If you do not need this report after it has served your purpose, please return it to 

the Geological Survey, using the official mailing label at the end

UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Professional Paper 186—L

THE CORRELATION OF THE UPPER CAMBRIAN SECTIONS

OF MISSOURI AND TEXAS WITH THE SECTION

IN THE UPPER MISSISSIPPI VALLEY

BY

JOSIAH BRIDGE

Shorter contributions to general geology, 1936

(Pages 233-237)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1937

For sale by the Superintendent of Documents, Washington, D. C. Price 5 cents

THE CORRELATION OF THE UPPER CAMBRIAN SECTIONS OF MISSOURI AND TEXAS 

WITH THE SECTION IN THE UPPER MISSISSIPPI VALLEY'

By JOSIAH BRIDGE

The Upper Cambrian section in the upper Mississippi 

Valley has long been accepted as the standard for North 

America, largely because it was the first to be studied 

in detail, because it contains a large number of distinct 

faunas, and because it is still the best-known and the 

most complete Upper Cambrian section in the Middle 

West. Various classifications have been proposed 

from £ime to time, but the latest and most detailed is 

that used by the ninth annual field conference of the 

Kansas Geological Society in the summer of 1935.2

It is not the purpose of this paper to discuss the 

merits and demerits of the Kansas Geological Society's 

classification, which is frankly a compromise that will 

require further elaboration, refinement, modification, 

and the elimination of certain names and their replacement by others before it can be generally accepted. 

Reference to it in this paper does not imply that it has 

been accepted either by the writer or by the United 

States Geological Survey. The proposed reduction of 

formations to three or four is certainly a step forward, 

for the Conference seems to have kept the definition of 

a formation—that is, a cartographic unit—firmly in 

mind and has drawn the boundaries on that basis. 

Whether some of the units now classed as members 

should be regarded as formations or not is beyond the 

scope of this paper. The proposed column is noteworthy in that it presents the most complete sequence 

of faunas published to date, and in then* proper order, 

thereby facilitating the correlation with other sections.

Table 1 of this paper presents a tentative correlation 

of the Upper Cambrian of three different areas—the 

upper Mississippi Valley, Missouri, and central Texas. 

The sequence of faunas as worked out in the upper 

Mississippi Valley is shown in the first column, and 

the presence of these faunas in the various stratigraphic 

units is indicated by a dot, or, if doubtful, by an interrogation point.

The determination of the succession of faunas is 

largely the work of Ulrich and Resser, Edwards, and 

Raasch; and although they are not in complete agreement concerning details of the stratigraphy, they and 

all other students of the Upper Cambrian of the Pacific 

province of North America agree very closely as to the 

details of the faunal succession.

1 Presented before the Paleontological Society, Dec. 27,1935.

2 Kansas Geol. Soc., Guidebook, Ninth Annual Field Conference, upper Mississippi Valley, p. 18, fig. 1 and elsewhere, 1935.

79233—37

The upper Mississippi Valley section is dominantly 

clastic, whereas the sections in Missouri and Texas 

are in the main calcareous. Therefore, lithologic 

correlations have been of very little value. Many of 

the faunas and especially certain elements of them are 

distinctly facies faunas, and this, together with the 

lack of study of the Missouri and Texas sections and 

certain miscorrelations in the upper Mississippi Valley 

section which have only recently been corrected, has 

greatly retarded correlations among these three areas.

Recent work in Texas by Miss Christina Lochman 

and the writer has shown that the section in the Central 

Mineral Region is nearly as complete as the upper 

Mississippi Valley section and that most of the faunal 

zones of the latter are present there. As now classified 

by the United States Geological Survey for the forthcoming geologic map of Texas, the Upper Cambrian of 

Texas comprises three formations and part of a fourth. 

These formations were all established on the basis of 

lithology and without direct reference to the newly 

proposed upper Mississippi Valley classification. There 

is, however, a striking similarity between the two 

classifications.

The Hickory sandstone, which forms the base of the 

Texas Cambrian section, appears to grade upward into 

the limestones of the Cap Mountain formation, and 

together these formations make a unit which is roughly 

the equivalent of the Dresbach formation of the 

Conference classification.

As the Hickory thickens the Cap Mountain thins, 

the combined thickness of the two formations remaining 

about constant. A further proof of the gradational 

character of the two formations is the presence of the 

Cedaria zone in both formations. This relationship will 

be more fully described in a forthcoming paper by Miss 

Lochman. The Crepicephalus zone is present, although 

Crepicephatus itself is not a common form. The dominant genera of this zone are Tricrepicephalus, which 

extends downward into the Cedaria zone, and Coosia. 

The Aphelaspis zone, characterized by Aphelaspis 

depressa (Shumard), is well developed and is probably 

the most widespread of all the Cap Mountain faunal 

zones. It occurs in the highest limestone beds of the 

formation immediately beneath a thick bed of glauconitic sandstone which Paige 3 included in the Cap

3 Paige, Sidney, U. S. Geol. Survey Geol. Atlas, Llano-Burnet folio (no. 183) 

p. 45 (field ed.), p. 6 (library ed.), 1912.

233
234 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1936

TABLE 1. — Tentative correlation of Upper Cambrian of upper Mississippi Valley, Missouri, and central Texas

Faunas

Gasconadia. 

Burenoceras.

Plethopeltis.

Acheilops.

Eurekia-Euptychaspis.

Dikelocephalus minnesotensis.

Scaevogyra. 

Lower Dikelocephalus.

Briscoia. 

Prosaukia. 

Ptychaspis. 

Billingsella. 

Eoorthis.

Camaraspis.

Hypseloconus, a local shore 

phase of the Camaraspis 

fauna.

Aphelaspis. 

Crepicephalus. 

Cedaria.

73

t-t

o

Cambrian Upper 

Upper Mississippi Valley 

(Kansas Geological Society Conference classification, 1935)

Oneota dolomite •

Not represented

Trempealeau formation

Franconia formation

Dresbach formation

Madison [sandstone] member •

Jordan sandstone of 

Ulrich

Jordan [sandstone] 

member • 

Norwalk sandstone 

of Ulrich •

Lodi [shale and siltstone] member •

St. Lawrence dolomite [member] •

Mazomania formation of

Ulrich

Franconia 

formation UJrich of 

Bad Axe [sandstone] member •

• 

Hudson [sandstone] member •

•

• 

Goodenough [sandstone] member

•

• 

Ironton [sandstone] member

•

Galesville [sandstone] member

• 

Eau Claire [sandstone] member •

•

Mount Simon [sandstone] member

Missouri 

(U. S. Geological Survey, 1936)

Gasconade dolomite •

Van Buren formation •

• 

Eminence dolomite •

?

Potosi dolomite •

Elvins group

Doe Run dolomite 

?

Derby dolomite

• 

• 

Davis formation

• 

•

Bonneterre dolomite 

• •

Lamotte sandstone

Texas 

(II. S. Geological Survey, 

1936)

• 

? 

?

Ellenburger limestone 

(lower part) •

• 

t

?

• 

•

Wilberns formation ?

•

• 

•

Lion Mountain sandstone member

Cap Mountain for- • 

~~~~~~ — -~__mation •

• ~""~"~^—- -~~ ;

Hickory sandstone

Mountain formation. This sandstone, which is perhaps the best horizon marker in the Central Mineral 

Region, is here designated the "Lion Mountain sandstone member of the Cap Mountain formation." The 

name is taken from Lion Mountain, in the northwestern 

part of the Burnet quadrangle. The section of the Cap 

Mountain formation exposed along State Highway 29 

on the southwest side of Lion Mountain is much thicker 

and far superior to the type section on Cap Mountain. 

The presence of the three faunas in both the upper 

Mississippi Valley and Texas definitely establishes the 

equivalence of this part of the section. Whether the 

Lion Mountain sandstone member is to be considered 

the full equivalent of the Galesville member of the 

Conference classification is, of course, purely conjectural.

In Missouri the lower portion of the Upper Cambrian 

section is composed of the Lamotte sandstone and the 

Bonneterre dolomite. The contact between the two 

formations is believed to be gradational, although St. 

Clair 4 has postulated an unconformity between them. 

The Cedaria fauna has been found in the lower 50 feet of 

the Bonneterre dolomite along the Farmington anticline east of the St. Francois Mountains, where the 

basal beds are predominantly limestone, and this 

occurrence serves to tie this portion of the section with 

the uppermost Hickory and basal Cap Mountain of 

Texas and with the lower part of the Eau Claire member 

of the Conference classification for the upper Mississippi 

Valley. The Crepicephalus and Aphelaspis faunas

4 St. Olair, Stuart, Geology of Ste. Genevieve County, Mo.: Missouri Bur. Geology 

and Mines, vol. 22, pp. 37, 44, 1928.
CORRELATION OF UPPER CAMBRIAN SECTIONS OF MISSOURI AND TEXAS 235

have not been found in Missouri, but one or both of 

them might well occur in the upper portion of the 

Bonneterre dolomite, which thus far has yielded no 

fossils.

Overlying the Cap Mountain formation in Texas is 

the Wilberns formation, which comprises all the strata 

between the top of the Lion Mountain sandstone member and the base of the Ellenburger limestone. It is 

almost exactly the equivalent of the Franconia of 

the Conference classification, or of the Franconia 

and Mazomanie of Ulrich's classification.5 The base 

of the Wilberns is marked by the widespread Camaraspis fauna, which serves to correlate it with the 

Ironton sandstone member of the Franconia. The 

other important trilobite genera in this asemblage are 

Elvinia, Burnetia, Housia, IrvingeUa, and Pterocephalia. 

Overlying the Camaraspis zone are the Eoorthis and 

BUlingsdla or Taenwephalus faunules, which together 

make up the Conaspis zone and serve to correlate this 

portion of the Wilberns with the Goodenough member 

of the Conference classification. The upper zones of 

the Wilberns are not as definitely known, but the 

Ptychaspis, Prosaukia, and Briscoia faunas are known 

to be present, and there are indications of the lower 

Dikelocephalus zone. These are contained in the socalled "post-Wilberns beds—Fort Sill and Signal 

Mountain faunal equivalents" of Dake and Bridge,6 

but until these formations are better known it seems 

wise to restrict the names "Fort Sill" and "Signal 

Mountain" to rocks in the type areas (Wichita and 

Arbuckle Mountains, Okla.). Beds carrying these 

faunas were locally included in the Wilberns formation 

by Paige, although at places he assigned beds at the 

same horizons to the Ellenburger limestone. The 

Wilberns as now defined includes these beds.

In Missouri the Camaraspis, Eoorthis, and Taenicephalus faunas occur in the Davis formation and serve to 

correlate it with the lower portion of the Wilberns and 

with the lower part of the Franconia (Ironton and 

Goodenough members of the Conference classification). A further tie between Missouri and the upper 

Mississippi Valley is found in the peculiar assemblage 

of gastropods known as the Hypseloconus fauna. This 

is distinctly a facies fauna characteristic of shallowwater conditions along a rocky coast and at present is 

known from only three localities—one at the base of 

the Franconia at Taylors Falls, Minn., the other two 

at the base of the Davis in Missouri.

* Ulrich, E. 0., Notes on new names in table of formations and on physical evidence of breaks between Paleozoic systems in Wisconsin: Wisconsin Acad. Arts, 

Sci., and Letters Trans., vol. 21, pp. 72-94, 1924.

6 Dake, C. L., and Bridge, Josiah, Faunal correlation of the Ellenburger limestone 

Of Texas: Qeol, Spc. America Bull., vol. 43, pp. 725-741, 1932,

The presence of the Camaraspis fauna in the base of 

the Davis is another reason for assuming that the nonfossiliferous portion of the Bonneterre may represent 

the Crepicephalus and Aphelaspis zones.

Overlying the Davis are two thin dolomitic formations—the Derby and Doe Run dolomites—which have 

yielded practically no fossils. Their position in the 

upper Mississippi Valley and Texas sections is therefore doubtful, but they are believed to represent the 

upper half of the Wilberns formation and the upper 

half of the Franconia, either wholly or in part. There 

is one tie with the Texas section which of itself is of 

no great value but which when taken with the general 

sequence of faunas is at least significant. Near the 

base of the upper half of the Wilberns formation, in 

what was called the "Fort Sill faunal equivalent," 

there are several layers of limestone filled with small 

spherical bodies which show traces of structure and 

have been provisionally identified as Girvanella sp.7 

These bodies occur above the Billingsella zone and 

beneath the Prosaukia zone. In Missouri small spherical bodies of approximately the same size are found 

at a definite horizon in the Derby dolomite, but dolomitization has destroyed all traces of structure. These 

bodies occur above the Taenicephalus zone, but as 

previously stated the Prosaukia zone has not been 

recognized in Missouri.

A further reason for correlating the Derby and Doe 

Run formations with the upper part of the Franconia 

(Hudson and Bad Axe members of the Conference 

classification) and with the upper half of the Wilberns 

is found in the presence of the Scaevogyra fauna in the 

overlying formation in all three areas. This fauna is 

characterized by various species of the gastropod 

Scaevogyra and the trilobites Plethometopus and Platycolpus. It occurs in the St. Lawrence dolomite member 

of the Trempealeau formation of the Conference 

classification, in the Potosi dolomite of Missouri, and 

in the basal portion of the Ellenburger limestone in 

sections along the Colorado River, Tex., thus serving 

to correlate the beds in these three areas. This same 

fauna has been found about 500 feet beneath the top 

of the Copper Ridge dolomite in eastern Tennessee.

The Trempealeau of the Conference classification 

is the youngest of the three formations recognized in 

that classification. It contains several lithologic units, 

many of which have been accorded formational rank 

by others. Most of these units contain distinctive 

faunas. The various classifications in current use are 

indicated in table 2.

' See The geology of Texas, vol. 1: Texas Univ. Bur. Econ. Geology Bull. 3232, 

1932,

79233—37-
236 SHOKTEK CONTRIBUTIONS TO GENERAL GEOLOGY, 1936

TABLE 2.—Various classifications of the late Upper Cambrian strata in the upper Mississippi Valley

Kansas Qeol. Soc. Conference, 1935 

(K. G. S. Guidebook, fig. 2)

a

0'•§ 

1

o3

r2'oS 

0>1o> S

Madison sandstone 

member

Jordan sandstone 

member

Lodi shale member

St. Lawrence dolomite 

member

Franconia formation 

Bad axe sandstone member

Ulrich, 1935 (personal communication)

Madison sandstone

Jordan sandstone

Trempealeau 

formation

Norwalk sandstone

Lodi shale

St. Lawrence dolomite

Mazomanie formation

U. S. Geol. Survey (present classification)

Madison sandstone

Jordan sandstone

St. Lawrence formation

Sandstone

Norwalk sandstone member

Lodi shale member

Mendota dolomite member

Shale

Minnesota, 1935 

(K. G. S. Guidebook, fig. 2)

Jordan sandstone

St. Lawrence formation 

(includes at base shales 

and sandstones placed in 

underlying formations in 

other classifications).

Overlying the St. Lawrence dolomite member of the 

Conference classification is the Lodi shale member, 

which carries the Dikelocephalus fauna, "universally 

(but with little justification) held to be the type fossil 

for the Upper Cambrian of the Pacific province." 8 

Beds carrying this fauna are not known in Missouri 

and Texas. Some ascribe this absence to nondeposition 

of a Lodi equivalent, or to deposition and subsequent 

erosion, although neither region shows conclusive 

evidence of a hiatus between the beds carrying the 

pre- and post-Dikelocephalus faunas. An alternative 

interpretation is that the Dikelocephalus fauna is made 

up of forms that lived in the mud and are restricted 

to areas in which the deposits are shales. This explanation receives additional support from the upper 

Mississippi Valley, where at some places, according 

to Raasch,9 the shales and siltstones of the Lodi shale 

member grade laterally into coarser clastic deposits, 

which have been called "Norwalk" by Ulrich, and 

"Jordan" by the Conference; and where this occurs 

the characteristic Dikelocephalus fauna is replaced by 

other forms. There are no shales in this part of the 

section in either Missouri or Texas, and this would 

explain the absence or scarcity of this fauna.

The Norwalk or lower Jordan faunas are still imperfectly known, and more detailed studies must be 

made before exact correlations are possible. However, 

Raasch 9 claims that all the genera described from the 

Eminence dolomite of Missouri 10 occur in the Jordan 

and Madison of Wisconsin. Characteristic genera 

among the trilobites are Euptychaspis, Triarthropsis, 

Calvinella, Stenochilina, and StenopUus. The gastropod 

Sinuopea is sparingly represented in the Eminence 

and is abundant at one horizon in the Jordan; these 

two occurrences mark the first appearance of that 

genus in these two regions. Near the top of the

• Baasch, G. O., Paleozoic strata of the Baraboo area: Kansas Geol. Soc. Guidebook, Ninth Annual Field Conference, p. 407, 1935. 

' Raasch, G. O., personal communication. 

10 See Missouri Geol. Survey, vol. 24, ch. 6,1930.

Eminence is a zone characterized by several large 

species of Plethopeltis and Calvinella, which may 

correspond to the Madison. Raasch records the 

unique trilobite Entomaspis from the Madison, and 

the same genus occurs in both the Eminence and 

Proctor dolomites of Missouri. The Proctor is a unit 

which some consider to be a distinct formation but 

which the writer considers to be the upper part of the 

Eminence formation in certain areas.

The correlation of the Eminence with a zone in the 

Ellenburger limestone lying above the Scaevogyra 

zone has been established by the presence of several 

Eminence species in the Elleoburger, among them 

Euptychaspis typicalis Ulrich and various species ,of 

StenopUus and Plethopeltis. 11

In Wisconsin the Madison sandstone is overlain 

by the Oneota dolomite, of Lower Ordovician age. 

This formation carries a large molluscan fauna which 

can be divided into several faunules. It is a widespread fauna and has been recognized in practically 

every important area of early Ordovician rocks in 

North America. By means of this fauna the equivalence of the Oneota dolomite with the Gasconade 

dolomite of Missouri and with beds at a horizon near 

the middle of the Ellenburger of Texas (the so-called 

Gasconade faunal equivalent) has been definitely 

established. All stratigraphers familiar with, this 

portion of the section agree with this correlation.

Among the characteristic gastropods that occur in the 

three areas under consideration are Gasconadia putilla 

(Sardeson), Helicotoma uniangulata (Hall), Pelagiella 

paucivolvata (Calvin), and many species of Ophileta. 

The cephalopods are represented by several genera, 

among them Clarkeoceras and Cameroceras, and many 

species are common to all three areas.

Beneath the Gasconade in Missouri is another formation of Lower Ordovician age, the Van Buren, which

11 Dake, C. L., and Bridge, Josiah, Faunal correlation of the Ellenburger limestone 

of Texas: Geol. Soc. America Bull., vol. 43, pp. 730-732, 1932.
CORRELATION OF TIPPER CAMBRIAN SECTIONS OF MISSOURI AND TEXAS 237

carries a fauna related to but different from that of the 

overlying formation. It is composed primarily of 

gastropods and cephalopods. Among the gastropods 

are numerous species of Sinuopea and Schizopea. 12 

Among the cephalopods which appear in this formation 

in great abundance, various species of Burenoceras and 

Dakeoceras are especially characteristic. For this 

reason it is termed the "Burenoceras zone." Strata 

carrying this fauna are unknown in the upper Mississippi Valley and at present are only doubtfully known 

from Texas, though there now seems to be reason for 

believing that this fauna occurs in the Ellenburger 

limestone in strata lying between beds carrying the 

Eminence and Gasconade faunas. It is known to 

occur in the Arbuckle limestone beneath beds carrying 

the Gasconade fauna. The strata carrying this fauna 

were probably the initial deposits of the advancing 

early Ordovician submergence, which did not reach 

the upper Mississippi Valley.

The correlation of these early Ordovician zones is 

well established, and the chief innovation of the 

present correlation is the placing of the Eminence and 

Potosi of Missouri and their Ellenburger equivalents 

as correlatives of the Trempealeau formation of the 

Conference classification.

It has been claimed that correlations based on similar 

associations of genera are of little or no value, and that 

the only correlations that can be trusted are those 

founded on a comparison of finely discriminated species. 

It is also assumed by some that a fauna, once developed, 

becomes practically universal in the sea in which it lives, 

and that it should be present in all the strata deposited 

in this sea during the time this particular fauna was 

living. However, there are many examples on record 

in which strata carrying faunas far more strikingly 

dissimilar than the ones that are considered to be 

homotaxial in this paper are correlated with one 

another because of their stratigraphic position between 

strata carrying cosmopolitan faunas. Also it is well 

known that the sea bottom today is not uniformly and 

universally populated, but that it contains areas which

'2 Butts, Charles, Geology of Alabama: Alabama Geol. Survey Special Eept. 14, 

p. 88, pi. 14, figs. 23, 24,1926. The name Schizopea Ulrich, 1926, takes precedence 

over Rhachopea Ulrich and Bridge (Missouri Bur. Geology and Mines, vol. 24, pp. 

190-193, 1930), and S1 . washburim Butts must be regarded as the genotype.

are crowded with living forms and other areas which 

are practically barren of life. It is just as logical to 

assume that two faunas which are for the most part 

specifically and even generically dissimilar can exist 

a few hundred miles apart in the same epeiric sea under 

slightly different environmental conditions as it is to 

invoke crustal warpings and erosion or nondeposition 

in order to make two very similar faunas occur in one 

area at one time and recur in another area at a later 

time. It is difficult to imagine a sea invading the 

continent from the southwest, as the Upper Cambrian 

seas are believed to have done, which would leave a 

series of deposits such as the Trempealeau formation 

(Conference classification) in the upper Mississippi 

Valley and at the same time fail to leave any record of 

its presence in any of the Cambrian areas to the south 

of it. It is also equally difficult to imagine how a 

second sea could come in from the same quarter (it 

must have done so, because it contains so many identical 

genera) and leave a second set of deposits in all the 

areas from which the first set were either eroded or 

never deposited and at the same time fail to leave a 

well-defined record in the one area where these earlier 

deposits remain. Yet these are the assumptions that 

must be made if the Potosi and Eminence formations 

of Missouri and the beds of pre-Gasconade age in the 

Ellenburger of Texas are to be considered as being 

younger than the Jordan sandstone of the upper 

Mississippi Valley. No one today questions the 

practical equivalence of the Cedaria, Crepicephalus, 

Aphelaspis, Camaraspis, Eoorthis, Taenicephalus, Ptychaspis, Prosaukia, lower Dikelocephalus, and Gasconadia 

faunas in the three areas under consideration. In view 

of this striking parallelism it seems more logical to the 

writer to regard the four known occurrences of the 

Scaevogyra fauna as a single zone instead of making the 

occurrence in the St. Lawrence of the Conference 

classification older than the other three. Similarly it 

seems best for the present to consider the occurrence of 

similar forms in the Jordan and Madison of the upper 

Mississippi Valley, in the Eminence of Missouri, and 

hi the lower'part of the Ellenburger of Texas as representing a single horizon instead of placing the upper 

Mississippi Valley forms in an earlier zone and the 

others in a later one.

o