Philadelphia Proc., vol. 8, pp. 72-73, 1856. 

7 Leidy, Joseph, Extinct Vertebrata from the Judith River and Great Lignite format-ions of Nebraska: Am. Philos. Soc. Trans., new ser., 

vol. 11, pp. 139-140, 1860. 

sCope, E. D., Extinct Batrachia, Reptilia, and Aves of North America: Am. Philos. Soc. Trans., new ser., vol. 14, pp. 1-252, 1871. 

9 Cope, E. D., Report on the vertebrate paleontology of Colorado: U.S. Geol."and Geog. Survey Terr. [Seventh] Ann. Rept. [for 1873], p. 434, 

1874. 

1o Cope, E. D., Review-of the Vertebrata of the Cretaceous period found west of the Mississippi River: U.S. Geol. and Geog. Survey Terr. Bull., 

vol. 1, 1st ser., No.2, pp. ~8, 1874. 

u Cope, E. D., Report on the geology of the region of the Judith River, Montana, and on vertebrate fos~ils obtained on or near the Missouri 

River: U. S. Geol. and Geog. Survey Terr. Bull., vol. 3, pp .. 565-598, plates 30-34, 1877. 

12 Idem. p. 576. · 
STRATIGRAPHY OF THE MONTANA GROUP. 107 

While this work was being carried on in the United States, G. :M. Dawson was engaged in 

the study of the Be1fy River formation of Canada, which he correlated with the Judith River 

fonnation, as follows: 1 

Briefly stated, it would appear from the investigations now reported on that considerable areas of the beds which 

in1874 I called "Lignite 'l'ertiary"-here and in previous announcements designated as Belly River series-must be 

relegated to a position below the Pierre shales, or at least to one below an upper portion of these shales. The beds 

thus separated as the Belly River series were, in 1875, by me correlated with the Judith River series of the Missouri. 

Additional and extensive collections of fossils since obtained and now being worked out confirm· and strengthen this 

correlation and lead to the presumption that the so-called Judith River series must also occupy a position well down 

in the undoubted Cretaceous. It may be added that this was the view originally held by Messrs. Meek and Hayden 

and supported, it would appear, not alone on the supposed analogies of the vertebrate remains examined for them by 

Prof. Leidy, but also on stratigraphic evidence-evidence which perfectly agrees with the impressions resulting from 

such cursory examination as I was able to make of the Missou-ri sections from the deck of a steamer while ascending 

the river in 1881. 

In 1885 the invertebrate fossils of the Belly River were described by J. F. Whiteaves,2 who 

comn1en ted on then1 as follows: 

Jitdging by their respective invertebrate faunas, it would seem impracticable to separate the "Belly River series" 

from the ]~a ramie, and more especially from the "Judith River group," on purely paleontological evidence. 

'!'he invertebrate fauna of the "Belly River series" seems to be essentially the same as that of the "Laramie" of 

the United States and Canada, unless more than one formation has been confounded under the latter name, and * * * 

it is at present scarcely possible to separate the "lower dark shales" of Dr. Dawson's Bow and Belly River report from 

the "Fort Pierre and Fox Hills" groups on purely paleontological grounds. 

In 1902 Osborn 3 made the following statements: 

The Survey had established beyond question, geologically, that the Belly River series is mid-Cretaceous, that it 

underlies the Montana or Fort Pierre-Fox Hills group and overlies the Fort Benton and Dakota groups. * * '* It 

soon appeared to the writer in the study of the :fine collection made by Mr. Lambe that the Belly River vertebrates 

of the Northwest Territory were of decidedly different and apparently of older type than those from the Laramie beds 

of Converse County, Wyo., described by Marsh, and were rather to be compared with those described by Leidy, Cope, 

and Marsh from Montana, chiefly from the Judith River beds, a region by no means distant geographically. 

Thus the correlation between the Belly River and Judith River series, proposed by the late Director, Dr. G. M. 

Dawson, in 1875, at first glance appeared to be confirmed faunistically; but this correlation is. not supported by the 

geological records, which all place the Judith River beds proper above the Fox Hills and Fort Pierre. * * *. 

'!'here is thus very little in common between the Belly River fauna and the Laramie fauna of Wyoming and Colorado so far as desc1·:ibed, except the dinosaur Ornithomimus and the very persistent chelonian Baena. Most of the 

dinosaurs will ·probably be found to be separated generically. 

On the other hand, so far as known, the Montana fauna has much in common with the Belly River, especially 

the 'l'estud:inata, Iguanodontia, and Ceratopsia. ; • 

In 1903 Stanton and Hatcher 4 studied both the Judit~ River and Belly River formations 

and defined the stratigraphic position of the Judith River as follows: ' :1 

Our field studies in the original Judith River area have established th~ stratigraphic succession of the Upper Cretaceous section and show that the Judith River beds lie beneath several h~~dred feet of marine Cretaceous. shales with. 

a characteristic :invertebrate fauna, and that they rest upon another marine formation which also bears an abundant 

fauna. '!'he overlying formation we have called the Bearpaw shales, because :it is well exposed in the area south, 

east, {\.nd north of the Bearpaw Mountains. The name Claggett format:io'n has been given to the underlying beds because 

they are well developed around the site of old Fort Claggett, near the mouth of Judith River. ViTherever the exposures 

in this region show lower beds the lignite and conspicuous sandstone ledges of the Eagle formation are seen, and still 

lower the dark Benton shales with a characteristic fauna are revealed. The Judith River formation itself has yielded 

a fauna of both vertebrates and invertebrates, most of which are peculiar to it. Its lithologic features also are different 

from those of any other formation in the section and make it easily recognizable. 

Beyond the typical area we found on .Milk River, in the neighborhood of Havre, a similar succession of formations 

fl'om the Cla.ggett to the Bearpaw, inclusive. The formation occupying the position of the Judith River beds here 

has the same lithologic and paleontologic characteristics as in the original area, with which it probably has direct 

connections al'ound the east end of the Bearpaw Mountains. It is therefore 'unhesitat.ingly identified with the Judith 

I Dawson, G. 1\L, Report on tho region in tho vicinity or the Bow and Belly rivers, Northwest Territory: Geol. Survey Canada Rept. Progress 

1882-1884, p. ll!lc, maps, 1885. 

2 Contr. Canadian Pnlcontology, vol. 1, pt. 1, pp. 55, 89, 18R5. 

s Osborn, H. :F., Distinctive characters or tho mid-Cretaceous fauna: Contr. Canadian Paleontology, vol. 3, pt. 2, pp. 7-21, 1902. 4 Stanton, '1'. W., and Hatcher, J. B., Geology and paleontology of the Judith River beds: U. S. Goo!. Survey Bull. 257, pp. 62, 66, 1905. 

37183°-15---8 
108 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

River beds. From Havre this formation was traced by means 'of practically continuous exposures and without essential 

change of lithologic and paleontologic characters into an area of Belly River beds mapped by Dawson. Here again 

the underlying Claggett formation was recognized by its fossils and lithologic features, and above the Judith River 

(Belly River) beds the Pierre shales of the Canadian geologists are clearly identical with the Bearpaw shales of our 

Montana section. · 

In other areas studied by us in Montana the same succession of formations was observed. Two horizons in this 

region are especially well characterized by marine invertebrates-one in the upper part of the Benton shales and the 

other in the Bearpaw shales. Wherever these were both present in one section the succession and recognition of the 

1ntervening formations were unmistakable. * * * 

Our principal conclusions from the season's work may be summarized as follows: 

1. The Judith River beds are distinctly older than the Laramie, being separated from the latter by at least several' 

hundred feet of marine shales, identical in their faunal and lithologic features with the Pierre, to which we have given 

the local name Bearpaw shales, from the Bearpaw Mountains, about which they are well exposed. 

2. The Belly River beds of Canada are identical with the Judith River beds of Montana. The name Judith River 

beds, having priority, should be the accepted name for this formation, and the terms Belly River and Fish Creek beds 

should be dropped. 

3. The marine sandstones and. shales immediately underlying the Judith River beds do not represent either the 

· Benton, as some. Canadian geologists have supposed, or the Fox Hills and upper Pierre, as most geologists of the 

United States who have examined them have beli~ved, but they constitute a distinct horizon within the Montana 

group which we have called the ylaggett formation, from old Fort Claggett, at the mouth of Judith River, near which 

they are well developed. · 

4. The Eagle formation, from its stratigraphic position and faunal relations, marks the base of the Montana group 

in this region. 

5. The Bearpaw shales, the Judith River beds, the Claggett, and the Eagle. formations all belong to the Montana 

group and together probably form the equivalent of the Pierre as that term is generally understood, though the 

possibility is recognized that in the typical area the Pierre may have more restricted limits. 

6. Faunas similar to that of the Fox Hills sandstone have a great vertical range and are likely to be found at any 

horizon within the Montana group where a littoral or shallow-water facies·is developed. The use of the term Fox Hills 

as a formation or horizon name outside of the oFiginal area in South Dakota is therefore of doubtful propriety, as 

experience has shown. 

In 1911 A. C. Peale, who had done work in the Judith River region in connection with the 

Hayden Survey, revisited that area and spent a .month in the field iJ;l a special study of the 

Judith River formation. As a result of this study Peale in 1912 published a paper 1 in which 

he contended for the Tertiary age of the formation, thus reverting to the opinions which had 

been held by some geologists before the work of Stanton and Hatcher. His conclusions are 

given in the following quotation': 

Our first conclusion, therefore, is that the Judith River beds and the Belly River series, although both of freshwater origin and lithologically very similar, are entirely distinct from each other, occupying stratigraphical positions 

separated by 1,000 feet or more of marine sandstones and shales. * * * Our second conclusion is that the Fox 

Hills formation, with its characteristic fauna and flora, immediately and unconformably underlies the Judith River 

beds and that it rests conformably upon exposu~es of characteristic Pierre shales throughout the Judith Basin. * * * 

We have no hesitation in stating the third conclusion, viz, that the Judith River formation is the representative if 

not the exact equivalent of the whole or some, perhaps lower, portion of the Lance formation, and that the latter name 

·should be replaced on the ground of priority of use by the name Judith River formation. * * * We are fully 

warranted in concluding, as pointed out by Dawson long ago, that the Belly River series is of Niobrara age. * * * 

Apparently the entire series from the base of the Eagle sandstone to the base of the Pierre shales is a unit representing 

the Canadian Belly River formation. 

The foregoing sketch briefly summarizes the views that have been held regarding the age 

and position of the Judith River formation. A review of the evidence shows that on the basis 

of its vertebrate remains the Judith River formation has generally been assigned to the Cretaceous, although differences of opinion have been expressed as to its exact position in the Cretaceous section. Before the characteristics of the Upper Cretaceous dinosaurs were well known 

Leidy, Meek, Hayden, and Cope thought that. the remains from the Judith River formation 

were closely allied to the Wealden (Lower Cretaceous) of Europe, and hence the formation was 

considered to be of Lower Cretaceous age. But as the Upper Cretaceous dinosaurs came to 

be better known it was generally recognized that the remains from the Judith River formation 

have their closest allies in the Upper Cretaceous. From that time on practically all vertebrate 

1 Peale, A. C., On the stratigraphic position and ·age of the Judith River formation: Jour. Geology, vol. 20, pp. 53D-549,64G-652, 738-757, 1912. 
STRATIGRAPHY OF THE MONTANA GROUP. 

pnleontologists have regarded the Judith River formation to be of Upper Cretaceous age. On 

tho other hand, the invertebrate evidence, though somewhat conflicting in its nature, has been 

regarded by the earlier writers as showing· a closer affinity with the Tertiary than with the 

Cretaceous~ Finally, the stratigraphic evidence has been interpreted, except by Dawson and 

by Stanton and. I-Iatcher, as indicating that the Judith River formation is younger than the 

Fox I-Iills, and therefore at the top of the Cretaceous or the base of the Tertiary. 

ItEVIEW 01" THE STitATIGRAPHY IN THE TYPE AREA. Oli' THE JUDITH RIVER li'ORMATION. 

I-Iayden's best account of the stratigraphy in the type area of the Judith River formation, 

fron1 which the following extracts are taken, was published in 1860. 1 

So intimately do the estuary beds at the mouth of the Judith seem to be connected with Cretaceous formation No.] 

that it will be .important to present such facts as are known in regard to it. * * * 

The Cretaceous rocks of the Upper Missouri have been separated into five divisions upon lithological and paleon· 

tological gt·otmds, and the sandstone formation at the mouth of Big Sioux and below forms the type of No. l, 2 Nos. 2 

and 3 are seen reposing upon No.1 at the mouth of Big Sioux, and near the mouth of the Niobrara River No.4 appears 

upon the summits of the bluffs, surmounting No. 3. At the foot of the "Big Bend" No. 3 passes beneath the water 

level of the river and is succeeded by No.4, which occupies the country to Grand River, where No. 5 makes its appearance on the summit.s of the hills. Near the mouth of the Cannonball River the Lignite Tertiary beds begin to overlap 

the Cretaceous strata but do not entirely conceal them along the banks of t]:le river until \ve reach "Square Buttes," 

about 30 miles below Port Clarke. · Prom this point to Milk River in latitude 48°, longitude 106°, only the Miocene 

beds of the Great Ugnite basin are exposed. * * * The Tertiary beds continue uninterrupted until we reach 

the mouth of Milk River, where, by a reverse dip of the strata, the Cretaceous formation rises to the surface from 

beneath the Tertiary. The Tertiary beds continue to overlap the Cretaceous, gradually thinning out upon the summits 

of the hills, until we reach the mouth of the Muscle Shell River, where the Cretaceous bed No.4 occupies the whole 

country. We thus see that in ascending the Missouri the dip of the strata is northwest as far as Port Union or some 

point .in that vicinity, and on reaching Milk River we can very distinctly observe the dip south or southeast, by which 

the underlying Cretaceous beds are exposed. We can also note the basin-like form in which both Tertiary and Cretaceous 1·ocks were deposited. Passing the mouth of the Muscle Shell we soon observe a somewhat remarkable bed 

rising above the water level of the Missouri, near the mouth of Little Rocky Mountain Creek, which, from its lithological character and position, we have hitherto considered as belonging to formation No. I. It first makes its appearance as a seam of carbonaceous grit, of a du1l-reddish color, very light and loose, like ashes, about 1 foot in thickness, 

separating No. 4 from a bed of sandstone beneath. As we ascend the river a bed of sandstone rises rapidly above the 

water level, very variable in its lithological character. * * * 

Thus far up the river we have observed no indications of disturbance of strata by subterranean influences, but 

on reaching a poi1~t about 5 miles above Grand Island a great thickness of rocks not before seen is uplifted so as to 

exhibit the beds, inclining at every angle from a horizontal to a vertical position. The beds are composed of variegated 

sands, clays, and earthy lignite, and some of them are fully charged with organic remains. * · * * 

About 10 miles below the mouth of the Judith River the marine strata of No.1 are seen to rise rapidly from beneath 

tl10 estuary and fresh-water beds, and on reaching the mouth of the Judith we have the following vertical section of 

No. l,a the estuary and fresh-water beds only capping the hills and soon ceasing to appear. 

It is evident that I-Iayden realized that the beds exposed nlong :Missouri River from Little 

Rocky Mountain Creek west to Judith River are older than his No. 4 (now called Bearpaw). 

The stratigraphic succession between the nwuth of }.{u~selshell River and Judith River as given 

in the above quotation isNo. 4. 

Fresh and brackish water beds. 

No. l. 

In 1875 :Meek and liayden announced independently (see p. 106) that the upper part of 

Ilayden's No. 1 had been definitely correlated with the Fox Hills. In 1877 Cope 4 corroboratecl 

1 Haydon, F. V., Geological sketch of tho estuary fllld fresh-water deposit of the badlands of tho Judith, with some remarks upon tho surroundIng formations: Am. Philos. Soc. ~eruns., now scr., vol. 11, pp. 126:-130, 1860. ' · 

2 Nos. 1 to 5 correspond to Dakota, Benton, Niobrara, Pierre, and Fox Hills, rcspcctively.-C. F. B. 

a Tho No.1 of this paragraph refers to what arc now called tho Eagle and Claggett formations.-C. F. B. 

• Cope, E. D., Report on tho geology of tho region of tho Judith River, Montana, fllld on vertebrate fossils obtained on or near tho Missouri 

River; U.S. Geol. and Geog. Survey 'L'err. Bull., vol. 3, p. 568,1877. 
110 SHORTER CON~RIBUTIONS TO GENERAL GEOLOGY, 1914. 

the succession established by Hayden, but·· divided Hayden's No. 1 into three fonnations. 

Discussing the section at the mouth of Judith River, Cope said: 

The ferruginous soft sandstone of the Fox Hills group is everywhere the line of demarkation between the black 

shales of No.4 below and the Judith River beds above. 

and, in the preceding· paragraph, 

A question remains as to the light-colored (buff or white) sandstone underlying No. 4. * * * Geographically 

considered it is approximately No. 3, since it occupies a region between that occupied by Nos. 4 and 5 and Fort 

Benton, where No. 2 is extensively exposed. 

·with these changes and additions the ~hove section becon1es: 

6. "No. 4" (Pierre shale)~ 

· 5. Judith River formation. 

4. "No.5" (Fox Hills sandstone). 

3. "No.4" (Pierre shale). 

2. "No. 3" (?), sandstone tentatively referred ·to the Niobrara formation. · 

.1. "No.2" (Benton shale). 

_ 'C_ope 1 recognized, however, that No. 4 at the mouth of Judith River does not agree in all 

i'~~pects with No. 4 exposed farther east on Missouri River. After discussing the underlying 

~-~ds (now called Eagle) he says the characteristic overlying shale (Claggett) "is from 50 to 200 

feet in thiclmess in the region of the Judith River, while on the lower river [Missouri] * * * 

it exhibits a thiclmess of nearly 1,000 feet above the water level." · · 

Substituting lithologic terms for names, the above section is as follows: 

6. Marine shale. 

5. Fresh-water formation. 

4. Marine sandstone. 

3. Marine shale. 

2. Marine sandstone. 

1. Marine shale. 

This· is identically the same lithologic succession as that established on :Missouri River in 1903 

by Stanton and Hatcher, and as that which occurs throughout the area described by the writer 

in the first part of this paper. Moreover, the work of Pepperberg 2 in 1908 and of the writer 3 

in 1912 shows that the same succession occurs east of the Bearpaw Mountains fron1 Missouri 

River north to 1\:filk River. . 

It is thus evident that this succession of formations prevails over a la~·ge area in northcentrall\-:fontana. In part of that area the normal sequence is undisturbed by faulting, so that 

the succession is established beyond question. This succession is shown in the· following section, 

in which the l~thologic designations of the preceding section are replaced by the geologic names 

now applied by the United States Geological Survey to the forn1ations: 

6. Bearpaw shale (marine). 

5. Judith River formation (fresh water). 

4. Claggett formation (marine sandstoJ?.e member). 

3. Claggett formation (marine shale member). 

2. Eagle sandstone (principally marine). 

1. Colorado shale (marine). 

QORRELATION OF .JUDITH RIVER FORMATION ON MISf?OURI RIVER WITH. THE FORMATION 

IMMEDIATELY UNDERLYING THE BEARPAW SHALE FARTHER SOUTH. 

That the formations described by Hayden and Cope which occur at the mouth of Judith 

River are identical with those shown on the accompanying map (Pl. X) has been shown in 

the discussion of the stratigraphy (pp. 96-103). · Two of theseformations----'-the Claggett (including 

the so-called Fox Hills sandstone) and. the Judith River-were traced continuously for more 

than·100 miles and were found to be exact equivalents of those at the mouth of Judith River._ 

1 Op. cit., p. 566. 

2 Pepperberg, L. J., The Milk River coal field, Montana: U.S. Geol. Survey Bull. 381, pp. 82-107, 1910. 

s Bowen, C. F., The Cleveland coal field, Blaine County, Montana: U.S. Geol. Sur\rdy Bull. 541, pp. 338-3.53, 1914. 
STRATIGRAPHY OF THE MONTANA GROUP. 111 

Peale has also shown the continuity of the Claggett (called by him Pierre and Fox Hills) from 

the n1outh of Judith River southward to Deerfield and has recognized that the formations in 

the type area of the Judith River formation can be traced with certainty as far south as the 

North :Moccasin Mountains, so that the correlation here made seems to be well established. 

Peale's statmnent 1 in this connection is as follows: 

'l'ho dark-colored shales of the Pierre resting on these sandstones [Eagle, but called Belly River by Peale] form 

tho surface of tho bench beginning several miles to the eastward of the coal mine [near Deerfield] and tlie road to Kendall passes over them, several good outcrops showing, especially to the north of the road, but they do not show on the 

Judith south of the mouth of Warm Spring Creek. However, the Pierre shales appear in the valley long before Fullerton 

is reached and at the latter place form the bluffs on both sides of Judith River in typical exposures containing characteristic fossils. The entire thickness does not show at Fullerton, but there is here an exposure of at least 400 feet. The 

total thickness is probably from 600 to 900 feet. Immediately below the Judith River beds, which form the summit 

of tho bluffs and the surface of the bench reaching to the eastward, there are from 50 to 100 feet of sandstone with Halyrnen,ites major and the following invertebrate fossils: Avicula nebrascana E. and S., Tancredia arnericana M. and H., 

Lunatia Sttbcrassa M. and H., Tellina equilateralis ·M. and H., and Mactra sp. These are identified by Dr. Stanton and 

referred by him to the Claggett~ but it seems to me they are undoubtedly of Fox Hills age, the beds containing them 

resting on Pierre shales and being immediately followed above by the Judith River beds. * * * 

A short distance below Fullerton the first of three well-marked f{!-ults that occur south of Judith Landing crosses 

Judith Hiver. The direction of this fault is nearly east and west and the dip of the beds thrown down is quite steep 

(about 20°) toward tho northwest. This outcrop, mainly of Fox Hills sandstone and a smaller part of Judith Hiver 

beds, is underlain by Pierre shales, and above the faulted beds are Pierre shales capped by Fox Hills sandstones (containing invertebrates and Halymenites major) which underlie the undisturbed Judith Hiver beds, which have a very 

slight inclination to the north or northwest. The lower slope of the hill back to the faulted beds is composed of Pierre 

shales capped with Fox Hills sandstones and overlying Judith Hiver beds. This fault line was afterward crossed 12 

miles to the eastward, near the crossing of Dog Creek. The second fault line parallel to this one is exactly like the first, 

but tJ1e third one, a few miles south of Judith Landing, is a block fault of Fox Hills sandstone with a steep dip on the 

southwest side. 

In order to establish further the correlation of the Judith River formation in Hayden's 

type area of that formation with the formation which the writer has mapped as Judith River 

in the area represented on Plate X, the following list of fossils is presented. This list shows 

the fossils collected n·on1 the Judith River formation in the type area and those collected east 

and south of 'f. 19 N., R. 19 E. 

Fossils collectedjrorn the Jttdith River formation. 

In Hayden's type area. 

Ostrea sub~rigonalis E. and S. 

Corbicula cytheriformis M. and H. 

Corbicula occiclentalis M. and H. 

Corbula subtrigonalis M. and H. 

Goniobasis convexa.M. and H. 

Goniobasis invenusta M. and H. 

Goniobasis sublrevis M. and H. 

Goniobas.is judithensis Stanton. 

Goniobasis gracilinta Meek. 

Goniobasis subtortuosa M. and H. 

Campoloma votula M. and H. 

Sphrorium planum M. and H. 

Sphrol'ium rocticardinale M. and H. 

Anomia gryphorhynchus Meek. 

Unio clanro M. and H. 

Unio primrovus White. 

Physa copei '\\TJ1ite. 

Hyalina occidentalis M. and H. 

Hyalina ovans.i M. and H. 

Valvata montanaensis Meek. 

Viviparus conradi l\L and H. 

Anodonta propatoris ''TJ1ite. · 

East and south ofT. 19 N., R. 19 E. 

Ostrea subtrigonalis E. and S. 

Corbicula cytheriformis M. and H. 

Corbicula occidentalis M. and H. 

Corbula subtrigonalis M. and H. 

Goniobas.is sublrevis M. and H. 

Goniobasis subtortuosa l\1. and H. 

Sphrerium sp. 

Anomia sp. 

Unio sp. 

Viviparus conradi M. and H. 

Anodonta propatoris \%ite. 

1 Poalo, A. C., On tho stratigraphic position and age of tho Judith River formation: Jour. Geology, vol. 20, pp. 542-543, 1912. 
112 SHORTER CONTRIBUTIONS TO GENEHAL GEOLOGY, 1914. 

The list of fossils from the southern part of the field differs from the Missouri River list 

only in being less complete. A full collection from the southern area and a specific determination 

of all the forms would doubtless duplicate most if not all of those in the Missouri River list. 

In addition to this duplication of species there is at many places, both on_ Missouri River 

and in the southern part of the field, a bed of Ostrea subtrigonalis at the top of the Judith River 

formation. This Ostrea bed is perhaps the best index bed in the Judith River formation, as 

it occurs immediately beneath the Bearpaw shale. The widespread occurrence of this bed at 

the same geologic horizon is therefore of itself sufficient evidence to establish the correlation 

of the formation in which it occurs within a single basin of deposition, although it may not be 

sufficient to establish a correlation of beds in separate ·basins. 

It seems to the writer that the evidence presented in the foregoing discussion shows 

conclusively that the Judith River formation in the type area along Missouri River is the exact 

equivalent of the beds which immediately underlie the Bearpaw shale in the adjacent areas 

nor.th and south of :Missouri River, and therefore that the Judith River formation is of Montana 

age.- This evidence may be briefly summarized as follows: 

1. The stratigraphic succession in the two areas is identical.· 

2. The invertebrate fossils of the· Judith River formation on Missouri River are identical 

with those in the formation underlying the Bearpaw shale farther south.· 

3. The bed of ,Ostrea subtrigonalis which occurs at the top of the Judith River formation 

on the Missouri also occurs at many places at the top of the formation underlying the Bearpaw 

shale in the area south of Missouri River. 

4. Two of the formations, the Claggett and Judith River, have been traced from Willow 

Creek, in the southern part of the area, to the nwuth of Judith River and found to be the exact 

equivalents of the Judith River and underlying formations at that place. 

One question may still be raised, namely, May there not be two formations (Belly River 

and Judith River of Peale and some others) which in Hayden's" type area" have been confused 

. and included under one name~ As there has never been a complete detailed survey of Hayden's 

. "type area," this question'can not be unequivocally answered in the negative. If this confusion 

exists, Hayden's section (see p. 109) would need to be revised so as to show two fresh-water 

formations below his "lignite Tertiary." Such a succession is hardly probable, however, as it 

is now well known that no such sequence of formations occurs either north or south of Ifayden's 

"Judith Ri-ver area." Furthermore, Stanton and Hatcher failed to find any such succession 

in that part of the "type area" which they examined in 1903. It is possible, however, that, 

owing to the highly disturbed condition of the strata, down-faulted blocks of the Lance formation 

may occur in some places in Hayden's" original area." If such blocks exist they are undoubtedly 

of small extent, and it is confidently believed that most if not all of the "estuarine deposits" 

described by Hayden belong, as indicated by him, to the same formation which he describes as 

capping the hills at the mouth of the Judith. This formation, as previously shown, is the 

equivalent of the Judith River formation on Willow Creek and there undoubtedly underlies the 

Bearpaw shale. (See Pl. X.) · 

PALEONTOLOGIC EVIDENCE OF THE AGE OF THE JUDITH RIVER FORMATION. 

As s_hown in the historical suml'nary (pp. 104-110), the Judith River formation was 

regarded by the earlier geologists as overlying the Fox Hills sandstone and was therefore supposed to be of late Cretaceous or early Tertiary age, notwithstanding the fact that the vertebrate 

remains were regarded as indicating a close relationship with the Cretaceous. 

The stratigraphic. relation .of the Judith River to the inclosing formations has been discussed above. In the following pages the paleontologic evidence of. the age of the Judith 

River formation is submitted. In .th}s connection it is necessary to compare the fauna of 

the so-called Fox Hills sandstone of the Judith River area (the marine sandstone forming 

the upper part of the Claggett) with the fauna of the underlying Eagle sandstone, and also 

with that of. the Fox Hills at its type locality, and to compare the fauna of the Judith River 

formation with that of the Belly River formation on the one hand and with that of the Lance 
STRATIGRAPHY OF THE MONTANA GROUP. 113 

formation on tlie other. 1'he writer has therefore assembled as complete lists as possible of 

the fauna of these formations, which are presented in tabular form in order to facilitate 

co~nparison. But before proceeding with this comparison the paleobotanic evidence of the age 

of the Judith River formation is briefly considered. 

THE l!"'LORA OF THE JUDITH RIVER FORMATION. 

Although stems and fragments of plants are common in the Judith River forn1ation, wellpreserved leaves which will serve for purposes of identification are extremely rare and have 

been obtained at only two localities-on. Cow Creek near Missouri River, and on Willow Creek 

about 10 1niles north of Musselshell post office. Both collections were made by Stanton and 

IIatcher in 1.903 a;nd were submitted to F. H. Knowlton for identification and 9-etermination 

of age. 1\::nowlton's descriptions and conclusions are published in Survey Bulletin 257, pages 

1.29 to 1.68, and the fmal paragraph of his article is quoted here: · 

From this review it appears that the flora of the Judith River beds that has thus far come to light shows very 

little n.fnnity with the true Laramie or the Fort Union but does exhibit an undoubted relationship with that of the 

Dakota group or with the Cenomanian and Senonian of the Old World, or, in broad terms, with th~ lower and middle 

portions of the Upper Cretaceous. 

Jtuowlton's statmnents regarding the specimens collected on Cow Creek are rather guarded, 

and Peale 1 has argued that the species represented by this collection is of Fort Union age. 

ICnowlton's statement regarding this species is therefore quoted here in full: 2 

From the base of the Judith River beds, at a point on Cow Creek, about 13 miles above its mouth, Mr. Stanton 

has obtained about 15 specimens of small detached leaves or leaflets that I am not able to distinguish from this species 

[11raJJa micro1>hylla]. 'While they are all smaller -than the usual examples from the type locality (Point of Rocks, 

Wyo.), they agree well in shape and the marginal dentation, but unfortunately have not retained the nervation, or, 

at most, but slight traces of it. This species, or at least what has been so identified, has been :figmed by Dawson, 

in Tyrrell's collections from Bad Lands, Reel Deer, and Rosebud rivers, and Pincher Creek, Canada, the age of which 

he regat·cls as "Lower Laramie," and also~ single doubtful example "from the Upper Laramie of Great Valley." 

Prof. Ward found this species abundantly atBmnsranch, on lower Yellowstone River, Mont., in beds supposed to be 

of Fort Union age, but, as I have shown in the ''Flora of the Montana formation,'' I can not believe that these should be 

referred to '11

• 1nicrophylla, for the reason that they are clearly compound leaves, rarely detached , whereas at the type 

locality and at all the points mentioned by Dawson they are always separated and show no evidence of having been 

compound. I found examples that are not to be distinguished, apparently, from the Bmns ranch £01·ms, on Wolverine Creek, in the Yellowstone National Park, in beds regarded as of true Laramie age, and in 1896 Mr. Stanton and 

myself found a large number of detached leaves in Converse County, Wyo., in clay peds in the lower portion of the 

true Laramie. It may be that my presumption of two forms being mixed under this name is not valid, but it is certainly remarkable that at two localities they should always give evidence of being compound and at all the other 

localities appeM· as detached leaves, with no indication of being compound, especially as the material is ample in 

most cases. It must be confessed, however, that when dealing with isolated leaves or leaflets· it is impossible to draw 

any satisfactory line between them. 

rrhis quotation shows that there- is no doubt as to the Montana age of the plants from 

'\Villow Creek, and that Knowlton also favors the correlation of the species fron1 Cow Creek 

with the Montana rather than the Fort Union flora. Peale, 3 in discussing the Willow Creek 

section, from which the leaves identified by Knowlton were obtained, says that the ''Belly 

H.iver beds [Judith River forn1ation of this paper] pass conformably beneath the soft dark 

shal~s of the Pierre," and'' there can be no doubt as to the Belly River age of these beds." There 

is thus a unanimity of opinion regarding the Belly River age of the formation exposed on Willow Creek. The writer has endeavored to show (pp. 1.01, 110-112) that this so-called BellyRiver 

formation (Judith River of this paper) on Willow .Creek is the exa~.t stratigraphic equivalent 

of the Judith River formation at the mouth of Judith River. The invertebrate fossils listed 

on page 11.1 bear similar evidence. The stratigraphic evidence and the evidence furnished by 

the fossil plants and invertebrates, therefore, point to the same conclusion, namely, that the 

Judith Hiver fonuation is older than the Bearpaw shale and is of Montana age. 

1 Jour. Geology, vol. 20, p. 739, 1912. 

2 U.S. Geol. Survey Bull. 257, pp. 144-145, 1905. 

s Op. cit., p. 549. 
114 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY,- 1914. 

INVERTEBRATES OF THE UPPER PART, OF THE CLAGGETT FORMATION (SO-CALLED FOX HILLS OF 

THE JUDITH RIVER AREA) COMPARED WITH THOSE OF THE EAGLE SANDSTONE AND THE FOX 

HILLS PROPER. 

The following table gives a complete list of invertebrates from the Eagle sandstone and 

the sandstone member constituting the upper part of the Claggett at the mouth of Judith 

River; also a comprehensive list of Fox Hills fossils collected near the type locality in the 

Cheyenne and Standing Rock Indian rese~vations of North and South Dakota. 

TABLE 2.-Invertebratefossilsfrom the Eagle sandstone, the upper part of the Claggett formation, and the type locality of · · the Fox Hills sandstone. 

NoTE.-References indicated by figures in the table are as follows: 1 Calvert, W. R., and others, Geology of the Cheyenne and Standing Rock Indian reservations, North and South Dakota: U.S. Geol. Survey Bull. 575, 1914. 2 Stanton, ·r. W., and Hatcher, J. B.;~ Geology and 

paleontology of the Judith River beds: U. S. Geol. Survey Bull. 257, 1905. 3 Collected by C. F. Bowen, 1912. • Meek, F. B., u. S. Gcol. and 

Geog. Survey Terr. Bull., vol. 1, 2d ser., pp. 39, 40, 1875. , Meek, F. B., U. S. Geol. and Geog. Survey 'l'err. Final Repts., vol. 9,1876. 

Ea,..le I U p&er part Fox Hills 

sandstone. ~~rn~~1f~~~ sandstone. 

. . I !~g~~~a~~~~~~~: ~e·e~~~-~·}::: :·.·.·~:·.·.·.·_-_-_-_-_·_-_·~::::::::::::::::::::::::::::::::: :::~:::::::::::: ::::~~: ::::::::::::(::::::::::: ~! 

!~fg~f: ~~~a~~~~:l·a~dds~:: ::::::::::::::::::::::::: :·:: :::::::::::::::::::::::::::: ~::::: ~:::::::::::::: ~: ..... x ·2 a.. ~! • 

Baculites ovatus Say........................................................................................ X 3 X 3 •••••••••••• 

Callista deweyi M. and H. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 2 ( ?) . . . • . . . . . . . . X 1 

Callista owenana M. and H... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X " ........... . 

8:~~:rR~ ~~~g~:i ~~~~- ii ~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ..... ~ .

3 

•••• :::::::::::: • • • • • x ·1- • • • 

g~~iih~~~~e~~~~~e~s~~- ~il(irr:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: _ .... ~ _

2

_ ~ ....... ~ _

2

_ ~ ~ _ ~ : 

Cinulia concinna M. and H.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 1 

g~~~fg~t:~~~~£:~f~llit~a::d<ir~:::: :::::::::::::::: :·:: :::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::: :::::::::::: ~-! Corbicula subelliptica var. moreauensis M. and H........................................................... . . . . . . . . . . . . . . . . . . . . . . . . X 1 

ti~ftlf~!;!~jnijijd;jl_;;;l;;;; ;:::;:::;;••;;l;;:;:;;;;•;;;;:••;;l;;•;::•••;;;;;•l::•:::::•:: ;;•:::::::•:[ I! !~:Yi:~~~g~}:~~o~:~~t~r::.~~~~~~~:·:~~~:~:: ~ :~:: ::::::::::::::::::::: ~::: ::::::::::::::::::::::::::::: :::::::::: :·: :::::::::::: B! ~~~t~:1!~~!i~~~~~-~-~ ~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::: ::::: ~ :":::: ..... ~ .!. ···-

~~~~~j~]~t~.;~·~:••····:···:·:···:·······:········:··:··········:·············:········ t~f~~~~~~~~~:~~iJ!~o~.':::: ~::::: ~::: ~::::: ~ ~::::::::: :·~::::::::::::::::::::::::::::::::::::::::::::::: ··:········· :::::::::::: ••.•• 

..... ~:·.•: ~ .

2

• ~ •• 

~····~i;•• • • • • • x ·1· • • • 

Lucina subundata H. and l\f........................................................ . . . . . . . . . . . . . . . . . . . . . . . . X 2 ....................... . 

Lunatia concinna H. and M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 1 

Lunatia occidentalis M. and H.............................................................................. . . . . . . . . . . . . . . . . . . . . . . . . X 1 

Lunatia subcrassa M. and H. . . .. . .. .. .. . .. . .. . .. .. .. .. .. .. .. .. .. .. .. .. .. . .. .. . .. .. .. .. .. .. . . .. . .. .. . . .. . . .. X 2 X 2 3 a X 1 

Mactra alta M. and H....................................................................................... X 2 X 2 •" X • Mactra formosa M. and H................................................................................... X 2 3 X 2 a • X 4 

l\factra·warrenana M. and H................................................................................ .. . .. .. .. . . . . . . .. . . . . . . . X 1 

Martesis cuneata M. and H ........................................ ~......................................... . . . . . . . . . . . . . . . . . . . . . . . . X 1 

Melania insculpta Meek ......... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 1 

~~~~1~i.~JF~r~:F~~~~::~::: :::::::::::: :·:: :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::: ~ :

2

:::: :::: :~ :":::: ••• • • ~ ·!-: · · X 14 

X1 

X1 

X1 

X 1 

X1 
STRATIGRAPHY OF THE MONTANA GROUP. 115 

'fABI,E 2.-Invertebratefossils from the Eagle sandstone,· the upper part of the Claggett formation, and the type locality of 

the Fox Hills .~andstone-Continued. . . 

Eagle Uf&erpart Fox Hills 

sandstone. ~or~~~f;~~ sandstone. 

Tone rod Ia mncricana 1\L and H ........................ :. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 2 4 5 X 1 G 

~L'ollina cquilatcralis 1\L and H.............................................................................. . . . . . . . . . . . . X 2 s 5 •••••••••••• 

1'ollina tnontanacnsis.... .. .. .. .. . . . . . . .. .. .. .. .. .. . . .. .. . . . . . . . .. . . .. .. . . . . . . . . . . .. . . .. .. . . .. .. .. . . . . .. .. . . X 2 •••••••••••••••••••••••• 

~Pollina scitula 1\L m1d H.................................................................................... . .. .. .. .. .. . .. .. . .. .. .. . X 1 

;~~~~~s£g~~~!~~~~~:~{f ~~l: ~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::: :: ~ :2: :: : E :5 :::::::::::: 

:{:~~~~~~~~~~~~~t~~~~ ~(I arr~ ~--- ·.: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :: :::: :: :: :: :::: ::: :: : : : : : : : :: : : :: :: : ..... ~ .

5 

•••• • • • • • x ·1· · · 

~~~g~g;~~~ro~~~a~~dM~ffii<i·H:·:.-::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::: ·····x·2·ar.· ··---~-~---· 

In order to facilitate the interpretation of this table it is summarized in the table below, 

which gives all the forms that occur in more than one of the formations under discussion. 

TABLE 3.-Forms common to two or more of the formations represented in Table 2. 

Eagle sandstone. Upper part of tho Claggett formation. 

~ ~~~~~~ ~~frl~!~~~~: :. ·.:::::::::::::::::::::::::::::::::: · A:~icui~ ·tieb~ascffiia:::::::::::::::::::::::::::::::::::: Baculitcs ovatus. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baculites ovatus. 

~~~~~t~~:~r~~~:~~::~-~::::::::::::::::::::::::::::::::::: -~~~~i~s~ii:~~~~-:-::::::::::::::::::::::::::::::::::: 1\fuctra alta............................................... Mactrp. alta .............................. · ............. . Muctra fonnosa ........................................... 1\factra formosa ....................................... . 

Nautnusdokayl. · · · ·: · · · · · · · · · · · ·· ·· ·· ·· ·· ·· ·· · · ·· · · ·· ·· · ·Tanci-eciia.affie~ic.atia:::::::: ::::::::::::::::::::::::::: 

Thetis circular is.......................................... Thetis circularis. · 

Fox Hills sandstone. 

A vicula linguiformis. A vicula nebrascana. 

Callista dowoyi. Cardium spociosum. Lunatia subcrassa. 

Mactra alta. 

1\factra formosa. 

Nautilus dekayi. Tancredia americana. 

This table shows that there are more species common to the Eagle and Fox Hills in its 

type locality than to the sandstone in the upper part of the Claggett (so-called Fox Hills) and 

, the Fox flills proper. It also shows that with one exception (Tancredia americana) every 

species common to the Claggett and Fox Hills also occurs in the Eagle. Only four specifically 

detennined forms occurring in the ~agle are not found in the higher formations and 12 specifically determined forms found in the Claggett are not found in the Fox Hills. The tables 

semn to indicate a closer relationship between the faunas of the sandstone divishn of the Claggett (so-called Fox Hills) and the Eagle than between -the former and the Fox Hills proper. 

They also show that the fauna of the Fox I-Iills, while related to that of the two older formations, is ·more diversified, just as the fauna .of the Bearpaw shale is related to that of the shales 

of the Claggett formation but more diversified. From the paleontologic evidence there seems to 

be no basis for assigning the marine sandstone in the upper part of the Claggett formation to 

the Fox flills sands~one, and therefore one of the principal arguments for assigning the Judith 

River formation to a position at the top of the Cretaceous or base of the Tertiary-namely, that 

it overlies the Fox Hills sandstone-loses its force. As shown on preceding pages the stratigraphic evidence is conclusive that the Judith River formation is much older than the Fox 

flills as represented at its type locality. 

INVEl'tTEBl'tATES OF THE JUDITH RIVER FORMATION COMPARED WITH THOSE OF THE BELLY RIVER 

AND LANCE FORMATIONS. 

A comparison of the invertebrates from the Belly River and Judith River formations 

with those from the Lance formation of Hell Creek, Mont., and Converse County, Wyo., is given 

in the following table.· This list has been con1piled from the lists published by Hayden and 

Stanton and from the collections made by the writer and his assistants in 1912. · 
116 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 4.-Invertebrate fossils from the Belly River and Judith River formations and the Lance formation of Hell Creek, 

Mont., and Converse County, Wyo. 

R~ferences indica~ed by figures in the table are as fo~ows: I Stanton, T. W., U.S. Geol. purvey Bull. 257, pp. 104-~19, 1905. 2 Stantoni T. W., Washmgton Acad. SCI. Proc., vol. 11, pp. 243-247, 1909. Collected by C. F. Bowen, 1912. Hayden, F. V., Am. Philos. Soc. Trans., vo . 11, p. 

132, 18GO. . 

~~~lr JI:?~!~ Lance 

formation. formation. formation. 

Anodonta parallela White .................................. : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 1 ? . . . . . . . . . . . . X 2 

~g:lrliW!ilEf~M~~~~~~~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: g ~ g ! :::::::::::: ~~i~~i ~!~~:~~~~~::: ~:::::::::::::::::::::::::: ~:::::::::::::::::::::::::::::::::::::::::::::::::: ~ .... ~ _:_ ... ::::: ~ :~:::: ::::: ~ :i::: 

lliit~!Vil!ii:l!liill!!ii!!!ii! !!i !!!! l!il!i!!i! 11: :11! : ii ~ !.l :::Jt: &~~~~EE ~~i~~f~:~~~~r:~~~:·:~~ ~:·:·:·:::: :~::::::: ::::::::::::::::::::::::::::::::::::::::::::::::: ::::: ~ :1:::: g ~ :::::::::::: g~:~~~f~ {?f~t~~fts~s~: !~ci ii::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ..... ~ .

1

.••• 9 : :::::::::::: 

Goniobasis sublmvis M. and H .................... :.. . .. .. .. .. . . .. .. . .. .. . .. .. .. . .. . .. . .. .. . . .. .. . .. . .. . .. .. X 1 X 1 s ........... . 

8~:~~~~ ~~~~?~!~~:t:r:M~!J\:i ·. ~: :::::::::::::::::::::::::::::-::::::::::::::::::::::::::::::::::::::::: ..... ~ .

1 

••••••••• ~ •

1

• ~ ••••••• x .2 •••• 

Helix occidentalis ................................. ,......................................................... . . . . . . . . . . . . X 4 •••••••••••• 

Helix vetusta M. and H...................................................................................... . . . . . . . . . . . . X 1 X 2 ? 

Helix vitrinoides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 4 •••••••••••• 

................... 

.................. 

................. ................... ............... . X I .......... .. 

.................... ................. .. X I? ........... . X I .......... .. 

X I? ........... . X I XI X I Xll· 9: ..... x ·:·w 

X • ........... . XH .......... !. 

l1~1~J.~~i~~::•:;:::;;:;;::;;::;::;;•:;:::;::::::;;:;:::::·::::;;:•;:;;;;;;·::;·:·;;·····~t;·•::·:~;.·:·····~:;!. ~~\r=l~~wr:~~~~~::::::::::::::::::::::::::::::::::::::::::::·::::::::::::::::::::::::::::::::::::: :::::::::::::::::::::::: z: 

Unio biesopoides Whitfield................................................................................. . . . . . . . . . . . . . . . . . . . . . . . . x 1 2 

:g~1~ ~~~~ow~~fi~1~~~::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::: :::::::::::: 9 ! 

g~~ ~~~~~~~~'ir~~~~;~~::::::::::::::::::::::::::::::::::::::::::: :.:::::::::::::::::::::::::::::::::::: ::::: ~ :1:::: ::::: ~ :1: ~:: ..... ~ ·:· ... 

g~~ i~Jli~~~~;r~~~~~~::::::::::::::: :·::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ::::: ~ :1:::: ..... ~ .:. 3 4' g:? Unio endlichi White................................................................................................................ X 2 

g:~ ~~~~;i~~~ ~n:.e. ~.-. ·. ~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: :::::::::::: : ~:::::::::: 9 : 

Unio letsoni Whitfield...................................................................................... . . . . . . . . . . . . . . . . . . . . . . . . X 2 

Unio percorn1gata Whitfield................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . X 2 

Unio postbiplicata Whitfield................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . X 2 

g~fg ~~f~:;vfl :?Ji~:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 9 : 9 : 8 :::::::::::: 

l~l~~~ii'fii:B~~··T:·:·•:••:••••:••::•••:••••••:••••••:•••••••••·••••::::•~•:::•••••••••••:• ·::::~:·::: :•·:•::.•:•· ·····g·;··· g~f~ ~~~~~~~~~)mite::::::::::::::::::::::::::::::::::::::::::::::::::::.:::::::::::::::::::::::::::: ..... ~ .

1 

.••...••. ~ .

1 

..•. · · • • · x ·1· · · 

g~~ ~~~~Fi~~~:l\~\~hi~~l::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: ..... ~ .

1 

.•.•.••.• ~ .

1

. ~ .

7 

...... X 'i .. . 

g~~~ ~~~~~;n;:~~t~iteaves:::::::::.:::::::::: ::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 9 ~ . :::::::::::: :::::::::::: 

Unio verrucosiformis Whitfield... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 2 

~r~~~~~~!H:~!~~~ .... :~: ·:: ·::::::::::::::::::::::::::::::::::::::::::: ~:::::::::::::::::::::::::::::: :: ~:: ~ :1:::: z ! ! :::::::::::: 

Viviparus plicapressus White ...... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 2 

Tills table is summarize'd in the following complete list of the forms common to two or nTore 

of_ the forJI!ations involved: . 
' STRATIGRAPHY OF THE MONTANA GROUP. 117 

TABLE 5.-Fonns 7.Vhich occur in more than one of the formations represented in Table 4. 

Bolly Hivor fornmtion. Judith River formation. 

Anodonta pamlloh\ Whlto .............................................................................. . Anodonta propatorls White ......................... Anodonta propatoris White ...................... . 

~;~g::::~ ~·:rJ:.~.~~:~r~l~i~l~t ~~~o-~ ~::::::::::::::::::::: ~~g~~: grJ~~~~an~~~t~~~~~:::::::::::::::::::: Bullnus atavus White............................... Bulinus atavus White ........................... . 

8~:::i>~l~::~: ~~~~ft:~~~~~~l~~o~.~~~~-~:::::::::::::::::: :::::::::::::::::::::::::::::::::::::::::::::::::::: 

Canq>oloma votu~a M .. and II ........................ Cam_pcloma vctu~a M .. and H .................... . CorbiCula cythcnfornus M:. and H.. . . . . . . . . . . . . . . . . . CorbiCula cythcnfonms M. and H ................ . Corblcuh\ occidcntalis M:. and H..................... Corbicula occidentalis M:. and H ................. . Corbula porundata M. and H.. . . . . . . . . . . . . . . . . . . . . . Corbula pcrundata M. and H .................... . Corbuh\ subtrlgonalls M. and H ..................... Corbula subtrigonalis M. and H .................. . Gonlobasls convoxa M:. and H....................... Ooniobasis convexa M:. and H ................... . Ooniolmsis lnvonusta M:. and H ..................... Goniobasis invenusta M. and H .................. . Ooniobasisjudlthonsis n. sp ......................... Goniobasis juclithcnsis n. sp .................... .. Oonlobasls subimvls M. and H...................... Goniobasis sublmvis M. and H ...... , ............ . Ooniobasis subtortuosa M. and H ................... Goniobasis subtortuosa M. and II ................ . HclL'C vctusta M. and II ........................ .. Hyalina (?) ovansi M. and H ........................ Hyalina (?) ovansi. ............................. .. Hyalhm (?) occldontalls M. ami H ................... Hyalina (?) occidentalis M. and II ............... . Melania whitcavcsi n. sp ............................ Melania whitcavesi n. sp .......................... . Mytllus subarcuatus M. and 11 ...................... Mytilus subarcuatus M. and H .. · ................. . Ostrol\ gh\bra M. and .II. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ostrea glabra M. and II .......................... . Ostron. sub trigona lis K and S....................... Ostrca subtrigonalis E. and S ................... .. Panopma simulatrlx Whltcavcs..................... Panopma simulatrL'C Whiteaves .................. . l,hysa co pol White.................................. Physa copei White .............................. . Planorpis (Bathyompbalus) amplexus l\L and H.. . . Planor}>is (Bathyomphalus) amplexus M. and H .. Sphmrmm planum M. and ti........................ Sphmnum planum M. and ti .................... . Sphmrium roctlcardinalo M:. and H.................. Sphmritun recticardinalc M. and H .............. . 'l'lmumastus llmnmiformis M. and H ................................................................... . Unlo consuctus Whitoavos .......................... Unio consuctus Whitoaves ....................... . 

Unio dn.nm M. nnd H .............................. . Unio cryptorhynchus White ..................... . Unio danm l\L and H ............................ . 

E~~~ flE[~~"~~~~-:·:·:·:·~~ ~:::: :::::::::::::::: 

Unio primmvus White ................ : ........... .. Unio prlscus M:. and II ............................. . Unio sonoctus White ............................... . Unlo subspn.tulatus l\L n.nd H ..................... . Vivlpnrus conmdi l\L and H ...... : . ............... . Unio subspatulatus M. and H ....... ·---....... .. Viviparus conradi M. and II ..................... . 

Lance formation. 

Anodonta parallela White. 

Campeloma multilineata M. and II. 

Campcloma producta White .. Campeloma vetula M. and II. 

Corbicula occidcntalis M. and II. 

Helix vetusta M. and H. 

Ostrea glabra M. and II. 

Ostrea subtrigonalis E. and S. 

Physa copci White. 

Sphmrium planum M:. and II. 

Thaumastus limnroiformis M. and H. 

Unio cryptorhynchus White. 

Unio danm M. and II. (?). 

This sum1nary shows that of 88 forms listed in the preceding table 19 genera and 38 species 

occur in two or more of the formations involved. Of these 38 species only 2 occur in the 

Judith River and Lance which do not also occur in the Belly River arid 4 speciPs occur in the 

Belly River and Lance but not in the ~udith River. There are 32 species common to the Judith 

River and Belly River, 9 common to the Judith River and Lance, and 7 common to all three 

formations. Although it is generally conceded that fresh and brackish water invertebrates are 

of less value than marine invertebrates for the detei·mination of age and correlation of formations, except in local basins, the large number of forms common to the Judith River and Belly 

River as contrasted with those common to the Judith River and the Lance seems to be signific~ult, and if the fresh-water forms have any weight whatever they certainly favor the correlation 

of the Judith River and Belly River rather than that of the Judith River and the Lance, and 

therefore they tend to establish the Cretaceous age of the Judith River formation. 

VERTJ!jBltATES OF THE JUDITH RIVER FORMATION COMPARED WITH THOSE OF THE BELLY RIVER 

AND LANCE FORMATIONS. 

In Table 6 is presented a complete list of vertebrates from the Belly River formation; the 

Judith River formation; the Lance formation of Hell Creek, Mont., Converse County, Wyo./ and 

adjacent localities; the Denver and Arapahoe formations of the Denver Basin; and the "Laramie" 

formation of Black Buttes, Wyo. A similar but less comprehensive table was published by 

Osborn} and most of the li tern. ture and determinations have been reviewed by Hatcher 3 and Hay. 4 

These publications have served as a basis for the present cGmpilation, though the writer has 

exn.mined also most of the original descriptions and for doubtful species practically aH the literature available. The table gives the name of the species, the fo_rmations in which it is feported 

to have been found, the fillder and date (where known), the location at which each spe.cimen has 

been found, the material on which each. determination is based, the authority and reference for 

the determination, and a column of remarks in which is given mainly a synopsis of the views 

of tho authorities who have reviewed and criticized the original determinations and the material on which those determinations were based. 

1 Converso County has been subdivided nnd tho areas referred to in tho table arc now in Niobrara County. 

2 Osborn, H. F., Distinctive characters of tho mid-Cretaceous fauna: Contr. Canadian Paleontology, vol. 3, pt. 2, pp. 11-15, 1902. 

a Hatcher, J. B., Geology and paleontology of tho Judith Hiver beds: U. S. Goo!. Survey Bull. 257, pp. 67-103, 1905; The Ceratopsia: U. S. 

Goo!. Survey Mon. 49, 1907. 

• Hny, 0. P., Tho fossil turtles of North America: Carnegie Inst. Washington Pub. 75, 1908. 
118 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith R~·ver, Lance 

[The numbers 1 to 6 used in the last six columns correspond to the numbers printed in heavy type over 

1 2 3 

"Hell 

Creek 

Species. Belly Judith beds" 

River for- River for- (Lance mation. mation. forma- . tion), 

Montana. 

--------

PISCES. 

Acipenser albertensis Lambie ......... . tx X 

Ceratodus (Rhineastes) eruciferus Cope. X tx 

Rhineastes sp. indet ....................................... . X 

4: 5 

"LaraLance mie"forfor- ~mation, 

mation, Black 

w_y- Buttes, 

ommg. w_yommg. 

----

X 

6 

Denver 

apdArapli.hoe formatious, 

Colorado. 

Finder. Date. 

1. Lambe ...........•. 1. 1901. ........ . 2. Not given. 4. Not given. 

1. Lambe ...........•. 1. 1901 ......... . 2. Sternberg. 

Ceratodus hieroglyphus Cope .................... . tx ........................ ······:··· ............ . Not given ......................•.•...... 

Diphyodus Iongirostris Lambe ..... ~. . . tX X 

Diphyodus sp ............................................. . 

Hedronchus sternbergii Cope ..................... . 

Lepisosteus (Lepidotus) occidentalis 

J_,eidy. 

X 

Le{Jisosteus (Lepiaotus) haydeni Leidy ......... . 

Myl<Jdaphus bipartitus Cope .......... . X 

'X 

tx 

tx 

tx 

X .................... 1. Lambe ............. 1901. ..•.....•... 

X 

Sternberg ...•........................... 

X X X 1. Lambe ............. 1. 1901 •..•...... 2. Hayden. 

Hayden ................................• 

X 1. Sternberg .......................... .. 2, 4. Hatcher. 
STRATIGRAPHY OF THE MO~TANA GROUP. 119 

(" I:lell Oreelc beds" and" Ceratops beds"), and Denver and Arapahoe formations. 

tho locality colwnns. 'rho letter t indicates that the observation relates to the type of the species.) 

Locality and stratigraphic po- siti9n as given by tho authors 

cited. . 

tl. Red Doer River district, 

Canada. 

2. Judith River formation llocality not givonl. 4. Lammio formation, Converso 

Cow1ty, Wyo. 

1. l3olly River series, Rod Doer 

Uh•or, Alberta. 

2. Jo~ort Union bods, Montana. 

Hell Crook beds, Montana. 

t. Jo~ort Union bods, Montana. 

tl. Bolly River series, Rod 

Deer River, Alberta. 

2. Judith Itivcr beds, Mon- tana. 4. Lnmmlo deposits, Converso 

Count:y, Wyo. 

Hell Crook bods, Montana. 

l~ort Union bods,. Montana. 

1. Belly River series, badlands, 

Itod Door River, Alberta. 

t2. l3adiands of Judith River, 

Montru1n. 

3. Hell Creek Mont. 4. Converso County, Wyo. 6. Cemtops bods near Denver, 

Colo. 

Material on which determination is based. 

tl. Strongly keeled dermal 

shield. 

2. Similar ossifications. 4. Not given. 

1. A.. number of fragments of 

cranial bones. 

t2. A basal and dentigerous lamina. 

Not given. 

t. A dentigerous plate. 

tl. teeJ~~car':.ith numerous 

2. Fragments of similar ~aws. 

4. Jo~rogments of similar Jaws. 

Not given. 

Authority and reference. 

tl. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 29, 1902. 

2. HatchorLU. S. Geol. Survey Bull. 2::>7, p. 69, 1905. 

4. Hatcher1 loc. cit. Williston, SCience, new ser., vol. 

16, p. 952, 1902. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 29, 1902. 

t2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 259, 1876; U. S. Goo!. and 

Geog. Survey Terr. Bull. 

3, p. 574, 1877. 

3. HatcherL U.S. Goo!. Survey Bull. 2::>7, p. 68, 1905. 

Brown, Am. Mus. Nat. Hi~t. 

Bull., vol. 23, p. 842, 1907. 

t. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 260, 1876. Hatcher, U. s. Goo!. Survey Bull. 257, p. 68, 1905. 

Remarks. 

2, 4. Of this and the 7 species which follow, 

Hatcher (op. cit., p. 67) says: "They are at present known from such insufficient mate- rial as to render them of little value for purposes of correlation." Hatcher says ossifications similar to the type material from 

Canada are common in the Judith River 

formation and in the Laramie (Lance formation) of Converse County, Wyo. 

2. Although Cope gives the locality and horizon as Fort Umon, Mont., the horizon is Judith 

River. Cope at that time was using Fort 

Union in the same broad sense that was given to Laramie. On page 253 of tho 

Acad. Nat. Sci. Philadelphia Proc.1 vol. 28, 

he uses· the expression "Fort Umon badlands of the Judith River," and on_pages 512-574 of U. S. Goo!. and Geog. Survey Terr. Bull. 3 he gives a list of -fossils from 

the Judith River formations, which includes all but one of the species described in 

the article in the Academy Proceedings. He therefore used the terms Judith River 

formation and Fort Union formation indiscriminately when referring to the Judith 

River area. (See also remarks on Actpenser albertensis.) 

See remarks on Acipenser albertensis. 

See remarks on Acipenser albertensis and Ceratodus eruciferus. 

tl. Lambe, Contr. Canadian 2, 4. Referring to the type material, Hatcher 

Paleontology, vol. 3, pt. 2, says: "Fragments of similar jaws are found 

p. 30, 1!)02. both in the Judith River beds and in the 

2, 4. Hatcher, U. S. Goo!. Sur- Laramie of Converse Cotmty.',' (See also 

vey Bull. 257, p. 69, 1905. remarks on Acipenser albertensis.) 

Brown, Am. Mus. Nat. Hist. 

Bull., vol. 23, p. 842, 1907. 

Founded on tl1e crown of a Cope, Acad. Nat. Sci. Phila- SeiJ remarks on Acipenser albertensis and Cerayoung tooth. delphia Proc., vol. 28, p. 258, 1876. Hatcher, U. s. Geol. Survey Bull. 257, p. 69, 1905. 

1. Numerous scales. 

t2. 'l'ype fotmded on 5 speci- mens of thick lozenge- shaped scales. 

~: ~~~~:o~ :;cutes associated 

with opisthoccelous verte- brro. 

6. Not given. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 29, 1902. 

t2. Leidy, Acad. Nat. Sci. 

Philadelphia Proc., vol. 8, 

p. 73, 1856. 

3. Brown~,.,. Am. Mus. Nat. 

Hist. JjUll., vol. 23, p. 842, 

1907. 

4. Williston, Science, new ser., vol. 16, .p. 953-1. 1902. 

6. Marsh, U. S. ueol. Survey Mon. 27, p. 527, 1896. 

todus eruciferus. . 

See remarks on Acipenser albertensis. 

t. Badlands of Judith River, t. Founded on a single speci- t. Leidy, Acad. Nat. Sci. Phil- Cope (U.S. Geol. and Geog. Survey Terr. Bull. 

Mont. men of a thick oblong adelphia Proc., vol. 8, p. 3, p. 574, 1877) makes L. occidentalis and L. 

square scale. 73, 1856. haydeni synonymous. 

1. Bolly River series, Rod Deer 1. Represented by many deRiver, Alberta. tached and isolated teeth. 

t2: l~ort Union beds, Montana. t2. 'l'ype fom1ded on detached 

4. LaramioofConvorsoCounty, and isolated teeth. 

Wyo. •i. Similar teeth. 

1. Lambe, Contr. Canadian 2. 

Paleontology, vol. 3, pt. 2, 

p. 28, 1902. 

t2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 260, 1876. 

4. Hatcher, U.S. Goo.!. Survey Bull. 257, p. 68, 1905: Williston,· Science, new ser., vol. 16, p. 953, 1902. 

Given also in list from Judith River formation, Cope, U. S. Geol. and Geog. Survey Terr. Bull. 3, p. 574, 1877. Hatcher (U. S. 

Geol. Survey Bull. 257, p. 68) says: "It 

would be impos<>ible to identify either gen- era or species from teeth of such simple form!' 

u 
120 SHQR.TER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 3 

"Hell 

Creek 

Belly Judith beds" 

River for- River for- (Lance 

rnation.l mation. formation), • Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black ahoe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. Date. 

---------------1--------------------1---------1-------1 

PISCEs-continued. I 

Platacodon nanus Marsh ............................................ . tx Hatcher ............................... . 

Larnna sp ........................................... ; ..... . 

AMPHIBIA. 

Hernitrypus jordanianus Cope .................. . X 

Scapherpeton tectum Cope ............ . X tx 

Scapherpeton laticolle Cope........... . . . . . . . . . . tx 

Scapherpeton excisum Cope........... . . . . . . . . . . tx 

Scapherpeton favosum Cope........... . . . . . . . . . . tx 

PLESIOSAURIA. 

Cirnoliasaurus magnus L~idy .... : ..... . X 

Ischyrosaurus (Ischyrotherium) anti- ......... . quum Leidy. X 

X Brown ...•.............................. 

. ......... ·'········ .................... 'Notgiven .............................. . 

X X 1. Lambe. 2, 3, 4, not given. 1. 1901 ......... . 

---------- ...... -.............................. · ................................................... t.. . 

X 

Lambe................ 1901. .•••...•••.. 

2. Stanton and Hatch- 2. 1903 ..•....... er. 4. ·Hatcher. t. Hayden. 

Uronautes cetiformis ............................ . tX(?) ........................................ Cope ......... : ........ ·········.········· 

I 
STR.ATIGRAPHY OF THE MONTANA GROUP. 121 

("Hell Oreek beds" and" Ceratops beds"), and Denver and Arapahoejonnations-Continuecl. 

:Locality o.nd stratl~raphic PO· M:atorial on which detormina- ~~~~~i~ ns given by ho authors tiou is bnsed. 

t. LammioofConvcrsoCounty, t. Detached teeth, two dental 

Wyo. fl~~~s with teeth in posiHell Crook beds, Montana. Not gh•cn. 

Authority and reference. 

MarshiAm. Jour. Sci., 3d scr., VO • 381 p. 1781 1889. 

Hatcher, Science, now scr., vol. 12, p. 719, 1900; Carnegie Mus. Annals, vol. 1, p. 128, 1901. 

Brownt.Am. Mus. Nat. Hist. 

BUll., vol.'23, p. 842, 1907. 

Remarks: 

When first described by Marsh this animal wo.s regarded as a mammal. The finding of more complete remains enabled Hatcher to determine its true relationship. 

Judith Hivor bods, Montrum. A single vertebra. Cope, Acad. Nat. Sci. Phila- Distinguished from Scapherpcton by tho posi delphia Proc., vol. ~~ p. tion of the foramen chordro dorsalis. 

1. Bolly Rivpr soriosi Rod 

Door H.ivcr, Canac a, be- tween Berry Creek tmd 

Dead Lodge Canyon. t2. Judith IUvcr bods, Mon- truw .. 3. Hell C;·ook bods, Montana. 4. Laramie of Converso County, Wyo. 

1. Several trunk vertcbrro and 

atlases. 

t2. 'l'ypo founded on a single vertebra; this was accom- panied by a fragment which resembles the articular portion of the !llandiblc. 

3. Not given. 4. Numerous vertebrro and 

fragments of the mandible. 

358, 1876. Hatcher, u. S. 

Gcol. Survey Bull. 257, p. 71, 1905. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 31, 1902. 

t2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 355,1876. 

3. Dro.wnB Am. Mus. Nat. }§~ ~. ull., vol. 23, p. 823, 

4. 'Villiston,Scicnce,newser., 

vol. 16, pp. 952-953, 1902. 

t. Judith lUvcr bods, Montana. t. Founded on an atlas and 

several dorsal vcrtebrro of 

different individuals: vcr- tcbrro may belong to S. tectum. 

t. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 356, 1876. Hatcher, U. S. 

Geol. Survey Bull. 257, p. 70, 1905. 

t. Judith River bods, Montana. t. Species founded on scat- t. Cope, A cad. Nat. Sci. Philatcred vcrtcbrro from throe delphia Proc., vol. 28, p. individuals of different 357, 1876. Hatcher, U. S. 

sizes. Geol. Survey Bull. 257, p. 70, 1905 . 

. t. Judith River bods, Montana. t. Species founded on a single t. Cope, Acad. Nat. Sci. Philavcrtobra. delphia Proc., vol. 28, p. 357, 1876. Hatcher, U. S. 

Geol. Survey Bull. 257, p. 70, 1905. 

Bolly River series, below Berry Fomtcen ·cervical vertebrm, 

Crook on Rod ·Door !liver, probably belonging to one Lambe, Contr. Canadian Paleontology, vol. 3, pt. 2, p. Alberta. individual. · 32, 1902. 

2. Judith IUvcr beds, Cow 

Crook (l or 7 miles above 

its mouth, Montana. 4. Laramie of Wyoming. (l!~ound with mmnmalsand 

reptiles described by Marsh, probably all from 

Converso County, though no ox act locality is given.) t. l3otwocn Grand and Moreau 

rivers, S.Dak. 

Ncar Armolls Crook, Judith 

IUvordistrict, Mont. . 

2. A number of vortobtal cen- tra. 4. Several vcrtobrro. 2. Hatcher, U. S. Ge:>l. Smvey Bull. 257, p. 72;.1905. 

4. Marsh, Am. Jour. ~ci., 3d ser., vol. 38, p. 83, 1889. 

Cervical, dorsal, and caudal Cope, Acad. Nat. Sci., Philavertebrro and portions of delphia Proc., vol. 28, p. limb and rib bones. 346, 1876. 

The type of this species is founded on vertebrro 

from the greensands of New Jersey_ described by Leidy in 1853. Hatcher (U. S. 

Geol. Survey Bull. 257, p. 71) says: "It is not improbable that Lambe's material belongs to a different genus and species." 

2

' ~~~~~h;ife~e~~~~I~~i~~ ~;c~r~~~p~~: ty.pe specimen was ·round by Hayden in 

South Dakota between Grand and Moreau 

rivers from an "outlier of the great lignite beds.'' Hatcher says the horizon was more nearly that of the Fox Hills or Pierre. 

Cope regards tho horizon as Fox Hills, but his 

Fox Hills would be the upper part of the 

Claggett formation. Hatcher says that the 

specimen came either from tho top of tho 

Claggett or from the bo.se of the Judith 

River. 
122 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 3 

"Hell 

Creek 

Belly Judith beds" 

River for- River for- . (Lance mation. mation. forma- · tion), 

Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black ahoe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. Date. 

---------------1------------------------1----------1-------1 

CHELONIA. 

Adocus (Compsemys) lineolatus Cope .. X 

·Neurankylus eximius Lambe ......... . tx 

Basilemys (Cope). 

(Compsemys) im·bricaria .. ~ ....... 

Basilemys (Compsemys) variolosa 

(Cope). 

Basilemys (Compsemys) ogmius (Cope). 

X 

tx 

X 

tx 

tx 

Basilemys sinuosa Riggs ................................. .. 

Baena antiqua Lambe................. . tx 

Baenacallosa Lambe .......................... .. tx 

X X 

X 

'Baena hatched Hay ........................ ·......................... tx 

Baena marshi Hay .................................................. . tx 

Boremys pulchra Lambe .............. . tx 

tX(?) 1. Lambe............. 1. 1901 ......... . 2. Sternberg. 2. 1876. 3. Brown. 4. 1877. 4. Isaacs. 6. Cope. 

Lambe ................ 1901. ... · ....... .. 

Sternberg............. 1876 ........... .. 

1. Lambe ............. 1. 1901 ......... . 2. Sternberg. 2. 1876. 

t. Dawson ............ 1873-74 ........ .. 

3. Brown .............................. . t. Riggs. · t. 1905. 

tl. Lambe............ 1. i901 .......... 

t. HatchE'r............ 1903 ........... .. 

.................... t. Hatr~her ............ 1900 ............ . 

t. Hatcher............ 1889 ............ . 

t. Lambe ............. 1901 ........... .. 
STRATIGRAPHY OF THE MONTANA GROUP. 123 

(" Ilell Creek beds" and" Ceratops beds"), and Denver and Arapahoe formations-Continued. 

J_,ocallty and stratigraphic po- sition as givun by tho authors 

cited. 

1. Dolly lliver series, Rod Door 

Hiver, A lborta. 

2. Judith River formation, 

Montana. a. Hell Crook, Mont. 

4. LammioofConvorsoCounty, 

Wyo. tG. Lignite bods of Colorado 

!Cross (U.S. Oool. Sun·oy Mon. 27, p. 244) gives tho 

horizon as probably Arap- ahoe. In a personal com- munication to tho writer 

~N 13 ·v;A~~~~t~so:~~:r;~~ are known to occur in tho 

Lammlo of the Denver 

Basin." Cross's interpre- tation of tho horizon Is 

therefore probably right.] 

t. Bolly llivor series, Rod 

Door ltivor, Alberta. 

t. Judith River beds, M:on- tnna. 

1. nolly River series, Rod 

Door River below Berry Crook, Alberta, and Willow Crook subdivision or tho Laramie. 

t2. Judith H.ivor bod~ Mon- tana. [Also by l:itanton 

and Hatcher in tho same formation.) 

Material on which determination is based.-

1. Fragments of right hypo- plastral, and margin of 

carapace. 2. Fragments of eostals. a. Fragment of a costal and 

,Peripheral (Hay, Joe. cit.). 4. 1' ragments or costal and 

plastral. 

tG. Two fragments, a verte- bral and sternal, which 

constitute the type. 

t. Several costals representing a part or the carapace. 

Founded on unsatisfactory 

~:~~i~~·w~~~)l ~~~e~o~a~~ referred tothetype. These 

fragments are probably costal plates. 

1. By Lambe, portions of a plastron and anterior half 

of shell. 

t2. Founded on carapace and 

plastron. 

t. Bolly llh•or series, sL'C miles t. Two small, poorly pre- west of tho first branch of served fragments of costal 

Milk lllvcr nonr Intitude bo~es. 

40° and between longitude 112° and 113°. 

a. Hell Crook, Dawson County, a. Fragments of epiplastral Mont. lip. t. Cora tops bods, Chalk Buttes, t. Wllole shell. near Powderville, Custer 

County, Mont. 

tl. Belly lliver series, Red 

Deer lllver below Berry Creek, Cnnada. 

Judith Hiver beds, Willow 

Creek, Mont. 

1. Part of a carapace, also the 

anterior end or a plastron 

f:~~a~ai~rJ~~f.~g to the 

An imperfect carapace and the 

greater portion of a plas- tron. 

Authority and reference. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 2, p. a8, 

1902. 

2. Hay, Fossil turtles of North Americl_\~ p. 248~ 1908. 

Cope, u. S. Geol. and 

Geog. Survey 'l'err. Bull. a, p. 57a, 1877. a. Brown Am. M:us. Nat. 

Hlst. Bull., vo1.-2a, p. 82a, 

1907. 

4; Hay, Fossil turtles or North 

America p. 248, 1908. 

t6. Cope, U. S. Geol. and 

Geog. Survey Terr. Bull. 

1, No. ~; p. ao, 1874. 

Hatcher, u.S. Oeol. Survey Bull. 257, p. 75, ~905. 

t. Lambe, Contr. Canadian 

Paleontology, vol. a, pt. 2, 

p. 42, 1902. 

Hay, Fossil turtles of North 

America, p. 2a1, 1908. t. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 257, 1876. 

1. Lambe, Contr. Canadian 

Paleontology, vol. a, pt. 2, 

p. a9, 1902. 

2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 257, 1876. Hatcher, U. S. 

Geol. Survey Bull. 257, p. 76, 1905. 

Remarks. 

This species was also reported from the mouth 

of Bighorn River, Mont. Hatcher thinks 

Lambe's determination of the Belly River 

specimens may be incorrect. Hay (loc. cit.) 

says: "It Is unsafe to identify as belonging to A docus lineolcitus specimens from the 

Judith Hiver and Laramie [Lance) beds 

before far better materials * * * have 

been collected from the type locality [Bijou Creek, Colo.] * * * It Is improbable that the species continued from 

the Judith-River epoch to the Arapahoe epoch." · 

Hay (loc. cit.) says that the species is rounded on very unsatisfactory material, that the 

fragments described belong to more than one species, and that better material will 

be required to determine the structure and 

generic position of Cope's C. imbricarius. 

Eugene Stebinger, of the U.S. Geological Survey, who has recently mapped the area from which Dawson obtarned the type specimen or B. ogmius, says that the beds are undoubtedly of Belly River age. The 

material obtained by Dawson was very fragmentary. Hay (op. cit. p. 229) says: "It is doubtful whether new materials 

could be identified by means or the type.'' 

t. Dawson, British North B. ogmius is made a synonym of B. variolosus 

AmericaBoundaryComm. by Hay (Joe. cit.) and Lambe (op. cit., 

Rept., p. 1ao, 1875. p. a9.) 

a. Brown~.-. Am. M:us. Nat. 

Hlst. jjUII., vol. 2a, p. 82a, 

1907. Hay, Fossil turtles 

of North America, p. 229, 

1908. t. Riggs, Field Columbian 

Mus. Pubs., Geol. ser., vol. 2, p. 249, 1906. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, p. 44, 1902. Hay, Fossil turtles or North America, p. 62, 1908. 

Hay, Carnegie Mus. Annals, 

vol. a, 1906; Fossil turtles 

of North America, p. 60, 

1908. 

Cora tops beds, Converso County, W~·o., south side or Lance brook, opposito the 

mouth of Doogie Crock. 

t. A carapace and plastron t. Hay, Carnegie Mus. Annals, A specimen from Red Deer River (Belly River 

nearly complete. vol. 1, p. a25, 1902; Fossil formation), Canada, referred by Lambe to 

J .. aramie deposits, Converso 

County, 'Vyo., between 

Lance and Buck crooks. 

Cast of the greater portion of 

the interior of the shell; the 

greater part of the central 

portion of the carapace and most of the left side, and a large part of the plastron. 

turtles or North America, this speCies has since been referred to p. 6a, 1908. Boremys pulchra. 

t. Hay, Am. Jour. Sci., 4th 

~~ssii ~~~ie¥" ;?\/;~~ America, p. 63, 1908. 

Belh• River series, mouth or The anterior half of the earn- t. Lambe, Ottawa Naturalist, 

:berry Creek, Red Deer pace and the complete vol.19, p. a2a, 1906. H!).y, Originally referred by Lambe to Baena hatcheri, later to B. pulchra, and finally to the pres- ent genus and species. Hay also describes 

it as Boremys pulchra. 

lliver, Alberta. plastron. Fossil turtles of North 

America, p. 92, 1908. 
124 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly Judith 

River for- River formation. mation. 

3 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

5 6 

"LaraLance mie" for- Denver 

for- · mation, and Arap- mation, Black ahoe forWy- • Buttes, mations, 

oming. Wy- Colorado. 

oming. 

Finder. Date. 

--------------1-------------------1---------:-------1 

CHELONIA-COntinued. 

Compsemys obscura Leidy ................................ . X 

Compsemys victa Leidy ................................... . X 

Aspideretes beecheri Hay ....................... . X X 

Aspideretes (Trionyx) foveatus (Leidy). - X tx X 

. .......................... ~ .. 3. Brown ............. 3. 1902 ......... . 

X X(?) 

tx 

X 

t. Hayden. 1855 or earlier. 

3. Brown . . . . . . . . . . . . . 3. 1902 ......... . 4. Isaacs, Hatcher. 4. 1877. 6. (?). 6. (?). t. Hayden. t. 1855 or earlier. 

2. Hatcher....... . . . . . 2. 1889 ......... . 3. Brown. 

t4. Hatcher and 

Beecher. 

1. Lambe............. 1. 1901 ......... . t2. Hayden. 3. Brown. 6. (?). 

Aspideretes? (Trionyx)vagans (Cope).. . . . .. .. . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . tX(?) t6. Cope, Hayden ..... 6. 1873 ......... . 

Aspideretes splendid us Hay •.................... tx Sternberg............. 1876 ............ . 

Aspideretes granifer Hay_ ........................ · tx Hatcher ............... 1887 ............ . 
STRATIGRAPHY OF THE MONTANA GROUP. 125 

("Hell Greek beds" mul "Ceratops beds"), mul Denver and Ar~pahoejormations-Continued. 

Locallty·and stratl~raphlc po- Material on which determina- ~m~j~ as given by he authors tion is based. 

3. If ell Creek, Dawson County, 3. Tho proximal ends of two Mont. costals. t. I.ong Lake, N. Dak. [In t. Type part of a costal plate. 

beds now regarded as Lance formation.] 

3. Hell Crook, Dawson County, Mont. 4. Lance Crook, Wyo. 0. Nort11cast Colorado, prob- ably llljou Creek, m1)en- vor or Arapahoe formation. t. Long J .. ake, N. Dak. [In 

beds now regarded as Lance forlnation.] 

3. Fragments including the 

right peripheral and the outer extremity of the hy- poplastron. 4. A right costal and a neural. t. A neural and parts of two costals. 

2. Jnsh·Crcok, Mont., south of 2. Two carapacEis. Mussolsholl lUvcr. 3. Not given. 3. llcll Crook Mont. t4. A nearly complete indit4. r .. anco Crock, Converse vidual. 

County, Wyo. 

1. l3elly River series, Red 

Door H.ivcr, Alberta.· 

t2. Judith !liver bods, Montana; also ncar Long Lake, 

N.Dak .. from Laramie. 

3. Hell Crock:, 1\font. 0. Certltops beds near Doover, 

Colo. 

tO. Lignite Crotacocus (probably Arapahoe formation, 

according to Cross, U. S. 

~u~ti g~~ke~o ~~~:~s ;z~i or })onver, Colo. Laramie 

formation1 ncar mouth of 

l3lghorn Jtive!J Mont., and 

Long Lake, .N. Dak., by Hayden. 

1. Anearlycompletecarapace, 

also hyposternal.and plas- tral bones. 

t2. Several costal and sternal 

plates. 3. 'l'hree neurals and portions of costals. 

6. Notgiven .. 

tO. A number of fragments of 

costals and sternals. 

Authority and reference. 

3. Brown~.-. Am. Mus. Nat. . Hist . .Hull., vol. 2il, p. 823, 

1907. Hay, Fossil turtles 

of North America, p. 235, 

1908. t. Leidy, J\cad. Nat. Sci. Philadelphia Proc., vol. 8, p. 

312, 1856. 

3. Brown, Am. Mus. Nat. 

Hist. Bull., vol. 23, p. 823, 

1907. Hay, Fossil turtles 

of North America, p. 233, 

1908. 

4. Hay, op. cit., p. 234. 

6. Hay, op. cit., pp. 233, 234. t. Leid;y, Acad. Nat. Sci. 

Philadelphia Proc., vo.l. 8, 

p. 312, 1856; Am. Philos. 

Soc. Trans., 1860, p. 153. 

Cross, U. S. Geol. Survey Mon. 27, p. 227, 1896. 

2. Hay, Carnegie Mus. Annals, vol. 3, p. 178, 1905. 

3. Brown~,.. Am. Mus. Nat. 

Hist . .Huli.~.-P· 842, 1907. 

t4. Hay, Am. Jour. Sci., 4th ser., vol.-18, p. 224, 1904. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 33,1902. 

t2. Leidy, Acad. Nat. Sci. 

Philadelphia Proc., vol. 8, 

pp. 73, 312, 1856; Am. 

Philos. Soc. Trans., vol. 

11, p. 148, 1860. 

3. Brown Am. Mus. Nat. 

Hist. Bull., vol. 23, p. 842, 

1907. Hay, Fo~sil turtles 

of North Amenca, p. 488, 

1908. -- 6. Marsh, U. S. Gepl. Survey Mon. 27, p. 527, 1896. 

tO. Cope, U. S. Gaol. ·and 

Goog. Survey Terr. Ann. 

Rept., p. 453, 1874. 

t. Judith Hivor basin, Mont. Alargebutimperfectcarapace. Hay, Fossil turtles of North . America, p. 490, 1908. 

JudithH.lvcrbods,Cowlsland, Nearly complete costal and 

Mont. ·fragments or other costals. 

Hay, U. S. Nat. Mus. Proc., 

vol. 35, pp. 168-169, 1908. 

Remarks. 

This species is included .in Osborn's Montana 

list (Contr. Canadian Paleontology, vol. 3, 

pt. 2, p. 12 1902), and in Peale's Judith 

River list (Jour. Geology, vol. 20, 1?· 754, 

1912), presumahly on the authonty of 

Cope's list (U. S. Geol. and Geog. Sur¥ey 

ro;~is Bo~~ai~eS· i~\~ ~~~f t~~ei"I~~~~ River." Cope's descriptions of the species are given in Am. Philos. Soc. Trans., vol. 

14, p. 124, 1869; U. S. Geol. and Geog. Survey Terr. Bull. 1, No. 2, p. 30, 1874; U. S. 

Geol. Survey Terr. Rept., vol. 2, p. 261, 

1875. In each of these descriptions Cope cites Leidy's original description, in which 

the locality is given as Long Lake. Clearl;v 

Cope did not fmd any specimens of this 

species in the Judith River collections. 

The reference of this species to the Judith River 

formation by Peale is based on the same authority as the preceding species, theremarks concerning which apply here, ex- cept that in the Am. Philos. Soc. Trans., 

vol. 14, p. 124, 1869, Cope gives the locality as "Bad land, Judith River, Nebr.," but, as in the other references cited, he refers to Leidy's original description, in which the 

locality is given as Long Lake. Cope 

has absolutely no record of having found 

this species in the Juaith River formation. 

It is also doubtfully reported by Cope from a locality south of Woody Mountain, 

Canada (British North America Boundary 

Comm. Rept., p. 33, 1875; U.-S. Geol. Survey Terr. Rept., vol. 2, p. 261, 1875). 

Knowlton (Washington Acad. Sci. Proc., 

vol. 13 1911) regards the formation as Lance, hence there is no basis for including this species in the list from the Judith 

River formation. 

2. Hay (Joe. cit.) says that it may belong to a distjnct species. . 4. The species was also collected by Marsh from 

the "Laramie" (Lance) of Wyoming, but was called by him Trionyx foveatus. 

2. Also reported in Cope's collection from the 

'Judith River basin (Hay, Fossil turtles of 

North America, p. 488, 1908). 

3. Hay (Joe. cit.) says: "Had they been found 

in the Judith H.iver formation they would 

without hesitation be referred to A. (ove- atus. * * * Only a complete shell of 

this Laramie form will settle the questions involved." '!'here is therefore doubt as to 

}~~~~\?~:~=~~ification of the specimens 

6. Hay (Joe. cit.) says that this probably belongs to A spideretes beecheri. 

Hay (Joe. cit.) refers Lambe's specimen of T. 

vagans to Aspideretes coalescens. 

Cope's reference of T. vagans to the Judith 

River formation may have been based on this specimen (Acad. Nat. Sci. Philadelphia Proc., p. 9, 1875; U.S. Goo!. and Goog. Survey Terr. Bull. 3, p. 573, 1877). 
126 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6._:_Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly Judith 

River for- River formation. mation. 

3 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black ahoe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. Date. 

-:--------------·------------------------·1---------1-----'----1 

CHELONIA -continued. 

Aspideretes (Plastomenus) coalescens 

(Cope) Hay. 

X 

Plastomenus costatus Cope ......... ~ ............ , ......... . X 

1. Lambe and McCon- 1. 1897, 1898, and 

nell. 1901. t. Dawson. t. 1873 or 1874. 

3. Brown .. . .. .. .. . .. . 3. 1902. t. Dawson. t. 1873? 

Plastomenus punctulatus Cope........................................................... tX(?) Cope .................. 1873 ............ . 

PlastomenusinsignisCope ........................................ :·· .............. _...... tX(?) Cope._ ................. 1873 ............ . 

Eubaena cephalica Hay.......................... ... . . .. .. . . .. .. . . . . . tX .................... Hatcher ............... (?) ............. . 

Eubaena latifrons Hay .......................................... ~... X .................... Brown ................................. . 

Tbescelus insiliens Hay.............................................. tx .................... Brown ................................. . 

Helopanoplia distincta Hay............ .. . . . . . .. . . . . .. .. .. . . .. . .. . . . . tx .................... Hatcher ............................... . 

Gyremys spect~bilis Hay ................... , .... . tx Sternberg............. 1876 ............ . t. Isaacs. 

Polythorax missouriensis Cope......... . . . . . . . . . . tX ......................... · ....................................... 1876 ............ . 

Glyptops depressus Hay .......................... ·......... . . . .. .. . . . . .. . . . . .. . . .. .. .. . .. tX(?) Cannon............... 1889 ............ . 
STRATIGRAPHY OF THE MONTANA GROUP. 127 

("Hell Creek beds 11 and" Ceratops beds"), and Denver and Arapahoejonnations-Continued. 

Locullty unci strutigmphic po- sition as given by tho uuthors 

cited. 

1. Bolly Hivor series, Hod 

Door llivor, Canada. t. Sonth or Woody Mountuin, 

Cn.nada, lutltudo 49°, longi- tude between 10G0 and 107°. 

[In bods rogurcled by Knowlton as tho oquiva- lon t of tho La nco formation.] 

3. Hell Crooki 12 miles south of 

Missouri .liver, Mont. t. South of Woody Mountain1 Canada, samo locality ann .horizon as Aspideretes (Plastomenus) coalescens, 

ubovo. 

Northeastern Colorodo, prob- ably Bijou Crook. lSoo comment by G. 13. HIChardson under Adocuslineolatus.] 

Materiul on which determinution is based. 

1. In 1897 part of dorsal and 

ventrol shields. In 1901 a campace originally described as Trionyx vagans. t. Type a part of the plastron, insufficient for final generic determination. Hay says that Cope erred in thinking a part of this belonged to the carapace. 

3. Caropace and plastron, 

parts of each. t. Fragments of a costal and a hypo plastron too fragmentary for final determination. 

Frogments of a costal plate. 

Northeastern Colorodo, prob- t. Frogment or the hypoplas- ubly Bijou Crock. rsco tron. comment by G . .B. R1char<lson under Aclocuslineolatus.] 

Laromlo or Converso County, ·A fino skull. 

Wyo. 

Laromio of Sovonmilo Crock, A skull without tho_Iower jaw. Weston County, Wyo., 5 

miles north or Cheyenne Uivor and 40 miles north- west or Edgemont, S. Dak. 

Authority and reference. 

1. Lambe.{ Ottawa Naturalist, vol: 1;51 p. 68, 1899; Contr. 

Canadian Paleontology, vol. 3, pt. 2, p. 3!!J 1906 ( T. 

vagans). Hay, .Ji·ossil tur- tles of North America, p. 438, 1908. t. Cope, British North America Boundary Comm. 

Hept.,p.23711875. Knowlton, 'Vashrngton Acad. 

Sci. Proc., vol. 13, pp. 53-

54. 

3. Hay, Fossil turtles of North 

America, p. 468, 1908. t. Cope, British North America Botmdary Comm. 

Rcpt., p. 334, 1875; U. S. 

Geol. Survey 'l'err. Rept., vol. 2, p. 94, Pl. VIII, fig. 8, 1875. 

t. c~~~¥: s. r?:~~· a~~~~~ Ann. hcpt. 1 p. 453{ 1873. 

Hay Fossil turt es of 

North America, p. 468, 

1908. Knowlton1 Washington Acad. SCI. Proc., 

vol. 13, p. 56, 1911 .. 

t. Cope, U.S. Geol. and Geog. Survey Terr. Seventh 

Ann. Rept. 1 p. 4531 1873. 

Hay Fossil turtles of 

North America, p. 468, 1908. . 

Hay1 .Fossil turtles of North 

America, p. 82, 1908. t. Hay, Am. Jour. Sci., 4th scr., vol. 18, p. 263, Pl. 

XII, 1904. 

Hay1 Fossil turtles of North 

America, p. 83, 1908. 

JJuromlo of Sovonmile Crook, 

Weston County, Wyo., 5 

miles north or Cheyenne llivor and 40 miles north- west or Edgemont, S. Duk. 

A verycomplctospccimenprc- t. Hay, Fossil turtles of North 

:Lance Crook, Converso County, Wyo. 

sonting both caropace and America, p. 95, pls. 24-25, 

plastron. 1908. 

A fragment of a costal plato and a portion of a hypo- plastron or hyoplastron. 

t. Hay, Fossil turtles of Noith 

America, p. 485, pl. 88, figs. 4, 5, 1908. 

t. Judith River deposits, Mon- Complete plastron and part of t. Hay, Fossil turtles of North tanu. a cam pace. America, p. 288, pl. 44, 

figs. 1, 2; text figs. 357, 358, 

1908. 

Remarks. 

1. Hay (loc. cit.) provisionally refers Lambe's 

speCimens of Trionyx vagans and Plas- tomenus coalescens from the Belly River 

formation to this genus and species. t. Knowlton (loc. cit.) regards the formation 

from which Cope's type specimen was obtained as Lance instead of Belly River or Judith River. Until the specific charac- ters and geolo~ic horizon of the specimens referred to this species are accurately determined it can not be positively asserted 

whether or not this species occurs in both 

the Belly River and Lance formations. 

No weight can be attached to the specimens of 

this and the preceding species obtained 

south of Woody :M:ountain, because them~­

terial, according to Cope (loc. cit),· is "too 

frogmentary for final determination, and 

the geologic horizon is doubtful. Hatcher 

regards it as Bell1. River; Knowlton (loc. cit.) as Lance. 'I he preceding sfJccics has 

~~~nt~~~~~~~ :o~et~~~~~~ ~ i~e.r only 

Cope also reports the species from the vicinity of 

Long Lake, N. Uak. (probably Lance]. 

The species was also included in the Judith 

River [Belly River] by Hatcher, but 

Knowlton (loc. cit.) has pointed out the . error in Hatcl;ler's reference. 

The reference or this species to the Judith Hivcr 

by Hatcher was an error.· See Knowlton, 

op. cit., p. 56. 

Fort Union bods, Montana. 

[Sec remarks on Ceratodus 

{Rhineastes) eruciferus p. 111).] 

Plastron, carapace, mandible, 

and some other material. t. Cope, Acad. Nat. Sci. Phila- Hatcher (U. S. Geol. Survey Bull. 257, p. 77, 

delphia Proc.;+ vol. 28, p. 1905) says that the species is fOtmdcd on 

Denver bods (?). . t. Fairly complete caropaco and plastron. 

258, 1876. .1:1ay, Fossil ample material. 

turtles of North America, 

p. 100, 1908. 

t. Hay, Fossil turtles of North 

America,·p. 55, 1908. 
128 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution o..f vertebrates in the Belly River, Judith River, Lance 

1 2 3 4 5 6 

"Hell "LaraCreek Lance mie" for- Denver 

Species. Belly Judith -beds" for- mation, andArap- Finder. Date. 

River for- River for- (Lance mation, Black ahoe formation. mation. forma- W,y- Buttes, mations, 

tion), ommg. Wy- Colorado. 

Montana. oming .. 

---------------- RHYNCHOCEPHALIA. 

Champsosaurus annectens Cope ....... . X tx 1. Lambe ............. 1901 ........... .. M:acoun. 1880. · Dawson. 1881. 

Weston. 1884. 

2. Not given. 

Champsosaurus brevicollis Cope ..... : ... __ .. __ .. _ tx 2. Cope •......... : .... --.. -........... --

Champsosaurus profundus Cope ..... _ .. ___ . _____ _ tx 2. Cope (?) •..•...••................•.•.. 

O),j' ..... 

Champsosaurus vaccinsulensis Cope .... ___ .. ____ _ tX 2. (?) ....... ~ .......................... .. 

Champsosaurus ambulator Brown ..... __ ............ .' .... _ tx Brown ................ ~902 ............ . 

Champsosaurus Iaramiensis Brown. __ . _______ .. _______ :. __ tx ................... _ .......... Brown ................ 1902 ........... .. 

Champsosaurus sp .................. __ . X X . . . . . . . . . . . . . . . . . . . . 1. Gilmore ....................•......... 

SQUAMATA. 

Chamops segni:;! Marsh .................... _ ...... _ ........ _ ...... _ .. _ tx Hatcher ............................... -

Coniophis precedens Marsh ......................... ___ .... T ....... .. tx __ ·_ .. __ . __ ... __ ..... Hatcher .................. : ............. . 

Iguanavus teres Marsh ................... _ ........ _ .... _ ... _ .... _ ... . tx . _ . ___ . ____ . __ ... _ . . Hatcher .................... -..... -..... -

CROCODILIDlE. 

Brachychampsa (Bottosaurus) perru- .......... · ...................................... .. gosa (Cope). tX(?) 
STRATIGRAPHY OF THE MONTANA GROUP. 129 

("Hell Oreek beds" and" Ceratops beds"), and Denver and Arapahoe formations-Continued. 

Locality and stratigraphic po- sition ns given by the authors 

cited. 

1. l3olly Itiver soriosA Red Deer 

Itiver, Mackay vrcok, ncar · Walsh station, Canadian 

Pacific lly., on Belly Ttiver; Ross Coulee ncar Irwin station, Canada. 

2. Judith Uivcr bods, Montana, and l!"ox Hills [Claggott formation], Armells 

Crook (oast of Judith 

River), Mont. 

Material on which determination is based. 

1. A largo number of verte- brro, none of which wore found together in their 

t2. ~:~E:1 ~~~~~b~~o~~~~~~~- ing which Cope says he 

"can not certainly con- nect the vortebrro of a series as those of a single individual." Brown (loc. cit.) says that the speci- men gtves ~od generic 

~~~~1~!':~us~~w~Y:~~~ tor material from these 

beds. 

Authority and reference. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 45, 1902. 

t2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 351, 1876. Brown, Am. 

Mus. Nat. Hist. Mem., 

vol. 9, pt. 1, p. 6, 1905. 

2. Judith Uiver beds, Mon- t2. A weathered axis centrum t2. Cope, Acad. Nat. Sci. Phil- tana. ofan immature individual, adelphia Proc., vol. 28, p. considered invalid by 352, 1876. Brown, Am. 

Brown (loc. cit.). Mus. Nat. Hist. Mem., vol. 9, pt. 1, p. 6,.1905. 

2. Judith Ttiver l)eds, Mo.n- tana. t2. A sacral, a cervical, and 3 

dorsal vertebrre believed to belong to the same animal, and isolated verte· brre of separate individuals. Considered valid by Brown (loc. cit.). 

2. Judith River beds, Mon- 2. One-half or a vertebral cen- tana. trum which Brown (loc. cit.) refers to the order 

Plesiosauria. 

Hell Creek beds, Montana. Fairly complete skeleton. 

Hell Creek beds, Hell Creek, Nearly complete skull and , Mont. skeleton. 

1. l3eds of Belly River age Not given. (~ewo Medicine formation), Milk Uiver, Mont. 

4. J .. ammie deposits, Converse 

County, Wyo. 

Laramie of Wyoming. [Presumably Converse County.) t. Maxillary bone containtng teeth; various other parts of the skull and skeleton, 

including vertebrro, have 

beon found at different 

localities. 

t2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 350, 1876. Brown, Am. 

Mus. Nat. Hist. Mem., 

vol. 9, pt.1, p. 6, 1~. 

2. Cope1 Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 353, 1876. Brown, Am. 

Mus. Nat. Hist. Mem., 

vol. 9, pt. 1, p. 6, 1905. 

Brown Am. Mus. Nat. Hist. 

Bub., vol. 23,p. 829,1907. t. Brown, Am. Mus. Nat. 

Hist. Mem., vol. 9, pt. 1, Pf.· 4, 22-25, pl. 4, fig. 2, 

p . 5, figs. 3, 3a, 5, 5a, 6, 6a, 

14, 15, 1905. 

t. Brown, Am. Mus. Nat. 

Hist. Mem., vol. 9, pt. 1, 

pp. 4< §-22, pls. 1-5, 1905; 

Am. MUS. Nat. Hist. Bull., 

vol. 23, p. 842, 1907. . 

1. C. W. Gilmore, oral com- munication. 

4. Williston, Science, new ser., vol. 16, pp. 952-953, 1902. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 43, p. 450, 1892. 

Cerntops heds, Wyoming. A single vertebra, but several t. Marsh, Am. Jour. Sci., 3d 

other vertebrre that may ser., vol. 43, p. 450, 1892. not. belong to the same individual were found at the same locality. 

Laramie of Wyoming. [Prob- t. Vertehrro. 

ably Converse County.) 

6. Bastem Colorado. [Cross, (U.S. Oeol. Survey Mon. 

27, p. 244, 18!)6) regards the 

formation as Arapahoe. See also comment by G. B. 

Uichardson under Adocus 

lincolatus, 1>. 123. 

t6. Numerous fragments with 

vertebrro and portions of 

skull. -

t. Marsh, Am .. Jour. Sci., 3d ser., vol. 43, p. 450, 1892. 

t6. Cope, U. S. Geol. and 

Geog. Survey Terr. Seventh Ann. Rept., p. 452, 

1874. Hatcher, U.S. Geol. 

Survey Bull. 257, p. 82,. 

1905. 

,Remarks. 

2. Regarding the specimen from the so-called 

Fox Hills [Claggett formation), Cope (op. cit., p. 352) says: "l can not account for . this circun1stance as it is the most abundant fossil of the Judith River beds." As 

the Judith River formation is now known to overlie so-called Fox Hills conformably, the occurrence is not remarkable. 

13rown (Joe. cit.) says that C. brevicollis is 

invalid. 

Hatcher (U.S. Geol. Survey Bull. 257, pp. 81, 

~~e \~i) t~?t\~~s~h1~~f&e~ei;;e~ ?a~~g a;~ known almost exclusively from disarticulated vertebral centra, and considering the 

usually very simple structure of these 

throughout the entire vertebral column in 

this group, it may at present be considered 

difficult, if not unpossible, to distinguish the Judith River forms from one another or from the later Laramie forms.'' "It has 

yet to be shown that most of the characters 

mentioned by Cope as distinguishing his 

SJ?ecies are not present in vertebrre from 

different regions of the vertebral column in 

the same individual." 

The materia :described with the type listed was found according to Marsh at different 

localities. It is-not certain that it all per- tains to the same species. 

Referred provisionally to this genus by C. W. 

Gilmore. The specimen originally described by Lambe as B. pcrrugosus, from the Belly River formation, has since 

been referred by him to Leidyosuchus ca~ 

densis Lambe. 
130 SHORTER CONTRIBUTIONS TO GENERAL G~OLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

1 2 3 4 

"Hell 

Creek Lance 

Belly Judith beds" forRiver for- River for- (Lance mation, mation. mation. forma- W_y- tion), ommg. :Montana. 

Species. 

------------ CROCODIT.ID.E-continued. 

Brachychampsa montana Gilmore.... . . . . . . . . . . . . . . . . . . . . tx X 

Crocodilus humilis Leidy:............. . . . . . . . . . . tX ........... X 

Crocodilus sp .•............................................ X 

Deinosuchus hatcheri Holland .................. . tx 

Leidyosuchus sternbergi Gilmore ......................... . tx X 

Leidyosuchuscanadensis Lambe ..•.... tX 

DINOSAURIA. 

Zapsalis abradens Cope ......................... . X. X 

Troodon formosus Leidy .............. . X tx X 

Aublysodon mirandus Leidy .................... . tx X 

Paronychodon Iacustris Cope........... . . . . . . . . . . tx 

5 6 

''Laramie"for- Denver 

mation, andArap- Finder. Date. 

Black ahoe forButtes, 

Wy- mations, 

Colorado. 

oming. 

----

.................... t3. Brown ............................. . 

X 2. Hayden ............................. . 4. (?). 6. (?). 

Brown ....................•.............. 

Hatcher and Utter- 1903 ...•.•....•.. ·back. 

3. Brown .. -............................ . 4. Sternberg. 4. 1910. 

Lambe................ 1897, 1901. ••• : •.. 

2. (?) .•.••...........•.•.•...•••....•... 4. Hatcher. 

1. Lambe............. 1. 1901. .•....... 2. Hayden. 4. Hatcher. 

2. Hayden ............................. . 4. Hatcher. 
STRATIGRAPHY OF THE MONTANA GROUP. 131 

("Hell Creek beds" and" Ceratops beds"), and Denver and Arapahoe formations-Continued. 

'Locnlity nnd stratiftnphic po- Materinl on which determina- ~~~~od~ 1\S givon by ho authors tion is bi\Sod. 

3. Roll Crock bods, 25 miles t3. Tho greater part of a skull. 

southeast of LismM, Daw- son County, Mont. 

2. Bndlands of Judith River 

[Judith· River formntion], 

M:ont. 

4. Ccmtops bods, Converso · County, Wyo. 6. Ccmtops bods (on p. 527), nom· .Denver, Colo.; Den- ver formation (on p. 227). 

Hell Crook bods, Montana. 

t. Judith IUvor bedsi Willow 

Crook, Mussolshel County, Mont .. 3 miles west of NoInn & Archer's ranch (stage crossing to Flat Willow). 

3. Hell Crook bods; Gilbert 

Crock, Dawson County, Mont., 135 miles northwest 

of Miles City. 4. Corntops bods, Converse 

County, Wyo., north side 

of Cheyenne H.ivor, 3 miles west of McKeow's ranch. 

t2. Ton specimens of shed crowns of teeth. 

4. Not given. 6. Not given. 

Not given. 

t. Several scutes, 2 vertebrre, 

1 cervical rib, 1 dorsal rib, 

fragments of ribs and pu- bis, and several hundred 

fragments of bones belong- ing to the skull, vertebrre, , and ribs, all badly broken. 

t3. Greater part of skull. 

4. Greater pm"t of skull, left ramus almost entire, ante- riot· part of right ramus, 8 

vertebnc, both humeri, 

right fibula, metatarsal 

nnd other frngments. 

Authority tmd reference. 

t3. Gilmore, U. S. Nat. Mus. 

Proc., vol. 41, p. 297, 1912. 

t2. Leidy, Acad. Nat. Sci. 

Philadelphia Proc., vol. 

8, p. 73, 1856. 

4. Williston, Science, new 

~~~ . vol. 16, pp. 952-953, 

6. Marsh, U. S. Geol. Survey Mon. 27, pp. 227, 527, 1896. 

Brown, Am. Mus. Nnt. Hist. 

Bull., vol. 23, p. 842, 1907. 

t: Holland, Carnegie Mus. 

Annnls, vol. 6, p. 281, 1909. 

t3. Gilmore, U.S. Nnt. Mus. 

Proc., vol. 38, pp. 485-502, 

1911. 

4. Gilmore, idem, p. 497. 

Bolly :River series, Rod Doer t. A. left mnndibular ramus, t. Lnmbe, Roy. Soc. Cannda 

River, Alberta. posteriorpartofacranium, Trans., 3d ser., vol. 1, 

portions of the skull, teeth, sec. 4, p. 219, 1907. 

and n number of vertebrre 

and scutes. 

2. Judith River beds, Mon- 2. Detached teeth. tnnn. 4. Numerous small teeth. 

4. Lnramie bods, Wyoming. 

1. Bolly River sol'ies, Red 

Deer Hivor, below mouth 

of Berry Creek, Alberta. 

2. 13ndlands of Judith Hivor1 !l{ont. 

4. Laramie of Converso County, Wyo. 

1. Two teeth which agree in 

every pnrticular with Lei-

' 'dy's type. t2. A single tooth, which con- stitutes the type. 4. Teeth similnr to those described by Leidy. 

2. Cope1 Acad. Nat. Sci. Philadelphia Proc., vol. 28, 

p. 345, 1876. 

4. Hatcher, U. S. Geol. Survey Bull. 257, p. 84, 1905. 

1. Lambe, Contr. Canadian 

Pnleontology, vol. 3, pt. 2, p. 47, 1902. 

t2. Letdy, Acad. Nat. Sci. 

Philadelphia Proc., vol. 8, 

p. 72, 1856. . 4. Hatcher, U. S. Geol. Survey Bull. 257, p. 83, 1905. 

Reml\rks. 

4. "'L'eeth which can not be distinguished from , those of the type have been found in the 

Lance formation of Converse Countr., 

Wyo." (Oral statement by C. W. Gilmore.) 

2. Of Leidy's material Hatcher (U. S. Geol. 

Survey Bull. 257, p. 82, 1905) snys: "The 

simple conical teeth on which the species was based furnished no characters for the 

positive identification of other material." 

This species, therefore, seems to be of little 

value for correlntion. The material from 

the Belly River formation originally re- ferred by Lambe to this species was later 

referred by him to Leidyosuchus canadensis. 

(See below.) 

A dermal soute referred to this species was found by C. H. Wegemann in sec. 23, T. 

41 N., R. 79 W., Natrona County, Wyo., in the Parkman sandstone member of the 

Pierre formation, of Montana age (U. S. 

Geol. Survey Bull. 452, p. 48, 1911). 

Lambe says: "The jaw WI\S · originnlly described as Bottosaurus p_errugosns and the 

teeth 1\S Crocodilus humtlis." He now con- cludes that. all the materinl represents a · single species, to which he gives a new name. It thus nppears that L. canadensis replaces B. perrugosus and C. humilis in the Belly River list of Lnmbe and Osborn. 

4. Hatcher (loc. cit.) says: "The meager description given by Cope, without figures, renders it impossible to certainly identify 

any of the forms of teeth known from these 

deposits with those referred to by Cope in 

his deScription. * * * Their exact na- ture must, for the present at least, remain 

uncertain." 

Of this and the three succeeding genera Hatcher 

(U. S. Geol. Survey Bull. 257, p. 83, 1905) 

says: "They are all founded on such fragmentary material as to be of little value 

except as bearing evidence of the diversity of the fnunn." 

2. Badlands of Judith River, 

Mont. 

t2. Several problematical teeth t2. Leidy, Acad. Nat. Sci. 2. Probably synonymous with Deinodon ori~innlly included by Philndelphia Proc., vol. horridus. (See remarks on that species.) 4. Laramie of Wyoming. Leidy in his type of Dea- 20, p. 198, 1868. 4. Hcaotmchmer0

n(lobc0.tchit.m) satyse: J"uSdim.thilnr~ ~vooetrh "nnred 

nodon horridus. 4. Hatcher, U. S. Geol. Sur- h "' .. 4. Tooth. vey Bull. 257, p. 83, 1905. Laramie." 

l!~ort Union of Montana. [Bods t. Detnchod teeth with sub- t. Cope, Acad. Nat. Sci. Phil- now identified as J"udith conic crowns. adelphia Proc., vol. 28, p. River formation.] 256, 1876. 

Hatcher (U. S. Geol. Survey Bull. 257, p. 84, 

1905) regards this species as a synonym o A ublysodon mirandus. It seems probable therefore, that Dcinodon horrid us, A ublyso 

don mirandus, and Paronychodon lacustri are synonyms. Osborn (Am. M:us. Nat. 

Hist. Bull., vol. 5, p. 320, 1893) says tha 

the teeth described by Cope "resemble 

those which we have referred to as the 

probable lower incisors of Meniscoossus." 

Apparently on this ground alone Peale 

(Jour. Geology, voJ. 20, p. 720, 1912) hi\S ~f~l.uded P.lacustris in his Converse Count:~ 
-132 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution,oj vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly Judith 

River for- River formation. mation. 

3 . 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black aboe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. :date. 

-------------:--1----1-----------------1---------11-------1 

DINOSAURIA-COntinued. 

Deinodon horrid us Leidy ............. . X tx 1. Lambe............. 189JJ i901 ....... 2. Hayden. 2 . .Not given. 

Deinodon (Lrelaps) incrassatus Cope ... X tx 1. Lambe............. 1. 1897, 1898 ..... 2. Isaacs. 

Deinodon (Aublysodon) Iateralis Cope ........... . X Sternberg .............................. . 

Deinodon (Lrelaps) explanatus Cope ... X tx X 1. Lambe............. 1. 1901 .......... 2. (?). 

4. Hatcher. 

Deinodon (Lrelaps) falculus Cope ............... . tx Isaacs .•.•............................... 

Deinodon (Lrelaps) hazenianus Cope ............. . tx ..... ".: ....... X 2. Not given ........................... . 4. Hatcher. 

Deinodon (Lrelaps) Irevifrons Cope ............... . tx Not given .............................. . 

Deinodon (Aublysodon) amplus Marsh tx Hatcher ..... · ........................... . 

Deinodon (Lrelaps) cristatus Cope ............... . X tx 2. Not given ................ · ........... . 4. Hatcher. 

· Ornithomimus tenuis Marsh ................... .. tx Hatcher ......... : ..................... . 

. 
STRATIGRAPHY OF THE MONTANA GROUP. 133 

(''Bell Greek beds" and '' Ceratops beds"), and Denver and Arapahoe formations-Continued: 

J~ocnlity and strnti{,'I'aphic po- sltlonnsglvon by tho authors 

cited. . 

1. Bolly River series, Rod 

Door Itivor, Canada. 

2. Badlands of Judith H.ivor, 

Mont. 

1. Bolly River bods near mouth of Berry Crook, H.od 

Door Jlivor. 

2. Judith lUvor bods, Montana. 

Fort Union beds, Montana. 

1. Bolly H.iver series, Red 

Door H.ivor, Alberta, Canada. 

2. Fort Union (Judith H.ivor) bods, Montana. 

4. J~aramio formation, Wyo- ming. 

l~ort Unwn (Judith River) bods, Montana. 

Material on which determination is based. 

1. A number of teeth; a few 

phalanges and a metatar- sal are also probably re- ferred to this species. t2. A number of teeth. 

1. Separate teeth and terminal 

pbalanges. t2. Twoteethofdifferentsizes, 

found ncar each other but not sufficiently near to warrant the belief that 

thor belong to the same individual. 

Detached teeth. 

1. One small tooth. 

2. Numerous small tooth. 

4. Teeth similar to those described by Cope. 

Authority and reference. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 49, 1902. 

2. Leidy, Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 72, 1856. Osborn, Am. 

Mus. Nat. Hist. Bull., 

vol. 21, p. 261, 1905. 

1. Lambe, Ottawa Naturalist, 

vol. 131 p. 69, 1899; Contr. 

Canadian Paleontology, vol. 3, pt. 3, p. 5, 1904. 

t2. Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, pp. 248, 341, 1876. 

1 and 2. Hay, U.S. Nat. Mus. 

Proc., vol. 35, p. 356, 1909. 

Cope, Acad. Nat. Sci. Philadelphia Proc., vol. 28, p. 248, 1876. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 49, 1902. . t2. Cope, A cad. Nat. Sci. Philadelphia Proc., vol. 28, pp. 249, 344, 1876. 

4. Hatcher, U.S. Geol. Survey Bull. 257, p. 86, 1905. 

Remarks. 

2. The uncertainty regarding the material on which Leidy founded the type is shown by the fact that later (Acad. Nat. Sci. Philadelphia Proe. for 1868, p. 198) he referred 

part of the teeth to a new genus and species (Aublysodon mirandus); whereas Lambe 

(loc. cit.) says that Leidy's first determination was correct and that the teeth used at a later date for the foundation of the 

genus Aublysodon are probably the an- terior teeth of Deinodon. Osborn concurs in this view. 

Two skulls from the Edmonton formation of 

Knee Hills Creek, Red Deer H.iver, Canada, were originally described by Cope (Am. 

Philos. Soc. Proc., vol. 30, p. 240, 1892) as Lrelapsincrassatus. ln1904 Lambc(Contr. 

Canadian Paleontology, vol. 3, pt. 3, pp. 5-27) bestowed on these specimens the name Dryptosaurus incrassfLtUs. In 1905 

Osborn (Am. Mus. Nat. H1st. Bull., vol. 

21, p. 265) gave them the name Albcrtosau- rus sarcophagus. Whatever the final disposition of these specimens it is evident 

that they do not belong to Lrelaps in- crassatus. 2. Hatcher (U. S. Geol. Survey Bull. 257, p. 86, 

1905) says: "These teeth are probably from near the anterior and postenor extremities 

of the series in some representative of D. 

horrid us Leidy." 

Several teeth about half the t. Cope, Acad. Nat. Sci. Phil- Hatcher (U. S. Geol. Survey Bull. 257, p. 86, 

size of those of D. expla- , adelphia Proc., vol. 28, pp. . 1905) says that these teeth may represent natus. 249, 344, 1876. anterior teeth of D. cxplanatus. 

2. Judith River bods, Montana. t2. Several detached teeth t2. Cope, Acad. Nat. Sci. Phil- 2. Hatcher says that these teeth are common in 

4. I..aramioformation. fromdifTorentlocalities. adelphia Proc., vol. 28, p. the Judith River and Laramie [so-called] 

4. Teeth similar to those de- . 343, 1876. formations. "They appear to pertain to the 

scribed by Cope. 4. Hatcher, U. S. Geol. Sur- anterior dentition of some of these carnivJudith River bods, Montana. 

Coratops bods, Wyoming. 

Founded on a single tooth. 

Fotmded on detached teeth 

similar to those of Aublysodon mirandus, but 

smaller. 

2. Judith llivor beds, Montana. 2. Detached teeth. 

4. Converso County, Wyo.(?). 4. Teeth. 

Judith River bods, Montana. Part of a third metatarsal. 

vey Bull. 25Z, p. 86,1905. orousdinosaurs, probably of D. horridus." 

t. Copei Acad. Nat. Sci. Philado phia Proc., vol. 28, p. 344,1876. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 44, p. 174, 1892. 

Hatcher (U. S. Geol. Survey Bull. 257, p. 86, 

1905) says: "It [the tooth which consti- tutes the typel is distinguished by the absolutely smooth character of the anterior 

edge, a character of doubtful value." 

Hatcher (U. S. Geol. Survey Bull. 257, p. 84, 

1905) says that Marsh's A. am plus and A. 

cristatus from the "Cera tops beds" of Mon- tana and Wyoming are not properly described and should be abandoned that 

teeth similar to those figured by Leidy are common in both the Laramie [so-called] 

and Judith River formations, but that they are not sufficiently characteristic to distinguish either genera or species. 

2. Cope Acad. Nat. Sci. Phil- 2. Hatcher (U.S. Geol. Survey Bull. 257, p. 86, · adeiphia Proc., vol. 28, p. 1905) says that the teeth resemble those of 

344, 1876. Troodon and possibly pertain to that 

t4. Marsh', Am. Jour. Sci., 3d genus. ser., vol. 44, p. 174, 1892. 4. See remarks on D. am plus. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 3~J pp. 81-86, 1890. 

Hatcher, u. S. Geol. Survey Bull. 257, p. 87, 1905. 

Hatcher (loc. cit.) says that the genus Ornithomimus is represented by such meager ma- terial that as yet it is .quite impossible to determine many of the more import:.u1t characters of the ~onus or to compare the 

various species w1th one another satisfac- tori~y: 
134 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic dis_tribution of vertebrates in the Belly River, Judith River, Lance 

- 1 2 3 4 5 6 

"Hell "LaraCreek Lance mie" for- Denver 

Belly Judith beds" for- mation, andArap- Finder. Date. 

River for- River for- (Lance mation, Black ahoe formation. mation. forma- Wy- Buttes, mations, tion), oming. W_y- Colorado. 

Montana. ommg. 

Species. 

---------------- DINOSAURIA-continued. 

Ornithomimus gran dis Marsh ....................................... . X Hatcher ............................... . 

Ornithomimus velox Marsh ........................... _ .............. . X tX 4. Hatcher.. .. .. .. .. .. 4. 1889 ......... . 6. Cannon. · 

Ornithomiillus altus Lambe ........... . tx X 1. Hatcher ......... ~ .. 1. 1901 ......... . 3. Brown. 

'. 

Ornithomimus sedens Marsh ........................................ . tx 4. Hatcher.... .. .. . .. . 4. 1891 ........ .. 

Ornithomimus minutus Marsh......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . tx 

Tyrannosaurus rex Osborn ............................... .. X 

Palreoscincus costatus Leidy .......... . X tx 

Palreoscincus sp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ . X 

Palreoscincus asper Lambe ............ . tx 

Palreoscincus latus Marsh ........................................... . 

Stereocephalus tutus Lambe .......... . X 

N odosaurus textilis Marsh ............ . X(?) ................... . 

Ankylosaurus magniventris Brown .. :.: .................... . X 

X 

X 

X 

X 

tx 

tX 

3. Brown .. .. .. .. . . .. . 3. 1902 ........ .. 4. Brown, Sternberg. 4. 1900. 

1. Lambe.·............ 1. 1901 ......... . 2. Hayden, Hatcher. 4. Hatcher. 

3. Brown .............................. . 4. Williston. 

1. Lambe............. 1. 1901 .......... 4. Not given. 

Notgiven .............................. . 

1. Lambe ........ : .... 1. 1897 ........ .. 

1·. Lambe ............. 1. 1897, 1898 ... .. 4. Not given. 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kaisen................ 1906 ..••......... 
STRATIGRAPHY OF THE MONTANA GROUP. 135 

("Hell Creek beds" and " Ceratops beds"), and Denver and Arapahoe jorrn9-tions-Continued. 

Locality and stratigraphic po- Material on which determinasltlon as givon by the authors tion is based. 

cited. > 

4. Coratops bods, Wyoming. [Soo • Remarks."] 4. J~~~~r, o~!bi~k~~on ft~~ second metatarsal from 

another. t. A considerable portion of a skeleton, 

4. Coratops bods, Wyoming. 4. Not given. 0. Donvor bods, Groen Moun- G. Bones of the limbs and feet. 

tain, near Denver, Colo. 

1. Bolly River series, below 

Berry Crook, Red Deer 

:River, Canada. 

3. lioll Crook bods, Montana. 

4. Coratops bods, Wyoming. 

4. Coratops bods, Converse · County, Wyo. 

1. Complete right hind limb, 

including the foot the 

phalanges of tho left foot in 

place, a pubic bone, and an ischium. 

3. Not given. 

4. Nearly complete pelvis with portion of the tail. 

4. A sacrum, complete ischia, 

cervical, dorsal, and cau- dal vertebrre. 

3. Canyon or Hell Crook'-Mont.; t3. The larger part of a skeleSovonmilo Creek, 6 miles ton. north or Choyonne River, 4. Occiput and brain case, darWeston County, 'Vyo. rna plates, and many 4. Converso County, Wyo. parts or the skeleton. 

1. Bolly Uiver series, below 

Berry Crook, Ued Deer 

lUvor, Canada. 

2. Judith Uivor beds, Cow Island, Mont. 

4. Laramie formation. 

3. Roll Crook bods, Montana. 

4. Coratops beds, Converse 

County, Wyo. 

1. A few teeth. 

t2. Founded on a single tooth 

discovered by Hayden. 4. Teeth or the same general 

pattern as that described 

by Leidy. 

3. Not given. 4. Not given. 

1. Bolly River series, below 1. One tooth. 

mouth or Berry Creek, Red 4. Teeth. 

Door Hivor, Canada. 

4. IA\ramie Cretaceous of Con- verso County, Wyo. 

Coratops bods, Wyoming. 

Bolly IUvor series, Red Deer 

lUvor, Canada. 

1. Bolly River series, Ued Door 

Hivor, Canada. 

4. Middle Cretaceous of Wyo- ming. 

Hell Creek bods, near Gilbert 

Crook, 120 miles northwest 

of Miles City, Mont. 

A sing!~ tooth. 

1. Portion of a cranium, sautes< part or a rib, teeth ana · plates of several individ, 

uals. 

1. Uepresented by upper part or cranium and a number 

of dermal plates doubtfully referred to N. textilis. 

4. Various portions of the skeleton, but the skull not known. 

Skull with two teeth, scapula, and coraooid, vertebrre, 

ribs and dermal plates. 

Authority and reference. 

Marshi Am. Jour. Sci., 3d ser., 

Hatc~erPB:. ~.~~i. ~~~: vey Bulf. 257, p. 87,1905. 

4. Marsh, Am. Jour. Sci., 3d ser., vol. 43, pp. 449-453, 

1892. 

t6. Marsh, idem, vol. 39, pp. 81-86, 1890; U. S. Geol. 

Survey Sixteenth Ann. 

Uept., pt. 1, p. 205, 1896; 

U. S. Geol. Survey Mon. 

27, p. 518, 1896. 

tl. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 50, 1902. 

3. Brown~.-. Am. Mus. Nat. 

Hist. J:Sull., vol. 23, p. 842, 

1907. 

t4. Marsh, Am. Jour. Sci., 3d ser., vol. 43, pp. 451-452, 

1892. 

Williston, Kansas Univ. Quart.~ yo!. 7, pp. 173-174, 

1898. .M.arsh, Am. Jour. 

Sci., 3d ser., vol. 43, pp. 449-453, 1892. 

t3. Osborn, Am. Mus. Nat. 

Hist. Bull., vol. 21, p. 259, 

1905; vol. 22, p. 281, 1906. 

4. Osborn, Am. Mus. Nat. 

Hist. Mom., new ser.;vol. 

1, pt. 1, p. 4, 1912. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 53, 1902. 

2. Leidy, Am. Philos. Soc. 

Trans., vol.ll, p. 146, 1890. 

Hatcher U. S. Gl}ol. Survey Buli. 257, p. 88, 1905. 

4. Hatcher, idem. · 

3. Brown~.-. Am. Mus. Nat. 

Hist. J:Sull., vol. 23, p. 842, 

1907. 

4. Williston, Science, new ser., yol. 16, pp. 952-953, 

1902. ' 

tl. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 54, 1902. 

4. Williston, Science, new ser., vol. 16, p. 953, 1902. 

Marsh, U.S. Geol. Survey Sixteenth Ann. Rept., pt. 1, 1896, p. 225. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 44, p. 173, 1892. 

1. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 55, 1902. 

1. Lambe, Ottawa Naturalist, 

vol. 13, pp. 68-70, 1899. 

t4. Marsh, Am. Jour. Sci., 3d ·ser., vol. 38, p. 175, 1889. 

Brown, Am. Mus. Nat. Hist. 

Bull., vol. 24, pp. 197-201, 

1908. 

Remarks. 

The type of this species has also been accredited to the Judith Uiver formation, but Hatcher 

(loc. cit.) says that it was found in tho Eagle sandstone near the mouth of Cow Creek, 

opposite Cow Island, Missouri River, 

Mont., and that "hereafter it should be re- ferred to the Eagle formation," which is 

considerably older than the Judith River. 

4. C. W. Gilmore says that this specimen is 

probably referable to Osborn's Tyranno- saurus. 

1. Specimens believed by Lambe to belon~ to this species have been found at vanous places by several collectors; among the 

specimens are a costal vertebra and pha- langes from the Edmonton formation. 

The specimen originally described (op. cit., vol. 

21) as Dynamosaurus imperiorus is now included in T. rex. 

Hatcher (loc. cit.) says: "Teeth of the same general form and pattern as those described 

and figured by Leidy are common in the 

Judith River beds and in the Laramie. As 

yet they have only been found detached, so that nothing is positively known of the na ture of the animals to which they belonged." 

1. Hatcher (U.S. Geol. Survey Dull. 257, p. 89 

1905) says that the characters on which 

Lambe based his determination may be due to age or to the position occupied by the 

tooth in the jaw rather than to specific distinction. 

A specimen referable to this genus has also been 

found by C. W. Gilmore in beds of Belly River age (Two Medicine formation) on Milk RhTer, Mont. 

1. In a personal communication to the write 

C. W. Gilmore expresses the opinion tha 

the specimens referred by Lambe to Nodo saurus tettilis were afterward made the type or Stereocephalus tutus Lambe. 
136 SHORTER CONTHlBUTIONS TO GENERAL GEOLOGY, 1914. 

- TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

1 2 3 4 5 

"Hell "LaraCreek Lance mie" forBelly Judith beds" for- mat ion, River for- River for- (Lance mation, Black mat ion. mation. forma- W_y- Buttes, 

tion), ommg. W_y- Montana. ommg. 

Species. 

----------------

DJNOSAURIA-Continued. 

Thescelosaurus neglectus Gilmore ................... : . .............. . tx 

DINOSAURIA (CERATOPSID.IE). 

Agathaumas Sylvestre Cope ....... _._ ......................................... . tx 

. . Agathaumas' milo, syn. of Hadrosaurus 

occidentalis. .......................................................................... 

Dysganus ( 4 species) Cope ............. , ........ . 

Centrosaurus apertus Lambe ......... . tx 

~onoclonius crassus Cope ....................... . 

Monoclonius dawsoni Lambe .......... . tx 

Mono~lonius sphenocerus C_ope .................. . 

Monoclonius fissus Cope ......................... . 

Cera tops montanus Marsh ............ : ......... .' 

Ceratops (Monoclonius) recurvicornis · (Cope). 

Ceratops (Monoclonius) (Lambe). - canadensis tx 

X 

tx 

tx 

tx 

tx 

tx 

6 

Denver 

and Arap- Finder. Date. 

ahoe formations, 

Colorado. 

Peterson .............. 1889 ............ . t. Hatcher, Utterback. t. 1891. 

. . . . . . . . . . Meek . . . . . . . . . . . . . . . . . 1872 ............ . 

X(?) 

Cope and Hayden ...................... . 

Lambe.:-.............. 1901.. .......... . 

Cope.................. 1876 ............ : 

Lambe................ 1901. .... ~- ... ~ .. 

t. Sternberg ........ -.. 1876 ............ . 

Notgiven .............................. . 

X(?) t2. Hatcher ........... 2. 1888 ......... . 6. Eldri_dge.. 

t. Cope . . . . . . . . • . . . . . . t .. 1876 ........•.. 

t. Lambe.,_ .............. : ............. . 
STRATIGRAPHY OF THE MONTANA GROUP. 137 

("Hell Creek beds" and " Oeratops beds"), and penver and Arapahoe jormations-C~:mtinued. 

Locality o.nd stratiUaphic.po- Material on which determina- sition as given by hoauthors tion is based. cited. 

Lance formBtion, Lance Creek, t. A nearly complete articuConverse Cotmty, Wyo. lated skeleton, the skull ~eterson's specimen], and and neck being the only oegie Creek, Converse important parts missing. Catmty, Wyo. [type speci- men]. 

Near Black l3uttes station on Nine vertebrrn, includin! a Union Pacific R. R.hsouth- perfect sacrum with or- orn Wyoming, in t e Bit- sals and caudals; both tor Creek series of coals. iliac and other pelvic bones, some bones of the 

ribs, limbs, and other 

parts not determined. 

.................................. .................................... 

Judith lUver beds. Teeth supposedly belonging to four species. 

I , 

l3oll~ Hivor series, Red Deer liver~ Co.nada. Large posterior crest and nasal 

horn. 

t. NoBr tho bose of the Judith t. Teeth, caudal vertebrrn, 

Hiver beds, near the three cervicals, the fore 

mouth of BirCh Creek, Mis- limbs, tibia, ilium, sacrum, sour! Uiver, Mont. parietals, femur. . 

t. Bolly River series, Red t. Part of a skull. 

Deor River, below mouth 

of 13orry Creek, Canada. 

t. Noar Cow Islo.nd, Missouri 

lUver, Mont. t. Portions of premaxillary na- sals and nasal horn. 

Not given. t. A rifht pterygoid, incomple e. 

2. Noar top of Judit.h River t2. An occigital condyle and a bods, on Cow Creek, Mont., pair of ontal,horn cores. 10 miles above its mouth 

1U1d just below where the 

Cow Island-Benton road 

descends to the creek. 6. Arapahoe beds, near Don- vor, Colo. 

t. North sido of Missouri River t. Parts of the skull, including opposite tho mouth of Dog the frontal o.nd nasal horn 

Creek. cores. 

t. Bolly llivor beds, Red Deer t. Part of a skull o.nd a lowe 

lUvor, Canada, below the jaw. mouth of Berry Creek. 

Authority and reference. 

t. Gilmore, Smithsonian Misc. 

Coll.j' vol. 61, No. 5, pp. 1-5, 913. 

Hatcher, U. S. Geol. Survey Mon. 49, p. 105, 1907. 

Cop~~e s. ~~~. ange:C~~t Ann. kept., p. 448, 1874. 

Hatcher, U. S. Geol. Surv1. 

Bull. 257, p. 90if905; U. . Geol. Survey on. 49, p. 67, 1907. 

" 

t. Lambe, Ottawa Naturalist, vol. 18, pp. 81-84, 1904. 

Hatcher, U. S. Geol. .Surv1. 

Bull. 257, p. 91li905; U .. Geol. Survey on. 49, p. 71,1907. 

Hatcher, U. S. Geol. Surv1. 

Bull. 257, p. 91if905; U .. Geol. Survey on. 49, p. 89, 1907. 

Hatcher, U. S. Geol. Survey Mon. 49, p. 87,1907. 

Hatcher, U. S. Geol. Survey Mon. 49, p. 81, 1907. 

2. Hatcher, U. S. Geol. Survey Mon. 49 p. 100 1907. 6. Marsh, Am. l-our. Sci., 3d ~~. vol. 36, pp. 477-478, 

Hatcher, U. S. Gaol. Survey Mon. 49, p. 81, 1907. 

Hatcher, U. S. Geol. Survey 

r~~be 49coft~. ~Iilla~~~ Paleontology, vol. 3, pt. 2, 

p. 63, 1902. . 

Remarks. 

Mr. Gilmore has told the writer personally tha 

the ~enus at least is present in the "Rei 

Cree beds" (Lance formation) of Mon tan a. 

A. R. Schultz, of the United States Geologica Survey, ~asses the opinion that the bed 

in which t is specimen was found are o Cretaceous age. 

Cope says that the specimens came from Colo 

rado, but does not give their stratigraphi c position. 

Four species of thiS genus were described b 

C.ope. After carefully reviewing all th 

y 

e literature, Hatcher says: "I am convince d 

that the genus was based on teeth pertain ing to two or more genera, belonging in par to Trachodontidrn and in part to Ceratop 

sidrn. * * * In the absence of the typ specimens, * * * the imperfect natur of the material, * * * the lack of an figures or sufficiently exact description * ·* * I feel warranted in excludmg i 

e 

e 

y 

{; 

from the recognizable genera of the Cera 

topsidrn." 

The material on which this species is fotmde was first referred to .Monoclonius dawson 

d 

i 

by Lambe (Contr.Canadian Paleontology) but a later study or the material convince· d 

Lambe that two species had been include d 

under one name. 

Hatcher says that owfJ to the fragment nature of the mater· , the species ought t be discarded. 

ary 0 

6. Marsh (op. cit., p. 478) says: "Remains o .the same reptile or one nearly allied ha f 

d 

weviously been found in Colorado," by G . Eldridge. Lull (U. S. Gaol. Surve y 

y 

e Mon. 49, p. 183, 1907) doubts the accurac of Marsh's determination and says: "Th 

fragmentary nature of the fossil preclud accurate determination." Marsh als es 

0 

seems to have been in doubt as to the cor rect identificatjon of the Colorado spec! mens. On :{>3.!-!e 227 of U. S. Geol. Surve 

Mon. 27, he mcludes C. montanus in his lis 

of Denver and Arapahoe vertebrates, bu 

he omits it from a list on page 527, which, bu 

~ 

for this one omission, is a duylicate of th 

list on page 227. If the later 1st expresse Marsh's final views C. montanus should b 

t 

t 

e 

s 

e excluded from the list of Denver and Arapa hoe vertebrates. 
138 .SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of ver~ebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly Judith 

River for- River formation. mation. 

.3 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and ArapBlack ahoe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. Date. 

--------------1---'-------------------1---------1-------1 

DINOSAURIA (CERATOPSIDlE)-contd. 

Ceratops (Monoclonius) belli (Lambe-) .. tx 

Cera tops paucidens Marsh ....................... . tx 

Polynoax mortuarius Cope ............................... · .......................... ·.... .. . tx 

Triceratops alticomis Marsh............ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . tX 

Triceratops horrid us Marsh ......................................... . 

Triceratops serratus Marsh ....... : ........................ . X 

Triceratops obtusus Marsh.· ................... : . ... · ................. . 

Triceratops prorsus Marsh .............. : . ......................... · .. 

TriceratopS> brevicomus Hatcher ... : ...................... . X. 

Triceratops sulcatus Marsh .......................................... . 

Triceratops (Sterrholophus) flabellatus 

Marsh. 

Triceratops elatus Marsh ............................................ . 

tx X 

tx 

tx 

tx 

tx 

tx 

tx 

tx ··.········ ··:······· 

t. Lambe ............. t. 1898 ......... . 

t. Hatcher ............................. . 

Cannon, G. L.... ... . . . 1887 ............ . 

t4. Guernsey, C. A ..................... . Wilson, E. B. 

3. Brown, G., and Lull 

4. Beecher, C. E. 

Hatcher •................................. 

Hatcher ............... 1889 ........... .. 

3. Brown .............................. . 4. Utterback. 

Hatcher ................................ . 

Hatcher ......•.......................... 

Hatcher ................................ . 
,STRATIGRAP:qY OF THE MONTANA GROUP. 139 

(''Hell Oreek beds" and'' Oeratops beds"), and Denver and Arapahoejormations-Continued. 

T.,ocallty and stratigraphic po- sition as given by tho authors 

cited. 

t . .J3olly Hiver series, Red 

Door Uivor, Canada. 

t. Upper rnrt or Judith Il.iver 

~~i~s~i~1ifr~~~{1~10~~ ~~~~- from a spring nonr tho old 

. ~{~K~~~:~~~~\ f~~~:li~g~~h~~ from Judith post ofllco. 

Colorndo. (Probably from l3iJou Crook 40 miles east or Donvot· (Cross, U.S. Oool. · · · Survey Mon. ·27, p. 244, 

1896).] 

Material on \vhich determination is based. 

Tho greater par-t or the co_a- lescod parietals. 

A left maxillary and premax- illary. 

t. Vertebrre and fragments or limb bones. Hatcher (U. 

S. Gaol. Survey Mon. 49, 

p. 113, 1907) says that frag- ments supposed by Cope to pertain to the ischia are now known to he hom cores. 

Authority and reference. 

Hatcher, U. S.· Gaol. Survey Mon. 49;. p. 96, 1907. 

Lambe, vontr. Canadian 

Paleontology, vol. 3, pt. 

2, p. 66, 1902. 

Hatcher,. U. S. Gaol. Survey Mon. 49, p. 10~, 1907. 

Hatcher, U. S. Geol. Survey Mon. 49, p. 112~ 1907. Cope, U.S. Geol. ana Oeog. Sur- . vey Terr. Seventh Ann. 

Rapt., pp. 447-451, 1874. 

t:. ·J:>onvor ·hods, · banks or ·A pair of supraorbital' ·hom· 

Groen Mountain Creek, cores. · t. Marsh,· Am. Jour. Sci., 3d ser., vol. 34, p. 323, 1887; 

vol. 38, p. 174~}889; U.S. . Oeol. Survey .Mon. 27, pp. 512-527 1896. Hatcher, U. .. S. Goo\. Survey Mon. 49, 

pp. 104-115,168,170,1907. 

ncar Donvor, Colo. 

t4. J,nramio formation, Con- verso County Wyo. in a tl"lbutnry or huck Crook, nonr Johnson Bros.' sheep mnch. · 6. Com tops bods, near Denver, 

Colo. . 

:a. Hell Crook bods, Hell Crook · ' canyon, Mont:.~ 25 miles 

from Mlssourlltivor. 

t4. The greater part of a skull, 

including the horn cores and port:ions or tho lower 

Jaws. 

6. :Fragm~ntary ro~ains. 

3. Skull .. t4. A nearly perfect:skull. 

t4. Marsh, Am. Jour. Sci., 3d ser., vol. 37.t p. 334t.)889; vol. 38 p.17J, 1889. Hatch- er, U.S. Gaol. Survey Mon. 

49, p. 117,1907. 

6. Marsh, U.S. Geol. Survey Mon. 27, p. 527, 1896; Am. 

Jour. Sci., 3d sor., vol. 37, 

pp. ~34-335, 1889. 

1 3. Brown~,_ Am. Mus. Nat. 

Hist . .1:mll., vol. 23, p. 842, 

1907. Lnll,Am.Mus.Nat. 

Hist. Bull., vol. 19, p. 685, 

1903. 

t4. Coratops bods, Converse 

County, Wy9. 3 miles 

above mouth of Dry Crook, · · ··nom·"Jacob"Mills's sheep· · · ranch. 

t4. Marsh, Am. Jour. Sci., 3d · · · · 'SOr., ·vol.· ·39; pp. 80-82,· 

1890. Hatcher, 1J. S. Geol. 

Survey Mon. 49, p. 122, 

1907. 

Middle or Llll'amfo, Converso 

County, Wyo., 1 mllo east of Lnnco Crook and 2 miles 

southeast or U-L ranch. 

Ceratops bods, Wyoming, about 100 ylll'ds from locality for T. serratus. 

3: Hon·erook'hods, Montana. 

4. Ncar summit or Ll\l'amio 

formatlon\v Co n'v or so 

~bg~J~ho m~~th !ndj~~1 a milo south of Lightning Crook. . 

;coratops bods,: Converso 

I County~,_Wyo., divide bo- . twoon .Huck ·and Lance 

1 crooks. ; 

·Comtops bods, 1 Converso ; County, Wyo:, on a ridge 1 botwoon l3uck Crook and 

Lance Creek. 1 

Middle of Coratop's beds, Con- verso County, ·wyo., ono- . · · · fourt.h· milo ·cast· of· Jjance 

Crock, opposite mouth of 

Lightning Cro1

ok. 

I 

t. A portion of tho .skull and 

jaws and vertobrre. 

_t. A nearly perfect skull with 

lower Jaw. 

3. Not given. ·.. · .... 4. A nel\l'ly complete skull 

and considerable portion of the skeleton. 

t. Fragmentary skull, lower 

jaw, humerus, several ver- tebrre, and other parts or skeleton. 

t. Marsh, Am. Jour. Sci., 4th ser.1 vol. 6, p. 92, 1898. 

Hatcher, U.S. Gaol. Survey Mon. 49, p. 140, 1907. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 3~l pp. 81-86, 1890. 

Hatcher, u. S. Gaol. Survey Mon. 49, p. 127, 1907. 

3. Brown, Am. ·Mus. Nat. Hist. 

Bull., vol. 23, p. 842, 1907. 

4. Hatcher.t U.S. Gaol. Survey Mon. 411, p. 141, 1907. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 39, p. 442{ 1890 . Hatcher, U.S. Goo .. Survey Mon. 49, p. 133, 1907. 

t. A nearly complete but dis-· t. Marsh, Am. Jour. Sci., 3d 

articulated sk1,dl, asso- s~r., vol. 38, p. 174{ 1889. 

ciatod with several verte- Hatcher, U. S. Goo. Surbrre,a few limb bones, etc.· vey Mon. 49, p. 143, 1907. 

t. Left side or a skull, very I t. Marsh, Am. Jour. Sci., 3d 

complete, showing all.the. ser., p. 265, 1891. Hatcher, · important cranial ·charac-. · · · · · U: S; 'Geoi. Survey Mon. 

tors; also lower jaw (de-. 49, p. 134, 1907. 

tache d). 

37183°-15----10 

Remarks. 

Hatcher (loc. cit.) says: "Cope's description 

and figures demonstrate * * * the inadequate nature of the material upon which 

the genus and species were based. The name should be dropped from paleonto- logical literature.'' 

This species· was first described as ·Bison alticornis by Marsh (1887). Later (1889) he 

transferred it to the genus Ceratops. Hatcher (op. cit., p. 116) says that the 

affinities arc . certainly with Triceratops rather than w1th Ceratops. 
140~ SHORTER CONTR.IBUTIONS TO :GENERAL GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly Judith 

River for- River formation. mation. 

3 

"Hell 

Creek 

beds" 

(Lance, 

formation), 

Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black ahoe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. Date. 

~.,....,..,__~~~~-~~----.....,..~1--- -.-. -.-----. -.-----------1----:-------1-..,..,....-----1 

DINOSAURIA (CERATOPSID.E)-contd. 

To.rosaw·us latus Marsh.:······ ..................................... :. tx ·Hatcher ................ ! .............. . 

Torosaurus glad ius Marsh ........................................... . tx Marsh ................................. . 

Triceratops calicomis Marsh .................... :. . . . . . . . .. . . . . . . . . . .. tX .................... Hatcher ............................... . 

Triceratops galeus Marsh............... . .. . . .. ... . .. .. .. ... . .. ... .... ..... ... .. .......... tX Eldridge .................. · ............ .. 

Piceratops hatcheri Lull. ........................................... . tx Hatcher ............................... . 

Manospondylus gigas Cope............. .. .. .. .... . . .... .... . . ..... ... X(?) 

Claorhynchus trihedrus Cope! ............ : . .. : . . . X(?) ..................................................... , .......... ; ................ . 

Stegoceras valid us Lambe ............. . tx 

DINOSAURIA (TRACHODONTID.E). 

Trachodon mirabilis Leidy ........ ~ .. .. X tx 

Trachodon (Hadrosaurus) breviceps ......... . (Marsh). tX 

X. 

Lambe • .. . .. .. .. .. . .. 1898 ............ . 1901. 

1. Lambe ...•....... , .........••......... 2. Hayden.· 4. Hatcher, Wortman, 

Hill. 

····-:····· .................................................................................................... . 
STRATIGRAPHY OF THE MONTANA GROUP. 141 

("Hell Creek beds" and" Ceratops beds"), and Denver and Arapahoe formations-Continued. 

Locality and stratigraphic po- sition as given by tho authors 

cited. 

Comtops beds, about ·1 milo 

o!\St of U-IJ ranch, which 

is at tho junction of Lance 

and Dry crocks, Wyo. 

AmJb~11g.c beds.' ncar Brighton: 

Ccmtops beds, Converso 

County, Wyo., on tho 

north sido of Lightning Crock, about 2 miles above 

tho mouth of the stream. 

Laramie of Converso County, Wyo., on low divide be- tween Lightning and Cow 

crooks, about 1 mile dis- tant from tho mouths of 

those streams. 

.Laramie of South Dakota; 

v~~r~~Wl a~~o f~o~~vo~~~ County, Wyo. t. Laramie of South Dakota. 

Laramie. [No locality was 

rAi~~s ~lca~~r~~OI~~~c~ ~~ Dakota, but Osborn 

(Contr. Canadian Paleontology, vol. 3, pt. 2, p. 15, 

1902) has included it in his 

Montana list.] 

Bolly Hlvor series, Red Deer 

luvor, Canada. 

1. Bolly Rivor series, near mouth or Berry Crook, Red 

Door Hlvor, Canada. 

t2. Badlands of Judith River, 

Mont. 

4. ConvorsoCounty, ·wyo. 

t. l~ammlo [Judith River formationl, Boarpaw M:ountaius, :rirout. 

Material or, which determination is based. 

t. Skull with lo\vcr jaw, 11 

dorsal vcrtcbrre, several 

ribs,part of the pelvis, and 

other parts of the skeleton. 

Nasal horn core. 

Authority and reference. 

t. Marsh, Am. Jour. Sci.., 4th ser., vol. 6, p. 92, 1898. 

Hatcher, U. S. Goo!. Survey Mon. 49, p. 138, 1907. 

Marsh, Am. Jour. Sci., 3d ser., vol. 38, p. 174, -1889. 

Hatcher, U. S. Goo!. Survey Mon. 49, pp. 132-183. 

t. A skull without the lower Lull, U. S. G~ol. Survey Mon. 

jaw. 49, p. 149, 1907. 

A skull without lower jaw. Posterior part ofparietals, summits of horn cores, and 

parts of maxillaries arc wanting. 

A nearly complete parietal, left squamosal, horn cores, one cpijugal, the occipital condyle, and other parts or tho skeleton. 

t. Two dorsal vertebrro, of 

.which only ono can be 

found now. 

t. Hatcher, Am. Jour. Sci., 

4th ser., vol. 20, p. 4li, 

1905. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 42, p. 266, 1891. 

Hatcher, U.· S. Geol. Survey Mon. 49, p. 150, 1907. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 42, pp. 266-267, 

1891. 

Hatcher, U. S. Geol. Survey Mon. 49, p. 152, 1907. 

Hatcher, U. S. Geol. Survey Mon. 49, p. 113, 1907; U.S. 

Gcol. Survey Bull. 257, p. 96, 1905. t. Cope, Am. Naturalist, vol. 

26, p. 757, 1892. 

t. A rostral and predontary, Hatcher, U. ·S. Geol. Survey both of which are now lost. Mon. 49, p. 114, 1907. 

Founded on two cranial frag- Hatcher, U. S. Geol. Survey 

ments, probably belonging Mon. 49.1. p. 98, 1907. to two species. Lambe, vontr. Canadian 

Paleontology, vol. 3, pt. 2, 

1. Numerous maxillm and 

rami, some with teeth well 

preserved,as well as a large number of principal bones. 

t2. "Specimeps of teeth, gen- erally much worn and in a fragmentary condition." 

4. By Wortman and Hill, a · skeleton; by Hatcher, a skeleton. 

Part of a right maxillary with 

teeth well preserved. 

p. 68, 1902. . 

1. Lambe, Ottawa Naturalist, 

vol. 13, p. 69, 1899. 

t2. Leidy, Acad. Nat. Scj. Philadelphia Proc., vol. 8, 

p. 72, 1856. HatcherJ. U.S. 

Geol. Survey Bull. "L.57, p. 96, 1905. 

4. Hatcher, Carnegie Mus. Annals, vol. 1, pp. 382, 386, 

1902; Science, new ser., vol. 12, p. 719, 1900. 1 

Remarks. 

I 

Hatcher (op. cit., p. 132) says: "The extremely fragmentary nature of the material on which the species was based precludes the 

possibility.ofdefiningitadequatelv. * * * 

The species should be abandoned.>' 

Cope's origimil material came from South Dakota, not from Montana. (See Hatcher, 

U. S. Geol. Survey Bull. 257, p. 96, 1905.) 

Hatcher (U. S. Geol. Survey Mon. 49, p. 114, 1907) says: "A comparison of the ver- . · ·tebra still preserved with others from the same region in tho vertebral column but 

belonging to the skeleton of a carnivorous 

dinosaur probably pertaining to some species of Dryptosaurus, from * * * Con- verse County, \Vyo., * * * demon- strates conclusively that the remains upon which the present genus and species were based belonged to the Theropoda rather 

than the Predentata, and that It was therefore not a member of the Ceratopsidre." 

This species is regarded b~ Hatcher (op. cit.) as belonging to the 'lrachodontidm rather 

than to the Ceratopsidm, but he says that 

in the absence of the type matenal the 

affinities can not be established with cer- tainty. 

Hatcher does not include this species' in the 

Ceratopsidre. He thinks that it belongs to a hitherto unknown reptile, and that it will 

probably be found to belong to another 

order. 

1. Lambe (Joe. cit.) states that remains of this 

species have also been collected by F. G. 

McConnell from the Laramie [so-called] at Scabby Buttc1 on Red Deer :River. ' 

2. Hatcher (Joe. Cit.) says: "It is scarcely pos- sible· to identify the various species of this 

genus or the genera of the family [Trachodo#tidm] from the teeth alone." 

4. In Science, vol. 12, Hatcher refers to finding a skeleton of Claosaurus of which he describes the dermal covering but does no~ 

give the specific name. In the Carne~ie 

Mns. Annals, vol. 1, he credits Cope With 

having first described this covering from 

the same species, Trachodon (Diclonius) 

mirabilis. 'l'he assumption is therefore 

justified that Hatcher's Claosaurus from 

Converse ·County, \Vyo., is ·synonymous with T. mirabilis. 

Hatcher (Joe. cit.) says that the teeth resemble 

closely those of T. selwyni Lambe. 
142 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY., 1914. 

TABLE 6.-Geologic d1'stribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly ,Judith 

River for- River formation. mation. 

3 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

Lance 

formation, 

Wyoming. 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black ahoe forButtes, mations, 

Wy- Colorado. 

oming. 

Finder. Date. 

~~------------------------l------1-----------.--------------------l-----------------l------------~l 

DINOSA URIA (TRACHODONTID.lE)-cont. 

Trachodon selwyni Lambe ........ . 

0 

•••• tx Lambe ........................... ; .... . 

I 

Trachodon marginatus Lambe ........ . tx Lambe .........................•....... 

Trachodon altidens Lambe ............ . tx Lambe .•............................... 

Trachodon longiceps Marsh ...................................... .' ... . tx Hatcher ............................... . 

Trachodon (Hadrosaurus) paucidens . . . . . . . . . . tX(?) ....... -~ ............................... Hatcher ............................... . Marsh. 

Trachodon (Claosaurus) annectens ............................. . (Marsh). 

Trachodon sp ............................................. . 

Thespesius (Hadrosaurus) occidentalis 

Leidy. 

X 

X 

X 

X 4. Hatcher, Sternberg. 4. 1891 ......... . 6. Not given. 

Brown ................................. . 

X 4. Sullins . . . . . . . . . . . .. 4. 1891 ........ .. t. Hayden. 

Pteropelyx grallipes Cope. ; . . . . . . . . . . .. .. . . . . . . . . tX . ....................................... Isaacs ................. 1876 ............ ·. 

Cionodon stenopsis Cope •.............. tx Dawson ........................... · ..... . 

Cionodon arctatus Cope................ .... . . . .. . . . . . . . . . . .. . . . . .. . . . . . . . .. .. . . . . . . . . . . . . . tX Not given ................... , .......... . 

Diclonius pentagonus Cope ...................... . tx Not given .............................. . 

Dic)onius perangulatus Cope ..................... . tx Not given .............................. . 

Diclonius calamarius Cope •••••.................. tx Not given ..................... · .......... , 
STRATIGRAPHY OF THE MONTANA GROUP. 143 

("Hell Creek beds" and" Ce:ratops beds"), and Denver and Arapahoe formations-Continued. 

Locality and strntigrophic po- Material on which dE>terminasltlon as glvon by tho authors tion is based. 

cltod. 

Authority and reference. Remarks. 

Dolly Ulver sorlos. (Location not glvon.] 

Founded on teeth differing t. Lambe, Contr. Canadian Hatcher (Joe. cit.) says that this species may be 

from those or T. mirabilis Paleontology, vol. 3, pt. 2, a synonym ofT. breviceps. 

Dolly Uivor sorlosJ.. Red Deer 

lUver district, \Janada. 

~bov~ei~fte~~~~~!~in~~~ g·e~1: ~g;~e~~~fi~2J?; ~: ing in a point. 97, 1905. 

t. Lambe·,· Contr. Canadian 

Paleontology, vol. 3, pt. 2, 

p. 71,1902. Hatcher, U.S. 

Geol. Survey Bull. 257, p. .. 97; 1905:..... . .... 

Humerus, radius, ulna of left 

fore limb, a metatarsal and 

phalanges, fra~ments of 

teeth of one mdividual, 

~~~e;:~i~~l~Ed~~o~fa{~d ... 

Dolly Itlvor sorlos, Uod Doer A. left maxilla with the teeth. 

Ulvor ~l.lstrlct, Canad~. 

t. Lambe, Contr. Canadian 

Paleontology, vol. 3, pt. 2, .... :ii. 76,1902. Hatcher, u; S. 

Geol. Survey Bull. 257, p . . 98, 1905.· . . ... 

Laramie or Wyoming. A nearly perfect right dentary Marsh, Am. Jour. Sci., 3d ser., bone. vol.'39, pp. 422-424, 1890. 

Laramie of Montana. A left maxillarb nearly com- t. Marsh, Am. Jour. Sci., 3d f~~t:~J1.Pt erportions or ser., vol. 37,.p. 336,1889. 

. ~ .. L,~~!\roico!Convcrsc County, 4. By Hatcher:-a nearly co.m- • yo. plete skeleton. 6. Ccmtops beds, ncar Denver, By Sternberg-a nearly coni- . Col9. . . . 'plete sk:eleton. 

Hell Creek beds, Montana. 

4. Laramie of Wyoming. 6. Ccratops :ncar Denver, Colo. . t .. Gra:n.d. Hiver, N.e~J: .. (N. Dale) 

Notgiven. · · 

Not given. 

4. A nearly complete ekull and 

skeleton. 

6. Not given. 

4. Marsh, Am. Jour. S.ci., 3d 

ser:J vol. 43, pp. 449-453, 

189:.::. Osborn, Science, 

~~;. ser., vol. ~'· P.·. 793, 

6. Marsh, U. S. Geol. Survey 

Mon. 27, p. 227, ~~~!), .. 

Brown~ Am. Mus.·Nat. Hlst. 

Bwl., vol. .23, p .. ~2, 1907. 

4. Marsh, Am. Jour. Sci., 3d · ser:J vol. 43, pp. ~9-453, 

· ·189:.::. Hatcher, Am. Jour . Sci.,3d sei"., vol. 45~ p: 143, 1S93. 

6. Cope, U.S. Geol. and Geog. · ·Survey· · Terr. Sev'enth 

Ann. Rept., pp. 432-466, 

1874. Marsh, U. S. Geol. 

Survey Mon. 27, p. 527, 

1896. t. Leidy, Acad. Nat. Sci. Philadelphia Proc., vol. 8, p. 3ll, 1856. 

Hatcher (loc. cit.) says that this species is based on material pertaining to different species, 

genera, families, and even orders. 

The only locality given is Montana. The fossils 

.may have come from either the Judith 

River or the Lance formation, as Marsh 

referred to both formations as the Laramie . 

4. Marsh described the Wyoming and Colorado 

specimens as Claosaurus annecten8. 

t: Judith River beds, near A considerable portion ·or a t. Cope, Am. Naturalist, vol. · · · · · Cow Island, Mont. stckeetlhet.on without skull or 23, p. 904, 1889. Hatcher, 

i. };ort U:n1oi1 (?)·beds, :near Milk lUvcr ncar latitude 

49° lllld .bctwccn.Iongitudcs 112° and 113°. 

Colorado. 

Fort Union beds [JuditJ'I River 

formation], Montana. 

l!~ort Union beds [Judith River 

formation], Montana. . .. 

t. Maxillary and teeth. 

A tooth, two dorsal vertebrre, · distal en.d of. a femur witl;l the condyles well pre- served. 

Detached teeth. 

Detached teeth. 

Fort tiill{m. beds !Judith River Detached teeth. 

!ormation), Montana. 

U. S. Geol. Survey Bull. . 257, p. 98, 1905. 

Cope, Acad. Nat. Sci. Phila; ··Eugene Stebinger, of the United States Geologi- delphia Proc., vol. 28, p. 9, cal Survey, who has recently mapped this · 1876. . .... area, says that .the formation is undoubt- t. Dawson,· British North edly of Belly River age. AmericaBoundaryComm. 

Rept.~p. 130,1875. Hatch- er, U. 1:::i. Geol. Survey Bull. . 257' p .. 9\!,, ~Q05. . . . . 

t. C~~e, U. S. Geol. Survey · · I err. R~pt . .~,.vol. 2, pp. 57-

62, 1875. Hatcher, Carnegie Mus. Annals, vol. 1, 

p. 381, 1902. 

t. Copei Acad. Nat. Sci. Philade phia Proc., vol. 28, p. 253, 1876. Hatcher, U. S. 

Geol Survey Bull. 257, p. 99, 1995, 

t. Copei A~ad; Nat. Sci. Phil- .. ade ph.Ia I roc., vql. 28, p. 254, 1876. Hatcher, U. S. 

Geol. Survey Bull. 257, p. 99, 1905. 

t. Copei Acad. Nat. Sci. PP.ilade phia Proc., vol. 28, p. 255,1876; Hatcher, U.S. 

Geol. Survey Bull. 257, p. 99, 1905. 

Concerning this and the next two specil!s; Hatcher (loc. cit.) says the genus lS gen_. erally considered as a synonym of Trachodon. In the absence of any figures it is 

doubtful if any or the species are identi• 

fiable without access to the types; and as these are no longer determinable in the 

Cope collection, it would not be amiss to drop the specific names referred to this 

genus. 
144 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

TABLE 6.~Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Bellv Judith 

River for- River formation. mation. 

3 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

Lance 

formation, 

Wvommg. 

5 

"Laram·ie" formation, 

Black 

Buttes, 

Wyoming. 

6 

Denver 

and Arap- ahoe formations, 

Colorado. 

Finder. Date. 

----------------------------1-------l--------------------------l---~---l----------------l-------------l 

AVES. 

cimolopteryx ra~s Marsh ............... · ........................... . tx Hatcher ...........•.. : ......... .' ....... . 

Cimolopteryx retusus Marsh .................................... , ... . tx .......... .......... Hatcher ..•.............................. 

MAMMAUA. 

Ptilodus primrevus Lambe ............ . tx Lambe ................ 1901 ............ . 

Ptllodus sp ............................................... . X Brown ......................•........... 

Meniscoessus conq uistus Cope. . . . . . . . . . . . . . . . . . . . . ... : ..... X . ... ~----- .......... 3. Brown ...........................•.•.. 4. Hatcher. 

X 

t. Wortman. t. 1882. 

Boreodon matutinus Lambe .......... . tX . .... _ ........... __ .. · ............................. Lambe, Hatcher ...............•........ 

Cimolomys gracilis Marsh ............................................ . 

Cimolomys bellus Marsh ............................................. . 

Cimolodon nitidus Marsh •............................................ 

Nanomys minuttts Marsh ............................................ . 

Dipriodon robttstus Marsh ........................................... . 

Dipriodon lunattts Marsh ............................................ . 

Tripriodon crelattts Marsh. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . ........ . 

Tripriodon caperattts Marsh... . . . . . . . . . . . . . . . . . . . . . ... : . . . . . . . · ....... . 

Selenacodonfragilis.Marsh ......•..•.... .............................. 

Halodon sculpttts Marsh ............................................. . 

Halodon serrattts Marsh. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........ . 

Camptomtts ampltts Marsh ........................................... . 

Dryolestes tenax Marsh ........ · ..... ; .. .". . . . . . . . . . . . ......... 1 ••••••••• _ 

Didelphops (Didelphodon) vorax Marsh ........ ~ ..... '.: ............... . 

Didelphops (Didelphodon) ferox Marsh. . . ............................ . 

Didelphops 

Marsh. 

(Didelphodon) compttts 

X 

X 

X'. 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

X 

Hatcher ........................•........ 

Hatcher .......................••........ 

Hatcher ................................ . 

Hatcher· ............•••.........•...•.... 

Hatcher ................................ . 

Hatcher ........................•........ 

Hatcher ............................... . 

. ................... Hatcher .............. ·········•····.···· 

Hatcher .............................•.. 

Hatcher .......................•........ 

Hatcher .......................•........ 

Hatcher ............................... . 

.................... Hatcher ............................... . 

Hatcher ............................... . 

Hatcher ......•........................ ·. 

.................... Hatcher ............................... . 
STRATIGR£\PHX. OF THE MONTANA .GROUP. 145 

("Hell Creek beds" and " Ceratops beds"), and Denver. and Arapahoe formations-Continued. 

Locality nnd strnti~mphic PO· Mntcrial on which determina- ~~~~od~ ns given by ~he authors t.ion is based. Authority and reference. 

J ... aramic of Wyoni.lng. 

Laramie of Wyoming .... 

13clly River' series, RE:d Deer 

1Uvcr, Canada. 

Hell Creek bcds,.Montana. 

3. Hell Creek beds, Montana. 4. l~aramic formation. Lot. L~~~~i~ gi §~~~h Dakota. 

Belly 1~ivcr series, Red Deer 

1Uvcr, Canada. 

Laramie of Wyoming. 

Laramie of Wyoming. 

Laramie of Wyoming. 

Laramie or Wyoming. 

Larmnio or Wyoming. 

J ... aramio of Wyoming. 

Laramie of Wyoming. 

I ... uramio or Wyoming. 

J ... uramio or Wyoming. 

Laramie of Wyoming. 

J ... aramio of Wyoming. 

J ... aramlo of Wyoming. 

Laramio of Wyoming. 

Larmnio of 'Vyoming. 

Larmnio of Wyoming. 

Luramio of Wyoming. 

A coracoid bone. 

A left coracoid. 

An imperfect right mandible 

and ramus with fourth 

premolar and first molar 

attached. 

Not given. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 38, p. 83 (footnote), 1889; vol. 44, p. 175, 

1892. 

t. Marsh, Am. Jour. Sci., 3d ser., vol. 44, p. 175, 1892. 

Lambe, Contr. Camidian Paleontology, vol. 3, pt. 2, p. 

79, 1902. 

Brownt Am. Mus. Nat. Rist. 

Bull., vol. 23, p. 842, 1907 . 

3. Not given. 3. Brown~_ Am. Mus. Nat. t. 'J.'wo molars and a distal ex- Hist . .tmll., vol. 23, p. 842, 

tremity or a humerus. 1907. 4. Cope, Am. Naturalist, vol. 

16, p. 830, 1882. 

By Lambe, a single tooth. 

By Hatcher, a jaw. 

An upper molar. 

An upper molar. 

An upper molar. 

A number of very minute 

tooth, of which a single tooth is taken as a type. 

A loft upper molar. 

A first or second molar. 

An upper molar. Several 

lower molars were found 

with the type, but the as- sociation may be acciden-

-tal. 

A lower incisor, associated 

with other incisors and 

other tooth in various states of pro~ervation, 

An upper fragmentary molar. 

Fourth premolar of the lower 

jaw. Two incisors, prob- ably from the same spe- cies, are also represented. 

A lower molar. 

A scapula, with which are as- sociated several parts of a skeleton and fragments of 

tooth,. -- . ·•· ·- ... · 

A lower jaw which does not show the number or form 

of tho teeth. 

Lambe, Contr. Canadian Paleontology, vol. 3, pt. 2, p. 79, 1902. 

Marsht Am. Jour. Sci., 3d ser., VOl. 38, pp. 81-90, 1889. 

Marsht Am. Jour. Sci., 3d ser., VOl. 38, pp, 81-90, 1889. 

MarshiAm. Jour. Sci., 3d ser., vo. 38, pp. 81-90, 1889. 

Marshi Am. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

MarshiAm. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

Marshi Am. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

MarshiAm. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

MarshiAm. Jour. Sci., 3d ser., vo . 38, pp, 81-90, 1889. 

Marshi Am. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

Marshi Am. Jour. Sci., 3d ser., VO . 38, pp, 81-90, 1889. 

MarshiAm. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

Marshi Am. Jour. Sci., 3d ser., vo . 38, pp, 81-90, 1889. 

Marshi Am. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

Several tooth and parts of the MarshiAm. Jour. Sci., 3d ser., skeleton. vo . 38, pp. 81-90, 1889. 

A number of teeth, of which 

the lower molar is taken as tho type. 

Several teeth, of which the 

lower molar is taken as the 

typo. 

MarshiAm. Jour. Sci., 3d ser., vo . 38, pp. 81-90, 1889. 

Marsh, Am. Jour. Sci., 3d sor., vol. 38, pp. 81-90, 1889. 

Remarks. 

.... 

In Sciencet newser., vol.12,p. 719, 1900,Ratcher 

says tnat all the mammals obtained by him under the direction of Marsh came from Converse County, Wyo. Hence all 

.the succeeding species are from that gen- eral locality. The 17 genera and 28 species whose names are printed In italic in the list 

'(taken from -yarsh) have according to Osborn (Am. Naturalist, vof. 25, p. 609, 1891), 

been reduced to "four or five genera, one of 

which can no~v be well defined (Meniscoessus), while the remainder are probably distinct genera, which we may be able to define by the acquisition of more material 

(Cimolomys, Didelphops, and Cimolcstos). 

There is no question that the majority of t~e r01;naining generic names are synonyms, although it is quite possible that some of the t~pes described, such as Oracodon and Pedwmys, may be found to repre- sent distinct or new genera." The remaining species of the list have 

been reviewed by the same writer ( Am.Mus. 

Nat. Hist. Bull., vol. 5, pp. 311-330, 1893), 

with a considerable reduction in the num- ber of genera. 

From Osborn's reviews, cited above, it 

appears that many of Marsh's species· are synonyms or are established on inadequate matenal, and that the list should be greatly reduced. 

In· a personal communication to the 

writer J. W. Gidley refers 12 of these species to Ptilodus and 7 to M:eniscoessus and states that iare uncertain, leaving 9 specie's as probably determined correctly by Marsh. 
146 SHORTER CONTRIBUTIONS TO GENERAL. GEOLOGY, 1914. 

TABLE 6.-Geologic distribution of vertebrates in the Belly River, Judith River, Lance 

Species. 

1 2 

Belly Judith 

Riverfor- Riverformation. mation. 

3 

"Hell 

Creek 

beds" 

(Lance 

formation), 

Montana. 

Lance 

formation, 

Wyoming. 

I 

5 6 

"Laramie" for- Denver 

mation, and Arap- Black ahoe forButtes, mations, 

'YY- Colorado. 

oming. 

Finder. Date .. 

-------------1----·1----------------1--------1--....:._;~--1 

MAMMALIA -Continued. 

Cimolestes inci.ms Marsh ............................................. . X Hatcher ............. _ ...•........ : . .. , . 

Cimolestes curt us Marsh ............................................ · .. . X Hatcher ................•.... ·.; ... · ..... . 

Pediomys elegans Marsh ...................................... _ ... __ .. X Hatcher .............. ·····.············· 

Cimolomys digona Marsh ........................................... . X Hatcher ...•.......... 

Selenacodon brevis Marsh ............................................ . X Hatcher ............................... . 

Stagodon tumidus Marsh ............................................. . X Hatcher ...•......... :··.··-············· 

Stagodon nitor Marsh ...............................•..... _ . _ .... __ .. X Hatcher .......... ." ...•................. 

Stagodon validus Marsh ........................................... , .. . ·X Hatcher ..... · .......................... . 

Oracodon anceps Marsh ... : .............. ,_ ............... · ........ · ... . X Hatcher .... , .......................... . 

Oracodon conulus Marsh. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , ........ . ·x Hatcher ............................... . 

Allacodon lentus Marsh .............................................. : X Hatcher ...•.................... , ...... . 

:Allacodon fortis Marsh .............................................. . X Hatcher· ............................... . 

Allacodon pumilus Marsh .......................... · ................. . X Hatcher· ............................... . 

:Allacodon rarus Marsh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. -- ...... · X Hatcher ........................ _ ...... . 

-Halodori formosus Marsh .......................... , .... ~ .... · ........ . X .................... 

1 

Hatcher .......................... __ .... . 

Cimolodon parvusMarsh ........................................... . X Hatcher . . . . . . . . . . . . . . . ... __ .... _ ....... . 

Cimolodon agilis Marsh ............................................. . X Hatcher ........................ _ ...... . 

Telacodon prrestans Marsh .......................................... . X Hatcher ................................ . 

Telacodon lrevis Marsh ...................... , .................•...... X Hatcher: ............................... . 

Batodon tenuis Marsh ............................................. . X Hatcher ............. , ...• ___ .......... . 
STRATIGRAPHY OF THE MONTANA GROUP. 147 

("Hell Creek beds" and "Ceratops beds"); and Denver and Araphoeformations-Continued. 

Locality and strotlgrophic po- Material on which determinn- sltionns given by tho authors Authority and reference. tion is based. Remarks. 

cited. 

I 

I 

IJammlc of Wyoming. Several tooth in a good state of 

. r~,~~c::;f~ls t~~c~ ~: 

Marsh\ Am. Jour. Sci., 3d scr., vo . 38, pp. 81-90, 1889. 

typo. 

· Laramie of Wyoming. A molar with several other· Marshi Am. Jour. Sci., 3d ser.; . -· .... ,. . . ·~~··- ---~ __ ,.. - teeth. VO • 38, pp. 81-90, 1889. · 

IJammlo of Wyoming. An up&or molar .and other Marshi Am. Jour. Sci.,.3d ser.,. toot . vo . 38, pp. 81-90, 1889. 

Lnromio of Wyoming. A number of remains, of which Marsh\ Am. Jour. Sci., 3d ser . ., . an upper molar is most vo . 38, pp. 177-180, 1889. 

characteristic and is taken .. as tho typo. . . 

.. ········· Laramie of W yomlng. An upper molar with .other 

tooth. 

Marshi Am. Jour. Sci., 3d ser., . . vo . 38, pp. 177-180, 1889. .. , Laramie of W yomlng. A premolar attached to a por- tion of tho maxillary. 

MarshiAm. Jour. Sci., 3d ser., vo. 38, pp. 177-180, 1889. 

IJaramic of Wyoming. Several molars and premolars. Marsh\ Am .. Jour. Sci.. 3d sor., vo . 38, pp. 177-180, 1889. .. IJaramie of Wyoming. Anterior part of right lower 

jaw.· 

Marshi Am. Jour. Sci., 3d ser., vo . 43, pp. 249-261, 1892. -

IJnrmnic of Wyoming. A number of premolars. Marsh\ Am. Jour. Sci., 3d ser., VO • 38, pp. 177-180, 1889. ~ . .. . .. .. IJaramic of Wyoming. A single tooth. ·Marsh\ Am. Jour. Sci., 3d ser., · · VO • 431 pp. 249-261, 1892 . ····· ... 

.. IJammio or Wyoming. An up~er molar and ·other Marshi Am. Jour. Sci., 3d ser., teet , · several of which· ' ... vo . 38, pp. 177~180, 1889 . ... ,, ... were found together. . . .. .. '' 

.. ., 

Lnromio of V{yoming. Entire upper series of. molars Marsh i Am. Jour .. Sci., 3d ser., .. and premolars. . . . vo . 43,. pp. 249-261, 1892 . .. IJnromlo or Wyoming. Several tooth. Marshi Am. Jour. Sci., 3d ser., vo. 38, pp. 177-180, 1889. . . 

. IJarJ\~nle or Wyonling: A few isolated molar teeth. Marsh\ Am. Jour. Sci., 3d ser., vo . 43, pp. 249-261, 1892. HO o .. . . •' 

Laramie of Wyoming. A fourth premolar. Marsh\ Am. Jour. Sci., 3d ser., vo . 38, pp. 177-180, 1889. 

Laramie or Wyoming. Isolated remains, including Marsh\ .Am. Jour. Sci., 3d ser., tho anterior ~ortion of a vo . 43, pp. 249-261, .1892. 

lower jaw wit 1 incisors in 

place. . .. Lnromie Of Wyoming. Left.lowor jaw with one molar 

in place. 

MarshiAm. Jour. Sci., 3d ser., vo . 43, pp. 249-261, 1892 . .. . Lammic or Wyoming. . A lo,~er jaw, also a lower molar 

with other specimens. . Marshi Am. Jour. Sci:, 3d scr., v·o . 43, pp. 249-261, 1892. .. 

IJammio or Wyoming. A ritJht lower jaw, containing MarshiAm. Jour. Sci., 3d ser., hrco molars in place; a de- v<i . 43, pp. 249-261, 1892. 

tachcd upper molar and 

premolar also referred to this form. 

JJammio of Wyoming. A lower jaw with canine in Marsh\Am. Jour. Sci., 3d ser.; place and several other vo . 43, pp. 249-261, 1892. 

specimens. 
148 SHORTER CONTRIBUTIONS TO .:.GENERAL._GEOLOGY, 1914. 

Exclbsive of the mammals··135 species a~e- described. In Table 7 are brought together 

for c·on.venience of comparison all the forms given in Table 6 which have been reported to 

occur in more than one of the formations involved (the "Hell Creek beds," Lance of Wyoming, 

and Denver and Arapahoe being considered collectiv~ly ~s ."Ceratops beds").- Table 7 therefore shows at a glance the forms common to the Judith River -and Belly River, to the Judith 

River and "Cera tops beds," to the Belly River and "Cera tops beds," and to all three of theae 

~~:n:~!lo_t_t9~S. I~ ~~o _in_dic_!t_tes forms whose 'specific identific~tion ~or certain of the formations 

is in doubt. . -- - - -

TABLE 7.-Species common to two or more of the formations represented in Table 6 .. · 

[Specific names in italic indicate doubt as to specific identity of the form from that particular formation: For basis of doubt see Table 6, columns - "Material" and" Remarks."] · · 

Bell~ Ri:ver.formation. Judith River formation. "Ceratops beds."a 

Pisces (total species 9): 

1,ecriapteondsue8r aerlubec~t;enaruais .. _· . .. ......... - · .... ·.................................... Acipenser albertenais .......... ...................... Acipenser alber~ensis . ...,, ,

1 , Ceratodus er.uciferus .......................... ..... . Diphyoduslongirostris............................ Diphyoduslongirostris .................. ,.......... Diphyoduslongirostris. 

Lepisosteus ( Lepidotus) occidentalis.. . . . . . . . . . . . . . Lepisosteus ( Lepidotus) occidentalis. . . . . . . . . . . . . . . . Lepisosteus ( Lepidotus) occidentalis. 

Myledaphus bipartitus........................... Myledaphus bipartitus............................. .Myledaphus tJipartitus. 

Amphibia (total species 5): . Scapherpeton tectum............................ Scapherpeton tectum. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scapherpeton tectum. Plesiosauria (total species 3): . lschyrosaurus antiquum .. .. ~ ................. ,..... Ischyrosaurus antiquum. 

Chelonia (total species 29): . Adocuslineolatus ................................ Adocuslineolatus .................................. Adocus lineolatus. 

Basilemys variolosus. . . . . . . . . . . . . . . . . . . . . . . . . . . . Basilemys variolosus ...... , ............ ·. , ........ . 

Trionyx foveatus................................ 4:fo~;r;t{~:Ce:~:~~:::::::::::::::::::::::::::::::: ~:Fo~;:j~~~~~~~heri. Rhynchocephalia (total species 6): . Champsosaurus annectens....................... Champsosaurus annectens ........................ . Crocodilia (total species 6): Crocodilus humilis .............. ·.·................ Crocodilus humilis. 

Dinosauria (total species 74): Troodon jormosus. .. . .. . . . .. .. .. .. .. .. .. .. .. .. .. . Troodon jormoaus... . . .. .. . . . . . . . .. . . . .. . . . .. .. . . . . Troodon jormosus. Deinodon horrid us. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Deinodon horrid us ............................... . Deinodon hazenianus.............................. Deinodon hazenianus. 

Aublysodon mirandus.... . . . . . . . . . . . . . . . . . . . . . . . . Aublysodon mirandus. 

Deinodon incrassatus ............................ ~~y~:~~nap;:r~~~:tu~:::::::::::::::::::::::::::::: Zapsalis abradens. 

Deinodon explanatus............................ Deinodon explanatus............................. Deinodon explanatus. Deinodon cristatus................................. Deinodon cristatus. 

Omithomimus altus ................................................................................. Omithomimus altus. 

Palreoscincus costatus........................... Palreoscincus costatus............................ Palreoscincus costatus. Palceoscincus asper ..................................................... ~............................ Palreoscincus asper. Nodosaurus textilis ............................... ....................... .-............................ Nodosaurus textilis. 

Trachodon mirabilis ............................. Trachodon mirabilis .............................. Trachodon mirabilis. 

Ceratops montanus................................ Ceratops montanus. 

a The term "Ceratops beds" is here used to include "Hell Creek beds," Lance formation of 'Vyoming, and Denver and Arapahoe formation 

of Table 6. 

The forms reported to be common to the "Cera tops beds" and one or both of the other 

formations are classified as follows: 

Pisces.................................................................................... 4 

Amphibia ................................................ -.... ·.- .. -....................... 1 

Plesiosauria ............................. --- .. ---- .. --.- .. --- .. -.-.--- .. -- .. -- .. --- ... -.. -.. 1 

Chelonia ..................... - . - . - -·. - -... - - - - - - - - - . -. -.... - - . - . - - - . - - -.. .-- ... -... - - - . . . . . . 3 

Dinosauria (only one of which is a ceratopsian)............................................... 12 

Crocodilia ..................... - - . -.. - -... - - - - - - - - -... -..... -.... - -... - - - . - - -.. -........ - . . 1 

The distribution of these species according to geologic formations is as follows: 

Pisces.-Out of 9 species described 5 are common to the Belly River and Judith River, and 4 of these are also 

common to the "Ceratops beds." ' 

Amphibia.-0£ 5 species described there is but 1 that occurs in more than one of the formations, and that 1 is 

co·m~on to the- three foi-ID:ations·. · · 

Plesiosauria.-Out of 3 species described there are none common to the Belly· River and either of the other formations and only 1 common to the Judith River formation and "Ceratops beds." 

Chelonia.-Out of 29 species described 3 ~re common to the Judith River and Belly River, 2 of'which are also 

common to the Lance, and only 1 is common to the Judith River and Lance and not found in the Belly River. 

Rhynchocephalia.-Out of 6 species described 1 is common to the Belly River and Judith River, and none are 

common to either of these formations and the Lance. 

Squamata.-N o species in common. 

Crocodilia.-Of 6 species described 1 is common to the Judith River and the Lance, and none are common to 

either of these formations and the Belly River. 
'STRATIGRAPHY OF THE MONT!\..~A . .G:ROUP. J49 

Dinosauria.-Of 74 species described 6 are common to the Belly River and Judith River, 7 are common tq the 

Belly River and Lance, and9 are common to the Judith Riverancl.Lance. 

Table 8 is introduced for the purpose_of showing in a concise way, those forms whose speci:fi.c identification for the l.ocalities.indicatecl is doubtful. 

'!'ABLE 8.-Species whose identification, from certainjorrnaiions, is based on inadequate material. 

['l'he typo of the species may or may not, however, be based on adequate material.] 

Species. 

Belly 

River 

formation. 

Judith 

River 

forma-' 

tion. 

"Hell 

Creek 

beds.'' 

Lance 

forma-; 

tion, 

Converse 

County, 

Wyo. 

Denver 

and 

Arapahoe formations. 

Material. 

(See also "Remarks," Table 6.) 

-------------1----------------1-------......:.... _______ _ Pisces: . Aclponsor albortensls ... ~............ X 

Coratodus oructrorus.. . . . . . . . . . . . . . . . X 

Coratodus hioroglyphus ....................... . Diphyodus longirostris ........ :. . . . . X · Hodronchus sternberg if. ............... , ....... . J,oplsostous haydenL ......................... . Leplsostous (Lopidotus) occidental is. X 

Mylodaphus bipartitus ....... :. . . . . . X 

Plosiosauria: . Cimo)lasaurus magnus............... X 

Ischyrosaurus antiquum ..................... . 

Chelonia: 

Adocus llnoolatus .................. . 

Basllomys im bricaria .•.............. 

Aspidoretes beecher I. ......................... . 

X 

X 

X 

X 

X 

X 

X 

x 

X 

X 

X 

Aspidorete.'l (Trionyx) foveatus ......................... . 

Rhynchocephalia: · C~awpsosaurus brevicollls .................... . X 

Crocodilla: 

X 

Crocodllus hum ills ........ _ ....................................... . 

Dinosaur fa: 

Troodon formosus .....•... _ ........ . X X 

X 

X 

X 

X 

X 

Zapsalls ahrodons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 

Deinodon incrassatus................ . . . . . . . . . . X 

Dolnodon falculus. . . .. . .. . . . . . .. . .. . . . . . . .. .. . X 

Delnodon hazen ian us... . . . . . . . . . . . . . . . . . . . . . . . x X 

Delnodon lrovifrons ............................ · X 

Delnodon amplus ....................................... _ . . .. . . . . . . X 

Dolnodon crlstatus ........................ , .. . X X 

Palroosclncns nsper ................. . X 

Nodosaurus toxt:ills ................. . X 

Dysganus (Ceratopsldro) .................... , .. X 

M:onoclonlns flssns .......................... .. X 

X 

X 

Cera tops tnontanus.................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 

Dermal shield. 

F~!~h:,~~s of cranial bones and a dentigerous 

A dentigerous plate. A jaw with teeth scars. The crown of a young tooth .. A single scale. . A few scales, which Hatcher says are insufficient 

and of little value for correlation. 

A few simple isolated and detached teeth, which 

Hatcher says are too simple to identify either 

genera or species. 

Several vertebrre, which Hatcher says may pertain to another genus and species; in some respects they resemble Ischyrosaurus antiquum. Vertebral centra, which Hatcher says may belong to another genus; the material is too incomplete for accurate determination. • 

Imperfect fragments of cos talc;, regarded hy Hay as ·inadequate for identification. 

Three fragments, probably costals, regarded·as ''cry unsatisfactory and inadequate by Hay. 

Two carapaces, of which Hay says no characters are observed which distinguish them from A. beecheri; 

it is not improbable, however, that they belong to a distinct species. The Denver specimen may belong to A. beecheri. 

The ''Hell Creek" specimens consist of 3 neurals 

and portion<; of costals, of which Hay- says: "Had 

they been found in the Judith Rtver deposits, they would without hesitation be referred to A. 

fovtatu.9. Perhaps only the finding of a complete shell of this 'Laramie' form will settle the ques- tion involved." 

A single vertebra of an immature individual. Bar- num Brown says the species is invalid.· 

Type from Judith River was founded on the crowns of teeth, which Hatcher says furnish no characters 

for positive identification of other material. 

The type from Judith River is founded on a single tooth. Hatcher regards the material as insufficient. 

Small teeth, which Hatcher says can not be cer- tainly identified with the type. 

Two teeth, which Hatcher says probably belong to D. horridus. 

Detached teeth, which Hatcher says may be ante- rior teeth of D. explanatu.s. Detached teeth, which Hatcher says may be ante- rior teeth of D. explanatu.~. 

A single tooth, regarded as of doubtful value by Hatcher. ., Founded on teeth which Hatcher says do not afford 

characters for either generic or specific distinction. 

Detached teeth, which Hatcher says do not afford 

characters for either generic or specific distinction. 

Type, a single tooth, of which Hatcher remarks 

that the characters assigned to it may be due to age and not to specific differences. 

Part of cranium, at first doubtfully referred by Lambe to this species, but later to Stereocephalus tutus. 

Genus and four species founded on teeth pertaining in part to Ceratopsidro and in part to Trachodontidre. Hat-cher regards . the genus as · unrecog- nizable. 

A right pterygoid, so fragmentary that Hatcher 

says the species should be discarded. 

Lull regards the determination as a case of mistaken 

identity. Marsh, to whom the determination is 

attributed, does not include it in his last list of 

vertebrates from the Denver Basin. (See "Remarks," Table 6.) 
150 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

·TABLE 8.-Species whose identification, from certain formations, is based on inadequate material-Continued. 

Species. 

Belly 

River 

formation. 

Judith 

River 

formation. 

"Hell 

Creek 

beds." 

Lance 

formation, 

Converse 

County, 

Wyo. 

Denver 

and 

Arapahoe formations. 

Material. 

(See also "Remarks," Table 6.) 

--------------1----------------1------------------

Dinosauria--Continued. 

Polynoax mortuarius ...................................................... . X Hatcher says the name should be dropped from 

paleontologic literature. 

Triceratops galeus ............................. • ............................. . X Nasal hom core; material so fragmentary that 

Hatcher says the species should be abandoned. 

Trachodon marginatus ............. . X .. .. .. .. .. .. .. . . .. .. .. .. .. .. .. .. .. .. .. .. Based on material which Hatcher says pertains to different species, genera, families, and even orders. 

Diclonius pentagonns ..................... · .... . X 

X 

X 

...... .... .. ........ .. ........ collection. Hatcher says it is doubtful if any of !

Detached teeth, no longer determinable in the Cope 

Diclonius perangulatus ....................... . Diclonius calamari us ......................... . .................. · · .. .. .. .. .. the species are identifiable and that the specific ............................ · · names should be dr?PPed. . 

Mammalia. (See" Remarks," Table 6.) 

By combining part of the data in Tables i and 8, the number. of species reported to be 

common to the several forri:tations and also the number of these forms whose specific identification for either of the formations is ~.oubtful are· brought out in Table 9. 

TABLE 9.-Number of probably valid and doubtful forms common to the formations represented in Tables 7 and 8. 

Plesi- Rhyn- DinoPisces. Am- osau- Che- cho- Squa.- Croco- sau- Total. phibia. ria. Ionia. ceJ?h&- mata. dilia. ria. ha. 

- ------------------------ Species common to the Judith River and Belly {Total. ...... :--··· 5 1 0 3 1 0 0 6 16 Probably valid.: .. 0 1 ·0 2 1 0 0 4 8 · River formations. Doubtful.. ........ 5 0 0 1 0 0 0 2 8 

Species common to the Belly River and Lance {Total ............. 4 1 0 2 0 ·0 0 7 14 Probably valid .... 1 1 0 0 0 0 0 4 6 formations. . Doubtful.. ........ 3 0 0 2 0 0 0 3 8 

Species common to the Judith River and Lance {Total .... ···:····· 4 1 1 3 0 0 1 9 19 

Probably valid· .... 1 1· 0 0 '. 0 0 O' 4 6 formations. . Doubtful. ......... 3 0 1 3 0 0 1 5 13 

Table 10 gives a list of the species in Table 6 which are based on inadequate material and 

regarded as of doubtful validity, and Table 11 gives the forms that are probably synonyms. 

TABLE 10.-Species whose types are of doubtful validity. 

[For basis of doubt, see Table 6, columns "Material" and "Remarks."] 

Pisces: 

Acipenser albertensis. 

Cera tod us eruciferus. 

Ceratodus hieroglyphus. 

Diphyodus longirostris. 

Hedronchus sternbergii. 

Lepisosteus occidentalis. 

Plesiosauria: 

Cimoliasa urus magn us'. 

Chelonia: 

Basilemys imbricaria. 

· Rhynchocephalia: 

Cham psosa urus brev:l.collis. 

Crocodilia: 

Crocodil us h umilis. 

Ceratopsldre: . 

Dysganus (genera and species). 

Monocloni us fissus. · 

Polynoax mortuarius. 

Triceratops galeus. 

Trachodontidre: 

Trachodon mirabills. 

Trachodon marginatus. 

Diclonius pentagonus. 

· Diclonius perangulatus. 

Diclonius calamarius. 

All other Dinosauria: 

Troodon formosus. 

Deinodon falculus. 

Deinodon hazenianus. 

Deinodon lrevifrons. 

Deinodon amplus. 

Deinodon cristatus. 

Deinodon incrassatus. 

Palreoscincus costatus. 

Palreosclncus as per. 
STRATIGRAPHY OF THE MONTANA GROUP. 

TABLE 11.-Forms which are probably synonyms. 

[See "Remarks," Table 6.] 

Belly 

.River 

formation., 

Judith 

River 

formation. 

"Hell 

Creek 

beds.'' 

151 

Lance Denver fo~ma- and Araptwn, . ahoe 

Converse formaCounty, tions 

Wyo. · 

Authority. 

---------------------,------1------------1·---1------

Pisces: 

Loplsostcus occidcntruls. 

L. haydcni .............................. ,....................... .......... X ............................. . Chclonlu: 

llosilemys variolosus. 

B. ogmius....................................................... X ....................................... . Dinosauria: · Deh10don horrid us. 

~~~~r;~~~~o~~~~~r:fu::::::::::::::::::::::::::::::::::::::::: :::::::::: ~ .............. ~ ............. . Trochodon broviccps. · · 'l'.solwynl...................................................... X ....................................... . 'rhosposlus (Hadrosaurus) occidcntalis. · Agathaumas milo ............................................... , ............................ : ..................... . 

Hatcher. 

Hay. 

Osborn, Lambe. 

Hatcher. 

Hatcher. 

Cope. 

The preceding tables show that there are in all, as identified, 16 species, 8 of which are 

probably valid, common to the Belly Riv~r and Judith River; 14 species, 6 of which are probably 

valid, common to the Belly River and Lance; and 19 species, only 6 of wh~ch are probably 

valid, common to the Judith River and Lance. 

So far as the number of species identified as common to the various formations goes, the 

vertebrates furnish no :ri:lore basis for correlating the Judith River and the Lance than for. 

... correlating the Belly River and the Lance, but they do show a slight preponderance of evidence 

in favor of the correlation of the Judith River with the Belly River. On the other hand, a 

study of the generic and sp.ecific relationships of the ;vertebrate faunas from the three formations shows a closer relation between the faunas of the Judith River and the Belly River than 

between either of these and that of the Lance. This is especially true of the Ceratopsidre, 

which form so important an element in the faunas of these three foemations and which in the 

present state of knowledge furnish the most reliable and conclusive evidence of all the vertebrates. 

With regard to the Ceratopsidre, tbe preceding tables show that with one doubtful exception 

(Oeratops montanus) there are no species or even genera which are reported as common to the 

faunas of the Judith River and Belly River on the one hand and the Lance formation on the· 

other; and that there are two genera of the Ceratopsidre (Cera tops and Monoclonius) which are 

reported to occur in the Judith River and Belly River formations but not in the Lance, and 

two genera (Triceratops and Torosaurus) which are reported to occur in the Lance but not in the 

Judith River or Belly River .. 

The remarks in Table 6 on Oeratops montanus, which occurs in t:Q.e Judith 'River formation 

and has been reported as occurring in the Denver formation (supposed to be approximately 

the equivalent of the Lance), show that there is doubt J:egarding Marsh's identification of the 

specimen from the Denver formation. Oeratops mo:ntanus is therefore not certainly known to 

occur except in the Judith River formation. With this exception there is not a single instance 

reported in which Ceratops or Monoclonius has yet been found in the Lance formation, although 

these genera occur in the Judith River and Belly River formations. Similarly, not a single 

specin1en· of Triceratops or Torosaurus has yet been reported from either the Judith River or the 

Belly River formation, although these genera are abundant in the Lance formation. 

It therefore appears that" the Ceratopsidre, which, as stated above, ~orl}1: an important 

element in the fauna of the Belly River, Judith River, and Lance forma~ions, $how a closer 

generic relationship between the Belly River and Judith River faunas than between either of 

these faunas and that of the Lance formation. I~ m_ay be profitable now to consider briefly 

the genetic relationship of the faunas of the Belly River, Judith River, and Lance formations. 

Most if not all paleontologists who are familiar with the faunas of ~hese formations agree 

'that there is a closer genetic relationship between the faunas of the Judith River and Belly 

River than between the fauna o~ either of these formations and that of the Lance; also that 
152. SHORTER. CONTRIBUTIONS T9 GENERAL GEOLOGY, 1914. 

the Belly River and Judith River forms are more pr.imitive than. those occurring in the Lance. 

These conclusions are adequately expressed in the following quotations from Osborn and 

Hatcher. Osborn 1 says: 

It soon appeared to the writer, in .the study of the fine collection made by Mr. Lambe, that the Belly River 

vertebrates of the Northwest Territory were of decidedly different and apparently of older type than those from the 

Laramie beds of Converse County, Wyo., described by Marsh, and were rather to be compared with those described 

by Leidy, Cope, and Marsh, from Montana, chiefly from the Judith River beds, a region by no means distant geogra phi call y. * * * 

There is thus very little in common between the Belly River fauna and the Laramie fauna of Wyoming and 

Colorado, so far as described, except th~ dinosaur Ornithomimus and the very persistent chelonian Baena. · Most of 

the dinosaurs will probably be found to be separated generically. . 

On the other hand, so far as known, the Montana fauna has much in common with th·e Belly River, especially 

the Testudinata, Iguanodontia, and Ceratopsia. 

Hatcher's conclusions 2 are in part as follows: 

When considered in its ent~ety, the vertebrate fauna of these beds [Judith River] is.remarkably similar to 

though distinctly more primitive than that of the Laramie. *. * * . . It is in the Ceratopsidre more than in any other group that we are at present able to contrast the Judith River 

and Laramie forms. * * * The primitive nature of the Judith River Ceratopsidre, as compared with the Laramie, 

is ~specially seen in the smaller size of the individuals, the less perfectly developed armature of the skull, and the 

imperfectly developed parietal crest. * * * . Briefly, the Judith River fauna, it is clear, is descended from the Jurassic and is the direct ancestor of the 

Laramie. Its retations with the former are not close, and several groups are absent in the one which are present in 

the other. Its relations with the. Laramie are much closer, as should be expected, considering the stratigraphic 

position. With orie or two possible exceptions, all the families represented in either of these two later deposits are 

present also in the other. Although several genera and species now appear to b,e common to both these formations, 

it is probable that when more perfect material is available they will be found, in most instances, to .be quite distinct, 

though some pertaining to more persistent types may prove to be identical. In every case where any group of the 

fauna has been studied from sufficient material it has been found to be represented by distinctly older and more 

primitive types than the related forms from the Laramie. 3 

Ip a personal c·ommunication to the writer C. W. Gilmore, of the United States National 

Museum, says: · · · 

The more we come to know these faunas the more evidence there is that the Belly River and Judith River 

species are distinct from those of the Lance formation. If the fauna of the Belly River and Judith River were known 

from more adequate material,_ instead of the frag:Qientary material now at our disposal, the apparent conflicting evidence would no doubt largely, if not entirely, disappear. 

' A study of the lists of vertebrates reported from the formations under discussion renders· 

one of two conclusions inevitable. Either the vertebrates are of little value for close time 

correlation or the identification of the stratigraphic horizon or of the material is at fault. As 

shown in the "Remarks" column of Table 6, many of the identifications have been made on 

inadequate and insufficient material, and in this connection the comments of so eminent an 

authority as W. D. Matthew/ which· have appeared in print since the tables of this paper were 

prepared, are of special significance. Matthew says: 

Deinodon Leidy is determinable as to family ·but is not determinable generically, as the genera of carnivorous 

dinosaurs are now distinguished. The same is true of·a whole series of genera and species described by Leidy and 

Cope from.the Judith River. The treatment of types and referred specimens of these genera by paleontologists as 

specifically distinguishable or identical has sadly _misled Dr. Pea~e in his recen,t discussion of the vertebrate evidence 

as to the age of the Judith River beds, leading him to present as conclusive evidence of identity in age a correspondence in fauna, which to those who kn~w the nature 'of the specimens on which the lists are based is no evidence at all. 

It is also possible that thereP.was a confusion of stratigraphic horizons, especially in the 

assignment of the earlier colh~ctions, and until the type are~ of the Judith River formation 

(from which most of the ·vertebrate remains ascribed to that formation have been. collected) 

is mapped in detail on an adequate base of large scale it can not be asserted. tha~ all the species 

1 Osborn, H. F., Distinctive characters of the mid-Cretaceous fauna: Contr.·Canadian Paleontology, vol. 3, pt. 3, pp. 7, 10, 1902. 

2 U. S. Geol. Survey Bull. 257, pp. 101-103, 1905. 

s Osborn and Hatcher here used the term "Laramie" for the formation which the United States Geological Surv~y now calls the Lance.-

C.F.B. 

• Matthew, w .. D., The laws of nomenclature in paleonto~ogy: Science, new ser., v?l. 37, pp. _788-792, May 23, 1913. 
STRATIGRAPHY OF THE MONTANA GROUP. 153 

attributed to the for1nation really belong there.- The extensive faulting that has disturbed 

the strata along Missouri River renders it possible, though it is not extremely probable, that 

blocks of the Lance formation may be faulted down among the beds of Judith River age and 

that some of the vertebrates collected by Hayden and others "from the badlands of the Judith" 

n1ay have been obtained fr01n the Lance formation instead of the Judith River formation, as 

they supposed. 

SUMMARY A.ND CONCLUSION. 

I 

The stratigraphic and paleontologic evidence as to the position and age of the Judith 

River formation has been presented in the foregoing pages. It is shown in the discussion of 

the stratigraphy that the Judith River formation has been traced from areas where its position 

beneath ·the Bearpaw shale is undisputed into the western part of the type area (namely, at 

the mouth of Judith River) and has been found to be identical with the Judith River at that 

locality. It has also been shown that at some localities along Missouri River, especially on 

Cow Creek, Stanton and Hatcher found the Judith River formation overlain normally and in 

flat-lying attitude by the Bem·paw shale, though over most of the area along Missouri River 

the Bem·paw has been completely eroded. Similar stratigraphic relations between the Judith 

River and Bem·paw have been observed by the writer between Missouri and Milk rivers in the 

area lying east of the Bearpaw Mountains. 

The paleontologic evidence shows (1) that the marine sandstone of the Claggett formation 

in1mediately underlying the Judith River formation at the mouth of Judith River is no more 

closely allied to the Fox Hills proper than to the underlying Eagle. sandstone, and -therefore 

the argument that the Judith River formation overlies the Fox Hills is unfounded; (2) that the 

flora of the Judith River formation, so far a3 it has been determined, is of Montana age; (3) that 

the invertebrates of the Judith River formation are more closely allied to the Belly River than 

to the Lance; (4) that almost all the vertebrates that are common to the Judith River and 

Lu.nce are also common to the Belly River and Lance, and hence, if the Judith River is to be 

n1acle the· equivalent of the Lance on tha basis of the similarity of the vertebrate fauna, the 

Belly River must on the same evidence also be made the equiv~ent of the Lance formation; 

(5) that the Ceratopsidre, which form so important an element of the Lance fauna, are generically and specifically unlike the representatives of that family in the Belly River and Judith 

River faunas. 

The evidence of the vertebrate fauna, so far as in the present state of knowledge it has 

any weight, an'd the evidence of the fresh and brackish water invertebra.tes, so far as it is 

decisive for accurate time determination, indicate a closer relationship between the Belly 

River and Judith River than between either of ·~hese formations and the Lance. Thi8 is in 

accord with the stratigraphic evidence, which shows. conclu3ively that both the Judith River 

and Belly River formations are separated from the Lance by a marine formation which is of 

undoubted Cretaceous aga. 

/ 

0. 
.J.'. 
I 

'I'HE CRETACEOUS-EOCENE CONTACT IN THE ·ATLANTIC AND GULF 

COASTAL PLAIN~ 

By LLOYD vVrLLIAM STEPHENSON. 

INTRODUCTION. 

The Cretaceous deposits of the Atlantic and Gulf Coastal Plain are. separated from the 

overlying Eocene .and younger formations by an· un~onformity of regional extent. Several 

authors, including 1-Iarris/ Dall, 2 Vaughan, 3 and Hill and Vaughan, 4 have briefly described 

this unconformity and have stated some of the important facts in regard to the differences 

exhibited by the faunas on the two sides of the contact. The magnitude of these differences, 

however, has. not been sufficiently appreciated by geologists, notwithstanding the published 

staten1ents of the authors cited. Eighteen years ago Harris wrote with reference to the 

Gulf region: · 

Between tho basal Eocene deposits and the uppermost Cret.:'tceous there is in this section of the country a decided 

break both stratigraphic and faunal, so that not one species is known certainly to have crossed from one formation to 

tho other. At or immediately above this line an entirely new fauna makes its appearance upon the scene. 

Fourteen years ago (1900) Vaughan stated in, regard to the unconformity along Frio 

Ri~er, Tex., t-hat- , 

'!'hose data prove absolutely that there must have been a break in the sequence of sedimentation long enough to 

permit a complete faunal revolution. 

In 1909 Stanton 5 said: 

'l'he succeeding Tertiary faunas, whether on the Pacific coast, the Gulf bqrder, or the Athi.ntic Coastal Plain, 

show a very striking change from the Cretaceous faunas that immediately precede them. The specific types are 

practically all different. 

The object of this paper is to present additional data bearing on the contact and especially 

to emphasize its importance in the geologic history of the Atlantic and Gulf Coastal J>lain. 

TREND OF THE OUTCROP AND NATURE OF .THE CONTACT. 

With certain interruptions the unconformity is traceable from New Jersey to the Rio 

Grande and, according to Dumble,6 thence far southward into Mexico. In some places the. 

contact is overlapped and concealed by Miocene or younger formations, and in others it is 

obscured by weathering and the similarity of the materials immediately below and above the 

unconformity. But for the greater part of the distance, where the contact is not concealed 

by transgressing formations, it is sharp and easily recognizable. The sea in which the basal 

Eocene strata were formed advanced across a land surface which had reached an old or nearly 

base-leveled stage of erosion, as is shown by the almost,· horizontal or broadly uneven attitude 

of the contact, which, however, presents numerous minor irregularities. Throughout much 

t liarrls, G. D., Tho Midway stage: Bull. Am. Paleontology, vol. 1, p. 119, 1896, 

~ Dall, W. H., A tablo of North Americnn Tertiary horizons: U.S. Geol. Survey Eighteenth Ann. Rept., pt. 2, pp. 332-335, 1898. 8 Vauglmn, '1'. W., Reconnaissnnco in tho Rio Grande coal fields of Te..'\:ns: U.S. Geol. Survey Bull'. 164, pp. 35, 36, 1900; U.S. Geol. Survey 

Goo!. Atlos, Uvalde folio (No. G4), pp. 2, 3, 1900. 4 Hlll, R '1'., and Vaughan, T. W., U.S. Geol. Survey Geol. Atlas, Austin folio (No. 76), p. 6, 1902. 5 Stanton, T. W., Succession and distribution of later Mesozoic invertebrate faunas in North America: Jour. Geology, vol. 17, p. 422, 1909. 

e Dum blo, 1~. T ., Tertiary doposlts of northeastern Mexico: Science, new scr., vol. 33; pp. 232-234, 1911. 

155 
156 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

of the linear extent of the Coastal Plam clays, sands~ or limestones carrying marine invertebrates 

of Eocene age rest upon sands, clays, or marls carrying Upper Cretaceous invertebrates. . The 

conglomer·atic material at the base of the Eocene is everywhere relatively thin and usually 

consists of a few inches to a few feet of coarse sand or small pebbles with an intermi..··dure of 

rolled chunks from the underlying formation, phosphatic nodules, casts of shells, shark teeth, 

and other fossil remains. Because of the marine origin of the beds below and above the contact 

the conditions are favorable for determining the faunal relationships of the formations. In 

. east-central Georgia, northern Virginia., and -the- Potomac River. region in Maryland the Eocene 

rests upon Lower Cretaceous deposits. 

The approximate trend of the outcrop of the Cretaceous-Eocene contact and its geographic 

E:xogyraponilerosa zone 

Jackson '&ld± 

Claiborne 

450* 

Wilcox 

ssd± 

~~·!>' 

Selma chalk 

and contem· 

poraneous 

beds of Ripley and Eula\1 

formations 

9SO':b 

Mortoniceras 5ub:rone··--_ Tombigbee 

: sand member 'f-------

Eutaw 

4501± 

Tuscaloosa 

10001::l:: 

" 

Unconformity 

Eocene 

position with reference to the fall line and to transgressing formations younger than Eocene are indicated 

on the map forming Plate XI. · 

GENERALIZED SECTION IN THE CENTRAL 

PART OF THE EASTERN GULF REGION. 

A generalized section of the Upper Cretaceous an,d 

Eocene strata in the central portion of the eastern 

Gulf region is given in figure 13. In the Cretaceous 

section are the Tuscaloosa, Eutaw, and Selma formations, named in ascending order. 

The Tuscaloosa is a plant-bearing formation composed of sands and clays of shallow-water origin. The 

lower part of the formation is correlated by E. W. Berry 

with the Dakota sa~dst.one of the western interior 

regwn; 

The Eutaw formation· is composed of sands, in 

Upper- part calcareous and glauconitic, and clays, all of marine 

Cretaceou5 ong1n. The upper or Tombigbee. sand member of the 

formation (also known as the Mortoniceras subzone) 

carries a purely marine fauna which includes 70 or 

more species. Several lines. of evidence seem to show 

with a fair degree of certainty that the ~1ortoniceras 

' subzone is approximately synchronous with the Niobrara formation of the western i::1terio1,' region. 

The Selma chalk has its fullest development in 

FIGURE 13.-Generalized section or the Upper Cretaceous and wes t-een tral Alabama and eas t-een tral Wssissippi, and 

Eocene series and their major subdivisions in west-central here the formation as a whole may be roughly correAlabama and east-central Mississippi. lated with the :Montana group of the we.stern interior 

-

region. This chalk formation merges to the east in Alabama and Georgia into nonchalky 

marine sands and clays referred to the Ripley formation, which carries an abundant 1narine 

invertebrate fauna, and to the northwest and north in Mississippi and Tennessee into· similar 

sands and clays referred in part to the Ripley formation and in part to the Eutaw formation. 

Two major faunal zones have been distinguished in the Upper Cretaceous deposits. The 

Exogyra ponderosa zone includes the Tombigbee sand and approximately the lower half of the 

Selma chalk; the Exogyra costata zone includes the upper part of the Selma chalk. These two 

zones are traceable through practically the entire linear extent of the Atlantic and Gulf 

Coastal Plain. In west-central Alabama· and east-central Wssissippi the Selma is unconformably. overlain by the Midway, an invertebrate-bearing group of marine origin, and in ascending 

order the Midway is succeeded by the Wilcox, Claiborne, and Jackson groups. 
U. S. GEOLOGICAL SURVEY 

GEORGE OTIS SMITH, DIRECTOR PROFESSIONAL PAPER 90 PLATE XI 

I Ul]' 

·17' =---c:--------c:--:71'>7~-

fl!-J' 

3]' 

If' 0 

-------+-------t--

] t)l' !)7 ' f)J' 

87' 85' 

I 

F 

87' 

83' 

/ 

8 1' 

I 

\ C 

Oo "") ' 

70' 

----

Hl ' 

\ ) 

~--- \ ' , c-.., 

I 

I 

I 

7!)' 

71' 6\cl' 

\. 

\ 'v 

\ 

\ 

\ 

77" 

---

· • •) 

MAP SHOWING APPROXIMATE TREND OF THE CRETACEOUS-EOCENE CONTACT IN THE ATLANTIC AND GULF COASTAL PLAIN 

AND ITS GEOGRAPHIC RELATION TO THE PALEOZOIC AND CRYSTALLINE ROCK BOUNDARY, AND TO TRANSGRESSING FORMATIONS YOUNGER THAN EOCENE 

ScaJ.e o;-,o ooo 

~~~==:B=e=E===--';;.,=='="'=3W=O ===~==="""'~-~~====3"'00 STAT_ lro41L[S 

1914 

H7' 

43' 

4 1' 

~1 ' 

I 

\ 

\ 

\ 

I 

I 

\ 

\ 

33' 

27' 

73' 
CUETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 157 

FORMATIONS IN CONTACT ELSEWHERE IN THE ATLANTIC AND GULF 

COASTAL PLAIN.· 

From a point near riouston, Chickn;saw County, Miss., to Tennessee the Midway rests upon 

the Ripley formation; farther north, in Tennessee, Kentucky, and southern Illinois, the deposits 

iinmediately below and immediately above the Cretaceous-Eocene contn.ct are of shallow-water 

origin and so far as known are barren of invertebrates. From. central Alabama eastward to 

central Georgia the ~iidway rests upon the Ripley formation, in part upon typical marine 

beds and in part upon shallow-water deposits which have been designated the Providence sand 

n1ember of the Ripley formation. · 

In east-central Georgia and southwest-central South Carohna the Claiborne group of the 

Eocene transgresses northwestward across both the older Eocene and the Upper Cretaceous and 

rests upon the Lower Cretaceous. The Upper Cretaceous reappears in eastern South: Carolina, 

nnd at Wilmington, N. C., the Peedee sand, of the Upper Cretaceous series, is overlain by the 

stratigraphic equivalent of the Jackson, the youngest Eocene division. A little farther north 

deposits correlated with the Claib~tne overlie the Peedee sand. In northeastern North Carolina 

and southen.stern Virginia the Eocene and Cretaceous are entirely transgressed by the Miocene, 

which extends westward to the fall line. Farther north in Virginia the Lower Cretaceous nnd 

Eocene reappear from beneath the<!\1ioceno, and in Maryland the Upper Cretaceous reappears 

from beneath the Eocene. In ~1aryland the Aquia formation, of the Eocene 1 which is correlated with the lower part of tho Wilcox of the Gulf region, rests unconformably in part upon the 

~1atawan formation nnd in part upon the Monmouth formation, of the Upper Cretaceous. 

The ~1onmouth, the younger of the two forn1ations last named, corresponds approximately to. 

the Exogyra costata zone of the Gulf region. In Now Jersey the ~1iocene again transgresses 

upon the Upper Cretaceous, although the Shark River marl, of the Eocene, which is probably 

about contemporaneous with tho Claiborne, appears in Monmouth County, where it rests upon 

the Manasquan formation, of the Upper Cretaceous. 

From the vicinity of Arkadelphia., Ark., southwestward to tho Rl.o Grande, Upper Cretaceous deposits bea~·ing n1arine invertebrat,es and roughly corresponding in age to the Exogyra 

costata zone ·of the eastern Gulf region are overlain almost continuously by marine Eocene 

strata which I-Iarris has correlated with the :Midway. The writer's work in southwestern Texas 

has resulted in the discovery of the contact at two localities and its approximate determination at several other localities along the Rio Grande and in its approximate determination 

at several places in Uvalde and ~1edina counties. In at least one area in southwestern Texas 

the ~1idway is transgressed by younger Eocene stra.ta. 

CRETACEOUS AND EOCENE FAUNAS COl\fPARED. 

At no known place between :Maryland and the Rio Grande are the Upper Cretaceous deposits 

immediately below the Eocene contact markedly younger than the uppo;r part of the Exogyra 

costata zone of the eastern Gulf region, nor are the Eocene deposits immediately above the conta.ct older than the :I\1idway. In this connection it should be stated that the Rancocas and 

.Manasquan formations of Now Jersey, which carry only a meager fauna, are thought to be some-. 

what younger than the Exogyra costata zone, and tho upper part of the Escondido formation of 

southwestern Texas may be a little younger than tha.t zone, although its fauna is composed of 

strictly Mesozoic types, of which the genus Sphenodiscus is the most striking example. The 

time represented by the unconformity at other places"throughout the Coastal Plain· is therefore 

approximately equal to or greater than the time represented by the unconformity in the eastern 

Gulf region. As the faunas above and below the contact are best known in the Gulf region the 

available data relating to .that region form the chief b~sis for the statements which follow. 

During the time represented by the unconformity separating.the Cretaceous and Eocene 

strata of the eastern Gulf region some very important changes took place in the molluscan 

life of the region. A preliminary study of the faunas has shown that 168 or more species 

belonging to the subkingdom :I\1ollusca existed in the zone of Exogyra costata of the Upper" 
158 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Cretaceous. Of these not a single species is known with certainty to have ·been fomid in the 

basal Eocene or ~1idway formation. Several specie~ of Cretaceous mollusks have been reported 

from. basal Eoc·ene beds at different places in the .Atlantic and Gulf Coastal Plain, but 

when the records are critically examined more or less uncertainty is found in each record, either 

as to the correctness of the identifications or as to the .authenticity of the localities at which 

they were reported to have been found. 

The 168 species of mollusks in the zone of Exogyra costata represent 89 genera. At least 

20 of the more common of the~e genera became e..~tinct before the Midway formation began 

to be deposited, and these are enumerated in the list which follows. One whole order, the 

Ammonoidea, whic~ included five or more genera, entirely disappeared. 

Genera· common in the zone of Exogyra costata (Upper Cretaceous), which became extinct before the deposition of the ~Midway 

formation (Eocene). 

J3reviarca. Cyprimeria. Belemnitella. 

Nem,odon. Legumen. Order Ammonoidea: 

Gervilliopsis. lEnona. Baculites. 

Inoceramus. Linearia. Scaphites. 

Exogyra. Leptosolen. Sphenodiscus. 

Paranomia. Perissolax. Hamites. 

Liopistha. Pugnellus. Turrilites. 

The genu~ Trigonia, which is common in the zone of Exogyra costata, does not appear in 

the Eocene of the Atlantic and Gulf Coastal Plain but occurs rarely in the post-Cretaceous in 

other parts of the world. One genus, Hamulus,. belonging to the subkingdom Vermes, or 

worms, ~ecame extinct. Some of the smaller forms of life, such as "Foraminifera, Bryozoa, 

and Ostracoda, have not been studied critically, and it is not known what changes may have 

taken place among them. However, R. S. Bassler has found that a bryozoan fauna which 

occurs in the Rancocas, the youngest but one of the Upper Cretaceous formations of New Jersey, · 

reappears in part with certain varietal changes in the Aquia formation (Eocene) in Maryland. 

Although practically all the species of ~ollusks in the Midway formation are different 

from those' found in the underlying Cretaceous, the number of genera _that make their first 

appearance in the Midway is probably less than the number of Upper Cretaceous genera that 

became extinct in the interval represented by the unconformity. However, using Harris's 

·paper, already cited/ as p'rincipal authority, the writer has been able to note at least seven 

.common genera in the Midway that are not found stratigraphically below that level in the 

eastern Gulf reg'ion; ·these are Chama, V.enericardia,. MeretrL"'{, Mazzalina, Calyptraphorus, 

Mesalia, and Enclimatoceras. Some of these genera are known in the Upper Cretaceous in 

other parts of the world. 

MAGNITUDE OF THE FAUNAL CHANGES. 

The. following comparisons will give some idea of the magnitude of the faunal changes 

that took place during the time represented by the unconformity. The Mortoniceras subzone 

of the Eutaw formation, which is thought to correspond approximately in age to the Niobrara 

of the western interior region, has yielded about 70 species of mollusks representing about 

43 genera. Of these, 40 species a)fd all but two or three of the genera range upward to the 

top of the Cretaceous. During the t~e required for the deposition of the beds carrying the 

Mortoniceras fauna and the overlying strata composing the Selma chalk and its nonchalky 

Tepresentatives, and probably during the time represented by the entire Upper Cretaceous 

;Section of the Chattahoochee region, the faunal changes were not nearly so great as 

those which occurred during the time that elapsed ·between the deposition of the upper-

:most Cretaceous strata and. that of the lowermost Eocene strata of the area-that is, during 

the time' represented by the .hiatus-for at the close of. the period of deposition 40 out 

,of 70 species and all but two or three of the 43 genera survived, while at the close of the 

1 Harris, G. D., The Midway stage: Bull. Am. Paleoutology, vol. 1,156 pp., 15 pis., 1898. 
CHETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 159 

pedod of erosion, out of 168 species representing 89 genera, few if any species survived, and! 

20 or more common genera, including one whole order, became extinct. 

T. W. Vaughan, who has a wide acquaintance with the Tertiary and Quaternary faunas 

of the eastern United States, is authority for the almost startling statement that "the changes 

that took place in the marine animal life of the Atlantic and Gulf Coastal Plain during the 

thne represented by the ·unconformity separating the Cretaceous and Eocene of this area are 

1n.ore striking than the changes that have. taken place between earliest Midway time and th& 

present day, for no great orders comparable to the Ammonoidea that lived during Midway 

time have become extinct." · · 

CRETACEOUS AND EOCENE FLORAS COMPAREp. 

The evidence afforded by the. Cretaceous and Eocene floras is in substantial agreement 

with that supplied by the invertebrates. The following is quoted from a letter repeived from 

:Mr. E. W. Berry, of Johns flopkins University: 

With regard to the Upper Cretaceous and Eocene floras of the eastern Gulf region, their differences are profound, 

and I believe the unconformity at the base of the Midway represents a very long interval. The last extensive Cretaceous floras in the Gulf region are, of course, a good way from the end of the Cretaceous, but they are totally different 

from the plants collected near Earle, Tex., in beds believed to belong to the Midway formation. Even when comparisons are made between these Midway (?) plants ·and the Wilcox flora of the Gulf and the late Cretaceous of the 

Rocky Mountain province, the contrast is just as marked, unless you are prepared to call the Denver formation Cretaceous. There are a number of Denver plants in the Gulf Eocene, but I do not recall a single Laramie plant. 

INTERPRETATION OF THE HIATUS. 

In an attempt to . explain the differences exhibited by the faunas "found in the beds below· 

and above the Cretaceous-Eocene contact. several factors are to be considered, including· 

time, the physical changes that may have caused the extinction or tl).e more rapid evolution 

of the forms of marine life, and the migration of new f~rms into the area. The unconformity 

that separates these deposits, extending throughout the length of the Atlantic and Gulf Coastal 

Plain of the United States and far into Mexico is, in itself, an evidence both of a· considerabl& 

lapse of time and of. great diastrophic movements. The area which was submerged during 

Upper Cretaceous time· was elevated and the shore line retreated far to· the east and south, 

probably a considerable distance beyond the present shore line and perhaps nearly to the edge 

.of the continental shelf. The faunas. were thus forced into new environments, which doubtless contributed in part to the extinction of old genera and species and to the development of 

new species. There is, however, little, if any, evidence of marked changes in climate or in the · 

temperature of the marine waters. · , · 

"!''here is evidence. that after the close of the Cretaceou.s period as recorded and before the 

beginning of the earliest recorded Eocene deposition some new forms came into the Atlantic 

and Gulf Coastal Plain province from an outside province or provinces. But the number of 

genera thus introduced is. probably relatively small compared with the number of genera 

that survived from the Cretaceous of the same province, though represented by new species. 

The faunal changes are therefore believed to be more largely due to evolutionary development 

from.forms that previously existed in the same province than to new elements introduced from 

outside provinces. 

It is pretty generally conceded by pal~ontologists that evolutionary changes have proceeded 

1nore rapidly at certain times during the earth's history than at other times; but if this 

quickening of development is admitted the hiatus, in order to produce the observed changes, 

n1ust have been of great duration even when measured in terms of geologic time. I-Iow much 

of that time should be classed with the Cretaceous and how much with the Tertiary can not be 

determined with the available data. It is reasonable to conclude, however, that Cretaceous 

tin1e did not efl:d with the deposition of the uppermost Cretaceous strata now preserved, nor did 

Tertiary time begin with the deposition of the lowermost Eocene strata. The line separating 

the two periods probably lies somewhere .toward the middle of the hiatus. 
160 SHOR-TER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914, 

UNPUBLISHED DETAILS RELATING TO THE CONTACT. 

During the last eight years the writer has had occasion to examine the CretaceousEocene contact at many places between Virginia and the Rio Grande in Texas, and some of 

.his observations have already been published.' :Many of the localities had been previously 

visited by geologists and the re~ults of their studies put on record. Perhaps the majority of 

the published sections are essentially correct, so that for the present purpose their description 

would be an unnecessary duplication.· Several sections in Alabama and Mississippi in which 

the contact is exposed have been incorrectly interpreted, and a restatement of the age and· 

structural relations is necessary. New data in regard to the contact in Alabama, Mississippi, 

and T3xas are also given on succeeding page~. · 

EASTERN GULF REGION. 

I. 

. VICINITY OF CLAYTON, ALA . 

.. . ·Langdon 1 mentioned an outcrop of Midway limestone in a cut on the Central of Georgia 

~ailw~y east of Clayton, Barbour County, Ala., a~ follows: "Two miles east of Clayton. this 

rock may be seen cropping out in a cut on the Clayton & Eufaula Railroad [now Central of 

Georgia Railway]." 

~ ... · ·Harris studied this section and in 1896 published a description of it,Z which is in essential 

agreeineht with the one here given. Although he recognized the unconformity between layers 

1 and 2 of the section given below, he did not interpret it to be the contact between the Cret.ac~ous and Eoeene. In 1910 the writer carefully examined this cut and other exposures 

~~.cil;lgr th.e railroad immediately to the east and found what he regarded as the Cretaceous- E'o.Gene contact. . · · · .. 'l.•:_J, ''• 

Section in cut of Central of Georgia Railway l! miles east of Clayton, Ala. 

.. .Eoc.~ne (Midway group): Feet. 

6. Deep-red ferruginous sand, grading down~ard into light-colored, rather fine sand ...... 10-12 

5. Dark to black laminated clay .......... .' .................................... .'....... 3-4 

4. Hard fossiliferous limestone (Clayton liinestone) in which were recognized Ostrea crenu-

: limarginata Gabb, Ostrea sp., Turritella mortoni Conrad, Turritella sp., and Venericardia sp.; the limestone appears to pass into sand toward the east................. 5 

3. Fine yellow, slightly micaceous massive sand with small oysters in the upper part:... 5-6 

'(A few rods east of the end of the cut and 1 or 2 feet lower than the base of layer 

No.3 the section: is continued as follows:) 

2. Strongly ferruginous sand and sandy clay, partly indurated, with small particles of 

lignite and some pyrite or marcasite....................... . . . . . . . . . . . . . . . . . . . . . . . . 1-2 

·Sharp, unconformable contact presenting minor irregularities. 

Upper Cretaceous (Providence sand member of Ripley formation): 

1. Greenish-gray compact coarse sand.................................................. 3+ 

The base of this section is estimated to be approximately 70 feet lower than the railroad 

track at Clayton station. 

In gullies and cuts within half a mile east of the section just described are exposures of 

coarse, irregularly bedded. sands and clays resembling the Providence sand member of the 

Ripley formation, which is typically developed east of Chattahoochee River. in Georgia. The 

sands are jn part arkosic, are very coarse, and contain pebbles having a maximum length 

of half an inch or 1nore; they also contain clay balls and some clay bowlders which attain a 

maximum observed diameter of 1 foot. Interbedded ~th the sands are lenses of drab sandy 

massive clay,. in places mottled a,nd blotched with yellow and purple. Local unconformities 

are common between the layers and lenses of sand and clay. A thickness of 40 or 50 feet of 

these materials was noted, but the base of the member did not appear in the exposures examined. 

1 Langdon, D. W., jr., The Tertiary and Cretaceous formations east of Alabama River (in Smith, Johnson, and Langdo:p., On the geology of 

the Coastal Plain of Alabama, Alabama Geol. Survey), p. 418, 1894. 

2 Harris, G. D., The Midway stage: Bull. Am. Paleontology, voL 1, No.4, pp. 149, 150, 1896. 
CRETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 161 

TROY, ALA. 

The contact between the Cretaceous and Eocene outcrops north of Troy in the northwardfacing slope of tho Conecuh River valley. Figure 14 is a generalized section from the town 

northward to the river, a distance of about 3 n1iles, showing tho relation ~ 0 '0 

between tho Cretaceous and Eocene strata. The details and approxi- iS -t,a 

mate thicknesses of tho beds are as follows: ~ J~f· :s:: 

Sectionjrom Troy, Ala., to Gonecuh River. . b ~ ~~,~ 3 a_ ~l ~; ! ~3 ~a Eocene (Midway group): 

f. Deep-red weathered massive sands, forming the surfacematerials ~;~.t Troy, grading downward into less weathered 

Feet. 

massive sands ......................................... · 80 

e. Gray glauconitic sand.................................... 20 

d. Limestone ,in which the following Eocene mollusks were 

recognized: Ostrea crenulimarginata Gab b, Venericardia 

sp., Turritella mortoni Conrad (Clayton limestone)...... 15 

c. Light-gray massive argillaceous sand....................... 30 

Probable unconformity. The exact contact between the Cretaceous and Eocene was not seen clearly exposed in the vicinity of Troy, but ·the general relation of. the deposits as 

observed in numerous expo~ures justifies the belief that the 

contact lies immediately above layer b at the point indica.ted 

in figure 14. 

Upper Cretaceous (Ripley formation): 

b. Drab to yellowish and reddish fine to coarse sands 

with interbedded subordinatej lenses and layers. of 

massive clay, lenses of ·laminated clay, white clay 

films and grains, and some clay balls (Providence sand 

member) ............................................. 100 

a. Dark-gray to black argillaceous, very micace01.is sand or 

sandy clay, containing fossils in the form of soft casts; 

Orassatellites pteropsis Conrad and Breviarca sp. recognized................................................. 30 

Layers a and b of the section are exposed along the road leading 

northward from· Troy to Orion; layers d to fare exposed in deep gullies 

at the headwaters of .a small branch just north of Troy. 

BRIDGEPORT LANDING, ALABAMA RIVER, ALA. 

Smith and Johnson1 in 1887 described in d.etail the section exposed 

in the bluff at Bridgeport Landi;ng, Alabama .River, Wilcox County, 

Ala .. With the exception of 10 feet of terrace materials at the top of 

the bluff, the whole section embracing a thickness of about 50 feet 

of strata was assigned by them to the Ripley formation (Upper Cretaceous). 

In 1910 the writer, in company with Dr. Smith, visited this 

landing and found in an .. indurated. layer 10 feet above water level 

the Eocene fossil Enclimatoceras ulrichi White, a~d a few feet 

t:O" g~c . .g ~ . CT!/1 I 

~ ~· I I ,.._ - 250:1:..!.-.., 

t SmiU1, E. A., and Johnson, L. C., Tertiary and Cretaceous strata or the Tuscaloosa, Tombigbee, and Alabama rivers: U.l~. Geol. Survey 

Bull. 43, p. 74, Pl. XIX, fig. 3, 1887. See also Smith, E. A., Johnson, L. C., and Langdon, D. W., jr., On the geology of the Coastal Plain or Alabama, Alaballla Geol. Survey, p. 262, Pl. XVI, 1894. ! 
162 

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SHOR.TER CONTRIBUTIONS TO GENERAL GEOLOGY, :J-914. 

OLD CANTON LANDING, ALABAMA RIVER, ALA. 

The Cretaceous-Eocene contact is clearly exposed in a bluff on Alabama 

River below Old Canton Landing, Wilcox County, Ala. This section was 

described in 1887 by Smith and Johnson/ but the contact was not recognized 

and that portion of the section which belongs to the Midway was referred to 

the Ripley formation of the Upper -Cretaceous. The locality was visited by 

the writer in 1909 and the results expressed in the section given below were 

obtained. In 1910 he again went to the locality, in company with Dr. Smith, 

_who concurred in this interpretation. 

Section at Old Canton Landing, Alabama River, Ala. 

Pleistocene (terrace deposit): Red ferruginous pebbly sand 'vith gravel Feet. 

in the lower portion (poorly exposed toward base).................. 25-30 

Unconformity. 

Eocene (Midway group): The steep slope is largely covered with vegetation, but in the road leading down to the landing nodular ·layers of 

calcareous sandstone are poorly exposed, and along the bluff below 

the landing, immediately above the contact, is 10 to 20 feet of greenish-gray, more or less glauconitic calcareous sandstone, underlain in 

depressions in the Selma chalk by loose glauconitic gray .sand with 

rows of indurated, concretionary masses (see Pl. XII), and in places 

rolled lumps of Selma chalk and reworked Cretaceous fossils. Along 

the immediate base of the Midway is a gray quartzite-like rock varying in thickness from a film to 1 foot. In the calcareous sandstone 

the following Eo~ene fossils, identified by C. Wythe Cooke, were obtained: A coral, Terebratulina? sp., Cucullrea saffordi (Gabb), Ostrea 

pulaskensis Harris, Turritella sp., Levifusus trabeatus (Conrad) var.? 

(U. S. G. S. collection 5480); in addition to these the writer recognized Venericardia sp. ·and Enclimatoceras ulrichi White............. 90-105 

Unconformity. 

Upper Cretaceous (Selma chalk): Light-gray chalky limestone, typical 

in upper part, somewhat sandy-below; contains 30 or more characteristic species of the Exogyra costata zone of the Upper Cretaceou~.. . . . 3-20 

The strata exposed in the lower 25 or 30 feet of the bluff exhibit 

numerous minor faults involving both the Cretaceous ·and Eocene. Figure 

15 is a rough sketch· of the structural features exhibited by the rocks exposed along the face of the bluff. (See also Pl. XIII, A:) 

MOSCOW LANDING, TOMBIGBEE RIVER, ALA . 

The .Cretaceous-Eocene contact is well exposed at Moscow Landing,· on 

Tombigbee River about 14· miles· below Demopolis, Ala. In 1887 the beds 

above the contact were referred by Sm1th and Johnson 2 to the Ripley formation (Upper Cretaceous), but in 19iO this mistaken correlatior;t was partly 

corrected by Smith.3 This exposure has been examined by T. W. Vaughan, 

E. W. Berry, and ·the writer, and all agree that the sandstone and conglomera tic lenses occupying depressions in the Selma chalk and overlain by 

strata of undoubted Midway age are basal Eocene deposits, ~nd not Cretaceous 

deposits, as interpreted by Smith. 

The Eocene sea advancing across an uneven surface planed off the tops 

of the elevations and rapidly filled the depressions. Mter the hollows were 

completely filled, and while the sea was still shallow, the waves continued for 

1 Op. cit., pp. 74-75, Pl. XIX, fig. 4. See also Smith, Johnson,. and Langdon, op~ cit., pp. 262-264, Pl. XVI. 

2 Op. cit., pp. 80-81, 133, Pl. X. See also Smith,.Johnson, and Langdon, op. cit., pp. 270-272, 358, 359, Pl. XVIII. 

a Smith, E. A., The Cretaceous-Eocene contact: Jour. Geology, vol. 18, pp. 430-434, 1910. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XII 

A. 

E . 

CONTACT BETWEEN THE SELMA CHALK (UPPER CRETACEOUS) AND 

MIDWAY GROUP (EOCENE) AT OLD CANTON LANDING, ALABAMA 

RIVER, ALA. 

The thin laye r of quartzite at th e base of th e vegetati on in A , a nd projecting co nspic uous ly in B, mark s the base of th e Eoce ne. 
U. S. GEOLOG ICAL SURVEY PROFESSIONAL PAPER 90 PL AT E XII I 

A. FAULT INVOLVING THE CRETACEOUS-EOCENE CONTACT AT OLD CANTON LANDING, ALABAMA RIVER, ALA. 

B. EX POSURE EX HIBITING THE CRETACEOU S-EOCENE CONTACT ON 

MACON-DEKALB ROAD 7!1 MILES SOUTH OF MACON, ALA. 

Ha lf a mil e north of th e crossing of Runnin g Water Creek . On acco unt of th e sim ilarity of th e mate ri a ls composing the uppe rmost Cret aceous (Se lma) a nd the 

lowermost Eoce ne (Mi dway) , th e contact was dete rm ined onl y by th e a id of 

the conta ined fossil s . T he basal Midway is here composed of reworked Se lma 

chalk. T he came ra case rests on th e contact. 
CH:ETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 163 

, I 

a short time to plane off the sen. bottom and slightly cut down the fillings in the depressions. 

Soon, however, as the land continued to sink, the deposition of regular massive strata began, 

covering both the trunc·ated elevations of the Selma and the planed-off :fillings in the depres- · 

sions and producing the appearanc·e of unconformity between the coarse fillings and the 

regularly bedded deposits above. The Cretaceous fossils found in these basal, lenslike sands 

and conglornerates were derived by mechanical mixture from the underlying Selma chalk. 

The following fossils collected from the Midway at Moscow Landing by T. W. Vaughan and 

the writer were identified by C. Wythe Cooke: 

Fossils from the Midway group at Moscow Landing, Tombigbee River, Ala. 

Collection of Collection of Collection or1 Collection or L.W. T.W. L.W. T.W .. Stephenson Vaughan (U.S. G. S. (U.S. G. S. Stephenson Vaughan (U.S. G. S. (U.'S. G. S. 

5585). 5G58). 5585). 5658). 

Trochocynthus hyntti Vnughnn............... X ........... . Crassatellites sp............................... '· X 

'l'orobratula (Chlldonophora) sp............... . . . . . . . . . . . . X V enericardia sp. . .. . . . . . . . . . . . . . . .. . . . . . . . .. . . X 

?;y!g/~l~~~~~ins~~~::::::: ::::::::::::::::::::::: ..... x· ......... ~- ... . Turritella humerosa Conrad var.?............. X ........... . Turritella mortoni Conrad ............................... . Cucullmasaffordi(Gabb)...................... X ........... . Ostroa puiMkonsls Harrfs..................... X X 

Crassntollitos gnbbi (Safford)?................. X ........... . 

Vermetus sp. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . X 

Enclimatocer!l.9 ulrlchi White................. X 

VICINITY OF LIVINGSTON, ALA. 

X 

X 

X 

Southwest of Livingston, Sumter County, Ala., the Midway (Eocene) rests unconfo~mably 

upon the Selrria chalk (Upper Cretaceous). Here, as at Moscow Landing, Old Canton Landing, 

. and elsewhere in westw. 

""--r--.--- 1 

.·.·.· .... ... 0 ••• 

I 

I 

I 

: ;:: :::;·;·:: :)·.:::;.::·_:~-: :·~.:·: ... 

I 

I 

..... ... • ... 

central Alabama, 

strata of the Midway 

group were mistaken 

for the Ripley formation by Smith 1 and 

his assistants. The 

·section represented 

b fi 6

1s, y gure 16 expresses 1 Midway group 

(Eocene) the writer's interpretation of an exposure 

on the Curls station 

road, half a mile 

southwest of the 

·courthouse and just 

I 

I 

f 

I 

I 

I 

I 

S~lma chalk 

(!..Jpper Cretaceous) Concealed 

~-~,--------------~--------------------~~~~~, I'-- - - - - - - -·----- - - -zoo' :1: ---- - - - - - ______ ~ 

west of Sucarnochee FIGURE 16.-Section showing Cretaceous-Eocene contact on Curls station road half a mile so.uthwest or the 

courthouse at Livingston, Ala. For details of section see text. 

Creek. In one of his 

trips to the locality (in 1910) the writer was accompanied by Dr. Smith, who concurred in 

' this interpretation so far as it relates to the beds immediately below and above the contact. 

The details of the section are as follows: 

Section on Curls station road southwest of Livingston, Ala. 

Pleistocene (terrace deposit): Feet. 

. h. Alluvial sand and clay .............. -.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Unconformity. 

Pleistocene or Eocen.e: 

g. Poorly exposed red ferruginous sand, grading down into coarse grayish sand (weathered 

phase of Midway or Pleistocene terrace deposit) ....... ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

I Smith, ll:. A., Johnson, L. C., and Langdon, D. Yof., jr., Geologic map of Alabama, Alabama Geol. Survey, 1894. 
I 

164 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Eocene (Midway group): Feet. 

f. Dark shaly calcareous clay .................................................. _ . __ . _ . _ . 4 

e. White massive limestone, apparently a chalk; contains Foraminifera. Weathers in conchoidal fragments................................................................. 6 

d. Massive argillaceous sandy limestone; contains the Midway Eocene fossils Area sp. and 

Ostrea pulaskensis Harris, the latter becoming numerous toward the base. In the basal 

portion occur phosphatic nodules and phosphatic casts and some shells of Upper Cretaceous fossils, present as a mechanicalmixture, as follows: Exogyra costata Say, Gyrodes 

sp., Pyropsis sp., Baculites sp., Hamites sp......................................... 4 

Contact obscure,, owing to similarity of materials above and below the unconformity. 

Upper Cretaceous (Selma chalk): 

c. Massive argillaceous chalky limestone................................................ 6 

b. Concealed ......... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

a. Chalky limestone similar to layer c; contains Exogyra costata Say .................... ·- . . 1 

In company with Dr. Smith the w~iter made a trip by way of the Ramsey road from 

Livings tori to Sumterville, a small village situated· about iO miles west of north of Livingston. 

Mter crossing Sucarnochee Creek within half a mile· of the courthouse greenish clays-the 

s. N. 

3~· . d Midway gro4p 

2.0 t--,,,-,-,--,-r--r-r-r-r---1--TI-.,... (Eocene) 

c 

10•. .. ....................... ":. .... ~ -~ o = o 0 0 _ • 0 _ 0 0 _ -;::_Cretaceous-Eocene contact ~ - o a a o o o o o o o = o ~ ~ .. o o .. .. Lines of P,hosphatic casts 

Selma ChaJI< , , (Upper Cretaceous) ' . 

:. -----------------------100':1:- ---------- -~---.- ----------~ 

FIGURE 17.-Section showing Cretaceous-Eocene contact on Sucarnochee Creek 5 miles northwest of 

Livingston, Ala. 

Sucarnochee clay of 

the Midway groupwere observed at intervals in road exposures for a distance of 

4 or 5 miles. At a 

crossing of Sucarnochee Creek about 5 

miles fro1ll Livingston 

the CretaceousEocene contact was observed where the stream had cut through the Eocene into- the underlying Selma chalk. Figure 17 and the subjoined section show the relations of the deposits 

as observed. The thicknesses given in the section are approximate. 

Section on Sucarnochee Creek .5 miles northwest of Livingston, Ala. 

Feet. 

d. Concealed by vegetation ..... ~ ................................................ _____ 10 

Eocene (Midway group): · 

c. Sandy limestone ... _ ....................................... _._ ... __________________ 8-10 

b. Coarse phosphatic sand with Cretaceous fossils, principally casts, mechanically derived 

from the underlying Selma chalk ..... ~ ............................ ___ .... _ _ _ _ _ _ _ _ 1~ 

Sharp undulating contact. 

Upper Cretaceous (Selma chalk): 

a. Massive chalky limestone. A line of phosphatic casts of Cretaceous fossils is cut off in 

places by the unconformity, and a similar line of casts occurs a little lower in the 

section .................. · ....... ·_ .............................. : . ...... _ ....... _ 10-12 \ 

The Cretaceous-Eocene contact was observed at several places within-·2 or 3 miles northwest of this locality., and at one pl9.ce phqsphatic casts of Cretaceous fossils mechanically included 

in the base of greenish clays (Sucarnochee clay) were noted. Sucarnochee clay was observed 

overlying the chalk to a point within 2 or 3 miles of Sumterville, the base of the clay gradually rising to the north and the clay finally feathering out south of Sumterville. These ob~ervations show that northwest of Livingston the Sucarnochee clay of the Midway group transgresses the older sandy and calcareous beds of the Midway, and south of Sumterville these 

beds are entirely overlapped and the clay rests directly upon the Selma chalk: 

VICINITY OF SCOOBA AND WAHALAK, MISS. / 

The town of Scooba, Kemper County, Miss., is underlain by the Sucarno9hee clay of 

the Midway group of the Eocene. Several poor exposures of greenish clays were observed in 

the streets and along the roads in the vicinity of t:qe town, and a poor exposure of similar clay 
CR.ETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN.· 165 

was noted along the Mobile & Ohio Railroad, 1 mile north of town. Clays of the same character 

overlain by 5 to 10 feet of sand of undetermined age (probably Eocene) were observed at 

intervals along the Giles road for a distance .of 2! miles east of Scooba. 

'rhree miles east of Scooba, where the road descends into a small valley, 6 feet of compact 

gray li1nestone belonging to the Selma chalk (Upper Cretaceous) appears in the roadbed -and 

is overlain by 6 feet of Tesidual sandy clay (Sucarnochee). From the chalk were obtained 

Exogyra costata Say, Gryphrea sp., Pecten venustus Morton, Plicatula sp. nov., and Lima sp. 

From this .Point to a place within half a mile of Giles, a small village about 6 miles east of 

Scooba, greenish clays overlain by a few feet of yellow sands, probably of l\1idway age, are 

'exposed at intervals. Half a mile westof Giles the section represented in figure 18 was examined and found to contain the following beds: • · 

Section half a mile west of Giles, Miss. 

Eocene (M:i~way group): Feet. 

b. Yellow sand, grading down into greenish-gray sandy sticky clay (Sucarnochee clay)... 5 

Unconformity. 

Upper Cretaceous (Selma chalk): 

a. Grn:y argillaceous chalky limestone, containing Ostrea plumosa Morton................ 10 

A few feet of sand corresponding to layer Q in this section appears in the public road "to 

a point about 3! miles east of Giles. In places this sand is underlain by 10 feet or more of 

greerush .clays. A mile and a quarter east of Giles the Selma chalk appears in a bald spot 

and is overlain by the greenish clays. The chalk yielded Ostrea larva Lamarck and Gryphrea 

sp. The Selma is also exposed in a bald spot in the road about 3! miles ~ast of Giles,· and 

w. E:. 151 

o' er.taceous-Eocene contact;. I : •.. I ~i:r ~ v, ;: '. I>I~Mr~~~~n~~up 5· ~ ~ s; £;1 1

:1 :I :I Ill~ 1 I:: 1 :

11 1 1 jll 1 11

1

r:.' II\ ~:,'1 ,1 SelrnachaJk 7 f- _I . ; ' I · ~- I I ~!. L I 1 I _ I 1. (Upper Cretaceous) c===::: r:: L I I == I II I I I I I I I I I I J1 I . I 

r--------------------------:-----40o'± --------------- --.--.--------~--1 

FIGURE 18.-Section showing Cretaceous-Eocene contact half a mile west of Giles, 5~ miles east of Scooba, Kemper County, Miss. 

here were found Ostrea larva Lamarck and Ostrea plumosa :Morton. Beyond this point to the 

east the Midway covering thins out and disappears and the surface materials consist of residual 

clays derived from the Selma chalk. About 10 feet of typical massive limestone of the 

Selma chalk is well exposed in the banks of a dry branch a short distance west of Ivy, Sumter 

County, Ala .. 

A trip was made from Scooba northward along a road which joins the Wahalak-Binnsville 

road in the Wahalak Creek valley about 6 miles from Scooba. Nun1erous exposures of greenish 

clay (Sucarnochee clay) of the Midway group were observed to the crest of the steep slope overlooking the Wahalak Creek valley. In the road leading down the slope the following section 

is revealed: 

Section in public road about 6 miles north of Scooba, Kemper County, Jf?:ss. 

Eocene (Midway group): Feet. 

3. Greeni.sh weathered clay (Sucarnochee clay)... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Unconformity. 

Upper Cretaceous (Selma chalk): 

2. Massive chalky limes.tone, containing phosphatic casts of characteristic Upper Creta-

. ceous fossils (Exogyra costata zone) in the upper 10 feet............................ 60 

1. Very sanely limestone, constituting an arenaceous phase of the Selma chalk............ 50 

The Minnie Portis Spring is a quarter of a· mile north of the ·post office at Wahalak, 

Kemper County, Miss., in a small branch which has cut its valley 25 or 30 feet below the upland 

level. The surface materials at the spring and in the immediate vicinity are the greenish 

clays belonging to the Sucarnochee clay, of the Midway group. This clay is closely underlain 
166 SHORTEP. .CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

by fossil-bearing calcareous sandy clays, also belonging to the Midway, as shown by the following 

log of a shallow dug well in a small branch valley a few hundred yards east of the spring.- The 

log is based in part on an examination of the materials thrown from the well and in part on 

oral statements by Mr. D. W. Portis. . 

Log of well near the Minnie Portis Spring, Wahalalc, Miss. 

I 

[Fossils identified by C. Wythe Cooke.] 

Midfaf~~~~s~c~~~~~:- ........................................................... : . ......................... : . ......... . 2. Light greenish-gray, very calcareous sandy clay, containing Ostrea pulaskensis Harris (U.S. G. S. collection 6571) .. . 1. Bluish-gray, very calcareous,clay, less weathered than·the preceding, containing Ostrea pulaskensis Harris (U. S. G. S. 

collection 6571) ............ , ......................................................... · ............................. . 

Thickness. Depth. 

Feet. 5 

10 

6 

Feet. 5 . 

15 

21 

The fact that llamulus onyx Morton, a Cretaceous fossil, was found associated with Ostrea 

pulaskensis Harris in layer 1 of the section doubtless shows that the ·selma chalk closely. 

underlies the Eocene and that this Cretaceous fossil was mechanically intern1ingled with the 

Eocene oysters. 

Crider 1 has noted the occurrence of Selma chalk along the bed of W ahalak Creek in the 

vicinity of W ahalak. He says: 

Three miles north of Scooba the western border of the Selma chalk outcrop is seen in a series of hills forming the 

south bank of Wahalak Creek. The bottom of the creek here is about 1! miles wide, with the steeper slope on the 

south side. The creek has channeled its bed into the white Selma chalk, which outcrops continuously throughout its 

course. The limestone occurs in the bed of the creek to a point 6! or 7 miles northwest of Wahalak, but the overlying 

. Porters Creek clay is present on the higher land on both sides of the creek. 

On the low range of hills south of Wahalak Creek, beginning near the Mobile & Ohio Railroad track and extending 

eastward, is a bed of sand rock 10 feet thick capping the tops of·the hills. It is a coarse-grained sandstone cemented 

with lime carbonate and contains numerous little bivalve shells. It is similar to sandstone found 7 miles east of Sucarnoochee and doubtless represents the lowest beds of the Ripley formation. 

Although the writer has not seen the calcareous sandstone mentioned in the second paragraph quoted, Crider's statement that it contains numerous small bivalve shells suggests that. 

the rock is the basal calcareous portion of the Midway group, which in western Alabam.a carries 

large numbers. of Ostrea pulaskensis Harris, doubtl~ss the fossil he noted. 

On the geologic map accompanying Crider's report the Ripley formation (Upper Cretaceous) 

is represented as outcropping in a narrow· area southwest of a northwesterly line passing through 

Scooba. The Selma. chalk is represented as. outcropping north~ast of the same line. The 

observations just recorded show that the Ripley is absent in this area and tna.t the Midway 

group (Eocene)-probably the Sucarnochee clay-transgresses the Selma chalk for 5 to 10 

miles to the northeast and east of Scooba. 

Although on the map Crider represents Scooba as situated in the Cretaceous area, in his 

text 2 he .states that the town is in the Flatwoods area, which is underlain by the Midway group. 

This and other statements in Crider's text show that with the exception of his reference of the 

relatively thin calcareous and sandy basal beds of the Midway to the Ripley formation his 

interpretation of the stratigraphy of the .area was correct. 

VICINITY OF SHUQUALAK, MISS. 

The Flatwoods, which are underlain by ~he Sucarnochee clay of· the Midway group, are. 

well developed immediately west of Shuqualak, Noxubee County, Miss. North of the town 

several poor exposures of Selma chalk (Upper Cretaceous) were observed in the Macon road, 

and in a field west of the road 1 mile north of town the Selma chalk is fairly well exposed in 

severn1 bald spots; here were found the characteristic Upper Qretaceous fossils Ostrca plumosa 

1 Crider, A. F., Geology and mineral resources of Mississippi: U.S. Geol. Survey Bull. 283, pp. 18, 79, 1906. 2 Idem, p. 78. 
CRETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN." 167 

Morton, Gryphma vomer Morton, and Pecten venustus Morton. The town. of Shuqualak is 

therefore situated about on the boundary between the Cretaceous and Eocene. 

The Cretaceous-Eocene contact was found in the :Macon-De Kalb road about half a n1ile 

north of the crossing of Running Water Creek and about 4 n1iles northwest of $huqualak. The 

exposure is a bald spot on the southward-facing slope of n. small branch and revettls the following 

section: 

Sect·ion in :Macon-De Kalb road about 7! miles south of Macon, Miss., and half a mile north of the crossing of Running 

Water Creek. 

[Midway fossils identified by C. '''ythe Cooke.] 

Eocene (Midway group): :Feet. 

3. Dark, greenish-gray compact calcareous clay containing Foraminifera and in tho lower 3 

to 5 feet lu.rge numbers of Ostrea pulasken,sis Harris (U. S. G. S. collection 6582)......... . 8 

2. Moderately hard bluish-gray, somewhat sandy and argillaceous limestone. The upper 2 

feet is a little harder than the lower portion and contains the following Eocene (Midway) 

species: Cucullma sa.ffordi Gabb?, Venericardia alticostata Conrad, Turritella mortoni Conrad (U. S. G. S. collection 6581). The basal portion weathers soft and a little shaly and 

contains Gryphma vomer Morton?, probp.bly a Cretaceous fossil derived mechanically 

from tho underlying Selma chalk................................................... 6 

Unconformity indicated by some reworking of layer 1 in layer 2 and by borings in layer 1 filled 

by tho darker materials of layer 2. 

Upper Cretaceous (Selma chalk): 

1. Gray, very hard, slightly sandy and argillaceous massive chalky limestone. Baclilites sp. 

was found loose on the surface near the upper part of this bed ....................... :. 4 

Owing to the close lithologic resemblance between layers 1 and 2 of the section the contact 

is inconspicuous and requires close s.crutiny to discover it. A v:iew of the exposure is given 

in Plate XIII, J!. . NORTHWEST OF MACON, ~USS. 

The position of the Cretaceous~ Eocene contact was approximately determined in an exposure 

on 1-Iorse. Creek, a quarter of a. mile north of Benjamin Taylor's store and 12 or 13 miles northwest of Macon, Noxubee County, Miss. The creek bank reveals 20 feet of massive, compact 

argillaceous, slightly siliceous chalky limestone belonging to the Selma chalk. The Qpper 2 

feet of the rock is perforated with borings filled with gray calcareous clay. Weathered out 

in the soil on the slope just above the exposed beds of the Selma were found the following 

Eocene (Midway) fossils (identified by C. Wythe Cooke): A· coral, Oucullma sa;,_ffordi Gabb ~' 

Ostrea pulaskensis !farris, Turritella sp., Natica (2 spec'ies), Xenophora sp., Cylicna ~ (cast), 

and Pleuratoma ~'(cast) "(U. S. G. S. collection 6572) .. The perforated portion of the. chalk was 

doubtless immediately below the contact with the overlying Midway. 

STARKVILLE, .MISS. 

The Selma chalk is exposed in gullies on the campus of the Agricultural and :Mechanical 

College, near Starkville, Oktibbeha County, :Miss., and these exposures have yielded 37 or more 

species of characteristic Upper Cretaceous fossils (from the Exogyra costata zone). A short 

distance north of the campus, in the :Mayhew road about 1! miles east of Starkville, the following section is exposed: · 

Upper Cretaceous: 

Section in lJfaylzew road li miles east of Starkvill"e, ~Miss. 

Selma chalk: :Feet. 

3. Moderately sandy and argillaceous chalky limeston~, with many foss~ls.............. 26. 

Ripley formation: 

2. Gray, finely micaceous, somewhat calcareous sand, with a few slightly inchmi.tecl 

ledges........................................................................ 20 

1. Moderately sandy, very calcareous clay .... -.- .................................. ~... 4 
168 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914, 

The writer 1 has shown that the chalky limestone revealed in gullies on the campus is a 

northward-extending tongue of the Selma and is stratigraphically higher than a long tongue of 

. the Ripley formation which extends southward from Chickasaw County and apparently 

pinches out inN oxu bee County. W. N. Logan 2 correctly referred layer 2 of the Mayhew road 

section to the Ripley formation, but he reg~rded the sand as overlying the limestone (layer 3) 

and as constituting an outlier of the Ripley. 

·. 

Starkville is 'located .on the Cretaceous-Eocene contact, which is exposed in cuts of the 

Illinois Central Railroad southwest of the station. The following succession of strata appears 

in a cut a _quarter of a mile southwest of the station: 

Se~tion in cut of Illinois Central Railroad a quarter of a rnile southwest of the station at Starkville, Miss. 

Eocene (Midway group): Feet. 

4. Weathered brown, finely micaceous sandy clay....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

3. Thinly stratified fine gray micaceous sand with yellow and brown streaks................ 7 

2. Concealed .................................................................... _ .. _... 2 

1. Greenish-gray to olive-green tough clay .................. ~ ..... _ .... _._._ ........ __ ._. 1 

The beds described in the section were referred by Logan 3 to the Lafayette formation, 

but the writer does not hesitate to correlate them with the Midway group of the Eocene. They 

constitute the eastward feather edge of the Midway, the main outcrop of which begins within 

less than 1t miles southwest of Starkville alop.g this railroad. · 

From the cut southwestward the railroad track de[3cends a rather steep grade, and half 

a mile from the station 6 feet of massive chalky limestone (Selma chalk) overlain by 2 feet 

of yellow residual clay is exposed in a shallow cut. A cut 1t miles southwest of the station 

reveals 4 or 5 feet of grayish to greenish-gray hard sandy residual clay, probably a weathered 

phase of the Sucarnochee clay of the Midway group (Eocene). The actual·contact between 

the Cretaceous and Eocene _was not observed in this vicinity. 

VICINITY OF HOUSTON, MISS. 

A cut of the Mobile & Ohio Railroad (Houston branch) at Houston, Miss., reveals the 

following section: 

Section in cut of Mobile & Ohio Railroad at Houston, Miss. 

Eocene (Midway group?): Feet. 

4. Residual yellow sandy ferruginous clay................................................ 7 

3. Gray massiv&, compact calcareous glauconitic, somewhat argillaceous, finely micaceous 

sand. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

2. Yellow loose ferruginous sand with scattered white grains of arkose?, poorly exposed.... 4 

Sharp contact.· 

Upper Cretaceous (Selma chalk): 

1. Gray massive, ve.ry calcareous glauconitic, finely sandy clay resembling an ::.mpure phase 

of the Selma chalk .................... ·~ ............................... _ ..... ___ .__ 2 

Baculites sp., probably derived from layer 1 of the section, was found on the dump at the 

end of the cut. . 

The Cretaceous-Eocene contact is exposed on the old Houlka road 1! miles north of. 

Houlka, as described in the following section: 

Section in the old Houlka road 1! miles north of Houston, Miss. 

Eocene (Midway group): Feet. 

7. Yellowish hard calcareous glauconitic sandstone ................................... _ . _ 7 

6. Dark-g~ay argillaceous glauconitic compact calcareous sand, containing Ostrea pulaskensis 

· Harr1s .............................................................. _ ..... _ . _ . _ _ _ 3 

5. Greenish-gray calcareous sandstone ......... ~ .... , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . t 

4. 'compact' red and yellow fine micaceous sand.--.---.---.-.-.-.---.-._·_-.-.- ... ---.~.- 1 

3. Reddish, ·rather coarse sandstone.................................................... i 

2. Yellow, rather fine stratifi-ed mealy sand ................................ __ .. _ .... ____ . 1 

Sharp contact. 

Upper Cretaceous (Selma chalk): 

1. Compact gray argillaceous limestone ........................................... _ .. __ . 2 

I U.S. Geol. Survey Prof. Paper 81, p. 17, Pl. IX, 1914. 2 Mississippi Agr. and Mech. Coli. Bull., vol. 1, No.2, p. 30, 1904. s Idem, p. 35. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XIV 

A. CRETACEOUS-EOCENE CONTACT IN CUT OF ST. LOUI S & SAN FRANCISCO RAI L ROAD 1 MILE EAST OF NEW ALBANY, MISS. 

T he contact is beneath the indurated layer. 

B. POTHOLES IN BASAL LIMESTON E OF THE MIDWAY FORMATION ON 

THE RIO GRANDE 1 MILE BELOW WHITE BLUFF, MAVERICK COUNTY, 

TEX. 

About 4 miles above th e Webb County lin e. 
CH.ETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN, 169 

. A cut of the New Orleans, Mobile & Chicago Railroad 3 miles north of Houston reveals 

about 8 feet of light-greenish to yellowish nodular limestone containing large numbers of Ostrea 

pulaslcensis I-Iarris. (U.S. q. S. collection5587; identified by C. Wythe Cooke) in the upper 4 feet, 

o\-rerlain by 8 feet of tough yellowish and greenish clay, probably residual from the limestone; 

this rock belongs to the Midway group of the Eocene. 

In the main public road 1 to 1! miles south of Ifouston reddish and yellowish ferruginous 

sands and clays, probably belo.nging to the Midway group of the Eocene, were observed overlying with a sharp unconformity the massive argillaceous chalky limestone ofJ the Selma chalk, 

whic!1 in places contains numerous characteristic Upper Cretaceous fossils (-Exogyra costata zone). 

The weathered representatives of the sands and clays of the Midway a~ Houston extend 

eastward above the Selma, capping the tops of the hills for a distance of .a-t--least 2 miles . 

. VICINITY OF PONTOTOC, MISS. 

A deep cut of the New Orleans, Mobile & Chicago Railroad about half a mile south of the 

station at Pontotoc·, Miss., reveals nearly 50 feet of reddish, yellowish-brown, and grayish 

glauconitic sands belonging to the Ripley formation (Upper Cretaceous). In a stratum of 

massive coarse yellowish-brpwn glauconitic sand, 15 to 20 feet. below the top of the section, the 

following poorly preserved characteristic Upper Cretaceous fossils (Exogyra costata zone) were 

recognized: Exogyra costata Say, Veniella conradi (Morton), Cardium tippanum Conrad. About 

30 feet of similar sands are exposed in a ballast pit along the same railroad about 2! miles 

northwest of Pontotoc. 

From a point a short distance west of the old right of way of the New Orleans, Mobile & 

Chicago Railroad, which lies a mile or more west of the present right of way, southwestward 

for several miles the p.ublic road passes. over light-yellowish clays which are probably weathered 

residual materials derived from the Sucarnochee clay of the Midway group. 

The Cretaceous-Eocene contact was not foun~ well exposed in the .vicinity of Pontotoc, 

but the data just given indicate that the boundary lies about a mile west· of the railroad station. 

VICINITY OF NEW ALBANY, MISS. 

The town of New Albany, Union County, Miss., lies about a mile west of the outcrop of 

the Cretaceous-Eocene contact. The relations of the two series are well exhibit~d in a cut of 

the St. Louis & San Francisto Railroad 1 mile east of New Alpany. (See Pl. XIV, A.) 

Section in cut of St. Louis & San Francisco Railroad 1 mile east of New Albany, jJfiss. 

Eocene (!lfidway group): Feet. 

6. Weathered red ferruginous argillaceous sand. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

5. Yellowish-brown ferruginous sand with masses of small irregular to roundish iron concretions, apparently arranged in lenses ............... __ ._ ........ ___ . ___ . _____ ._______ 7 

4. Weathered yellowish-brown ferruginous sand ....... __ ........... _._;~._._._ ... _______ 9 

3. Yellow massive, somewhat sandy limestone, containing the Midway species Venericardia 

sp. and ~rritella mortoni Conrad (U. S. G. S. collection 6573; identified by C. Wythe 

Cooke). Mechanically included in the base of the limeston,e were found the following 

Upper Cretaceous fossils: Pecten argillensis Conrad, Crassatellites sp., and Cardium 

tippanum Conrad ................................. _ . __ ~ .. _ ... ___ .. _ ... ____ . _ .. _ . _ . 6 

2. Yell ow, very calcareous sand .... __ ... _ . __ . _ . ___ ....... _ . ____ . __ . ___ . ___ .. _ . _ . _ . ____ . . t-I 

Upper Cretaceous (Ripley formation): 

1. Dark-gray massive, very compact argillaceous sand with a few poorly preserved specimens 

of Exogyra costata Say, Pecten argillensis Conrad, and Baculites sp _. _____ . : ·- . __ . _____ . 5 

SOUTHWESTERN TEXAS. 

MAVERICK COUNTY. 

Roemer i in 1848 discussed the geographic position <?f the Cretaceous-Eocene contact in 

Texas u.s follows: 

An ideal line drawn from Presidio de Rio Grande on the Rio Grande in a northeast direction, and crossing the San 

· Antonio River at the town of the same name, the Guadalupe at New Braunfels (the German settlement), the Colorado 

1 Roemor, Ferdinand, Contributions to tho geology of Texas: Am. Jour. Sci., 2d ser., vol. 6; p. 21, 1848. 
170 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914:. 

at Austin, the Brazo~ at the falls of this river, the Triillty below its forks, and reaching from there to the Red River 

in the same northeast direction, divides the Tertiary strata and the diluvial and alluvial deposits (of the level and 

"rolling" part of the country) from the Cretaceous and older formations (of the hilly and mountainous sections). 

In 1889 Penrose 1 stated, with reference. to the Cretaceous ·along the ·Rio G-rande: 

It may be said, p.owever, that Cretaceous fossils have been found at Eagle Pass,· and from there clown the river to 

the Webb County line are found great quantities of ammonites and other fauna of that epoch. In fact, it is not until 

we reach a point 3 miles below the northwest corner of Webb County that true Tertiary (or Laramie) forms are found. 

Supposing the Cretaceous and Tertiary parting to cross the river at this point, we would do away with the much mooted. 

question of the westerly extension to Las Moras Creek, above Eagle Pass, as drawn by Loughridge, Conrad, and others, 

and the slight deflection to the west could easily be accounted for by the supposition of an embayment on the Rio 

Grande at the time of the deposition of these strata, similar to that which existed at the same time on the Mississippi. 

Roemer ;makes the line of parting across the Rio Grande at Presidio de Rio Grande, 10 miles above Laredo, while Schott 

refers to all the country from the mouth of the Pecos to the Gulf of Mexico as the "Cretaceous basin of the Rio Bravo" 

(Rio Grande). It seems probable now, so faras can be judged without a further study of the fossils, that Roemer was 

nearer right than the others, and that, as has been pointed out by Hill, the line as drawn by Conrad was based on. 

certain Tertiary fossils which had been misplaced in the collection. 

* * * * * * * 

At a point 5 miles below Las Cuevas Creek are the Angostora Rapids. These ar~ caused by a reef of oyster shells, 

of the same kind as mentioned above, which run across the river and are covered on either bank by the same gray or 

buff sandstones. For 16 miles below here, by ·river, we find almost uninterrupted outcrops of similar deposits of desiccated and indurated sands and clays, containing many ammonites and other forms similar to those found at the Cretaceous exposure in Anderson County. At this point we come to what is known as Las Isletas. · The river is a half 

mile wide and very shallow. It i~ full of small islands, consisting of sand bars and covered by mesquite and cane. 

The bottom of the river is rocky and causes almost continuous rapids for 5 miles. 

For 12 miles below Las Isletas, and to a point 3 miles· below the north line of Webb County, we see many outcrops 

of a formation-similar to those already described and with similar fossils. But here the fauna changes and the character 

of the strata becomes more glauc.oniferous. 

Dumble 2 in 1892 discussed the same section as follows: 

From this point [10 miles below Eagle Pass] to the falls of the Rio Grande, just above the Webb County line, the 

exposures are but repetitions one of another-brown, buff, blue, or green clays, with sandstones, sometimes friable and 

sometimes so indurated as to be semiquartzites. Abundant fossils, consisting of ammonites (Placenticeras), oysters, 

and gastropods, are found. The rapids (or falls of the Rio Grande), which continue almost to the line between the 

· two counties, are formed by the edges of some of these ammonite-bearing beds as they pass below water level. From 

·this poip.t to Webb Bluff, a distance of 3 miles, no fossils were found; but there was no change in the lithologic character of the rock" materials, nor could the clays at the base of the Webb Bluff sedion be distinguished in any way from 

those observed at the rapids above. 

Webb Bluff section. 

Gravel. F~et. 

Sandstone, white and glistening, with mica and some little iron; calcareous sandstones; clay, with 

cannon-ball concretions; and small se'am of grahamite ................................... _ .. _ _ 30 

Greensand mads with many Tertiary fossils; nodules of carbonate of lime; specks of glauconite._ 7-8 

Stiff, plastic dark-greenish or blue clay, jointed ..... _ .................. _ ... _ ... _ .. _ ... _. __ .__ 10 

We have, therefore, only 3 miles in which there can be any room for deposits intermediate between strata containing fossils of recognized and decisively marine Cretaceous forms and those contai~ng marine Eocene forms. The 

average clip does not exceed 100 feet per mile, and we saw nothing in any of the exposures on either bank of the river 

in this space to indicate a change until we reached Webb Bluff itself. The entire appearance of the upper portion of 

this bluff was so different from that of the materials we had been examining for the three previous days that it was 

remarked even before we landed. 

Vaughan 8 in 1900 sai~, with reference to the location of the contact ~ Maverick .County, 

Tex.: 

It is at about the point where the foregoing section was made [4! miles above mouth of San Ambrosia Creek] that 

the southern fence of the India ranch pasture is reached. This fence is, according to the statements of a colored 

cowboy, between three-fourths of a mile and a mile above the Webb-Maverick county line. Just beyond this 

fence, within the India ranch pasture, hematitic concretions containing Venericardia alticostata Conrad and a species 

of Glycymeris (Pectunculus) of the type of G. staminea (Conrad) were found in the clays. A little farther up the river 

was a large mass of sandstone resting on the clays and containing- beautiful specimens of Turritella mortoni. The sandstone was so hard that no attempt was made to get the shells out. 

1 Penrose, R. A. F., jr.,·Geol. Survey Texas First Ann. Rept., pp. 38-41, 1889. 

2 Dumble, E. T., Geol. Soc. America Bull., vol. 3, pp. 228,229, 1892. 

a Vaughan, T. W., Reconnai!;sance in the Rio Grande coal fields of Texas: U.S. Geol. Survey Bull. 164, pp. 38-39,53,1900. 
U. S. GEOLOGICAL SURVEY 

0 

LEGEND 

es=::::::e::~:::so::::===l::::::==::=:==:3'or===::::l's MILES 

100°30' 

MAP OF MAVERICK CO.UNTY, TEX., SHOWING 

OF THE CRETACEOUS-EOCENE CONTACT 

NORTHWARD THROUGH THE COUNTY. 

PROFESSIONAL PAPER 90 PLATE XV 

THE 

FROM 

APPROXIMATE TREND 

THE RIO GRANDE 
CH.ETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 171 

From 1! to 2 ~rules above the fence referred to the thinly bedded sands and clays are seen to be underlain by thinly 

bedded sands, passing downward into thin ledges of soft sandstone. . 

This has carried the Eocene to a point at least 2 to 3 ntiles above the Webb-Maverick county line. The horizon of 

the Eocene ls l\:I:idwn:yan. 'l'he following five species of fossils were collected [list revised by Mr. Vaughan]: 

Turr.itella mortoni Conrad. 

Ostrea crenul.imarginata Gabb. 

Glycymer.is (Pectuncul~1s) sp. indet. 

Vener.icardia planicosta Lamarck (var.). 

Vener.icardia perantiqua Conrad?. 

Harris has identified from the Dumble-Penrose collection made 3 miles below the Webb-Maverick county line 

fossils that are probably Midwayan, lower Eocene, but the writer has been unable to obtain a list of the species 

found there. Harris 1 says: "We should note the peculiar fauna, Midway, in part at least, found by Dr. White 18 miles 

southeast of Eagle Pass. It consists of Oucullrea nwcrodonta (perhaps sa.ffordi), Pectunculus, and Venericard.ia. The 

shelly matter of these species is completely crystallized. The matrix was evidently a calcareous ~ight sand or 

sandstone. 11 

* * * * * * * 

:From the foregoing discussion of the Eocene-Cretaceous contact and from the sections of the Eocene it has already 

been made evident that there is not yet sufficient data to trace accurately the boundary between the Cretaceous and 

the Eocene. This boundary crosses the Rio Grande some miles, at least 4 or 5, above the north line of Webb County; 

it runs northeastward 1 or 2 miles northwest of India ranch, and passes some 16 miles west of Carrizo Springs. From 

here the boundary continues northeastward and crosses the Nueces River about the north line of Zavalla County. It 

continues nort~ of east to the Frio River, crossing that stream 2 miles below the Engelmann ranch, and 5 miles, in a 

straight line, north of the south line of Uvalde County. The last-mentioned point is the only absolutely determined 

contact. The others are supposed or inferred from the data at hand. 

In 1903 Dumble 2 took exception to Vaughan's statement in regard to the exact geographic 

position of the exposures from which he (Vaughan) obtained certain Eocene fossils and endeavored to show thu,t these exposures were probably close to Webb Bluff. 

· Additional stn.ten1ents with reference to the Cretaceous-Eocene. cont!lct along the Rio 

Gi·ande were made by Dumble 3 in 1911 n,s follows: 

Major Emory, in the first part of the Boundary Survey report, on page 68, gives a description of Las Isletas and 

tho falls of the Rio Grande, with a full-page illustration opposite. This description would indicate that the falls of 

tho Rio Grande and Las Isletas were the same. The truth is that Las Isletas is located about the n;wuth of Castano 

Crook, while the falls are some 4 miles lower down the river, just below the mouth of Caballero Creek. 

It will thus be seen that our collections were made from localities directly on the line of travel of the Boundary 

Survey party, and it seems highly probable that the original specimens described by Conrad were in reality obtained 

from these same beds. 

rrho horizon is the uppermost portion of our Escondido beds.· The fossils are among the latest Cretaceous forms 

of which we have any present knowledge in this region. 

'l'he Cretaceous-Eocene contact is well shown 3 miles below '!'oro Colorado, just above the falls of the Rio Grande 

and on Caballero Creek. 

Tho only other records I can find of any of these forms are as follows: 

Prof. G. D. Harris, .in " 'l'he Tertiary geology of southe~n Arkansas, 11 gives a list of fossils collected by Dr. C. A. 

White, in 1887, at his camp 18 miles southeast of Eagle Pass, Tex., which were supposed to be basal Tertiary. Among 

these there is a Cardium which Mr. Harris figures both in this paper and later with his Midway fauna, "Bulletin of 

American Paleontology, No. 4, 11 without giving it a specific name. 

'!'his camp was probably at the Eagle Pass-Laredo road crossing near the junction of Cuevas and Pena creeks, and 

on or near the.Cretaceous-'l'ertiary contact. The Cardium is unquestionably the Cardium congestum of Conrad, while 

the other forms named by Prof. Harris are from the. overlying-Midway. 

The fossils obtained by White 18 miles southeast of Eagle Pass, as determined by Harris/ 

are Oucullrea macrodonta (Whitfield), Pectunculus sp., Vonericardia sp., and Cardium sp. 

Dun1ble, in the paper published in Science just Cited, does not state the position of the 

fossil localities described with reference to the Webb County line, but Las Isletas (or Las Islas), 

which he says is located n,bout the mouth of Castano Creek, is in :Maverick County, approximately 

7 miles by tho river above the Webb County line; according to his further statement, this would 

place the intersection of the Cretaceous-Eocene contact with the Rio Grande about 3 nliles 

above instead of 3 miles below the county line. 

t Harris, G. D., Tho Midway stage: Bull. Am. Paleontology, vol. 1, pp. 127-128, 189G. 

2 Dumblc, E. T., Geology of southwestern Texas: Am. Inst. M:in. En~. Trans., vol. 33, pp. 931, 932, 1903. 

a Dumblc, E. T., RedisCO\'ery of some Conrad forms: Science, new ser., vol. 33, p. 971, 1911. 

37183°--15----12 
172 

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SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

In the autumn of 1912 the writer made investigations in :Maverick 

County which resulted in the exact determination of the Cretaceous-Eocene 

contact along the river and th~ approximate determination of the outcrop 

of the contact northward through the county .. (See Pl. XV.) 

The accompanying profile section (fig. 19) shows roughly the structure and stratigraphic relations of the beds exposed between White Bluff, 

5 miles ~:tbove the Webb County line, and a prominent westward-facing 

bluff about 2 miles above the county line .. The succession is as follows: 

Section on Rio Grande below White Bluff, Maverick County, Tex. 

Pleistocene· (terrace deposit): Feet. 

g. Gray massive loamy sand, with a band of pebbles along the 

base in places ......................................... 20-50 

Unconformity. 

Pliocene or Pleistocene (Uvalde formation): 

f. Thin surficial covering of gravel, in places cemented with•a 

white spongy matrix of lime~........................... 3-4 

U nconformi ty. 

Eocene: 

Sandstone of Midway or Wilcox age: 

e. Irregularly bedded meq.~um to coarse grained sandstone, 

with subordinate thin laminated layers of gray clay; 

includes some thick, relatively short massive lenses 

of sandstone, but in the main the rocks are crossbedded. Vegetable particles and small pieces of lignite are common. At one place there is a basal conglomerate 2 or 3 feet thick composed. chiefly of pebbles of iron c<~.rbonate derived· from the concretions 

in the lmderlying strata (d) . . . . . . . . . . . . . . . . . . . . . . . . 150 ± 

Unconformity; sharp contact, undulating slightly. 

Midway formation: 

d. Massive clark-gray (light gray or greenish gray where 

weathered), more or less argillaceous and gla.uconitic, 

slightly indurated sand, with harder ledges at intervals 

of 5 to 15 feet. Subordinate layers of shaly clay were 

noted.· Concretions of iron carbonate are common in 

the upper 50 feet and in places occur in layers. Fossils wer.e found at the points indicated (field Nos. 

304 and 305; see lists on p. 173) ................ 150-200 

c. Gray fossiliferous limestone in layers 1 to 1! feet thick, 

interbedded with greenish-gray sand in layers 1 to 2 

feet thick; becomes sandy and glauconitic in the basal 

portion, which also contains some balls and fragments 

.of clay ~erived from the underlying Cretaceous strata. 

Fo8sils obtained from the limestone are enumerated on 

page 173. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

Unconformity; contact sharp and undulates slightly. 

Upper Cretaceous (Escondido formation): 

b. Greenish-gray shaly clay with crystals of gypsum; ·contains 

a few .interbedded len'ses of fine greenish-gray sandstone; 

grades downward into next layer....................... 38 

a. Greenish-gray glauconitic sand, partly indurated to nodular 

layer~; contains numerous Upper Cretaceous fossils (see iist 

on p. 173)." ........ .-·:.................................. 40 

At White Bluff (see 1nap, Pl. XV), at the upstrea1n end of the profile 

section, the Cretaceous-Eocene contact is clearly exposed for a distance of 

several rods (see Pl. XVI) and lies 90 or 95 feet above the river. At the 

upstream end of the prominent part of the bluff the base of the Eocene 

limestone is fault~d down 25 or 30 feet below the position slwwn in, the 

photograph. . The section is as follows: 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XVI 

A. 

B. 

CRETACEOUS-EOC EN E CONTACT ON THE RIO GRANDE AT WHITE BLUFF, 

MAVERICK COU NTY, TEX . 

About 5 miles above the Webb County I i ne. Th e contact I ies at the base of the 

projecting ledge of rock. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XVII 

.A. CONTACT BETWEEN THE MIDWAY FORMATION AND OVERLYING SANDSTONE OF MIDWAY OR WILCOX AGE ON THE RIO GRANDE IN 

MAVERICK COU NTY, TEX. 

About 2~ mil es above th e Web b County line . 

B. SANDSTONE OF MIDWAY OR WILCOX AGE IN A PROMINENT WESTWARDFACING BLUFF ON THE RIO GRANDE IN MAVERICK COU NTY, TEX. 

About 2 miles above the Webb County line. 
CH.ETACEOUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 173 

Section at White Blu.f[, ~Maverick County, Tex. 

Pliocene or Pleistocene (Uvalde formation): Feet. 

5. Gravel cemented with a white spongy matrix of lime................... . . . . . . . . . . . . . . . . . . . 1 

Uncor;tf<;n·mity. · · 

Eocene (Miclway.formation): 

4. Gmy fossiliferous limestone in layers 1 to 2~ feet thick, interbedded with greenish-gray sand in 

layers 1 to 2 feet thick. The immediate base of the limestone is sanely and in places strongly 

glauconitic and.contains balls and fmgmCI').ts of the unclerlytng Cretaceous clay, present as a 

mechanical mixture. The limestone contains the following Eocene fossils (field No. 301), 

identified by T. W. Vaughan: Leda sp., Cucullcea macrodonta Whitfield, Cytherea ripleyana 

Gabb,· Venericardia smithii Aldrich, and Venericardia perantt:qua Conrad (U. S. G. S. 

collection 6575). A costate Anomia (field No.· 302), probably derived from the underlying 

Cretaceous, is present as a mechanical mixture in the immediate base of the limestone .... _ 12 

Unconformity; contact sharp and undulates slightly. 

·Upper Cretaceous (Escondido formation): 

3. Greenish-gray shaly clay with crystals of gypsum. Contains a few interbedded lenses of fine 

greenish-gray sandstone. Grades downward into next layer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 

2. Greenish-gray glauconitic sand, partly indurated to nodular layers. Contains numerous 

Upper Cretaceous fossils, including Ostrea cortex Conrad, Cardium sp., numerous poorly 

preserved gastropods, and Sphenodiscus pleurisepta Conrad· (field No. 303)................. ~0 

1. Concealed to water's edge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

According to Mr. Vaughan, the.fossils inla.yer No.4 indicate the Midway age of the stratum. 

The :next place exa1nined on the river was at a point about 1 1nile below White Bluff and a 

quarter to half a 1nile below the Blesse ranch house, which is on the }t1exican side. (See map, 

Pl. XV., and proftle section, fig. 19.) I-Iere the basal Eocene lin1estone, which is so prmninently 

exposed near .the top of vVb.ite Bluff, dips below water level in the river bed. The. rock is well 

exposed on the Texas side of the channel and extends for a considerable distance out into 

the river, which has cut a relatively narrow channel through the rock parallel to and near the 

south bank. ' · · 

The writer was not able positively to identify the "falls of the Rio Grande" described by 

Du1nble and others, but at this point a rise of the river a few feet above the ordinary low-water 

, stage would result in n1ore conspicuous rapids at the outcrop of this Eocene lin1estone than 

would be produced by other ledges of Cretaceous and Eocene rock which appear at many places 

in the bed of the river at low water, beth above and below this point. It therefore semns 

likely that this is the so-called falls. 

The base of the lin1estone is not exposed, but the thiclmess was esti1nated to be ro or 15 feet. 

The i:nlerence is probably justified that here, as at White Bluff, the Cretaceous-Eocene contact 

lies inunetliately below the limestone, and the contact would therefore cross the ri~er directly 

above the outcrop of the rock in the river bed. The limestone contain's Venericardia sp. and 

other Eocene for1ns. The surface of the rock in the river ~bed has been strongly potholed and 

presents a rough, jagged appearance. (See Pl. xry, B.) 

A nearly continuous series of exposures appears along the left bank of the river from this 

point downstremn to the pron1inent westwar·d-facing bluff indicated on the n1ap, a distance of 

about 2. miles. The beds overlying the lin1estone (division d of profile section, fig. H)) dip 

downstrea1n at the rate of at least 100 feet to the n1ile. In dark greenish-gray glauconitic sand, 

estimated to be 30 or 40 feet above the base of this division, a few black casts of gastropods 

and Venericardia sp. were collected (U. S. G. 8". collection 6576; field No. 304), and about 35 

feet below the top of the division black casts of Venericardia, sp. CU: S. G. S. collection 6577; . 

field No. 305) were obtained. The beds of this division are of purely marine origin, as 

shown by the fossils and the glau~onite. 

The Jnarine division is overlain unconformably (see Pl. XVII, A) by irregularly bedded 

sandstones (cli,7 ision e, fig. 19), which fonn th~ rnajor part of the pron1inent westward-facing 

bluf[ at the downstren,Jn end of the section. (See Pl. XVII, B.) This bluff rises 100 or 110 feet 

above wn,ter level (aneroid reading), but only the upper 60 or 70 feet is well exposed. Inter.:. 

.. 
174 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

bedded with the coarse sandstones in this section is a band of gypsiferous shale 10 to, 15 feet 

thick, the top of which is about 20 feet below the top of the sandstone. The gypsun1 occurs 

' in sean1s and separate crystals. The relation of these irregularly bedded sand.stones to the 

typical Carrizo sandstone of Owen 1 has not been determined, but they probably occupy a lower 

stratigraphic position, being equivalent in age either to a portion of the typical Midway 

group of Alabama or to the lower part of the overlying Wilcox group. The highest part of 

the bluff is capped by 3 or 4 feet of surficial gravel of the Uvalde formation. 

Mr. Vaughan has inforn1ed the writer that the fossils enumerated in United States Geological Survey Bulletin 164, page 38, were found in beds below the typical Carrizo sandstone 

of Owen, and they may have come from the stra.ta represented by division d of the profile section 

(fig. 19). According to Mr. Vaughan, 'the. fossils indicate the Midway age of the containing 

beds. No fossils were found in division e of the section, and therefore no additional evidence 

regarding its age can be presented. 

The next exposure examined on the Rio Grande was a prominent westward-facing bluff. 

4 miles nearly due west or perhaps a little south of west of the Jacal ranch house and about 

9 miles above the :Maverick-Webb county line. The section is as follows: 

Section at westward-facing bluff on Rio Grande about 9 miles. above the Maverick- Webb 90unty line. 

[Station 1 on the map, Pl. XV.] 

Pliocene or Pleistocene (Uvalde formation): Feet. 

6. Gravel............................................................................. 10 

Unconformity. 

Eocene (Midway formation): 

5. Greemsh sandy clay, with indurated layers a few feet apart, weathered and poorly exposed. 20 

4. Hard gray limestone inlayers 1 to 2 feet thick, with interbedded thinnor layers of greenish 

:fine, slightly indurated sand. The limestone is replete with Venericardia sp., Cucullrea 

sp., and other Eocene fossils (field No. 306a). A costate Anomia derived mechanically 

from the underlying Cretaceous strata occurs-in the base of the limestone............. 13 

Exact contact not clearly exposed. 

Upper Cretaceous (Escondido formation): 

3. Greenish-gray shaly gypsiferous clay, with subordinate interbedded thin layers and some 

thicker layers of fine hard gray sandstone weathering greenish gray. . . . . . . . . . . . . . . . . . . 35 

2. Greenish-gray massive marine sand, slightly indurated, some layers more indurated than 

others, and forming slightly projecting ledges. Fossils are numerous and the following 

were recognized: Brevia rca sp., Ostrea cortex Conrad, Anomia sp. (With costre), Mactra sp.? 

and Sphenodiscus sp. (field No. 306)....... ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 

1. Concealed by talus and Recent alluvium .................................... ·......... 35 

The Cretaceous-Eocene contact is here about 120 feet above the water level of the river. 

The description given applies particularly to the upper end of the bluff, where a good exposure is 

afforded by the northwestward~faci~g side of a short gully. Good exposures of the fossiliferous 

beds of the Escondido formation (layer 2 of the section) extend southward for half a mile or 

nwre along the bluff. 

A wire fence extends from the ,Jacal ranch house in a direct line west of sou~h to White 

Bluff (see Pl. XV), and about 3 miles from the ranch house crosses a low peak, the. top of which 

is nearly as high as the general level of the upland in the vicinity of the "ranch house (200 feet 

·o! more above the river). The sandstone of Midway or Wilcox age is fairly well exposed in 

the upper 40 feet of this peak and consists of rather soft mediun1 to coarse gray shaly sandstone with several more n1assive layers forming ledges.· A few indistinct impressions of small 

pelecypods were noted. 

Near t.he same fence, on the crest of a gravel-covered ridge, about 1! miles from the Jacal 

ranch house, poorly preserved prints of V enericardia sp. were found in a partly exposed ledge 

of hard calcareous ferruginous sandstone. · 

.r · A number of observations hn.ving an important bearing on the location of the CretaceousEocene contact in }.1averick County were niade along the road leading from the Jacal ranch 

t Owen, J., Texas Geol. Survey First Rept. Progress, pp. 70-73, 1889. 
CRETACEOUS-EOCENE CONTACT' IN ATLANTIC AND GULF COASTAL PLAIN. 175 

house to Eagle Pass by way of the Biboro tank. (See map, Pl. XV.) About 6 miles from the 

ranch house (station2, Pl. XV) a poor exposure of gray sandstone corresponding to tho sandstone 

of :Midwn.y or Wilcox ago sho,vn in division e, figure 19, was observed in a small branch near · 

the road, and associated with it were fragments of rock exhibiting cone in cone structure. 

Fragtnents of similar sandstone were noted along the same road for the next 3 miles toward 

Eagle Pass. From about the tenth to the eleventh mile from the ranch house tho road where it 

cuts tluough the surficialloams and gravels of the Uvalde formation reveals greenish to yellowish 

clays, locally ferruginous and containing concretions of iron carbonate in different stages of oxidation. In ferruginous material, about 11 miles .from the ranch house (station 3, Pl. XV), 

prints of Venericardia sp. (U. S. G. S. collection 6578; field No~ 307), identified by C. W. Cooke~ 

were obtained. 

. The next in1portant exposure studied was n,t the crossing of Biboro Creek just below 

Biboro tank (stu.tion 4, Pl. V), which is·esti1nated to be about 18 miles by tho wagon road from 

Eagle Pass. Tho bed of the creek at the road crossing is about 20 feet below the general level 

of the surrounding upland. Ledges of bard gray fossiliferous limestone and greenish-gray 

calcareous sandstone crop out below the dam of the tank. From the limestone fossils were 

collected and identified by T. W. Vaughan and C. W. Cooke as follows: Oucullcea rnacrodonta 

'Vhitfi.eld, Lucina sp., Cytherea ripleyana Gabb, Venericardia perantiqua Conrad var. smithii 

Aldrich~' and Enclimatoceras sp. nov. (U. S. G. S. collection 6583; :field No. 308). 

The. rock corresponds exactly in its lithologic and faunal character to the basal Eocene 

litnestone exposed along the Rio Grande south and west of tho J acal ranch house (division c 

of the profile section, fig. 19). The exact base of the limestone was not discovered. According 

to :Messrs. Vaughan and Cooke the fossils indicate the :Midway age of the containing bed. 

Within less than half a mile of Biboro Creek in the direction of Eagle Pass (station .5, 

Pl. XV), fragments of fine greenish-gray sandstone belonging to the Escondido formation of 

the Upper Cretaceous were noted along the road. In descending the northwestward-facing 

slope of Cuevas Creek, about It miles from Biboro tank, the roadbed reveals greenish-gray, 

more or less argillaceous, slightly indurated sand, in which some layers are more indurated 

than others and form ledges. The rock is fossiliferous and the following poorly preserved forms 

were colJected: Brevin.rca sp., Ostrea cortex Conrad, Anomia sp., Cardium sp., Mactra sp. ~' 

and Sphenodiscus pleurisepta Comad· (field No. 309). These are characteristic species of the 

Escondido forn1ation. Sin1ihu beds are exposed in the bed of Cuevas Creek at the road crossing, 

and here a few well-preserved specimens of Sphenodiscus sp. were collected (field No. 310). 

Although the base of the Eocene limestone was not seen in the vicinity of Biboro tank, the 

appearance of Cretaceous strata within less than half a mile to the northwest shows that the 

contact between the two systems lies a short distance west of the tank, and it must intersect 

B:iboro Creek below the road crossing, possibly within a few rods. Between Cuevas Creek 

and Eagle Pass the only strata exposed, except the surficial gravels and loan1s of the Uvalde 

fonnation, belong to the Upper Cr~taceous. 

The next place north of Biboro tank at which data· bearing on the' geographic position of 

the contact. were obtained was in the valley of Picoso Creek between the Chimeneas ranch 

house and the Joe Williams ranch house. (See map, Pl. XV.) Aside from the sur:ficialloams 

and gravels of the Uvalde formation, the only rocks observed along the road from Eagle Pass 

to the Chin1eneas ranch house belonged to the Upper Cretaceous. A few hundred yards east of 

this rap.ch house (station 6, Pl. XV) a layer of hard nodular fossiliferous limestone crops out in 

the bed of a small creek and along the gentle bordering slopes and yielded specimens of Exogyra 

costata Say and O'ardium spillmani Conrad~ (field No. 314). The rock therefore belongs to the 

Escondido forn1ation of the Upper Cretaceous. Similar rock was observed in the bed of the same 

creek about a mile east of the ranch house, and also in the bed of Picoso Creek at a road crossing 

about 2t 1niles northeast of the ranch house (station 7, Pl. XV), where poorly preserved speeimens 

of Exogyr:a costata Say were noted. 
176 SHOR.TER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Fron1 the crossing. of Picoso Creek along the road northward for 2 or 2! ·miles and then 

eastw~rd toward the Joe Williams ranch house (see Pl. XV), poor exposures of sandstone of the 

Escondido formation were noted here and there to a point within about 1 mile west of the 

ranch house, beyond which the road was heavy with sand. In the immediate vicinity of the 

ranch house several srnall exposures of gray, rather coarse sandstone having the characteristics 

of the sandstone unconformably overlying the ;marine Midway on the Rio Grande (division e, 

fig. 19), were observed. Fron1 the Joe Williams ranch house southward to Picoso Creek, a 

distance of 2 or 2! miles, several small outcrops of this sandstone appear along the road. A 

fairly good exposure of the sam~ formation was found in the bed of a small branch, perhaps 2 

miles south of the ranch house (station 8, Pl. XV). I-Iere the rock consists of soft medium to 

coarse grained irregularly bedded massive to thin-bedded sandstone, containing numerous 

grains, films, and small b'alls of white clay, and on weathering the surface is mottled with red. 

, These observations indicate that the Cretaceous-Eocene contact lies about 1 mile west of 

the Joe Williams ranch house. The intersection of the contact with Picoso Creek is probably a 

little west of south of the ranch house. 

A few small outcrops of the gray sandstone corresponding to division e of figure 19 appear 

along the road leading west of north from the Joe Williams ranch house to the Burke ranch 

house, a distance of 3 or 4 miles. The san1e sandstones were noted in small, inconspicuous· 

exposures at numerous places along an abandoned roadway which leads in a general northerly 

direction from Burke's ranch house across .Chacon Creek to Black's ranch house, an air-line 

distance of 5 or 6 miles. They were seen also about 1 mile nort~west of Black's ranch house 

(station 9, Pl. XV) in several small exposures in and near the road leading toward the Salado 

ranch. No significant exposures were found beyond these outcrops, but specimens of Sphenodiscus sp. were observed loose in the bed of a small creek about 1! miles a little north of east· of 

the Salado ranch house. · 

At an abandoned tank on Salado. Creek just south of the Salado ranch house along the 

Eagle Pass-Uvalde road (station 10, PLXV) typical sandstones of the Escondido formation 

were examined. The rock is a gray hard, more or less calcareous sandstone and contains fossils 

among which were recognized Breviarca sp., Ostrea cortex Conrad, Gyrodes sp., and two species 

of Sphenodiscus (field No. 315). 

From the Salado ranch house along the road running 4 or 4! miles in a southeasterly direction to Chiltipin tank, which is situated in a small valley draining eastward (station 11, Pl. XV) 

characteristic sandstones of the Escondido formation were observed in many small outcrops. 

Along the sides of the valley below the tank are large masses of hard gray sandstone, weathering 

brown; belonging to the Escondido formation. Son1e lenses are very fossiliferous, but the fossils 

are not easily separated fron1 the matrix. The following forms were recognized: Breviarca sp., 

Ostrea cortex Conrad, Anomia sp., unidentified gastropods, and Sphenodiscus sp. 

The data above presented show that the outcrop of the Cretaceous-Eocene contact probably 

lies within 1 or 2 miles west of the Joe Williams ranch house, and that north of this place the 

possible outcrop is lirnited to an area a few miles wide which lies west of the Burke and Black 

ranch houses and east of Chiltipin tank and. the Salado ranch house. 

As no marine invertebrate-bearing beds corresponding to the strata of the Midway formation 

(Eocene), which outcrop along the Rio Grande, were seen in this area, it appears that the gray. 

sandstones unconformably overlying the marine· Midway deposits on the Rio Grande have 

here transgressed westward, concealing the marine Midway strata and resting upon the Escondido formation (Upper Cretaceous). 

ZAVALLA AND UVALDE COUNTIES. 

Vaughan 1 bas approximately determined the Cretaceous-Eocene contact in the northwestern part of Zavalla County and the southern part of Uvalde County as far east as Frio 

River a11.:d ex~ctly at one locality on Frio River. The ·only additional data resulting from the 

1 Vaughan, T. W., Recmmaissance in the Rio Grande coal fields of Texas: U.S. Geol. .Survey Bull. 164, pp. 53, 54, Pl. I, 1900; U.S. Geol. Survey Geol. Atlas, Uvalde folio (No. 64), pp. 2; 3, 1900; idem, Brackett folio (in preparation). 
CH.l~TACJ~OUS-EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 177 

writer's field studies west of Frio River relate to certain outcrops west of south of the old Fenley 

ranch house. About 4! 1niles south of the Eagle Pass and Uvalde road, near the ZavallaMn.ver.ick county line, about a quarter of a 1nile south of a new ranch house (station 12, Pl. 

XV), is a sn1all exposure of hard gray quartzite-like rock showing faint stratification lines 

and having the characteristics. of the gray Eocene sandstones on the Rio Grande shown in 

figure 19, e. About lt miles north of this P?int, near the road leading northward to the UYalde 

and Eagle Pass road (station 13), are seYeral small outcrops of rock typical of the Escondido 

forn1ation of the Upper Cretaceous (" Pullia1n" formation of Vaughan), consisting of hard 

greenish-gray fine-grained calcareous sandstone. These data limit the possible outcrop of the 

contact to a ·belt less than 2 miles wide. 

'rho writer has exa1nined so1ne of the fossils which were obtained by Vaughan fro1n his 

Myrick formation just above the Cretaceous-Eocene contact on Frio River in the southeastern 

part of Uvalde County, 2 1niles below Engelmann's ·ranch, and which he states indicate the 

:Midway age of the strata in which they were found. The matrix is a weathered glauconitic 

phase of the basal Eocene (Midway) limestone, division c of the profile section giYen ir! figure 19. 

The Myrick formation, which Vaughan estimates to be 800 feet thick, must therefore include 

strata belonging to the Midway formation and to overlying undifferentiated Eocene fqrmations. 

'1.11e fossils collected and identified by Vaughan fron1 the basal stratun1 of the Eocene at this 

. locality are the following .(U. S. G. S. collection 3181): 

Cucullrca saffordi (Gabb). 

· Ostrea crenulimarginata Gabb? 

Ostrea pulaskensis Harris. 

Venericardia peril.ntiqua Conrad. 

Venerica.rdia sp. 

Lucina sp. 

Cytherea sp. 

Natica sp. 

Turritella humerosa Conrad. 

Turritella mortoni Conrad.· 

Levifus~s trabeatus (Conrad) var.? 

Naut~lus sp. nov. 

In the eastern part of Uvalde County the Cretaceous-Eocene contact was determined by 

the writer to be in the northwestward-facing slope of Elm Creek near the Schuddemagen ranch 

house, which is just north of the junction of the creek with Sabinal River. (See map, fig. 20.) 

With the exception of u. prominent limestone ledge (layer 4 of the section below; see also Pl.· 

XVIII, A) the strata forming the hill are not well exposed, but by· a close inspection of small 

outcrops along the slope the following section was determined.: 

Section in north'Westwardjacing slope of Elm Creek near the Schuddemagen ranch house, 11 miles south of Sabinal, Tex. 

[Station·14, fig. 20.] 

Pliocene or Pleistocene (Uvalde formation): Feet. 

6·. Gravel, not well exposed............................................................ 20 

Eocene (Midway formation): 

5. Fh1e greenish-gray, slightly calcareous sand with numerous interbedded thin layers of 

sandstone, the whole poorly exposed. At one place the basal 2 or 3 feet is replete with 

Ostrea sp. (apparently new) (U.S. G. S. collection 6278; field No. 247d) . . . . . . . . . . . . . 50 

4. Massive sandy limestone with poorly preserved fossils, prominently exposed along the 

hill slope. Messrs. Vaughan and Cooke have identified the following species from this 

limestone: G lycymeris sp., Ostrea sp., Venericardia perantiqua Conrad var. smithii 

Aldrich, Oljtherea rizJleyana Gabb, Natica sp., Turritella morltoni Conrad,. Turritella 

sp., Calyptraphorus velatus Conrad var., Pseudoiiva cf. P. unilineata Aldrich, Phos? sp., 

Pleurotoma sp. (U.S. G. S. collection 6279; field No. 247c)........................... 10 

Exact Cretaceous-Eocene contact was not observed, but it probably lies at the top of layer 3. 

Upper Cretaceous .(Escondido formation= "Pulliam" formation of Vaughan): 

3. Fine greenish-gray calcareous sand, poorly exposed................................... 45 

2. Soft greenish-gray fine calcareous sandstone from which were obtained Ostrea sp., Anomia 

sp., and Sphenodiscus sp. (field No. 247a); poorly exposed.......................... 3 

1. Greenish-gray fine calcareous sand, poorly exposed................................... 18 

Layer 4 of the section (Pl. XVIII, A) correspond~ in lithologic ch.aracter to t.he basal 

Eocene limestone exposed along th~ Rio Grande in the southern part of Maverick County 

(division c of the profile section, fig. 19, p. 172), and :Messrs. Vaughan and Cooke state that the 

fossils indicate the Midway age of the stratun1. · 

S1nall outcrops of Cretaceous rock were noted at seYeral places between the Sehuddemagen 

ranch house and Sabinal. 
178 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

MEDINA COUNTY. 

The position of. the Cretaceous-Eocene contact ·was determined approximately along the 

road leading fron1 D'Hanis, Medina County, Tex., a little east of south to Yancey. At a point 

7 t nliles from D'Hanis, near the crest ·of a nort~eastward-facing slope (station 15, fig. 20), 

· about 15 feet of hard white lin1estone is moderately well exposed. Among fossils collected 

from this limestone C. W. Cooke identified Oucullcea macrodonta Whitfield~, Ostrea crenulimarginata Gabb, Venericardia perantig_ua Conrad, Lucina sp., and unidentified gastropod 

fragments (U.S. G. S. collection 6584; field No. 340). In its lithologic character the rock corresponds to the basal Eocene lin1estone in Maverick County (division c of the profile section, 

fig. 19), and according to Mr. Cooke the fossils indicate the Midway age of the bed. 

The exact base <;>f the limestone was not observed, but along the road about a quarter of 

a mile north of the outcrop and not more than 10 or 15 feet lower than the lowest exposed 

portion of the linle99030. stone 'the Cretaceous 

5E3:::::::e==:=o:c:·===··::E5 :==:==:==:il0=:::=:::=:::::~:15:==:====:320 MILES 

fossils Ostrea cortex 

Conrad and Anomia 

sp. were found in an 

·impure yellow limestone. The contact i.s 

therefore determined 

within a horizontal 

distance of less than 

a quarter of a mile. 

No direct aneroid 

reading was made, 

but the base of the 

liwestone of Midway 

age is estimated to be 

at least 160 feet.higher 

than the bed of Seco 

Creek west of this locality. 

Between the locality just described 

and D'Hanis, aside 

from surficial loams 

and gravels, only Cre- FraunE 20.-Sketch map showing outcrop of Cretaceous-Eocene contact in portions of Uvalde and Medina 

counties, Tex. The full line indicates places where the contact ha{:! been determined with a fair degree taceous strata \Vere 

of accuracy; the dashed line indicates the approximate or inferred position of the outcrop. 0 bserved. 

On Hondo Creek 3! miles south of Elstone, half a mile south' of the Lon Moore cro.ssing 

(station 16, fig. 20), masses of gray to brown, strongly cross-bedded mediun1 to :fin·e, slightly 

·calcareous sandstone wi.th interbedded thin layers showing cone in cone structure are prominently 

exposed, in the bed of the creek and along the left bank for several hundred yards. (See Pl. 

XVIII, B.) Although no fossils were found, this rock has the lithologic aspect of some phases 

of the sandstone (division e, fig. 19) unconformably overlying the marine Midway on the Rio 

Grande. Similar sandstones appear in .the creek bed for the next nlile below this point, and 

other outcrops of sands, sandstones, and clays, probably Eocene, were observed still farther 

down the creek witP.in 6t miles below Elstone. 

At a locality on Hondo Creek known as Rock Crossing (station 17, fig. 20), which is about 

1 i miles below the crossing of the road leading due east from Elstone and one-half to threequ_artersof a mile above the Blue Water Hole (on the Elstone-Biry road crossing), fossiliferous 

strata of Cretaceous age are well exposed. (See Pl. XIX,_ A.) The section is as follows: 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XVII I 

A . BASAL LIMESTONE OF MIDWAY FORMATION ON SOUTHEAST SIDE OF 

ELM CREEK 11 MILES SOUTH OF SABINAL, TEX . 

Near Schuddemagen ranch house. 

B. EOCENE SANDSTONE IN BED OF HONDO CREEK 31':2 MILES SOUTH 

OF ELSTONE, TEX. 
U. S. GEOLOG ICAL SUR VEY PROFESSIONAL PAPER 90 PLATE X IX 

A . ESCONDIDO FORMATION IN BED OF HONDO CREEK. AT ROCK CROSSING, MEDINA COUNTY, TEX. 

About 1! mil es be low the crossi n11 of th e road lead ing east from Elstone. Sph ene- di sc us (severa l va ri et1 es) occ urs ab un da ntl y in th ese strata. 

B. BASAL LIMESTONE OF MIDWAY FORMATION ON LEFT BANK OF HONDO 

CREEK IN MEDI NA COUNTY, TEX. 

Abo ut a qua rter of a mil e above t he crossing of th e road leadi ng east from Elstone. 
CRETACEOUS ... EOCENE CONTACT IN ATLANTIC AND GULF COASTAL PLAIN. 179 

Section at Rock Crossing on Hondo Creek, Medina County, Tex. 

Pleistocene (terrace deposit): Feet. 

7. Heavy bed of gravel with a few feet of loam at the top. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 

Uuconforrnity. · 

Upper Cretaceous (Escondido formation="Pulliam" formation of Vaughan): 

6. Layer of brown :fine-grained slaty sanclstone0with thin lenses of coquina in the lower 

part; contains poorly preserved fossils ........................................... t-1~ 

5. Fino greenish-gray to yellowish sand with fossils in the lower part . . . . . . . . . . . . . . . . . . . l! 

4. Greenish-gray to brown nodular fossiliferous fine-grained sandstone containing large 

numbers of Sphenodiscus. Many square rods of the bed of the creek above the falls 

are formed of this rock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 

3. Greenish-gray to yellow fine massive sand which erodes easily ....................... . 2! 

2. Greenish-gray to brown nodular fossiliferous :fine-grained sandstone with many speci-

.mens of Sphenodi.scus ......................................................... . l 

1. Greenish-gray fino calcareous, irregularly indurated ·massive sand containing fossils; 

erodes. easily ...................................................... _ ............ . 5 

Layera 1 and 2 fonn the head of a shallow gorge which i:S a waterfall ~hell' there is running 

water in the creek. ·(See Pl. XIX, A.) Layer 4 also forms a sn1ull waterfall a few rods farther, 

up the creek 

The following fossils (field No. 221) were obtained fr01n layers 1 to 5 of the section: 

Ostroa cortex Conmd. 

Ostt·ea sp. 

Anomia sp. 

Cardium sp. 

L1matia? 

Tmritella sp. 

Undetermined gastropods. 

Nautilus sp. 

Sphenodiscus pleurisep'ta Co mad. 

Sphenodiscus (several varieties or 

species). · 

About a quarter 9f a mile below Rock Crossing 12 feet of strata lithologically corresponding to layexs 1 to 5 of the section appear in a vertical bluff along the left bank of the creek. 

Several fu:te large specin1ens of Sphenodiscus were obtained here (fielct'No. 223) .. · 

According to these observations, the Cretaceous-Eocene contact must intersect the creek 

between stations 16 and 17, which are 2 or 2! nules apart. It is probably nearer station 16 

thn,n station 17. 

Abo.ut a quarter of a nllie above the crossing of the road lea9-ing due east fron1 Elstone 

(station. 18, fig. 20) the left bank of Hondo Creek exposes 12 or 15 feet of hard, sandy, slightly 

glmiconitic lhnestone, son1ewhat like coquina in appearance. (See Pl. XIX, B.) The rock is 

poorly fossiliferous, but Ostrea sp. and Turritella mortoni Conrad~ (field No. 219) were recognized. About three-eighths of a nllie below this point, one-eighth of a mile below the crossing 

of the road lending due east fron1 Elstone, a loose bowlder found in the bed of the creek and 

obYiously deriv-ed fr01n the lituestone :yielded a few poorly preserv-ed fossih, an1ong \Vhich Messrs. 

Cooke and V nughan hav-e recognized the following species (U. S. G. ·s. collection 6280; field 

No. 220): 

Loda olougatoidoa Aldrich var.? Harris. 

Glycymeris sp. 

Ostroa. sp. 

~:[odiola sa:ffordi Gabb. 

Venericardia sp. 

Cytherea sp. 

Corbula sp. 

Turri tell a sp. 

The rock is therefore of Eocene age. It has the general appearance of the basal limestone 

of the :Midway fonuation noted 7! ·nllies southeast of D'Hanis and near the Schuddemagen 

rn.nch and is believed to correspond to the basallin1eatone of the Midway exposed on the Rio 

Grande .in southern Ma,-rerick County (division c of the profile section, fig. 19). 

I-Ialf a mile above~ the locality just mentioned large n1asses of gray n1edium-grained crossbedded, slightly calcareous sandstone, w'eathering brown, ,appear along the left· bank of the 

·creek (station 19, :fLg. 20). They are slightly out of place, having fallen fron1 their original 

position. These rocks n,re unlike the fine-grained sandstones of the underlying Escondido 

for.mat:ion (Upper Cretac9ous) and closely resmnb,le some phases of the Eocene in this part 

of ~rexas. The sn .ndstone and the limestone noted a quarter of a nule above the road crossing 
180 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

east of Elstone (p. 179), occurring 1~·to 2 m.iles above the Cretaceous strata exposed at Rock 

Crossing on Hondo Creek, indicate a fold or fault which brings the Eocene down to the level 

of the creek bed, farther upstream than it would be if the ..:;trata were:itegularly inclined. 

About 3 miles upstream from the sa~dstone ju:3t described and 1! or 1! miles below the San 

Antonio and Hondo road crossing (station 20, fig. 20), Cretaceous sand was found exposed in the 

right bank of the creek as described in the following section: 

Section in right bank of Hondo Creek 1~ or 1f miles below the San Antonio-Hondo road bridge. 

Pleistocen~ (terrace deposit): Feet. 

3. Brownish massive loam ....................................................... ' .... 20-2i.> 

2. Conglomerate composed of pebbles and cobbles of chert and flint with intermixed bowlders and slabs of brownish sandstone; the cementing material is lime ........ ~..... 2-6 

Upper Cretaceous (Escondido formation): 

1. Fine greenish-gray argillaceous sand, in part cemented into a ra.ther soft sandstone.... 2 

A fmv hundred yards above this' exposure numerous large slaba of g1~ay sandstone, weathering brown, appear in the bed of the creek, arid though not seen in place they n1ark the outcrop 

of a ledge of sandstone of the Escondido formation. With the exception of Pleistocene terrace 

deposits, no strata younger than Cretaceous were observed i\>long Hondo Creek between the 

locality last described and the Balconea escarpment. . 

SUMMARY OF RESULTS IN SOUTHWESTERN TEXAS. 

The data set forth on the preceding pages show that along the Rio Grande in the southern 

part of Maverick County the following succession of formations· exists: 

General section on Rio Grande in southern ~Maverick County, Tex. · 

Eocene: 

Sandstone of Midway or Wilcox age: 

4. Irregularly bedded medium to coarse sandstone, with interbedded layers and 

lenses of clay (maximum thickness not determined). 

Unconfor~ty. 

Midway formation: 

3. Massive dark-gray, more or less argillaceous and glauconitic, slightly indurated 

8and, with harqer ledges at intervals of 5 to 15 feet and with subordinate layers 

of shaly clay; concretions of iron carbonate in upper 50 feet; contains some Feet. 

poorly preserved marine fossils of Midway age .. · .............................. 150-200 

2. Gray fossiliferous limestone, with interbedded thinner layers of greenish-gray 

sand; contains marine fossils of Midway age. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12- 13 

Unconformity. 

Upper Cretaceous: 

Escondido formation: 

1. Greenish-gray shaly clay conformably· underlain by greenish-gray glauconitic, 

partly indurated sand containing characteristic U:pper Cretaceous fossils. (Total 

thickness of formation estimated by Dumble to be 3,300 feet, but probably 

much less.) 

The ba~allin1estone of the Midway formation has been traced eastward as far as Hondo 

Creek, Medina County, the underlying formation being the Escondido for.mation of the Upper 

Cretaceous. In an area including the northeastern part of Maverick County, the northwestern 

part of Zavalla County, and the southweatern part of Uvalde County the Midway appears 

to be completely overlapped by a northwestward transgression of younger sandstone of Midway 

or Wilcox age. 

The lower part of the Escondido formation of southwestern Texas certainly corresponds 

to at least a part of the Exogyra costata zone of the eastern Gulf region. Exogyra costata Say 

has not been found in the upper part of the Escondido fonnation, and it n1ay be that that part 

is· son1ewhat younger than this zone. The fauna of the formation has not been critically studied, 

but tb e an1n1oni te S phenodiscus pleurisepta Conrad ranges throughout practically the whole 

thickness of the terrane, being most abundant near the top, where it is represented by several 

varieties. The fauna ia therefore strictly Mesozoic in its aspects, and in a geologic sense the 
CR.ETACEOUS-EOCENE CONTACT IN' ATLANTIC AND GULF COASTAL PLAIN. 181 

upper part of the Escondido is not very n1uch younger than the Exogy·ra costata zone. These 

uppennost strata probably do not appreciably bridge the great hiatus between the Cretaceous 

11ncl ·Eocene. · 

LITE;JtATURE. 

It is impr11cticl1ble in this paper to give a COlnplete bibliography of the literature relating 

to the Cret11ceous-Eocene contact in the Atlantic and Gulf Coastal Plain. The papers enu1ner11ted below include only those in which 1nay be found con1pilations of the available data 

reln,ting to the contact in the areas treated. Nearly all the papers· cited contain bibliographies 

and references to older literattJre and nutps showing the outcrop of the contact. 

GENERAI •. 

1891. White, C. A., Correlation papers-Cretaceous: U. S. Geol. Survey Bull. 82, 273 pp., geologic map. 

1892. Clark, W. B., Correlation papers-Eocene: U. S. Geol. Survey Buil. 83, pp. 1-94, generalized geologic map. 

1896. :Harris, G. D., The Midway stage: Bull. Am. Paleontology, vol. 1, pp. 117-270. 

1897. Clark, W. B., !,tnd others, Upper Cretaceous deposits of New Jersey, Delaware, and Maryland: Geol. Soc. 

America Bull., vol. 8, pp. 315-358, geologic map. 

1898. Dall, v:,r, H., A table of North American Tertiary horizons: U. S. Geol. Survey Eighteenth Ann. Rept., pt. 2, 

pp. 332-335. . . 

·1912. Willis, Bailey, and others, Index to the stratigraphy of North America: U. S. Geol. Survey Prof. Paper 71, 894 

pp ., geologic map. 

1914. SteplH:Jnson, L.W., The Cretaceous deposits of the eastern Gulf region: U. S. Geol. Survey Prof. Paper 81, pp. 

· 9-40, geologic map. 

NEW JERSEY. 

1897. Clark, W. B., and others, Upper Cretaceous deposits of New Jersey, Delaware, and Maryla~1d: Geol. Soc. America 

Bull., vol. 8, pp. 315-358, geologic map. 

MARYLAND. 

1897. Clark, W. B., and others, Upper Cretaceous deposits of New Jersey, Delaware, and Maryland: Geol. Soc. America 

Bull., vol. 8, pp. 315-358, geologic map. 

1901. Clark, \V. B., and Martin, G. C., The Eocene deposits of Maryland: Maryland Geol. Survey, Eocene, 331 pp., 

geologic map. 

VIRGINIA. 

]912. Clark, W. B., Miiler, B. L., and Berry, E. W., Physiography and geology·of the Coastal Plain province of Virginia: Virginia Geol. Survey Bull. 4, pp. 1-222, geologic map. 

NORTH. CAROLINA. 

1912. Clark, W. B., Miller, B. L., and Stephenson, L. YV., The stratigraphy of the Coastal Plain of North Carolina: 

North Carolina Geol. a~d Econ. Survey, vol. 3, pp. 34-330, geologic map in pocket. 

SOUTH CAROLINA. 

1908. Sloan, Earle, Catalogue of the mineral localities of South Carolina: South Carolina Geol. Survey, 4th ser., Bull. 

2, pp. 434-485, geologic map. 

GEORGIA. 

1911. Veatch, Otto, and Stephenson, L. W., Preliminary report on the geology of the Coastal Plain of Georgia: Georgia 

. Geol. Survey Bull. 26, 466 pp., geologic map. 

ALABAMA. 

1887. Smith,~. A., and Johnson, L. C., Tertiary and Cretaceous strata of the Tuscaloosa, Tombigbee, and Alabama 

rivers: lJ. S. Geol. Survey Bull. 43 1 189 pp. 

1894. Smith, E. A., .Johnson, L. C., and Langdon, D. W., jr., Geology of the Coastal Plain of Alabama: Alabama Geol. 

Survey, 759 pp. . 

1894. Smith, E. A., Johnson, L. C., and Langdon, D. W., jr., G.eologic map of Alabama: AlabaJl:l:a Geol. Survey. 

1914. Stephenson, L. W., The Cretaceous deposits of the ea,stern Gulf region: U. S. Geol. Survey Prof. Paper 81, pp. 

9-40, geologic map. · 
182 SHORTER. -CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

MISSISSIPPI. 

1860. Hilgard, E. W. [State geologist], Geology and agriculture of the State of Mississippi, 391 pp., geologic map. 

1906. Crider, A. F., Geology and mineral resources of Mississippi: U.S. Geol. Survey Bull. 283, 99 pp., geologic map. 

1914. Stephenson, L. W., The Cretaceous deposits of the eastem Gulf region: U.S. Geol. Survey Prof. Paper 81, pp. 

9-40, geologic rna p. 

TENNESSEE, KENTUCKY, AND ILLINOIS. 

1906. Glenn, L. C., Underground waters of Tennessee and Kentucky west of Tennessee River and of an adjacent 

area in Illinois: U.S. Geol. Survey Water-Supply Paper 164, 173 pp., geol_ogic map. 

ARKANSAS. 

1906. Veatch, A. C., Geology and underground water resources of northern Louisiana and southern Ark<tnsas: U. S. 

Geol. Survey Prof. Paper 46, 422 pp., geologic map. 

1908. Branner, J. C., The clays of Ark<tnsas: U.S. Geol. Survey Bull. 351, 247 pp., geologic map. 

TEXAS. 

1892. Dumble, E. T., Notes on the geology of the valley of the middle Rio Grande: Geol. Soc. America Bull., vol. 3, 

. pp. 219-230. . . 

1900. Vaughan, T. W., U.S. Geol. Survey Geol. Atlas, Uvalde folio (No. 64), 7 pp., geologic map. 

1900. Vaughan, T. W., Reconnaissance in the Rio Grande·co<tl :fields of Texas: U.S. Geol. Survey Bull. 164, pp. 1-72 

sketch map. 

1901. Hill, R. T., Geography and geology of the Black and Grand prairies, Texas: U. S. Geol. Survey Twenty-first 

Ann. Rept., pt. 7, pp. 666, geologic map. 

1902. Hill, R. T., and Vaughan, T. W., U.S. Geol. Survey Geol. Atlas, Al~stin folio (No. 76), 8 pp., geologic map. 

1911. Go1don, C. H., Geology aJ?.d underground waters of northeastem Texas: U. S. Geol. Survey Water-Supply 

Paper 276, 78 pp., geologic map. 

1911. Dumble., E. T., Rediscovery of some Conrad forms: Science, new ser., vol. 33, pp. 970-971, 1911. 
'rifE HISTORY OF A PORTION OF· YAlVIPA RIVER, COLORADO, AND 

ITS POSSIBLE BEARING ON THAT OF GREEN RIVER. 

By 'E. T. HANCOCK. 

Few regions offer more interesting geologic problems relating to drainage than the Uinta 

Mountains, in Utah and Colorado, and the ar3a immediately east of them. In fact, the writer's 

attention was primarily attracted to this field by the diversity of opinion regarding the antecedent origin of Green River. Although the present paper deals mainly with that portion of 

Yampa River .:-ast of Juniper Mountain, the conclusions reached are believed to have a definite 

bearing on the Green River problem itself. The paper is introduced by a brief discussion of 

the structural features of the region east of the Uinta Mountains, for a clear understanding of 

the relation of the minor uplifts to the great Uinta fold will better enable the reader to appreciat~ 

the possible bearing which the writer's conclusions may have in the solution of that problem. 

The 1nain range of the Uinta Mountain~i is a broad, flat-topped anticline, which bas an 

easterly trend and a length of over 150 miles and which separates the Green River Basin on 

the north from the Uinta Basin on the south. The conspicuous portion of the Uinta fold 

terminates in northwestern Colorado, but along the continuation of its axis to the east lies 

a long, gentle anticline which reaches the foothills of the Park Range. This anticline was called 

by White 1 "the inceptive portion of the Uinta fold." The axis of the anticline is coincident 

with the low, broad valley known as A.-rial Basin, and in a recent report Gale 2 refers to it as 

the Axial Basin anticline. According to White, along the eastern end of the main fold the 

strata abruptly dip east beneath the younger Tertiary beds. Upon the Axial Basin anticline 

have been developed two local uplifts which he called the Junction Mountain upthrust and 

the Yampa Mountain upthrust. T4ese he regarded as the result of a locally intensified application of the same force by which the main fold was elevated. The peculiar relation which exists 

between these two "upthrusts" and the course of Yampa River renders it necessary that the 

reader shall clearly understand their character. 

According to 'Vhite,3 the westeril base of Junction Mountain is 2 or 3 miles east of the 

east end of the main Uinta fold. There the same strata that plunge down on the east side 

of the Uinta Range rise even more abruptly, and the Paleozoic formations which constitute 

the high n1ountain peaks of the Uinta Range are uplifted to a maximum height of nearly 2,000 

feet above the surrounding lowland. White says that the sti~ata involved in the Junction 

:Mountain uplift occupy an elongate oval area, the longer diameter _of which is nearly 12 1niles 

and the shorter abqut 4 n1iles in length. The direction of the longer diameter, being approxinlately northwest, is obliquely transverse to the general direction of the axis of the main fold. 

White 4 describes Juniper Mountain (then kqowi1 as Yampa Mountain) as another "upthrust" 

of the Paleozoic formations which also rises directly upon the axis of the inceptive fold. It 

is likewise oval in outline, and has a longer diameter of about 7 miles and a shorter diameter of 

less than 4 miles. The longer diameter is aln1ost at right angles with that of the Junction -

:Mountain "upthrust" and nearly transverse with the inceptive portion of the Uinta axis. The 

Uinta :Mountain uplift involves many thousand feet of sedimentary rocks of Paleozoic, :Mesozoic, 

and Cenozoic age. According to Powell,5 the great mass of the Uinta Range is composed of 

. 1 White, C. A., On tho geology and physiography of a portion of northwestern Colorado and adjacent parts of Utah and Wyoming: U.S. Geol. 

Survey Ninth A1m. Ropt., p. 61J2, 1889. 

2 Gale, H. S., Coal fields of northwestern Colorado andnortheastern Utah: U.S. Geol. Survey Bull. 415, p. 97, 1910. 

a White, C. A., op. cit., p. 701. 

t Idem, p. 702. 

G Powell, J. W., Report on tho geology of the eastern portion of the Uinta Mountains and a region of country adjacent thereto, p. 141, 1876. 

183 
184 SHORTER. CONTRIBUTIONS TO GENERAL GEOLOGY, 1914, 

sandstones of what he called the "Uinta group." The map given by White/ compiled in part 

from the published maps of Powell, Hayden, and King, shows the Junction Mountain and 

Juniper ¥ountain uplifts as being composed mainly of carboniferous beds, with a small area 

of the so-called "Uinta" quartzite outcropping near the summit in each uplift. Clearl}7 , then, 

the only ess·ential differen~e between the two local uplifts and the main Uinta Mountains uplift· 

is one of magnitude .. The relation of some of the recent Tertiary formations to these uplifts 

will be discussed later. · Readers desiring a terse description of the course of Green River 

through the Uinta Mountains are referred to White's report. 2 

The course of Green River .across ·the uplifted Paleozoic rocks of the Uinta Range with 

entire disregard for structure is so remarkable as to arrest the attention of every observer. 

The peculiar course of the river is even more striking in view of the fact that apparently it 

might easily have gone east of the uplift, making its channel in the soft formations of the lowland. But the course of Green River through the Uinta Range is no more remarkable than 

that of the Yampa, which empties into Green River from the east, in its relation to the Junction Mountain al\d Juniper Mountain uplifts. Yampa River has its origin among the mountains of the Park Range, where its numerous tributaries flow as turbulent streams through 

rocky defiles and narrow valleys. Emerging from the foothills of the Park Range, it enters a 

more or less open country and traverses the formations involved in the Axial Basin anticline 

and the Juniper uplift with apparent disregard for rock structure. Throughout most of this 

part of its course, which leads diagonally across the strike of the beds upturned along the north 

side of the Axial Basin anticline, it has developed well-defined intrenched meanders. Finally 

it reaches the hard Paleozoic metamorphosed limestones and sandstones of Juniper Mountain, 

where, iil.stead of continuing in the soft beds around the north end of the uplift, it swings southward and cuts its way by means of a short canyon through the hard Paleozoic rocks that form 

the north flank of the uplift. From Juniper Mountain the river flows quietly over the lowlands 

of Axial Basin to Junction Mountain, which· it cuts through in a similar manner. The opportunity seems to have been especially favorable for the Yampa to join Snake River near the 

north end of Junction Mountain, for it trends in that direction throughout more than half its 

course after leaving· Juniper Mountain. Instead of that, however, it makes a distinct bend 

southwestward to Junction Mountain, and without swerving to the right or left cuts through 

.the upturned strata of hard rock in a narrow canyon, the almost perpendicular walls of which, 

according to White, reach a maximum height of 1,000 to 1,200 feet above the lowland at either 

end of the canyon. Beyond ,Junction Mountain the river flows quietly for about 10 miles 

through Lily Park. Then instead of joining Green River by way of the lowland on either the 

north or the south side of the Uinta Range it boldly enters the east end of the range itself by 

crossing the. upturned strata, as in. the· two uplifts previously described. The remainder of 

the river's course is· through a narrow canyon; in places 1,200 feet deep, which opens into the 

canyon of Green River northeast of the point where that river emerges on the south side of the 

Uinta Range. (See Pl. XX.) 

As an introduction to the discussion of the drainage east of Juniper Mountain, the views 

that have been held by some ·of the earlier geologists regarding the origin of Green and Yampa 

rivers will be very briefly stated. Powell, 3 as a result of his early explorations, ~ays that the 

proof is abunda:nt that Green River cut its own channel and ~hat it was running before the moun-

.tains were formed----," that the river did not cut its way down through the mountains from a 

height, of many thousand feet above its present site, but, having an elevation differing but little 

perhaps from what it now has, as the fold was lifted it cleared away the obstruction by cutting 

a canyon, and the walls were thus elevated on either side." The antecedent origin of certain 

of the river valleys of the great Rocky Mountain region had previously been suggested by Hayclen.4 In a paper read in May, 1896, Irving 5 says: "It is· a fact no longer disputed that these 

. 1 White, C. A., op. cit., p. 684. 

2 Idem, p. 707. 

a Powell, J. W., Exploration of the Colorado River of the West and its tributaries, p. 152, 1875. 

• Hayden, F. V., Am. Jour. Sci., voL 33, M~y, 1862; U, S. G~oL Survey Terr. Sixth Ann. Rept., for 1872, p. 85, 1873. 

5 Irv'ing, J. D., The stratigraphical relations of the Browns Park beds of Utah: New York Acad. Sci Trans., vol. 15, p. 258, 1896. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XX 

o 0 5- .10 ISMILES 

~ 

TE:RTIARY TeRTIARY(?) ~-

rti;iBrown.s.._Park ill]' u I Undi/(erentiated~P~t-Lar:amie~l 'L.aram(e" • • fOrma/JOn , Tert1ary P. !Ormat1on rormat1on. •. UNCONFORMITY. 

CRE:TACEOU"$ JUii'ASSIC AND EAii'LY PALEOZOIC LATE TEii'TIARY TRIASSIC CARBONIFEROUS OR OLOEii' 16NEOUSR0CI(S 

UndifferentiatedCre~~ ~r=........._ . . ~6].·:.· ., . u ~~-' tacequ_s, we,stofl08.th T 1./ndifli>rentiat. ~ l/.ndifferentJated :·.i:j.; Umta ; >b'~ Basalt 

%e;~f/,!,f;'t:!ia~;Jt,:s· :!,!/t,:,';;~;'e ~r;;g.:,~;,;nd ::·.-·.:.· 9uartz1te ~; ~ and LaramiebtzCA. · . · 

"b~'ffolft~{i'Y/Je ted 

CJ_ Lewis shale ~Mesav.;rde~ M?Jn~os D ~ rormat10n. mJI shale 

MAP SHOWING THE COURSE OF YAMPA RIVER, IN MOFFAT COUNTY, COLO., FROM GREEN RIVER EAST TO 107° 30' WEST LONGITUDE. 
HISTORY OF A PORTION OF YAMPA RIVER, COLO. 185 

deep canyons in the quartzite, by which the river crosses the mountains, were first established 

.in the softer overlying formations and that these formations furnished much of the corrosive 

1naterial by 1neans of which the harder rocks were cut away." In 1897 Davis, 1 in commenting 

on the above-quoted statement of Irving, said: 

It is not clear whether the overlying formations here mentioned were higher members of the Uinta arch or unconformably overlying Tertiaries. If the former, the writer would support Powell's explanation of the antecedent origin 

of the river; if the latter, he would support Emmons's view that the river is of superposed origin. In either case 

discussion on the question is hardly closed. Indeed, considering how frequently the Green is referred to as an 

antecedent river, it is remarkable that so little attention is given to the doubts that have been expressed regarding 

that manner of origin and to the difficulties that such an origin involves. 

Davis also calls attention to the fact that two •recent textbooks on geology 2 credit the 

antecedent explanation. Davis 8 himself sftys: · 

The Green River was unquestionably laked by the uplift of the Uinta Range, and to this extent it is a defeated 

and i10t an antecedent river. Between its two meridional portions,.north and south of the range, the river makes a 

great bend to the east, turning from the higher toward the lower part of the uplift-a remarkable coincidence if this 

was an antecedent turn. 

A few n1onths la~er E1n1nons, 4 referring to the above-cited article by Davis, said: 

Long before the appearance of the two textbooks he quotes (Tarr and Scott), LeConte and Geikie had each referred 

to it as antecedent and illustrating the slow uplift of mountain ranges, in apparent unconsciousness that any other view 

is possible: Suess, 5 on'the other hand, in his exceedingly careful review of the structure of this region, adopted my 

view without any reference to that of Powell. 

Throughout the remainder of his article Emmons points out some of the difficulties involved 

in the antececlent origin advanced by Powell, and :finally closes 6 by saying: 

I have for a long time been hoping, and still hope, that some other geologist may make a more thorough examination than I was able to make at that time and determine the nature and extent of this singular formation [referring 

to the Bi.shop ("Wyoming") conglomerat"e], which has never been satisfactorily accounted ,for. Whatev:er may be 

the outcome of such an examination, it would seem proper that the antedecent origin of this river should be held in 

abeyance until some positive evidence of it can be furnished. 

White,' in his concluding remarks on the geology of northwestern Colorado, lays especial 

en1phasis on the antecedent origin of Green and Yampa rivers. In order that his views on the 

origin of Yan1pa River, as related to the Junction Mountain and Juniper Mountain uplifts, 

n1ay be clearly understood a passage is quoted directly from his closing remarks: 

The facts already presented show that the elevation of not only the narrowest folds but even that of the two upthrusts 

which have been described did not cause the rivers under which their elevation began to swerve from their original 

courses, as the elevation progressed, to the extent of more than a few rods. This fact is exemplified in Split Mountain, 

where Green River cuts a short deep canyon through that prominent spur of Yampa Plateau; but it is more conspicuously shown where Yampa River traverses both the Junction and Yampa [Juniper] Mountain upthrusts. 

The writer's field observations during the last two years lead to conclusions that are not 

wholly in aGcord with those of White relative to the antecedent origin of Yampa River where it 

cuts its narrow canyon through Juniper Mountain. The field observations opposed to the view 

of antecedent origin are briefly as follows: 

The main portion of the mountain is con1posed of sandstone and hard red quartzite, including layers of conglomerate. This forn1ation was mapped by White as equivalent to that 

for:ming the core of .Junction Mountain and also to the typical qua1tzite and sandstone forming 

the 1nain core .of the Uinta Range. · The sumn1it and northern flank of the mountain are 

composed of metamorphosed limestones ·and sandstones interbedded. In passing east up 

Yan1pa River as far as the Government bridge,· and thence northeast and finally north for 

several 1niles, one crosses approxin1ately at right angles to the strike the same forn1ations that 

1 Davis, ,V. :M., Current notes on physiography: Science, new ser., vol. 5, p. 647, 1897. 

2 'l'arr, H. S., Elementary geology, p. 319, New York, 1897. Scott, W. B., .An introduction to geology, p. 325, New York, 1897. 

u Davis, W.:M., op. cit., pp. 647-648. 

• Emmons, S. F., Origin of Groen River: Science, new ser., vol. 6, p. 19, 1897. 

o Suess, E., Antlitz der Erdo, vol. 1, p. 736. 

o Emmons, S. F., op. cit., p. 21. 

7 White, C. A., op. cit., p. 710. 
-~"\4. 

186 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

are involved in the structure of the Axial Basin anticline and the Juniper Mountain uplift. 

With the exception of that portion of the section included between the Carboniferous beds and 

the White Cliff sandstone (Jurassic) the entire sequence is well exposed. In all probability 

from 15,000 to 20,000 feet of beds are included in_ the section between the top of the "Laramie" 

and the highest Carboniferous beds exposed. The highest Carboniferous beds exposed at the 

east end of the canyon dip about .15° E. From this point the dip increases to 31° at Juniper 

Hot Springs, about a mile farther east along the south bank of Yampa River. From the hot 

springs eastward the dip decreases; for example, the basal beds of the Mesaverde formation 

about three-quarters of a mile northeast of the Government bridge dip about 15° NE., and near 

parallel 40° 30' the Lewis shale dips 6°-8° NE. If the erosion accompanying and following 

the formation of the Axial Basin anticline and the Juniper Mountain uplift were the last event 

in the geologic history recorded hy the rocks of this region, then the hypothesis of the antecedent 

origin of the deep canyon through Juniper Mountain might be accepted, but such is not the case. 

The period of erosion must have been followed by one of subsidence and deposition, for upon 

the upturned and eroded edges of all the formations ·studied by the writer, from the Carboniferous to the post-"Laramie," rest a series of horizontal Eocene ( ~) beds known as the Browns 

Park formation. The basal beds of this formation where best exposed consist of soft, more or 

less unconsolidated reddish and yellowish-brown sandstones. These beds usually contain a 

large amount of conglomerate, the ·pebbles of which consist of schist, gne\ss, coarse and fine 

grained granite, white and red quartzite, and white and reddish vein quartz. At least 50 feet 

of such beds lie horizontally above the gently dipping Mancos shale in the bank of the river in 

the southwest corner of sec. 22, T. 6 N., R. 94 ,¥". These basal beds grade within a few feet 

into the overlying soft white sandstone which comprises much the greater part of the formation. 

Powell 1 describes the Browns Park "group" as occurring in the valley of Browns Park, a deep 

basin of ~rosion in the axis of the Uinta fold, near the east. end of the Uinta Range. He says: 

Eastward, both on the north and south sides of the area of outcrop, the beds are seen to rest unconformably upon 

all of the Carboniferous, Mesozoic, and Cenozoic formations previously mentioned. The unconformity with the upper 

Green River, lower Green River, and Bridger beds is well exhibited in the Dry Mountains in many :fine exposures. 

* * * Conglomerates are found at the base, in some localities having a great development. 

White, 2 who afterward studied the region, described the eastward extension of the beds 

from.Browns Park to Cedar Mountain (then known as Fortification Butte). The map accompanying his report, compiled in part from the published n1a.ps of Powell, Hayden, and King, 

represents these . beds as completely surrounding both the Junction Mountain and Yampa 

[Juniper] Mountain uplifts. They were seen by the writer to be in almost a horizontal position 

and in direct contact with the Carboniferous beds aromid the north end of the-Juniper Mountain uplift. For about 3 miles east along the river only a narrow belt of the older beds intervenes between the alluvium and the Browns Park formation, which occurs as a thin cap on the 

low hills. The original thickness and the height to which this formation reached can not be 

ascerta.ined. The fact, however, that there are points on the Browns Park formation in almost 

any direction from Juniper Mountain at elevations equal to or greater than that of the highest 

Carboniferous beds exposed where the river cuts through the mountain strongly. indicates that 

the rocks of the canyon were at one time covered by the Browns Park formation. 

Beds resembling in every way the yellowish-brown conglomerate beds at the base of the 

Browns Park formation in sec. 22, T. 6 N., R. 94 W., cap the hills near the center of A.xial Basin, 

about 12 miles southeast of the east end of the canyon. Gravel, probably resulting from the 

disintegration of these beds,· occurs as a mantle over the upper part of the Mesaverde formation 

along the high ridge about 7 miles e·ast of the canyon. The easternmost beds of the Browns 

Park formation observed by the writer occur about half a mile east of Cedar Mountain (Fortification Butte in the old reports). The mountain itself is about 20 miles east and ·6 miles north 

of the canyon· and is composed of the Browns Park forma:.tion protected by a capping of bas~lt. 

1 Powell, J. W., Report on the geology of the eastern portion of the Uinta Mountains and a region of country adjacent thereto, p. 168, 1876. 

2 Whit~, C. A., op. cit., p. 691. 
HISTOitY OF A PORTION OF YAMPA RIVER, COLO. 187 

In 1878 White 1 maintained that the Brom1s Park formation could not be of later date than 

Pliocene Tertiary. In the course of his argument he sa.icl: 

Furthermore, a remarkably extensive flow of basaltic trap, covering a large region which lies mainly to the eastward but which formerly extended much within the limits of this district, took place after the deposition of the Uinta 

group [refening to the Browns Park formation] and also after it had suffered displacement and erosion, to some extent 

at least: This is known to be the case because the trap is found resting upon the unevenly eroded surface of a portion 

of the Uinta group at" Fortification Butte. · 

In the field sea!3on of 1Q13 the ·writer succeeded in finding a portion of the sandstone resting 

upon the basalt at Cedar :Mou~1tain and on examination found the sandstone to contain numerous 

rounded n1asses of the basalt, indicatu1g that instead of being all much older than the basalt, 

ns White hnd supposed, it is really in part younger. The fact that deposition of some sandstone 

beds occurred after the formntion of the basalt indicates that the Browns Park formation may 

have been n1uch ·thicker than has hitherto been supposed. The elevation of the Browns 

Pad( forn1ation on Cedar Mountain is about 860 feet higher than that of the highest Carboniferous beds exposed at the canyon where Yampa River cuts through the north end of 

Jtu1iper Mountau1. The Browns Park formation is also from 800 to 1,000 feet higher than 

the tops of the ridges across which Yampa River has intrenched its meanders in the rocks of 

the Mesaverde formation east of Juniper Mountain. 

As ·previously stated, the conspicuous portion of the· Uinta fold terminates in northwestern 

Colorado, but in line with its axis to the east there is a long, gentle anticline which reaches the. 

foothills of the 1

Park Range and "rhich is commonly known as the Axial Basin anticline. Upon 

this anticline have been developed two distinct uplifts-Junction Mountain and JUil.iper Mountain. If Yatnpa River is antecedent its present course must have been established prior to the 

uplift which resulted in the forn1ation of the A..xial Basin anticline and the Junction Mountain 

and Juniper Mountain uplifts, and it must have lowered its channel through Junction and 1

Juniper 1nountains and intrenched its meanders down through the Mesaverde formation east 

of Juniper Mountain while the beds were being uplifted into their present position. But attention has ah·eady been called to the fact that during and after the period of upheaval sediments 

1nany thousand feet in thickness were eroded almost to a common plane. After the period of 

erosion the region was submerged and many hundred feet of additional sediments were laid 

down. Powell, 2 in his table of the gr~:mps of sedimentary strata of the Plateau province, gives 

the thickness of the Browns Park "group" as 1,800 feet, while White 3 gives it as 1,200 to 1,800 

feet. If Yampa River was antecedent to. the formation of the Axial Basin anticline and the 

J·uniper Mountain and Junction Mountain domes, its channel from the east end of the Uinta 

:Mountains to a point as far east ~s Cedar· Mountain-a distance of about 50 miles-would 

obviously have been completely buried by Browns Park sediments. The river, therefore, could 

not have n1aintained it~ channel, and it is beyond the bounds of probability that, after cutting 

tb1·ough the Browns Park sediments, it should have reestablished itself in its original bed and 

discov-ered its old canyons through Junction and-Juniper mountains. 

The distribution of the Browns Park formation and the altitudes at which the beds have 

been observed make it very probable that the upper beets of the formation were sufficiently 

high to cover to a considerable depth all that portion of .the Juniper Mountain uplift which is 

tra,rersed by the canyon, as well as the Cretaceous beds down through which the river has 

intrenched its Jneanders. This probability is strengthened by the wide distribution throughout 

northwestern Colorado and southern Wyoming of beds which have not yet been definitely 

cortelated with the Browns Park forn1ation but which bear a similar relation to the underlying 

Cretaceous and "1'1ertiary beds. · 

1 White, C. A., Uoport on tho geology or a portion or northwestern Colorado: U.S. Geol. Ulld Geog. Surves Terr. Tenth Ann. Rept., p. 38, 1878. 

~Powell, J. W., lleport on tho geology or tho eastern portion or the Uinta Mountains Ulld a region of coWltry adjacent thereto, p. 40, 1876. 

a White, C. A., On tho geology and physiography or a portion of n<,>rthwestern Colorodo and adjacent parts of Utah Ulld Wyoming: U. S. Geol. 

Survey Ninth A.un. ltopt., p. 686, 1889. 

37183°-15-13 
188 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

On the basis of the field observations here briefly recorded the conclusion is reached that 

Yampa River, instead of beiug antecedent, is superimposed and that the present course of the 

river was not established until after the emergence that followed the deposition of the Browns 

Park sediments .. ·These observations would seem to indicate that the series of·events in the 

development of the present course of the stream was as follows: 

After the river had deepened its channel in the Browns' Park formation sufficiently to 

encounter the hard Paleozoic rocks of the Juniper Mountain uplift these rocks acted for a time 

as a barrier. The gradient of the stream for son1e distance above the barrier was diminished, 

arid there resulted a condition of local base-leveling. In other 'words, the stream for some distance above the obstruction approached the condition of old age. After it reached grade and 

·lost the power of degrading its bed, lateral planation resulted in the development of a :flood plain 

upon which the river established its meandering course. Below the barrier the stream was 

al;>le to deepen its channel much more rapidly in the soft beds of the Browns Park formation. 

As a result the river developed a steep gradient for some distance below the barrier of uplifted 

Paleozoic rocks and in all probability formed a series of falls on the lower side of the barrier. 

Ultimately it succeeded in cutting ·through the barrier. This· being accomplished, the gradient 

of the channel and the velocity of the water above the hard-rock _obstruction were increased, 

and consequen~ly the riye:t was enabled to intrench its previously established meanders down 

through the Cretaceous beds along the north limb of the JL~ia:l Basin anticline. An appreciable 

dip was observed at many places where the Browns Park b.eds are in contact with· the older 

formations. This may be due entirely to original deposition on a sloping surface or in part to 

minor subsequent uplift. If subsequent uplift occurred, that may also have been a factor in the 

rejuvena.tion of the stream and the formation of the intrenched meanders. 

Then:} is a very noticeable parallelism of the smaller strean1s both north and south of Axial 

Basin. The writer has observed numerous exposures where the sandstone of the :Mesaverde 

formation is traversed by a very pronounced system of parallel joints. The joints in most 

places appear to have been developed almost at right angles to the strike of the formation, 

especially ·w;h.ere the beds are dipping rather steeply. This is well shown in Plate XXI. ' As 

the courses of the smaller streams are nearly at right angles to the strike of the :Mesaverde 

formation, it~is quite probable that they were determined to a considerable extent by th.e existence of joints. . . 

Published desqriptiqns indicate that the structure of Junction :Mountain is not 'unlike 

that of ·Ju¢per ¥~1intam. The map prepared by White 1 shows the .Browns Park formation 

as a continuous\belt. extending !rom Yan1pa [Juniper] :Mountain to the western border of 

Browns Park.·· .. ·If surrounds the- Paleozoic beds of the Junction :Mountain uplift.. Powell/ 

in his structure· section through Junction :Mountain, show·s the Browns Park formation as 

lying about' 'soo feet below the older beds wher.e the mountain 'is traversed by Yampa River. 

The Browns Park formation, where it' laps oyer the :Mesaverde formation, about 5 miles southeast of Junction ~fountain, is mapped by Gale 3 at an elevation that is about 650 feet higher 

than that of the older beds at the canyon as shown on Powell's atlas map of the Uinta ~1ountains. These facts strongly suggest that at .one time the Browns Park formation entirely 

covered at least that· portion of Junction Mountain through which Yampa River cut its deep 

canyon. The fact that the present .<?.hannel of the river is in the Browns Park formation 

through the· entire distance from Juniper ~1ountain to Junction ~fountain, together with the 

probability that the Browns Park- beds at one time completely .covered that portion of ·June-· 

tion Mountain including the canyon, certainly justifieg the conclusion that this portion of 

Yampa River also established .its course subsequent to the mnergence following the deposition 

of the Browns Park formation. 

1 White, C. A., Geology and physiography of a portion of northwestern Colorado and adjacent parts of Utah and Wyoming: U.S. Geol. Survey 

Ninth Ann. Rept., Pl. LXXXVIII, 1889. . 2 Powell, J. W., Report on the geology of the eastern portion of the Uinta Mountains and a region of country adjacent thereto, p. 10, 1876. 

s Gale, H. S., Coal fields of northwestern Colorado and northeastern Utah: U.S. Geol. Survey Bull. 415, Pl. XVIII, 1910. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 90 PLATE XXI 

A. 

B. 

JOINTING IN SANDSTONE OF MESAVERDE FORMATION. 

A , At t he "Tra nsfer," T. 2 N. , R. 92 W., Meeker qu ad ra ngle, Colo. ; B , In T. 4 N. , R. 91 W. , Mon- ument Butte qu ad ra ngle, Co lo. 
HISTORY OF A POHTION OF YAMPA RIVER, COLO. 189 

As regards the course of Yampa River fr01n this point to Green River, and of Green River 

itself, no suggestions based on personal observations can be offered. However, those who 

hn.ve studied the Uintn. uplift, including Powell and En1mons, agree that the uplift began at 

the close of the Cretaceous period, and t4at later at least 8,000 feet of Tertiary sediments, derived 

in part, if not wholly, fron1 the degradation of the arch itself, were deposited along both flanks 

of the range. According to Powell, these Tertiary formations bent clown, while the older beds 

were uplifted. The present course of Green River for a distance of about 30 niiles through 

Browns Park is in the Browns Park formation. In view of these facts, together with the conclusions which have beei1 reachecl.relative to the origin of one of the principal tributaries of 

Green H.iver, it is believed that the assertions of the antecedent origin of' Green River should 

be accepted only after n1ore facts have been obtained bearing on the original extent and thickness of the late Tertiary forn1ations, as well as on the diastrophic history of the Uinta Range. 

TI-IE INORGANIC CONSTITUENTS OF ECHINODERMS. 

By F. W. CLARKE and W. C. WHEELER. 

INTRODUCTION. 

In a recent paper 1 on the composition of crinoid skeletons we showed that crinoids contain 

large quantities of magnesia, and that its proportion varies with the temperature of the water 

in which the creatures live. This result was so novel and surprising that it seemed desirable 

to examine other echinoderms. and to ascertain whether they showed the same characteristics 

and regularity. A number of sea urchins and starfishes were therefore studied; their inorganic 

constituents being analyzed in the same manner as those of the crinoids. The specimens for 

analysis were carefully selected by ~1r. Austin H. Clark, of the United States National Museum, 

to whom our thanks are due 

SEA URCHINS. 

'I'he following sea urchins were chosen for a_nalysis: 

1. Strongylocentrotus (b·obachiensis (0. F. Muller). Upernivik, Greenland, latitude 72° 481 N. 

2. Strongylocentmtus fragil·is (Jackson). Albatross station 2946, off southern California. Latitude 33° 58' 0011 N ., 

longitude l:L9° 301 4511 W. Depth of water, 274.5 meters; bottom temperature, 13.6° C. 

3. Echinarachnitts parma (Lamarck). Coast of New England. 

4. Enco7Je califomica (Verr.ill). Galapagos Islands, on o'r near the Equator. ' 

5. Lytechimts anam.esus (H. L. Clark). Albatross station 2938, off Wilmington, California. Latitude 33° 35' 

1511 N., longitude 118° 08' 30" \V. Depth, 86 meters; bottom temperature 15° C. 

6. Loxechinus albm (Molina). Port Otway, Patagonia. Latitude about 46°-47° S. 

7. Tetrapygus niger (Molina). Coast of Peru. 

8. Tretocidaris aJfinis (Philippi). Albatross stations 2316 arid 2317, off Key West, Florida. Latitude 24° 25' N., 

longitude 81° 471 W. Depth, 85 meters; bottom temperature 24° C. 

9. Jl'eterocentrot1ts mammillatus (Linne). Low or Paumotu Archipelago, southern Pacific Ocean. Latitude 

between 14° and24° S. 

In the following analyses the loss on ignition ·covers carbon dioxide, water, and organic 

matter, the last item being often large. The deficiencies in summation are due to undetermined sea salts, adherent to or inclosed by the specimens. The C02 needed is calculated to 

satisfy the bases. 

Analyses of sea urchins. 

___________ .:,__ ____________ --------------------- 8102 .................................................................... . HsOs ................................................................... . 

~~~.::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::':: 

i~~;<>;i ii.-i·litio~::::::::::::::::::::::::::::::::::::::::::::::::::::::::: 

0.12 

.34 

2.58 

47.34 

Trace. 

48.53 

98.91 

C02 needed ...................... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40. 04 

0.26 

.65 

2.68 

41.08 .39 52.21 

97.27 

33.87 

0.14 

.27 

2.97 

49.17 .05 45.74 

3.86 

5.03 

4. 75 43.42 

Trace. 

43.01 

98. 34 100.07 41.80 40.40 

1 U. S. Geol. Survey Prof. Paper 90-D (Prof. Papet 90. pp 33-37), 1914. 

8.52 

3.01 

3.04 

37.92 

.19 45.38 

98.06 

32.90 

0.05 

.17 

3.07 

45.87 

'!'race. 

49.47 

98.63 

39.41 

191 

0.31 

.30 

2.82 

48.86 

Trace. 

44.98 

97.27 

41.41 
192 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

Rejecting the excess of volatile matter and recalculating to 100 per cent, we have the 

following composition of the inorganic constituents of the seven sea urchins of the preceding 

table: · Revised analyses of sea urchins. 

4 

------------------------1----------------------------

Si02 .................... · ..... , ........................................... 0.13 R20a.................................................................... .37 MgCOa.................................................................. 5. 99 

2:~~0~:::::: :::::::::::::::::::::::::::: :~:::::::::::::::: ::::::::::::: · T~~-c~~ 

0.31 

.so 

7.05 

90.79 

1.05 

0.15 

.2S 

6.61 

92.S4 .12 

3.92 

5.10 

12.26 

7S. 72 Trace. 

9.95 

3.52 

7.45 

7S.60 .4S 

0.05 

.19 

7.27 

92.49 

Trace. 

0.33 

.32 

6.31 

93.04 

Trace. 

100. 00 100. 00 100.00 100. 00 100.00 100.00 100.00 

I 

Sea ll:rchins Nos. 8 and 9, Tretocidaris and Heterocentrotus, must be considered separately 

from the others. No. 9, a giant form, was the subject of four analyses, the shell or test, the 

dental pyramid, the small white spines on the border of the peristome, and the large purplishred spines. The large red spine analyzed was 15 centimeters long and weighed 13 grams. 

Analyses of Heterocentrotus mammillatus. 

Test. 

Actual analyses. 

Dental 

pyramid. Wbite spines. Red spines. 

Si02 ....................................... : .. ; ............ ~.................... 0. 02 0. 02 0. 05, 0. 05 R20a. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 . OS .13 . 26 MgO ................ :. . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . .. . .. . .. ... .. . . . . .. . .. . .. . . 5.21 5.50 3. 74 4.47 

CaO .. -----········'··-··--·······················-·-·-····-·····--·········--·· 43.60 46.02 48.26 47.72 

r~~:oii iillitio~:: ::::::::,:::::::::::::::::::::::::::::::::::::::::::::::::::::: T::.c~2 TI~.c~o Tl~.ci6 T::_~g I-----9-8.-5-S·I----9-8-.6-2-I----98-.6-4-~I------9-S-.4-9 

C02 needed ................................................... : ...... __ ._._ ... . 39.99 42. 21 42.03 42. 41 

·Shell. 

Revised analyses. 

Dental 

pyramid. ·White spines. Red spines. 

Si02---········································································· 0.02 0.02 0.05 0.05 . R20a........................................................................... .15 .09 .14 .28 

~!c?3a~ ·. ·_::: :::: :::::::::::::::::::::::::::::: :: ::: ::::::: : : :::::::::::::::::::: ~~: ~g ~~: ~~ 9t ~~ s~: ~~ CaaP20s ...... : ............................................ · ............. _ ........ 1 

___ T_r_ac_e_. 

1 

___ T_ra_c_e._

1 

_____ T_r_ac_e_. 

1 

_____ T_ra_c_e. 

100.00 100.00 100.00 100.00 

From these analyses we see that the inorganic constituents of Heterocentrotus are not 

uniformly distributed. The shell and teeth are alike and rich in magnesium carbonate; the 

coarser spines are much less magnesian. The composition of the entire skeleton, if it can be 

called so, would probably be somewhere near that of the red spines alone, only a little higher 

in magnesia. 

A similar example is offered by No. 8, Tretocidaris .. In the specimen analyzed the shell 

and spines were 'taken separately, but the spines were dead when the urchin was collected. 

The analyses are as follows: · 

Analyses of TretoCidaris a .!finis. 

Actual analyses. Revised analyses. 

Shell. Spines. 

Si02-····-·-·····················--·-·········· 0.11 0.53 Si02 .•........................................ R20a ......................................... , . 15 . 14 

~~gg_._._._::::::::::::::::::::::::::::::::::::::: ~: ~5 4~: n 

R20a ......................................... . 

~!cC3aa_- _-_-::::::::::::::::::::::::::::::::::::: 

i~~:oii iiflitio~:::::::::::::: ::::::::::::::::: TI:.ci2 Tl~.cis CaaP20s: ......... -.- .. -.-.-.-.---.-.• ------- · · · 

1-----1----11 98.40 9S.81 C02 needed .................................. . 44.40 41.41 

Shell. 

0.12 

.17 

9.33 

90.38 

Trace. 

Spines. 

0.56 

.15 

4.63 

94.66 

Trace. 1----1----- 100.00 100.00 
INORGANIC CONSTITUENTS OF ECHINODERMS. 193 

I-Im·e again the spines are lower in their content of magnesia than the shell. 

In two of the analyses, Nos. 4 and 5, large percentages of silica and sesquioxides appear. 

These are due to inclosed or adherent sand and mud, which were visible in the specimens but 

not readily ren1ovable. On rejecting these impurities and recalculating to 100 per cent, the 

perc~ntages of magnesium carbonate become 8.49 ·and 13.47, respectively. With thes·e corrections, and assuming the -percentages found for the shells rather than the spines in Nos. 8 and 9, 

the following table has been constructed: 

Percentage of magnesium carbonat~ in sea urchins. 

Locality. Latitude. 

~,trongylocen1:t'otus drobachiensis. . . Greenland .. :.... . . . . . . . 72° 48' N .......... . letmpygus mger................... Peru................... (?) ............... . 

Echinaradmius parma ..... .'....... New England.......... 42°-45° N ........ . Strongylocentrotus fragilis. . . . . . . . . California.............. 33° 58' N .......... . Loxechinus albus .................. Patagonia ............... 46°-47° S .......... . ~~ytecl~inu~ an~m.esus............... California ............. ~ 33° 35' N .......... . lretoc1dans affims....... ... . . . . . . . . Key West .............. 24° 25' N .......... . Heterocentrotus mammillatus ...... Paumotu ............... 14°-24° S .......... . Encope californica..... . . . . . . . . . . . . 9alapagos. . . . . . . . . . . . . EquatOr .......... . 

Depth. 

:Meters. 

m 

274. 5 

(?) 

85 

85 

(?) 

(?) 

Temperature. 

1fr 

13. 6 

(?) 

. 15 

24 

(?) 

(?) 

Per cent. 

5. 99 

6. 31 

6.61 

7. 05 

7.27 

8.49 

9.33 

12.30 

13.47 

A comparison of these figures with those found for the crinoids shows the same regular 

v-ariation with tmnperature. The sea urchins from cold regions are relatively low in magnesia; 

those fr<nu the Tropics .are high. There is, however, one apparent exception-the urchin from 

Pei:u. r.rhis abnormality may be due· to growth in v-ery deep water, which is almost always 

cold, or to the I-Iumboldt current, which flows northward from the Antarctic Ocean. It is 

unfortunate that actual ten1perature observations are so few in this series of analyses. They 

resmnble those of the crinoids very closely, except that the latter seem to average somewhat 

higher in 1nagnesiu1n carbonate. :More analyses are needed to determine the fact. 

STARFISHES AND OPHIURANS. 

Eleven starfishes, including brittle stars, were analyzed, as follows: 

1. Asterias vulgaris (Packard). Eastport, Maine. Latitude 44° 55' N ., longitude 67° 001 W. 

2. Asterias tanneri·(Verrill). Albatross.station 2309. Latitude. 35° 43' 3011 N., longitude 74° 52' W. Depth, 

102 meters; bottom temperature not given. 

3. Asterina 1niniata (Brandt). Pacific Grove, California. Latitude 36° 36' N ., longitude 121 o 55' W~ 

4. LeJJlasterias compta (Stimpson). Albatross station 2250. Latitude 40° 17' 1511 N., longitude 69° 511 4511 W. 

Depth, 86 meters; bottom temperature, 10.8° C. 

5. Benthopecten spinosus (Verrill). Albatross station 2568. Latitude 39° 15' 00" N., longitude 68° 08' 0011 W. I . 

Depth, 3,249 meters; bottom temperature, 2.7° C. 

6. Lttidia clathrata (Say). Near Charleston, South Carolina. Latitude 32° 471 N., longitude 79° 5.7' \V. Depth, 

between 2 and 22 meters. · . 

7. Acanthaster planci(Linne). Palmyra Island, in the Pacific Ocean, west of. south from Hawaii. Latitude 5° 49'N. 

8. GorgonoceJJhal'ttS arcticus (Gray). Off Cape Cod, Massachusetts. About latitude 42° N. 

9. GorgonoceJJhalus caryi (Lyman). Alaska. 

10. 0JJhioglypha sarsii (Li.itken). Albatross station 217.6. Latitude 39° 32' 3011 N., longitude 72° 21' 30" W. 

Depth, 553 meters; bottom temperature, 5° C. 

11. Ophiodcrma cinerettm (Mi.iller and-Troschel). Ensenada Honda, Culebra Island, east of Porto Rico. Latitude 

18° 201 N., approximately. 
194 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. · 

The last locality is in or on the edge of the equatorial current. The Albatross stations were 

all fixed on cruises between Cape Hatteras and Nantucket. The analyses are as follows: 

Analyses of starfishes. 

2 3 9 10 11 

------------------ Si02 ........ : ....................................... 0.45 0. 79 0.03 1.21 2.06 0.27 0.19 1. 77 1.08 0.98 0.21 R20a ................................................ .21 .55 .20 .48 . 79 .36 .14 .62 . 72 .53 .09 

~!g:.-:::::::::::::::::::::::::::::::::::::::::::::: 2.59 3.83 3.98 3.05 3.93 4.89 4.36 3.36 2.82 3.99 5.80 35.71 33.51 36.85 30.35 40.54 41.30 33.18 36.13 29.80 42.14 41.32 P205 ................................................ .07 .24 .14 .13 .11 .14 .07 .22 .32 .29 .07 Loss on ignition .......... , .......................... 60!18 54.89 57.64 63.91 51.66 52.03 62.07 55.72 63.37 50.95 51.58 

99.21 98.81 98.84 99.13 99.09 98.99 100.01 97.82 98.11 98.88 99.07 C02needed......................................... 30.84 34.30 33.05 27.08 35.94 37.70 30.81 31.65 25.80 37.29 38.79 

Revised analyses of starfishes. 

2 4 8 9 10 11 

-----------------1---------------------------------

Si02 ................................................ 0.64 1.01 0.03 1. 94 2.47 0.32 0.27 2.39 1. 77 1.15 0.24 R20a ................................................ .30 . 70 .27 . 77 .94 .42 .20 .84 1.18 .62 .12 

~;5ga .·.' .' .':::::::::::::::::::::::::::::::::::::::::: 

7. 79 10.28 11.24 10.27 9.88 12.13 13.33 9.53 9. 71 9.84 14.11 91.06 87.44 88.06 86.57 86.42 86.77 85.99 86.60 86.18 87.65 85.34 CaaP20a ............................................. .21 .57 .40 .45 .29 .36 .21 .64 1.16 • 74 .19 

---------------------- 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

In the following table the analyses are arranged in the order of ascending magnesium carbonate, like those of the sea urchins: 

Percentage of magnesium carbonate in starfishes. 

Locality. Latitude. 

Eastport ............... . Cape Cod .............. . Alaska ................ . Station 2176 ............ . Station 2568 ............ . Station 2250 ..... ~ ..... .. Station 2309 ............ . 

Asterias vulgaris .. _ .. _______ . ___ ... Gorgonocephalus arcticus. _. _______ . Gorgonocephalus caryi ___ . _ . __ -... Ophioglypha sarsii .. _____ ... _ .... _ .. Benthopecten spinosus. __ .. __ . ____ . Leptasterias com pta .. ___ .... _ ..... Asterias tanneri. ___________ . ___ . _. 

44° 55' N .......... - 42° ± N ......... .. 

(?)- - . --.---.-.-.-- 39° 32' N __ ... _ . _ .. . 

39° 15' N .......... . 40° 17' N .......... . 35 o 43' N ........ -- . Asterina miniata ...... ____ .. _ ... __ . California ............. . 36° 36' N ...... -... . Luidia clathrata .. ______ . _. ____ . _ .. _ Charleston ____ . _ . _ .... _ 32° 4 7' N ___ --_ .... . Palmyra Island. __ . __ . __ Culebra .. , . _ . ___ .. __ ... Acanthaster planci. .. _ .. ____ .. _. _ .. Ophioderma cinereum. _______ ... _ .. 5° 49' N ........ __ .. 18° 20' N .......... . 

CRINOIDS. 

Depth. 

~Meters. 

g~ (?) 

553 

3,249 

86 

102 

Hj (? 

(? 

Temperature. 

o C. 

(?l (? 

(? 

5 

2. 7 

10 .. 8 gl 

(1~ (?) 

MgC03 

Per cent. 

7.79 

9.53 

9. 71 

9.84 

9.88 

10.27 

10.88 

11.24 

12. 13 

13. 33 

14. 11 

In order to maJm the comparison between the three groups of echinoderms more complete, two additional crinoid skeletons were analyzed, as follows: 

1. Zygometra microdiscus (Bell). Aru Islands, near the western tip of New Guinea. Latitude 5°-6° S. 

2. Chlorometra rugosa (A. H. Clark). Near Rotti, Lesser Sunda Islands. Latitude 10° 391 S., longitude 123° 401 E. 

Depth, 520 meters. 

Analyses of crinoids. 

Actual analyses. Revised am.>lyses. 

Si02 ........................ :.................. 0. 04 0. 05 Si02---~....................................... 0. 05 0. 06 R20 8 •••• ,..................................... • 48 . 23 R20a.......................................... . 62 • 27 

C

Mag0o_._·_·.--............ _ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ ._ 4. 92 3. 99 MgCOa........................................ 13. 37 9. 87 - 37. 19 42. 72 CaCOa......................................... 85. 48 89. SO 

i~~:·a:ii ignition.'::~::::::::::::::::::::::::::: 55:~~ ·Trrc:9 caaP2oa ....................................... 1 ___ . 4_8_~ ___ T_m_ce_. 

1----1-----11 100.00 I 100.00 97.85 98.68 

C02 needed .................................. . 34.47 37.95 
INORGANIC CONSTITUENTS OF ECHINODERMS. 195 

Combining these data with those given in our paper upon the crinoids, we have the following table: · 

Genus. 

Heliometm ...................... . Promachocrinus .................. . Ptilocriuus .. _ .. _. _ ................ . Anthometra ...................... . Psathyrometra .................. _ .. Hathrometra .................. __ .. Florometrn ......................... . Chlorometra .................. _. _ .. Bythocrinus .............. · ......... . Pentametrocrinus .. _ ............. _ Hypalocriuus .... _ ................ . 1\{etacrinus ........................ . Param etra ........................ . Ptilometra ....................... . Isocrin us .......................... . Catoptometra ............ _ ... _. _. __ _ 

Crinometra ....................... . ']' . t .rop10me ra ....................... . Endoxocrinus .............. , ..... . Pachylometrn. .................. _. _ Cras_pedometra ................... . Caplllaster ................ ___ , ___ _ 

Zygometra ....................... . 

Percentage of magnesium carbonate in crinoids. 

Locality. 

Northern Japan ....... . Antarctic ............. . British Columbia ...... . Antarctic_ .......... _ .. Northern Japan .. __ . __ _ 

Massachusetts._ ........ . Washington ............ . Rotti ......... _________ _ 

Gulf of Mexico ........ . Southern Japan ....... . Philippine Islands ____ . Southern Japan ....... _ Philippine Islands .... . Australia .............. . 

Cuba.····-------------

Philippine Islands ..... 

~~~rii_._._ ·_ ~ ~ :·~: ~ ~ ~ ~ ~ ~: ~: Cuba ............ ____ . _ 

Philippine Islands .... . Philippine Islands .... . Philippine·Islands .... . Aru Islands ............. . 

Latitude. 

43° N ............ . 67° s __ , _________ _ 

52° 39' N .... - ----. 67° S .•............ 44°N ............ .. 39° 56' N ......... - 4 7 o 29' N ......... - 10° 39' S .......... . 

28° 38' N .... ------ 34° N ___ .... _____ _ 

9° 37' N .......... . 30° 58' N ......... . 9° 15' N .......... . 

33° 15' S.- .. ---- .. -

24° N ... ---------- 80 N -·------------ 239 10' N ......... . 

25° 54' S .. --------- 24° N ............ . 8° N .............. . 5° 12' N. _. _. _. _ .. . 6° N ______________ _ 

5°-6°s ___________ _ 

D Temper- M CO epth. ature. ' g a· 

Meters. 

315 

375 

2,858 

375 

(?) 

329 

1,145 

520 

255 

1,123 

612 

278 

502 

(?) 

(?) 

104 

59 

(?) 

(?) 

1,044 

32 

36 

(?) 

o C. 

1. 5 

'-1. 8 

'1.8 

-1.8 

1.6 

7. 8 

3. 3 

(?) 

(?) 

3.4 

10.2 

13. 3 

12 

q~ ~?) 26.2 

(?) 

~p 

c?~ (?) 

(?) 

Per cent. 

7.28 

7.86 

7.91 

8. 23 

9.25 

9.36 

9.44 

9.87 

10.09 

10. 15 

10. 16 

10.34 

11.08 

11. 13 

11.56 

11.68 

11. 69 

11. 77 

11.·79 

12. 20 

12.34 

12. 69 

13.37 

·The percentage of magnesiun1 carbona.te in Chlorometra is low for the latitude of the 

locality; but that is doubtless clue to the depth of the water (520 meters) in which the erinoid 

lived. The probal?le temperature at that depth was between 7° and 10° C .. 

GENERAL CONSIDERATIONS. 

From the evidence now available, it seems ahnost certain that the inorganic constituents 

of any echinoderm will have the composition. of a moderately magnesian limestone. There 

may be exceptions, but none has yet been found. The three tables, for crinoids, sea urchins, 

and starfishes, all tell the same story, and with remarkable unanimity. Furthern1ore, the 

proportion of magnesium carbonate appears to be a function of temperature, the organisms 

fron1 warm regions being richer in it than the cold-water forms. The exceptions to this rule 

are apparent rather than real; for cold or warm currents and varying depths of water account 

for all semning irregularities. The sea urchins seem to be a little· poorer in magnesia than 

either of the other groups, but the analyses are fewer and therefore less conclusive. Silica and 

sesquioxides are probably altogether extraneous, although it is possible that small quantities 

of thmn n1ay really belong to the organisms. In phosphate of lime the starfishes are richest, 

and all the specimens analyzed contain it in sn1all amounts. Whether it is an essential constituent or not is uncertain. As shown by Meigen's reaction, all the echinoderms studied are 

calcitic, and no evidenceof aragonite in them was found. 

The temperature regularity shown by the analyses offers an inte:resting biological problem 

with which we can not undertake to cope. It is not due to differences of eomposition in the 

solid 1natter of sea water, for that is practically uniform all the world over. In all the great 

oceans, and even in minor bodies of water like the Mediterranean, the Baltic, and the Black 

Sea, the proportion of magnesia to lime is very nearly if not actually constant. In gaseous 

contents and especially in carbon dioxide the waters vary; the gases being more soluble in 

cold than in warn1 water. Whether this fact has any relation to the phenomenon under discussion we can not attempt to say. We can only report the facts and leave their biological 

·discussion to others. 
196 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1914. 

On the geological bearing of the evidence now before us it is easy to speculate; but here 

great caution is needed. It would be unwise to assume that magnesian sediments are n1ore 

·abundantly deposited in warm than in cold climates, and so to develop a system of what might 

be called paleoclimatology. Against such an attempt there are two obvious reasons. First, 

the sediments are only in small part derived from echinoderm ren1ains. Other agencies are 

more impDrtant in the formation of marine limestones. Secondly, a dense population, so to 

speak, of cold-water organisms may deposit much more magnesia than a sparse population of 

warm-water forms. The data now in hand, with all their suggestiveness, are· too few to warrant 

any far-reaching generalizations. It is our intention to carry ·the investigation still further, 

studying other marine invertebrates by the same methods as those which we have followed 

here. If other analysts choose to enter this field of research, their results will be ·welcomed 

by us. 
INDEX. 

A. 

Page. 

ApJshnpa quadrangle, Colo., dike rooks in, distribution and character or. .............................................. 17-18 

d.lko rocks in, potrogruphy of ................................. 1&-28 

googrnphic relations of ............................... 18 (Pl. IV), 29 

Arnpnhoo formntion, vortobrnto fossils from .................... 117-153 

Augite minetto and tingunite dike, occur ronco and charncter of ... 20-21 

Augite vogoslto dike, olivine beal"ing, analyses of.................. 22 

OCCUITOI~CO nnd charncter of. ....................... 21-24,22 (Pl. V) 

B. 

Bartsch, l'nul, fossils oxnm.inod by............................... s:; 

13nsnlt, olivine phlgloclnso, nnnlysos of..:......................... 27 

oUvino plngioclnso, occmronco nnd chnrnctcr of .. 26 (Pl. VII), 26-28 

types of...................................................... 27 

Dnsslor, H .. S., fossils identified by, in Cooper marl............... 85 

BosUn, K S., Geology of tho pitchblende orcs of Colorado......... 1-5 

Bcarpaw shale, distribution Mel character of..................... 102 

Bolly llivor formation, correlation of ............................. 64-66 

invortobmto fossils from ................................... 115-117 

vertebrate fossils from ..................................••.. 117-153 

Bowen, C . .!!~,., ~eho stratigraphy of tho Mm~tana group, with special 

roforonco to tho position nnd ago of tho Judith River 

formntlon In north-ccntrnl Montana ................. 95-153 

Bridgeport Landing, Aln., Crotaceous-Eocono contnct at.......... 161 

Browns Pnrlc formntlon, position of ........................ 186-187,188 

c. 

Calhoun mine .• Colorado, pitchblende from ............... 4-5,5 (Pl. II) 

CMyon ltango, Utah, field work on.............................. 51 

geology or. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53-59 

oro deposits in....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59-60 

stratlgmphy of ••................. , ........................... 53-57 

structure of ...........••...................................... 57-58 

topography of................................................ 52 

Charleston, S.C., artesin.n wells at, mineralogy of waters from .... 90-94 

Citadel Groen well at., record of.. ............................. 84-85 

deep well at, method employed in drilling . .' ................. 59-70 

origin of water from ...................................... 89-90 

qunntlty and quality of water from ....................... 70-71 

record of................................................ 71-79 

strata pcnotrut.ecl bY, ........ ~ ............................. 85-89 

Chesapeake J3ny, erosion and deposition in. See Choptu.nk River. 

n1aps of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-8 

Chop tank lllver, Md., mouth of, erosion and sedimentation at... 7-15 

mouth of, geology of ........................................ ·. 9 

n1nps of ................................. .'.. . . . . . . . . . . . . . . 9 

topogruphy of. ........................... .' .... 9-15,10 (Pl. III) 

Clnggott fonnntlon, distribution and character of ................ 9&-100 

fossils from ............................................. 102,114-115 

Chuk, Austin H., ack·nowledgmunts to .......................... 33,191 

Clnrkc, }~. W., and Wheeler, W. C., 'l'ho composition of crinoid 

skeletons ............................................. 33-37 

nud Wheeler, W. C., 'l'he inorganic constituents of cchinodonus ..................................... : ... : .... 191-196 

Clayton, Ala., Cretaceous-Eocene contact ncar.................... 160 

Coast and Geodetic Survey, charts by: ............... :........... 7-8 

Coastal Plain, Atlantic and Gulf, formations in contact in....... 157 

·Colomdo; dike rocks in. See Apishapa quo.drMgle. 

pitchblende in. See Qunrtz Hill, Colo. 

uraniun1 in .................................................. . 

Colomdo shale, distribution and character of...................... 97 

Colomdo, southwestem, stratigmphy of .......................... · 39-50 

Page. 

Cook Point, Md., changes at .... , ..................... 10 (Pl. III), 12,15 

Cooke, C. Wythe, fossils determined by ............ 163,166,167,178, 1i9 

Cope, E.· D., cited ........................................... ·99, lOG, 110 

Copper, occurrence of, in tho Canyon Range, Utah .......•....... 59-60 

Cornwall, England, pitchblende in............................... 3 

Cretaceous-Eocene contact, at Old Canton Landing, Ala., plato 

showing.............................................. 163 

at White Bluff, Texas, plates showing ........ ,............... 172 

east of New Albany, Miss., plate showing.................... 168 

in the Atlantic and Gulf Coastal Plain . . . . . . . . . . . . . . . . . . . . . . 155-182 

literature of ............................. ·.· ................ 181-182 

SO'!lth or Macon, Ala., plate showing.......................... 163 

trend or, map showing....................................... 156 

.in Maverick County, Tex., map showing................. 170 

Cretaceous fauna co.mparod with Eocene .......... : ............ 157-159 

Crider, A. F., cited............................................... 166 

Crinoid skeletons, analyses of. ......................... 34-35,37, 19•1-195 

composition or existing~.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-36 

composition of fossil. ......................................... 36-37 

Cross, Whitman, Dike rocks of the Apishapa quadrangle, Colo ... 17-31 

·and Larsen, Esper S., Contributions to the stratigraphy of 

southwestern Colorado ............................... 39-50 

Cushman, Joseph A., fossils identified by ......................... 79-83 

Cutler formation, occurrence of, in Piedra Valley, Colo ..... ~..... 48 

D. 

Dakota sandstone, overlap of.. ................................. :. 40-44 

Davis, 'V. ?.I., cited ..... .' ........................... ·............. 185 

Dawson, G. M., cited ............................................ · 107 

Denver formation, vertebrate fossils from .. : .................... 11i-153 

Diabase, sodic, occwTence and character of....................... 28 

Dolores formation, distribution of, in Piedra Valley, Colo ........ 47-48 

Domes in north-central Montana................................. 103 

Dumble, E. '1'., cited .......................................... 170,171 

E. 

Eagle sandstone, distribution and character of. ................... 97-98 

fossils from ................................................. 114-115 

'Echinoderms, inorganic constituents of.. ....................... 191-196 

Elbert formation, occurrence of, ill Piedra Valley, Colo........... 50 

Emmons, S. F., cited ..................... ~...................... 185 

Eocene conglomerate, distribution of, in the Canyon Range, 

Utah ................. : ....... ~ ................... : .. 56-57 

Eocene fauna compared with Cretaceous .................... : .. 157-159 

Eocene sandstone, plate showing................................. 178 

Escondido for~ation, plate showing.............................. 179 

F. 

Faults in north-central Montana................................. 104 • 

Folds in north-central Montana.................................. 103 

Fool Creek canyon, Utah, generalized section along, flgmeshowing. 55 

Fossils, Cretaceous and Eocene compared ...................... 157-159 

from Claggett formation and Bearpaw shale................. 102. 

from deep \\;ell at Charleston, S. C ............................ 79-83 

from Eagle sandstone, Claggett formation, and Fox Hills sand-

. stone ...... : ........................................ 114-115 

from Judith River, Bolly River, and Lance formations ..... 115-117 

from Judith River, Belly River, Lance, Denver, and Arapahoe 

formations ......................................... 117-153 

from Judith River formation ............................... 111-112 

from limestone of the Canyon Range.. . . . . . . . . . . . . . . . . . . . . . . . 54 

from Montana group on1'wo Medicine River .............. 62,63,64 

Fox Hills sandstone, fossils from ............................... 114-115 

197 
198 INDEX. 

G. 

German mine, Colo., pitchblende from .......................... . 

Gilbert, G. K., 'vork of. ......................................... . 

Page. 

4 

17 

Gilmore, C. W., cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 

Girty, G. H., fossils determined by.............................. 54 

Granite gneiss, pre-Cambrian, pitchblende in ... ~ ............... . 

Green River, bearing of history of Yampa River on ............ 183-189 

course of. •................ '................................... 184 

Gulf region, east-central part of, generalized section in............ 156 

Gulliver, F. P., work of.......................................... 17 

Gunnison Valley, Colo., overlap in ............................. ,. 40-44 

H. 

Hall, James, cited ................................................ 83-85 

Hancock, E. T., The history of a portionofYampa River, Colo., 

. and its possible bearing on that of Green River ...... 183-189 

Harris, G. D., cited ............................................ 155,171 

Hatcher, J. B., and Stanton, T. W., cited ............... 99,107-108,152 

Hayden, F. V., cited ................................... 104,105,106,109 

and Meek, F. B., cited....................................... 106 

Hayden Survey, stratigraphic breaks and overlap established by. 39-44 

Hermosa formation, occurrence of, in Piedra Valley, Colo ........ 48-49 

Hess, F. ·L., aid of............................................... 1 

Hills Point, Md., changes in ......................... 10 (Pl. III),12,15 

Horse thief sandstone, exposure of, on Two Medicine River ....... 62-63 

Houston, Miss., Cretaceous-Eocene contact near ................ 16S-169 

Hunter, J. -F., Erosion and sedimentation in Chesapeake Bay, 

around the mouth of Chop tank River................ 7-15 

I. 

Idaho Springs formation, occurrence and character of............ 3-4 

Irving, J. D., cited ....................................... ~ . . . . . 184-185 

J. 

Jame~ Island, Md., changes in ..................... 9-10,10 (Pl. Ill),15 

Judith River formation, age of, paleontologic evidence on ...... 112-153 

correlation of. ........................................ 64-66,110-112 

distribution and character of. .............................. 100-101 

invertebrate fossils from ................................... 115-117 

flora of. ...................... ·. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113 

literature on ............................................... 104-110 

vertehrate fossils from ...................................... 117-153 

Junction Mountain, Colo., how formed........................... 183 

Juniper Mountain, Colo., how formed .......................... 183-184 

K. 

Knapp, I. N., cited.............................................. 70 

Knowlton, F. H., cited.......................................... 113 

fossil plants identified by. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 

L. 

Lake Bonneville beds, exposures of, in the Canyon Range, Utah.. 57 

Lamprophyre, character of....................................... 29 

Lance formation, distribution and character of................... 103 

' invertebrate fossils from .................................. ,. 115-117 

vertebrate fossils from ... , .................................. 117-153 

La Plata sandstone, distribution of, in Piedra Valley, Colo ....... 46-47 

on schist of Uncompahgre formation, plate showing..... . . . . . 44 

position of, in Piedra Valley, Colo.......... . . . . . . . . . . . . . . . . . . 44-46 

stratigraphic break below .............................. ·.. . . . . 39-44 

Larsen, Esper S., and Cross, Whitman, contributions to the 

stratigraphy of southwestern Colorado ............... 39-50· 

. Lead, occurrence of, in the Canyon Range, Utah ................• 59-60 

Leidy, Joseph, cited.............................................. 106 

Limestone, Carboniferous, distribution of, in Canyon Range, Utah. 53-54 

Livingston, Ala., Cretaceous-Eocene contact near .............. 163-164 

Loughlin, G. F., A reconnaissance in the Canyon Range, westcentral Utah ......................................... 51-60 

M. 

McElmo formation, distribution of, in Piedra Valley, Colo....... 46 

Macon, Miss., Cretaceous-Eocene contact near ............... ·..... 167 

Magnesium carbonate in crinoid skeletons ....... ~ ................ 33-37 

in echinoderm skeletons •................................... ·191-196 

Matthew, W. D., cited............................................ 152 

Maverick County, Tex., Cretaceous-Eocene contact in ...... 169-176, 180 

map of....................................................... 170 

Medina County, Tex., Cretaceous-Eocene contact in •••....••... 178-180 

Page. 

1\feek, F. B., cited............................................... 106 

and Hayden, F. V., cited.................................... 106 

Mesaverde formation, jointing in, plates showing................. 188 

Mesozoic formations, structure of................................. 44 

Midway formation, basal limestone of, plates showing .......... 178,179 

and overlying sandstone, contact between, plate showing..... 173 

and Selma chalk, contact between, plates showing........... 162 

Midway or Wilcox time, sandstone of, in Maverick County, Tex., 

plate showing........................................ 173 

Minette dike, analyses of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 

· occurrence and character of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-20 

1\folas formation, distribution of, in Piedra Valley, Colo ............ 49-50 

Montana, area between Judith and Musselshell, geologic map of.. 104 

area between Judith and Musselshell, stratigraphy of. ...... 96-103 

structure of .•........... · ............................... 103-104 

Montana group of northwestern Montana, relations of. ............ 61-68 

relations of, to the Belly River and Judith River formations .. 64-66· 

relations of the continental to the marine sediments in ....... 66-68 

stratigraphy of. ............................................. 95-153 

Monzonite porphyry, character of ...... : . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

Moscow Landing, Ala., Cretaceous-Eocene contact at ........... 162-163 

N. 

New Albany, Miss., Cretaceous-Eocene contact near.............. 169 

0. 

Oak Creek canyon, Utah, generalized section along, figure showing. 55 

Old Canton Landing, Ala., Cretaceous-Eocene contact near....... 162 

Olivine. See Augite vogesite and Basalt. 

Ophiurans, analyses of ......................................... 193-194 

Osborn, H. F., cited ........................................... 107,152 

Ouray limestone, occurrence of, in Piedra Valley, Colo........... 50 

Overlap in the Gunnison Valley, Colo ...•......••................ 40-44 

P. 

Palmer, Chase, Mineralogy of waters from artesian wells at Charleston, S. C ............................................. 90-94 

Peale, A. C., cited ............................................. 108,111 

Penrose, R. A. F., jr., cited...................................... 170 

Piedra Valley, Colo., stratigraphy of. ............................ 42-44 

Pirsson, L. V., cited.............................................. 30 

Pitchblende, occurrence of, in foreign countries................... 1-3 

occurrence of, in United States............................... 1 

... origin of ......................... ·.· .................... ·.··· .. . 

Pontotoc, Miss., Cretaceous-Eocene contact near.................. 169 

Potholes in Midway formation, in Maverick County, Tex., plate 

showing....... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 

Powell, J. W., cited ............................................ 184,186 

Q. 

Quartz Hill, Colo., geology of..................................... 3-5 

pitchblende at............................................... 1 

Quartzite, distribution of, in the Canyon Range, Utah ........... 54-56 

R. 

Ragged Point, Md., changes in ....................... 10 (Pl. III), 13, 15 

Roemer, Ferdinand, cited ................... , .................. 169-170 

s. 

San Juan Mountains area, Colo., stratigraphy of ................. 42-44 

Scooba, Miss., Cretaceous-Eocene contact near .................. 164-166 

Sea urchins, analyses of. ....................................... 191-193 

Selma chalk and Midway group, contact between, plates showing. 162 

Sevier Canyon, Utah, Lake Bonneville beds at mouth of, plate 

showing............................................. 56 

Sharps Island, 1\fd., changes in ....................... 10 (Pl. III), 11,15 

Shuqualak, Miss., Cretaceous-Eocene contact near ... _ ..•.....•. 166-167 

Spanish Peaks, Colo., relations of, to Apishapa quadrangle ..... _. 17, 

. 18 (Pl. IV), 29 

Stanton, T. W., cited............................................ 155 

and Hatcher, J. B., cited ............................ 99,107-108,152 

Starfishes, analyses of. ......................................... 193-194 

Starkville, Miss., Cretaceous-Eocene contact naar ............... 167-168 

Stebinger, Eugene, The Montana group of northwestern 1\Iontana. 61-68 

Stephenson, Lloyd William, A deep well at Charleston, S.C .... 69-94 

The Cretaceous-Eocene contact in the Atlantic and Gulf Coastal Plain ......................••.•................. 155-182 

Stose, G. '\V., aid of............................................... 17 
INDEX. 199 

T. 

Page. 

'J'albot form!\tion, distribution and character or................... 9 

'J'ilghm!\n Isl!\lld, Md., changes in ........ , ......... 10 (Pl. III), 12, 15 

~l'ingtmito and augite minette dike, occurrence and character of.. 2Q-21 

~l'roy, Ala., Cretaceous-Eocene contact near....................... 161 

'rwo Medicine formation, exposure of, on Two Medicine River, 

l\iont ................... .. :... ..... .......... .. .. .. .. . 63 

'L'wo Medicine River, Mont., section on ........................... 61-62 

. u. 

Uinta 1\fountains, howformcd........ .. .. .. . .. . . . . . . .. .. .. .. . . .. . 183 

Uncompahgre formation, distribution of, in Piedra Valley, Colo.. 50 

Uranium, sources of, in United States .... :.· ....... :............. 1 

Utah, uraniumin ............................................... . 

west-central, reconnaissance in ............................... 51-60 

Uvalde County,'l'cx., Crctaceous-Eocme contact in ............. 1 76-17i 

v. Vmtgho.n, 'l'. W., cited .................................. 155,159,17Q-1il 

fossils determined by ....................................... 1ii, 179 

Virgcllc srutdstone, exposure or, on 'l'wo Medicine River, Mont •.• 62-63 

Vogcsitc, hornblende augite, analyses of.......................... 25 

occurrence and charucter of ..... ~ ................. 2-! (Pl. VI), 24-26 

Sec also Augite vogesite. 

w. 

Page. 

Wahalak, Miss., Cretaceous-Eocene contact near ...•............ 164-166 

'Vater analyses, interpretation of. ................................ 91-92 

Wheeler, W. C., and Clarke, F. W., The composition of crinoid 

skeletons. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33-37 

and Clarke, F. W:, The inorganic constituents of echinoderms .................................................... 191-196 

White, C. A., cited .................. , .......................... 185, 187 

Whiteaves, J. F., cited ........... ,............................... 107 

'Vilcox or Midway time, sandstone of, in Maverick County, Tex., 

plate showing... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 

Wood mine, Colo., pitchblende from ........... 4, 4 (Pl. I), 5 (Pl. II), 5 

Y. 

Yarr;1pa River, Colo .. course of. ............................. 184, 187, 188 

history of part of.. ......................................... 183-189 

map showing part of. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184 

Yates, Charles, aid of............................................. 8 

z. 

Zavalla County, Tex., Cretaceous-Eocene contact in ........... 176-177 

Zinc, occurrence of, in the Canyon Range, Utah .... '.............. 59-60