. 'DEPARTMENT OF THE INTERIOR 

HUBERT WORK, Secretary 

UNITED STATES GEOLOGICAL SURVEY 

GEORGE OTIS S~nTH, Director 

Professional Paper 134 

UPPE.R Ol~E'rAOEOUS AND ~rEB.TIARY FORMATIONS OF 

rrHE ·wES~rERN PARrr OF rrHE SAN JUAN BASIN 

COLORADO AND NEW MEXICO 

BY 

JOHN B. REESIDE, JR. 

AND 

:FLORA OF THE ANIMAS FORMATION 

BY 

F. H. KNOWLTON 

WASHINGT.ON 

GOVERNMEN,T PRINTING OFFICE 

1924 
ADDITIONAL COPIES 

OF THIS PUBLICATION MAY BE PROCURED FROll 

THE SUPERINTENDENT OF DOCUMENTS 

GOVERNMENT PRINTING OFFICE 

WASHINGTON, D. C. 

AT 

40 CENTS PER COPY 
CONTENTS. 

Upper Cretaceous and Tertiary formations of the western part of the San Juan Basin of Colorado and 

New Mexico, by J. B. Reeside, jr ________________________________________________________ _ 

Summary of the paper _______________________________________________________ ------------- Introduchlon ____________________________________________________________________________ _ 

Stratigraphy ___________ :.. ______________________________________________________________ -,.._ 

General sechlons~---------------------------------- ----------------------------------

Dakotasandstone ________ ~----------------------------------------------------------- 1\1ancos shale ____________________________________________________________ -_-_-_------

Type locality and distribution ____________________________________________________ _ 

i....ithologic character __________________________________________________________ -_--

Thickness in San Juan Basin and adjacent regions-.----------------------------.-------

Relation to adjacent formations _________________ ~ ____________________ -=-_----------

Fossils _________________________________________________________________________ _ 

Age and correlation ______________ · __________________ ., ____________________________ _ 

Mesaverde group _______ ~ _________________________________________________ ------------

Type locality and distribution ____________________________________________________ _ 

Lithologic character ____________________________ -.- ________ · _______________________ _ 

Th~kness ___________________________________________________________________ ----

Relation to adjacent formations ________________________ --- ___________ -- __________ _ Fossils _________ . ________________________________________________________________ _ 

Age and correlation _____________________________________________________________ _ 

Le,vis shale _____ "' _________________________ · ______ · ____________________________________ _ 

Type locality and distribution __________________________________________ · __________ _ 

Lithologic character __ .:. __________________________________________________________ _ 

Th~kness-------------·------------~--------------------------------------------

Relation to adjacent formations __________ -·-- ______________________________________ _ 

li'ossils _______________________________________________ - - - - - - - - - - - - _ - - - - - - - - - - - - - -

Age and correlation __________ · ____________________________ · _____ .. _________________ _ 

Pictured Cliffs sandstone _____________________________________________________________ _ 

Type locality and distribution ____________ -·- ______________________________________ _ 

Lithologic character _____________________________________________________________ _ 

Th~kness-----------------------------------------------------------------------

Relation to adjacent formations ___________________________________________________ _ 

Fossils-----~----------------------------------------------~---------------------

Age and correlation ____________ :.. ________________________________________________ _ 

Fruitland formation _____________________ . ____________________________________________ _ 

Type locality and distribution ___________________________ ~ ________________________ _ 

Lithologic character _____________________________________________________________ _ 

Thickness-----------------------------------------------------------------------

Relation to adjacent formations _____ .: _____________________________________________ _ 

Fossils------~------------------------------------------------------------------- Age and correlation ___________________ · __________________________________________ _ 

K~tiand shale ______________________________________________________________________ _ 

Type locality and distribution ___________________________________________________ .:. _ 

Lithologic character ________ .,. ____________________________________________________ _ 

Th~kness-----------------------------------------------------------------------

Relation to adjacent formations ___________________________________________________ _ 

Fossils-------------------------------------------~------------------------------

Age of Fruitland formation and Kirtland shale--------------------------~------------ McDermott formation _______________________________________________________________ _ 

Definition, type locality, and distribution __________________________________________ _ 

Lithologic character _____________________________________________________________ _ 

'fhickness _____________________ ·_------ _----------·------------------·-------------- Relation to adjacent formations __________ -.---- ____________________________________ _ 

Fossils---------~------------------------~---------------------------------------

Age and correlation ________________ · _____________________________________________ _ 

Ojo Almno sandstone_.:. ______________________________________________________________ _ 

Type locality and distribution ____________________________________________________ _ 

~;~:~~; ~:~~-~~~~1~t~c-t~~ = = = = = = = = = = = = = = = = = = = = = = = = =::::: =: = = =: = = = =: = = = = = = = = = = = = = = = = = = = = = III 

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IV CONTENTS. 

Upper Cretacequs and. Tertia~y formations of the western part of the San Juan Basin of Colorado and 

New Mexico, by J. B. Reeside, jr-Continued. 

Stratigraphy-Continued. 

Ojo Alamo sandstone-Continued. 

Relation to adjacent formations _______ . ___________________________________________ _ Fossils _________________________________________________________________________ _ 

Age and correlation _____________________________________________________________ _ 

Animas formation (restricted) _____________________________________ · ______________ · _____ _ 

Type locality and distribution ______ · ______________________________________________ _ 

Lithologic character ____ . _______________________________ ~ _________________________ _ 

Thickness------------~----------------------------------------------------------

Relation to adjacent formations ___________________________________________________ _ 

Fossils-----------------~------------------------------------------------~-------

N aci~Y=~~dg~~~~~l~~~o-~ -_ ~ ~: = =: =: =· ~::: =: = = = = = =: = = =: = = = = = = = = = = = = = = = = = = = = =: = = = = = =: = = = = = = Puerco formation _______________________________________________________________ _ 

Distribution __________________________________ -~ ____________________________ _ 

Lithology and thickness ______________________________________________________ _ 

Relation to adjacent formations ___________ ~ __________________________________ _ Fossils ________ :_ ________________ .:_ ___________________________________________ _ 

Age and correlation _________________________________________________________ _ 

Torrejon formation _____________________________________________________ ~ _________ _ 

Distribution ______________ ~ _________________________________________________ _ 

Lithology and thickness _______________________________ -· __ ~ ___________________ _ 

Relation to adjacent formations _______________________________________________ _ 

Fossils---------------------------~------------------------..: ________________ _ Age and correlation of the Puerco and Torrejon formations _______________________ _ 

Wasatch formation __________________________________ ------------ ____________________ _ 

Identification and distribution in San Juan Basin _______ _. ___________________________ _ 

Lithologic character and thickness ________________________________________________ _ 

Relation to adjacent formations ___________________________________________________ _ 

Fossils _____________________________ :_ __________ ~---------------------------------

Age and correlation ______________________________ ..: ______________________________ _ 

Summary of the relations of the formations within and without San Juan Basin _____________ _ 

Physical history of the western part of the San Juan Basin from Mancos time to Wasatch time, inclusive _____________________________________________________________________________ _ 

BibliographY------------------------------------------------------~---------------------

Local sections--- -T-----------------------------------------~--------------------------- Flora of the Animas formation, by F. H. Knowlton _____________________________________________ _ 

Introduction----------------------------~-----------~----------------------------------- Localities ____ ~ ________________________ :.. ________________________________________________ _ 

Forms included in the flora ____________________________________________________ ~ __________ _ 

Relation between the floras of the Animas and Puerco formations _________________________ ~ ___ _ 

Relation between the floras of the Animas formation and the Cretaceous ______________________ _ 

Relation between the floras of the Animas formation and the basal part of the Wasatch formation 

("Tiffany beds" of Granger) in this region __________________________________________ . _____ _ 

Relation between the floras of the Animas and McDermott formations _________________________ _ Summary and conclusions ___________________________________________________________ ~ ____ _ 

Systematic descriptions _________________ -________________________________________________ -. _ 

Index ________________________________________ . _____________ -.- ______________________ ~...: ______ _ 

ILLUSTRATIONS. 

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PLATE I. Geologic map of the western part of San Juan Basin, Colorado and New Mexico____________ 2 

II. Columnar sections of formations around the margin of San Juan Basin____________________ 2 

III. Columnar sections showing the faunal zones of the Mancos shale, Mesaverde group, Lewis 

shale, and Pictured Cliffs sandstone of the west side of San Juan Basin_________________ 10 

IV. Diagram showing the approximate correlation of the formations of San Juan Basin with those 

of other regions in the western interior_ __________________ "' _______________ .:. _ _ _ _ _ _ _ _ _ _ 48 

V-XIX. Flora of the Animas formation __ :_ _________ ..: _______ --- _____ - ____ ---------- ___ --- _____ -_ 99 

FIGURE L Index map showing location of San Juan Basin and area covered by Plate L _ _ _ _ _ _ _ _ _ _ _ _ _ _ 3 

2. Diagram showing the differencesin naming of beds exposed near Ojo Alamo, N. Mex_______ 29 

3. Diagram showing the relations of the formations along the west side of the San Juan Basin_ 48 

4. Diagrammatic section across San Juan Basin from Durango, Colo., to Pueblo Bonito, N. Mex_ 48 

5. Tentative correlation of the formations of San Juan Basin with the European time scale___ 49 
UPPER CRETACEOUS AND TERTIARY FOR~fATIONS OF THE WESTERN 

PART 0}, TIIE SAN JUAN BASIN OF COLORADO AND N.EW MEXICO. 

By JoHN B. REESIDE, Jr. 

SUMMARY OF THE PAPER. The Torrejon formation overlaps the Puerco forthe mation northward and is in turn overlapped by the 

Wasatch formation. This paper presents the results of studies in 

Upper Cretaceous and Tertiary formations of the San 

Juan Basin of Colorado and New Mexico. It includes a more or less detailed description of the formations, a geologic map of the area, and columnar 

sections. The formations described are the Dakota 

sandstone, Mancos shale, Mesaverde group (Point 

Lookout sandstone, Menefee formation, and Cliff 

House sandstone), Lewis shale, Pictured Cliffs sandstone, Fruitland formation, Kirtland shale with 

Farmington sandstone member, McDermott formation (the lower part of the Animas formation as 

heretofore defined), Ojo Alamo sandstone,· Animas 

formation (restricted), Nacimiento groqp (Puerco and 

. Torrejon formations), and Wasatch formation (including "Tiffany beds" of Granger at base). 

Some of the conclusions reached in the paper are 

as follows: 

The Mancos shale contains successive faunas like 

those of the Greenhorn limestone, the Carlile shale, 

the Niobrara formation, and the basal part of the 

Pierre shale of the region east of the Rocky Mountains. 

The Mesaverde group in southern and central San 

.Juan County, N. Mex., represents the ·same time 

interval as the upper part of the· Mancos shale, the 

Mesaverde group, and the Lewis shale near D·urango, 

Colo. 

The Pictured Cliffs sandstone, Fruitland formation, 

and Kirtland shale may be traced with essentially the 

same characteristic features around the entire west 

side of the basin. They appear to represent the same 

time interval everywhere. 

The lower part of the beds with andesitic debris 

hitherto included in the Animas formation is much 

older than the Animas formation and is separated from 

the overlying beds by an erosion interval. For these 

lower beds the name McDermott formation is herein 

introduced, and the name Animas formation is restricted 

to the beds above the break. · 

The Ojo Alamo sandstone and at least the lower 

pn,rt of the Animas formation as restricted in this 

paper are of nearly the same age and overlie the most 

widespread stratigraphic break in the whole series of 

beds described. 

The Puerco formation is probably of the same age 

as the upper part of the Animas formation, though 

possibly later than any part of the Animas formation 

now present. 

The Laramie formation of the Denver Basin has no 

recognizable ·equivalent in the region, beds with 

Montana fossils being directly followed by beds containing a flora that Knowlton correlates with the 

Denver flora. The post-McDermott hiatus appears 

to represent all of Laramie time. 

The Wasatch formation in the southern part of the 

San Juan Basin apparently succeeds the Torrejon 

formation unconformably, .the hiatus representing 

early Wasatch deposits which to the north were called 

"Tiffany beds" by Granger. In the northern part of 

the basin the Torrejon formation grades without 

interruption into the Wasatch formation . 

INTRODUCTION. 

Many papers on the geology and paleontology of the San .Juan Basin have been published, some of them written in the earliest 

days of exploration in the region. Much of 

the work done, however, was of a strictly 

reconnaissance type and left many problen1s 

to be solved by later and more detailed observation. It is the purpose of this paper to 

summarize the earlier knowledge of the stratigraphy and to present some of the results of 

later work that contribute to its better interpreta ti011. 

The San Juan Basin, in· the larger sense of 

that ·term, includes the roughly rectangular 

region that extends from,Durango, Colo., on· 

the north, to Gallup, N. Mex., on the south, 

a distance of 125 miles, and fron1 the Great 

Hogback on the west to Gallina, N. Mex., on 

the east, a distance of 100 miles. The southern third of this large basin is occupied by 

nearly flat-lying rocks of the Mesaverde 

group, and the northwest corner, in the Mesa 

Verde, is occupied by the flat-lying rocks of 

the Mesaverde group. The northern twothirds of the basin, excluding the Mesaverde, 

1s occupied by concentric inward-dipping 

1 
2 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

band~· of outcrop of the formations above the F. H. Knowlton has identified the fossil plants 

Mesaverde group. This northern two-thirds and supplied lists of species and comments on 

of the basin therefore approaches more nearly them, Mr. C. W. Gilmore has identified the 

the ideal conception of a simple structural reptilian fossils, and Mr. J. W. Gidley the 

basin and may be considered the San Juan mammalian fossils. These gentlemen have 

Basin proper. It. is w~th the western part of also read parts of the manuscript and offered 

this narrow-er San Juan B·asin only that this suggestions for its improvement. 

report deals. (See fig. 1.) Free use has been made of all the published 

The later data presented in this paper that and unpublished data available to the writer, 

concern the part of the San Juan Basin lying and for this use due credit is given in the approin New Mexico were gathered during the priate places. 

course of a study designed primarily to obtain · The geologic map (Pl. I) includes material 

detailed information regarding the coal ·re- derived from several sources. The main body 

sources of San Juan County. The work was of the map is original. A strip on the north 

begun in 1915 by C. M. Bauer, assisted by side sp.owing the formations beneath the 

H. R. Bennett and the writer. Papers by Mr. Pictured Cliffs sandstone is taken from GardBauer, _C. W. Gilmore, T. W. Stanton, and ner's unpublished map of the Ignacio quadF. H. I{nowlton 1 on the stratigraphy and rangle. A patch in tl;te northwest corner is 

paleontology of the area studied were pub- taken from the La Plata folio. A strip in 

lished in 1916. The work was continued Colorado on the west side showing the formaduring parts of the field seasons of 1916, 1917, tions beneath the Pictured Cliffs sandstone is 

1920, and 1923 by the writer, assisted in 1916 taken from Pishel's unpublished map of the 

by F. R. Clark, in 1917 by· Harvey Bassler, Red Mesa quadrangle. Much of the part of 

and in 1920 by C. E. Dobbin. A paper by Chaco Valley shown is taken fron1 ·Bauer's 

Mr. Bauer and the writer 2 embodies the eco- published map, 4 and ·a strip on the extreme 

nomic data obtained during four seasons, and west side is taken from Gregory's map of the 

another by Mr. Gilmore 3

- describes reptilian Navajo country.5 · 

remains obtained in 1916. The area examined more or less in ·detail 

The later data P.resented in this paper t~at during the course of the field work extends 

concern the part of the San Juan Basin lying from the east side of the Ignacio quadrangle 

in Colorado were gathered by M.A. Pishel in westward to the edge of the Red Mesa quadhis examination of the Red Mesa quadrangle· rangle, southwestward across the Red Mesa 

in 1913, by J. H. q-ardner in his -examination quadrangle to- the Colorado-New Mexico 

of .the Ignacio quadrangle in 1909, and by the boundary,· and thence southward across the 

writer in· 1920 and 1921. The writer had the ·middle half of San Juan County, N. Mex., to 

assistance in 1920 of T. C. Hopkins and in the south side, an area approximately 100 miles 

1921 of Q. D. Singewald. long and 45 miles wide. The detailed work 

The writer is indebted to various colleagues extended also across the S()Uthern "part of the 

for advice and assi5tance. Mr. Whitman Cross eastern fourth of San Juan County, and much 

has forwarded both the field. work and the of the rest of this eastern strip was covered in 

office work in many ways. His interest in the rapid reconnaissance, such geographic locageologic problems of the region has been a tions as were n1ade being based on the reconconstant stimulation, and his wi~e ~nowle~ge naissance topographic map of the Largo quadhas been freely placed at the wnter s .service. rangle, which covers the area. Reconnaissance 

He has read the completed. ~.anuscnpt and trips without mapping were made eastward 

ma~e many very helpf~l cntwlsms and sug- from the Ignacio quadrangle to Pagosa Juncgestwns ~nd h~s exa~lned and commented tion, Colo., to trace the Fruitland, Kirtland, 

on the hthologw spemmens collected. Mr. An' d 1 ____________ · f t' t d · ________ 1mas, an over y1ng orma 1ons eas war ; 

I Contributions to the geology and paleontology of San Juan County, and into the area between Escavada Wash and 

N.Mex.: U.s. Geol. Survey Prof. Paper 98, pp. 271-353, 1916. M d' A · S d 1 C t N M 2 Bauer, C. M., and Reeside, J. B., jr., Coal in the central and eastern e 10 rroyo, 1n an OVa OUn y, · ex., 

parts of San Juan County, N.Mex.: U.S. Geol. Survey Bull. 716, pp. 

155-237, 1921. • Bauer, C. M., Stratigraphyofapartofthe Chaco River Valley: U.S. 

s Gilmore, C. W ., Reptilian faunas of the Torrejon, ~uerco, and under- Geol. Survey Prof. Paper 98, pl. 64, 1916. 

lying Upper Cretaceous formations of San Juan County, N.Mex.: U.S. 5 Gregory, H. E., Geology of the Navajo country: U.S. Geol. Survey 

Geol. Survey Prof. Paper 119, 1919. Prof. Paper 93, pl. 2, 1917. ' 
U. S. GEOLOGICAL SURVEY 

8 

.. " 

Diagram lo show source of data 

contained in this map 

T.30 N. 

T 29 N. 

T.ll N . 

J. H . Gardner- Unp~hlished geologic map or the 

/gnac;o qvadrgngl~. FOrmat/on houndilrt'i,s 

henealh the f'iclvredCiif'/'ssandslone 

Wh i+man Cross- U.S. Geological Survey Gt'ologtc 

A flas, La Plafii fOlio (No. 60),1898 

M.A. Pishel - Unpvbkshed geologic n>ap of' the 

Red Mest? 9uadrangle. rormah"on 

bovndanes beneath !he PtCiuredC/if'/'.s 

sandsTone 

H ·E. Gregory- U.S. Geological Survey Prof: Paper 

93, pl. 2, 1917. Boundary .between 

Mancos shale and Mesaverde group 

C. M.Bauer- U.S. Geologica/Survey Prar.Paper 98, pl. 64, 1916. ' 

I 

( 

\ 

( 

I 

) 

R. 10 W. 

R . l3 W. 

\ 

~· ·. '\. 

R. 9 W. R. 8 W. 

\ 

i 

( __ _ 

/ 

... J 

./ 

\ 

R. 7 w. 

PROFESSIONAL PAPER 134 PLATE I 

R. 6 W. 

Tw 

T. 36 N. 

""--·--~ _:i~l~ 

;..~ ~// J: ~~~ / ~. 

0 

T. 32 N. 

Wasatch formation 

(Including the "7'iffuny be dB" of 

Grctnger on the northern sifle 

of the basin; 

UNCONFORMITY in southern part of basin; gradation in 

northern part 

Torrejon 

~ and Puerco 

formations, undifferentiated 

(Naoi.·,tie-ttto group) 

UNCONFORMITY 

T34N. 

>-

ll: 

<( 

;:: 

ll: 

w 

.... 

I T.28 N. 

\Rocks nearly I 

\horiz.ontal 

\ 

T.27N. 

I 

I f---..,L---~t-rli:f.'+!!-----'~~-t-----n--:-::T:+.- -t---JL------\- --- - - - "'\ _______ J_ Kirtland shale, containing the Farmington sandstone 

member (Kkfl 

T. 9 N. 

-· . I 

T. 8 N.• I 

I 

I 

/Bennett Peak 

f,< • ,f.~FordsPeak 

I I .L------~-~-- 1 I 

T.7 N. 

T.6 N. 

R. I W. 

T. 5 N. '-.. ... ......__ 

GEOLOGIC ~AP OF THE 

\ 

'VJ1~S'TERN PART OF THE SAN ,JUAN BASIN 

COLORADO AND NEW" NlEXICO 

I 

Scale 250,ooo 

5.___.____. _ _._-"--..LO _______ L5 ______ _..:.;10 MILES 

1924 I 

_j_ 

R . R.ll W. 

I 

I 

Ttp I 

I I 

~-1 ---- -~~~~ ""t~'\• ;g E. ----- I Huerfano -- :,:---~-----t- I. I 't f'if,~ I. 

R.IO W. 

I 

t' I 

I '-J 

I 

\ Tw . 

II I \ ci 8 

::I '- ul ---"- - ----

" 

" '-

,.-''-. 

T. 25 N. 

Fruitland formation 

Pictured ~ Cliffs sandstone 

[!I] 

Lew1s shale 

G 

Mesaverde group 

(ClVf Hcnu~e sand8tone. i!.fenefu jormatwn., and Point Lookout Bandstone) 

Mancos 

~ shale 

,, ~ 

Dip and strike 

of beds 

I 

I T22N. 

I 

I 
U S C .... OLOGICAI SURVLY 

w 

z 

w 

u 

0 

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w 

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UJ 

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At hulet<~ Count} 

Colo 

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I 

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Piedra Rivet d1v1de 

Ardnuet 1 County, Ct 

I 

I .§ I 0){/j I .::(1) 

I 

I 

I 

I 

2 290 

<.) 

Flouda River 

La Plata County 

CQIO 

00 

60 

1600 

ty 

Lew1s 

Dakota and">tone 

Colorado 

New Mexico 

bt 1te houndat y 

10 

1 J1N It 14 W 

&an Juan Gount;y N Mex 

11 

&an Juan H1ver 

&1nJuan County 

N Mex 

12 

Amc~nllo Arroyo 

S·mJ J'ln Count} 

N Me< 

--- ---

Potnt Lookout 

-------- Manc,os shale 188S 

H 

Btimhatl 

Wash &an 

Juan County 

N Mex 

16 

0Jo Al1mo 

Ano; J &an 

Juan County 

N Mex 

15 

Huntet 

\\ <1 h '31n 

JmnCounty 

N '\lex 

-~----

PHQFE,&::,IONAL PAPbl 1.14 PLAH, ll 

18 

E vw Hi a W 1sh 

81n J u.tn Goun t) 

N Mex &KI.:fCH MAP '10 ;,HOW 

fO.,ITION OI SfUION& IN D!ACHAM 

17 

Mt.yets Creek 

S1nJumCount) 

N Mex 

---

~ 

ApplO'Cll!l 1te positiOn ot top of Pictured Ghffs sc~RdbtJne used d d"ttum pi me 

1-iSectwn mdiv1ted by number 

19 

Lut.htb &tore 

'-landovalCounty N Mex d 

---

"\ 

""' 

""' ""' 20 ""' Hw Puer o &andoval County 

"\. N Mex 

"' 

-----

a Ad.tpted from C:r1rdner J ,H m Lee W f Stl 1ttgraphy of the co 1! 

fields of New 1\Il.XM Geol i:Jo<. Amema Bull vol .!3 p tJ84 1912 

Pishel \1 A unpuhhbhed dc~t1 

(, Ad tpted from Baue1 (, M &trat1g1 1phy of <1 p11 t of the Ch 11.0 Rtvel v dleJ &an Ju1n County N Mex U & Gt.ol umvey Ptol P 1pe1 

9b pi b4 1916 

d Ad 1pted .ftom unpubhbhed sedton me1~:>uted b) L A C.tllett 

C:r,udnel J R lhe Puet<.o 1nd lotreJon foun.ttion~:> of the N<~cmnento 

gtOUIJ JoUl Geology vol 18 p 717 1910 .tnd !he cod fldd between 

::,Ill Mateo and Cuba N Mex U & C. eo! &Ul vey Bull JHl pp 

171 179 1910 

EXPLANATION 

; 0 D ~ 5hale s,nclstone Conglomf'rate Coal 

COLUMNAR SBCfiONS OF fORMAfiONE> AROUND MARGIN Of SAN JUAN BASIN, COLORADO AND NEvV MhXICO 
. ; '· 

GEXERAL SECTIONS. 3 

principally to trace the Ojo Alan1o sandstone 

eastward. The general position of the area 

studied is shown in Figure 1. 

The geographic features of the region have 

been described at varying length in the papers 

by Bauer, Gregory, and others, references to 

which n1ay be found in the bibliography. 

' These descriptions need not be repeated here 

other than to say that most of the region is in 

every 'vay typical of the semiarid Southwest, 

Area covered by this report 

include sediments of Upper Cretaceous and 

Tertiary age. Older Mesozoic rocks not 

descr.ibed here occur around the border of the 

basin, and within it there are small bodies of 

igneous rock of somewhat uncertain age 

though probably Tertiary. The area also 

includes gravel mesas, river terraces, and allu- . 

vium of Quaternary age, which are not 

described here. The. writer's attention has 

been given chiefly to the formations from the 

San Juan Basin 

FIGURE 1.-Index map showing location of San Juari Basin and area covered by Plate I. 

though the norther~ edge approaches closely 1 J:ewis shale to the Torrejon form~tion, incluenough to the foothills of the San Juan and La s1ve. The Mancos shale was examined at only 

Plata n1ountains to receive a greater rainfall a few places, the Mesaverde group as a whole 

and support a denser vegetation of plants that only near San Juan River in the Great Hogrequire n1ore moisture. back and on Animas River near Durango. The 

STRATIGRAPHY. base of the Wasatch formation has been the 

·GENERAL SECTIONS. upper limit of study over much of the area 

The rocks of the San Juan Basin described examined, though in Colorado some time was 

briefly· in the subjoined table and at greater spent on this formation, especially on Granger's 

length in the succeeding pages of this paper "Tiffany beds," at its base. 
4 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Cretaceous and Tertiary formations of the western part of the San Juan Basin, {n Colorado and NewMexico. 

Sys- Series tern. Formation. 

Wasatch formation. 

Qharacter. 

Massive, persistent gray to brown 

resistant conglomeratic sandstone interbedded with variegated shale; red shale abundant. 

In the extreme northern rim of 

the basin variegated shale 

chiefly, with beds of coarse ar- kose that contain an abundance 

of pink feldspar. Fluviatile. 

The "Tiffany beds" of Granger are the basal part of the formation in the northern part of the 

basin but are not differentiated 

in lithology; they are not known 

in the southern part of the basin. 

Thickness.a 

2 

1, 000+ 900+ 

Unconformity in the southern part of the basin; conformity in the northern part.b 

Torrej on and 

Puerco formations un- differen tiated. 

In the north; lenticular gray to 

brown conglomeratic resistant 

sandstone interbedded with red 

and gray shale; underlain by 

gray and greenish-gray shale and 

soft white to yellow conglomeratic sandstone. In the south, 

light-gray shale with some red 

layers and some soft whitish 

sandstone, underlain by gray to 

black shale with rare red bands, 

soft white sandstone, and soft 

yellow sandstone with concre- tions. Fluviatile. The faunas 

of these two formations are interpreted to demand a hiatus be0 40G-1, 450 

(?) 250+ 

(?) l. 140 

tween them, but no.ne has been 

definitely recognized yet. The 

Puerco formation is believed to 

be confined to the southern part 

of the basin. 

Unconformity.--------------- --------------------------------1----------I-----------I--------I---------

Animas formation 

(restricted) to 

north. (Contemporaneous with 

Ojo Alamo sandstone to south.) 

At base coarse beds with weathered 

and waterworri andesitic debris 

and pebbles of siliceous rocks. 

Remainder of formation shale 

and sandstone with much andesitic debris and occasional beds 

of fine conglomerate. Whole 

formation pistachio-green to tan, 

with very rare reddish layers. 

Fluviatile. 

Gray to brown coarse sandstone 

containing lenses of siliceous 

pebbles and lenses of variegated 

shale. Fluviatile. 

2, 670 100 0 0 

0 0 400 130 

Ojo Alamo sandstone c to south. 

(Contemporaneous 

with Animas formation to north.) Unconformity.---------------1--------------------------------l--~-----l-----------l---------l--------

.......... 

~ 

00 .......... ::l ~ 0 

Q;) 

00 ~ 

::l c:'S 0 ...., Q;) Q;) 

~ 

c:'S 0 "" ...., 

"" Q;) 

"" Q;) 

0 0.. 

0.. 

p 

McDermott formation. 

In the north, andesitic tuff and 

tuffaceous sandstone and shale, 

mostly purple, with a small 

amount of conglomerate of pebbles of siliceous rocks. The proportion of purely volcanic material decreases southward, and 

in the south the whole formation consists of variegated shale 

and brown sandstone with a minor amount of volcanic debris. 

Heretofore included in Animas 

formation in the north. 

266-300. l9G-245 40 40 

a 1, Eastern La Plata County, Colo.; 2, northern San Juan County, N.Mex., and southern La Plata County, Colo.; 3, central San Juan County N.Mex. (San Juan River); 4, southern San Juan County, N.Mex. b Unconformity present only where lower part ("Tiffany" zone) of Wasatch formation is absent. · c The Animas formation and Ojo Alamo sandstone are not known to touch anywhere, and their mutual relations are not certainly known, but 

they are believed to be contemporaneous, at least in part. 
GENERAL SECTIONS. 5 

Cretaceous and Tertiary formations of the western part of the San Juan Basin, in Colorado and New Mexico-Con. 

Sys· Series tem. Formation. Character. 

Thickness. 

-------~----------~------~------

2 

Local unconfprmity .-----1----------------------l--------l--------·l------l----

Kirtland shale. 

Light-gray to blue-gray shale, 

with some black carbonaceous 

and brown shale and soft white 

sandstone. Fluviatile. 

Farmington sandstone member; 

gray to brown indurated sandstone lenses separated by gray 

shales. Thins southward from 

San Juan River. Fluvib.tile. 

Shale and soft sandstone iike 

those of upper member. Fluviatile. 

Gray sandy shale, gray-white 

cross-beded soft sandstone, 

Fruitland formation. brown indurated sandstone, 

carbonaceous shale and coal. 

Of fresh and brackish water 

origin. 

Pictured .Cliffs sandstone. 

Lewis shale. 

0. 

Cliff House 

sandstone. 

Buff to light .. yellow and gray I 

sandstone interbedded in the 

lower part with thin gray shale. 

Marine. 

Greenish-gray anci dark-gray sandy 

shale with occasional lenses of 

brown sandy limestone and buff 

concretions. Marine. 

Yellow to red-brown sandstone 

with some sandy shale. Some 

beds massive, cliff-forming. Marine. 

0-135 

480 

215 

340 

125 

2, 290 

e 90 

19Q-475 110 0 

350 455 0 

240-370 . 271 700 

43Q-530 241 230 

16Q-240 275 70 

d 1, 710 475 140 

750 369 

g 1-------------l--------------------l·-----l--------l--------l-------

!;b Gray shale, with some sandstone <l) and coal. Coal beds grouped 

"g Menefee forma- near top and base of formation; '"' barren interval between .. Rocks ~ tion. of fresh and brackish water 

gj origin, with only a few marine ~ beds. 

Point Lookout 

sandstone. · 

Mancos shale. 

Dakota sandstone. 

Massive buff or cream-colored to 

red-brown sandstone. Marine. 

Dark-gray and drab sandy shale, 

with Tocito sandstone lentil, 35 

feet thick, about 735 feet above 

base. Marine. 

Brown sandstone with some shale 

lenses and c()al; cherty conglomerate at base. · 

1, 800 

250 

d 356 1, 076 (?) 

d 274 300 (?) 

2, 000± 1,889 (?) 

200± 200± (?) 

a Unpublished data collected by M.A. Pishcl in the Red Mesa quadrangle, Colo. . e From section on Florida River measured by J. H. Gardner. See Lee, W. T., and Knowlton, F. H., Geology and paleontology or the Raton 

1\-Iesa and other regions in Colorado and New Mexico: U. S. Geol. Survey Prof. Paper 101, p. 187, 1917. 

82587--24 t--2 
Holmes, 1877.a 

Canyon .Largo series 

of Newberry. 

"Puerco marls" 

of Cope. 

Shaler, 1907. b 

Wasatch (?). 

Puerco marl. 

----? I~~~~~~.~~ 

Laramie (?) group 

(Upper coal 

group). 

Pictured 

group. 

Cliffs 

Laramie formation. 

Correlation of previous ·usage of formation names with that in this -paper. 

Gardner, 1909.c 

Wasatch formation. 

Torrejon formation. 

-~?~~ 

Puerco formation. 

Brown, 1910. d 

New Mexico. 

Sinclair and 

Granger, 1914. • Bauer, 1916.1 Bauer ~nd Reeside, 1920.• This paper. 

Wasatch formation 

[Not described]!· Wasatch'. (Not described.] Wasatch formation. (including the "Tiffanv beds" of Granger 'in lower part). 

--?--

Puerco formation. 

lv~'-"""'~vvvvvv~vv·-1 I ~~~w~~~""""~~~~~~v~~~~~~~~~~"""-~'~ 

Wasatch formation 

(near .Qjo Alamo). 

Formation 

mined. 

undeterTorretj?n for- I vvvv·~vvv~v·~vvv~vvvvvvV'I ~vv~~~v~~~ rna wn. 

Puerco formation. 

Torrejon and Puerco 

formations. 

Torrejon and Puerco 

formations. 

Torrejon and Puerco 

formations. 

... ....._......_,......,..,.....,.~~~-......_..............,........._1.......,.......,......-'""""',.....~ ............... ""'Y~I~~~~~~ ~~~~v~~~~vv~~~1 ~-~~~~,...... ...... ,..,,....,...:.....,~~~~ 

Unnamed con- glomerate. 

Oj o Alamo 

beds. 

Ojo Alamo 

beds. 

Wasatch formation · near San Juan River; 

Ojo Alamo sandstone 

:qear Ojo Alamo. 

Ojo Alamo sandstone 

south of Pinyon I Ojo Alamo sandstone. 

Mesa. 

I I I ,~~r.~~~~~/V'/V'~~~~~~~ 

Kirtland shale, including the Far.tpington 

sandstone member. 

Ojo Alamo sandstone 

north of Pinyon 

Mesa; Kirtland 

shale, upper part, 

south of Pinyon 

Mesa. 

McDermott 

tion. 

formaLaramie for- 1--- ? ---1--- ? --- mation. 

Kirtland shale, including the Farmington 

sandstone member. 

Kirtland shale, including the Farmington 

sandstone member. 

Fruitiand formation. 

Pictured Cliffs sandstone. 

\ 

Fruitland formation. 

Pictured Cliffs sand- - stone. 

Fruitland formation. 

Pictured Cliffs sandstone. 

~ 

q 

1-cj 

1-cj 

t_:!:j 

!:d 

0 

~ 

~ 

f-3 

> 

0 

t_:!:j 

0 

q 

m 

> z 

t::l 

f-3 

t:rJ 

H 

~ 

5; 

k1 

~ 

0 

!:d 

~ 

> f-3 

H 

0 

z 

m 

H 

z 

m 

> z 

c.., 

q 

> z 

td 

> m 

H 

~ 
Sand shale gr"oup. Lewis shale. Lewis shale. I [Not described] [Not described] Lewis shale. Lewis shale. Lewis shale. 

---

Upper escarpment Cliff House sandstone. Cliff House sandstone. sandstone. Mesaverde Mesaverde Menefee formation. Menefee formation. Middle coal group. formation. formation. Mesaverde formation. Point Lookout sand- Point Lookout sand- Lower escarpment stone. stone. sandstone. 

Colorado. Mancos shale. Mancos shale. Mancos shale. Mancos shale. Mancos shale. 

a Holmes, W. H., Geology of the San Juan district: U.S. Geol. and Geog. Survey Terr. Ninth Ann. Rept., for 1875, p. 244, 1877. ~Shaler, M. K., A reconnaissance survey of the western part of the Durango-Gallup coal field of Colorado and New Mexico: U.S. Geol. Survey Bull. 316, pp. 378-379, 1907. 

c Gardner, J. H., The coal field between Gallina and Raton Spring, N.Mex.: U.S. Geol. Survey Bull. 341, p. 338, 1909. • d Brown, Barnum, The Cretaceous Ojo Alamo beds of New Mexico, with description of the new dinosaur genus Kritosaurus: Am. Mus. Nat. Rist. Bull., vol. 28, pp. 267-274,1910. • Sinclair, W. J., and Granger, Walter, Paleocene deposits of the San Juan Basin, N.Mex.: Am. Mus. Nat. Rist. Bull., vol. 33, pp. 297-316,1:1914. 

J Bauer, C. M., Stratigraphy of a part of the Chaco River valley, San Juan County, N.Mex.: U.S. Geol. Survey Prof. Paper 98, pp. 273-278, 1916. o Bauer, C. M., and Reeside, J. B., jr., Coal in the middle and eastern parts of San Juan County, N.Mex.: U.S. Geol. Survey Bull. 716, p. 162, 1920. 

~ z 

trJ 

!:tl 

>- t"i 

U1 

trJ 

0 

\j 

0 

z 

rn 

~ 
. Correlation of previous usage of formation names with that in this paper-Continued 

Colorado. ' --------

Cross, 1899.a Schrader, 1906.b Taff, 1907.c Shaler, 1907.d Gardner, 1909.e Gardner, 1912.1 Granger, 1917.u This paper. 

Wasatch formation (inWasatch (?). Wasatch formation. Wasatch and eluding" Tiffany beds" 

Tiffany beds. of Granger in lower 

part. 

Later Tertiary ~w~?~~~ rocks. I ~~~?- ? 

Tertiary. [Not described.] Torrejon formation. ~~~~~w~~~~~~~-

Puerco marl. Animas formation 

with coarse lentil Animas formation. 

~~~~~~~~- w~~~~~~w~ at base. .·-...---.......... ~-------~~~ 

[Not present.] Animas formation. Animas formation McDermott formation. (Tertiary). 

? ? ~w~~~ ~~~(Local.)~~~ 

I 

Kirtland shale with 

Farmington sandstone 

member. 

''Laramie'' formaLaramie (?) for- Laramie forma- Laramie forma- Laramie forma- tion with Pictured 

mation. tion. tion. tion. Cliffs sandstone Fruitland formation. member near base. 

[Not described.] 

Pictured Cliffs sandstone. 

Lewis shale. Lewis shale. Lewis shale. Lewis shale. Lewis shale. Lewis shale. Lewis shale. 

Cliff House sandstone. 

Mesaverde forma- Mesaverde for- Mesaverde for- Mesaverde for- Mesaverde for- Mesaverde formation. Menefee formation. 

tion. mation. mation. mation. mation. Point Lookout sandstone. 

Mancos shale. Mancos shale. Mancos shale. Mancos shale. Mancos shale. Mancos shale. Mancos shale. 

Dakota sandstone. [Not mentioned.] Dakota sand- Dakota sand- Dakota sand- Dakota sandstone. Dakota sandstone. 

stone. stone. stone. 

~ I 

a Cross, Whitman, U.S. Geol. Survey Geol. Atlas, La Plata folio (No. 60), pp. 4-5, 1899. b Schrader, F. C., The Durango-Gallup coal field of Colorado and New Mexico: U.S. Geol. Survey Bull. 285, pp. 241-257, 1906. c 'l'aff, J. A., The Durango coal district, Colo.: U.S. Geol. Survey Bull. 316, pp. 322-323, 1907. . a Shaler, M. K., A reconnaissance survey of the western part of the Durango-Gallup coal field of Colorado and New Mexico: U.S. Geol. Survey Bull. 316, pp. 378-379, 1907. e Gardner, J. H., The coal field between Durango, Colo., and Monero, N. Mex;: U.S. Geol. Survey Bull. 341, pp. 352-353, 1909. f Gardner, J. H., in Lee, W. T., Stratigraphy of the coal fields of northern central New Mexico: Geol. Soc. America Bull., vol. 23, pp. 584-589, 1912. Also in Lee, W. 'l'., and Knowlton, F. H., Geology and 

paleontology of the Raton Mesa and other regions in Colorado and New Mexico: U.S. Geol. Survey Prof. Paper 101, pp. 185-187, 1917. g Granger, Walter, Notes on Paleocene and Lower Eocene mammal horizons of northern New Mexico and southern Colorado: Am. Mlis. Nat. Hist. Bull.; vol. 37, p. 829, 1917. 

00 

q 

~ p; 

0 

~ 1-3 

~ 

0 

t;j 

0 

q 

r.n 

~ 

z 

t;; 

~ 

;....; 

~ 

~ 

~ 1-:!j 

0 

~ ~ 

1-3 

H 

0 

z 

r.n 

H 

Z, 

r.n 

~ 

z 

c.; 

~ z 

td 

~ 

m 

~ 
MANCOS SHALE. 9 

DAKOTA SANDSTONE. of gray shale with son1e thin beds of sandstone. 

The Dakota sandstone is the basal formation. The remainder of the upper two-thirds is gray 

of the Upper Cretaceous series of the region. shale with a number of zones of yellow-brown 

'1"} . calcareous concretions and son1e zones of .1. 1e wnter examined it at only one locality, 

near Durango, Colo.; where it consists of platy gray, rather soft sandstone that \veathers 

variable gray to brown cross-bedded sandstone, like shale. Beneath t4is upper two-thirds, 

with a cherty conglomerate at the base; it con- about 735 feet above the base of the fonnation, 

tains also shale lenses and beds of impure coal. appears a notable bed of sandstone, 35 feet 

Its thickness is about 250 feet. At .many thick, brown, coarse, cross-bedded, containing 

other localities its thickness is reported to lenses of pebbles of chert and quartz as n1uch 

range fron1·2oo to 250 feet. The contact with as half an inch in diameter, and resistant 

the Mancos shale is transitional. The relation enough to make a cliff. It is known as the 

of the Dakota sandstone of this region to that Tocito sandstone to the petroleurn geologists 

of distant regions is not well known. It may who have mapped the region for oil cornpanies, 

. represent a greater or lesser time interval than though sometimes also called by thern Frontier 

the typical Dakota sandstone. sandstone. In this report it will b~ called the 

Tocito sandstone lentil of the Mancos shale . 

. MANCOS SHALE. 

Type locality and distribution.-The Mancos 

shale was so designated by Cross. 6 from the 

exposures near the town of Mancos, Colo. 

The name has since been applied extensively. 

Shaly strata in the lower part. of the Upper 

Cretaceous as far away as central Utah, northern Colorado, northeastern Arizona and northcentral New Mexico have been ~rouped ·together as :Mancos shale. Along the west side 

of the San Juan Basin the forn1ation underlies a 

broad area between the Mesaverde group and 

the Dakota sandston~. On the north side the 

belt of outcrop is narrower but is marked as a 

pronounced valley between the underlying 

Dakota sandstone and the overlying MesaYerde group. 

· Lithologic character.-The Mancos shale at 

the type locality, near l\1ancos, Colo., consists 

of sof~ dark-gray or nearly black shale with 

thin lenses and concretions of limestone. 7 The. 

writer examined the entire thickness of the 

Mancos shal~ ~n Anirnas River near Durango, 

Colo., where l t lS a gray to very dark m·arine shale 

with a few thin layers of gray sandstone near 

the top and son1e layers of in1pure limestone 

near the base. It contains ferruginous yellowbrown concretions at many horizons. On 

Chaco and San Juan rivers near the Hogback 

the upper two-thirds of the formation is exrosed an~ was exainined. The uppermost part 

IS rnuch hke that on Animas River, consisting 

° Cross, Whitman, U. S. Geol. Survey Geol. Atlas, Telluride folio 

(No. 57), p. 4, 1899. 

7 Cross, Whitman, op. cit., p. 4. . 

The name· is derived from the outcrops of the 

sandstone near the Tocito trading post, in 

San Juan County, N. Mex. Only a sn1all 

thickness of the beds beneath this sandstone 

is visible at the ·surface, but a well drilled to 

the Dakota sandstone shows that the lower 

third of the Mancos is gray to nearly black 

shal~. · The writer examined hurriedly the 

Tocrto sandstone and the underlying beds at 

a lo~ality 25 miles southwest of that just 

descrrbed, near Beautiful Mountain. Here the 

Tocito forms a hogback ridge and the gray 

to nearly black shale beneath it contains some 

calcareous layers and some sandy layers. 

The Mancos shale is easily eroded and at · 

most localities in the western part of the San 

Juan Basin makes a pronounced valley between 

the ridge of Dakota sandstone and that of the 

sandstones of the Mesaverde group. 

~hiclcness in San Juan Basin and. adjacent 

:eg~~ns.-The Mancos shale at the type localIty Is 1;200 feet thick. Farther north near 

Telluride, Colo.,8 it reaches a thickness of 2,000 

feet. The formation is 1,800 feet thick at 

Durango and is said by Gardner 9 to be 1 600 

feet thick on Florida River, Colo., and' by 

Shaler 10 to be 1,000 to 1,400 feet thick in San 

Juan County, N. Mex. The last-n1entioned·. 

~gure is about the thickness one might expect 

In San Juan County by a comparison of the 

s Cross, Whitman, op. cit., p. 4. 9 Gardner, J. H., in Lee, W. T., and Knowlton, F. H., Geology and 

pale~ntology of the Raton Mesa and other regions in Colorado and New 

~x10o: U. S. Geol. Survey Prof. Paper 101, p. 187, 1917. 

Shaler, M. K., A reconnaissance of the western part of the Durango-· 

Gallup coal field of Colorado and New Mexico: U.S. Geol. Survey Bull. 

316, p. 378, 1907. 
10 UPPER CRETACEOUS AND T'ERTIARY FORMATIONS IN SAN .JUAN BASIN. 

thicknesses and the relative positions of some 

of the faunal zones.· However, logs of wells 

drilled on the Southern Ute Indian Reservation 

. near the southwest corner of sec. 31, T. 32 N., 

R. 13 W., show that the thickness there is 

approximately 2,000 feet, and a section measured by the writer in sec. 19, T. 29 N., R. 16 W., 

supplemented by the logs of wells drilled at the 

same locality, shows a thickness of about 1,880 

. feet. Possibly the two areas are nearer the 

center of the basin and the thickness is greater 

because of greater subsidence of the basin during deposition. In the Rio Grande valley 

southwest of the San Juan Basin the thicknesses as given by Lee 11 show a considerabl~ 

range-1,000. to 2,400 feet-and several important sandstone members occur wit~in the 

shales. To the west, in Arizona, Gregory 12 

found 550 feet as the thickness at Salakhai 

Mesa, 565 feet at Chilchinbito, and 620 feet 

atLolomaiPoint. In Socorro County, N.Mex., 

to the south of the area here considered, there 

is· an essentially marine series, 2,080 feet thick, 

of yellow sandstone and drab and yellow sandy 

shale with a few beds of clay and several beds 

of coal, described by Winchester 13 as the 

Miguel formation. It occupies apparently the 

approximate position of the Colorado part of 

the typical Mancos shale and is overlain by 

a fresh-water series, lithologically similar to 

the Miguel formation and named the Chamiso 

11 Lee, W. '1'., and Knowlton, F. H., Geology and paleontology of the 

Raton Mesa and other regions in Colorado and New Mexico: U.S. Geol. 

Survey Prof. Paper 101, p. 174, 1917. 

u Gregory, H. E., Geology of the Navajo country: U.S. Geol. Survey 

Prof. Paper 93, p. 74, 1917. 

1a Winchester, D. E., Geology of Alamosa Creek valley, Socorro 

County, N. Mex.: U. S. Geol. Survey Bull. 716, pp. 5-8, 1920. 

formation, which seems to occupy the position 

of the Montana part of the typical Mancos 

shale and an undetermined amount of the later 

beds. The Chamiso formation bears coal and 

fossil plants of Montana age and is 1,850 feet 

thick. 

Relation to adjacent formations.-The contact of the Mancos shale with the overlying 

·Point Lookout sandstone is conformable-in 

fact, it is one of gradual transition, and a 

dividing plane must be arbitrarily chosen. 

The lower contact where seen in the Ignacio 

quadrangle is likewise transitional. 

Fossils.-Eighteen collections of fossils ·were 

made from the Mancos shale in New Mexico, 

seventeen from the upper two-thirds and .one 

from the lower third. Nineteen collections 

were n1ade in Colorado, scattered throughout 

the formation. The species identified in· these 

lots are listed i~ the accompanying table and 

also in Plate III. 

Several distinct and widespread faunas are 

represented in these collections. For want of 

better names they may for the present be 

designated by the names of the formations in 

which they are especially well developed and 

characteristic. These faunas are, in ascending 

order, the Greenhorn fauna, the Carlile fauna, 

the Niobrara fauna, the Telegraph Creek 

fauna, the Eagle fatina, and the Pierre fauna. 

A rather widespread fauna at the base of the 

Mancos shale has been reported from the general region but was not observed by the writer. 

It contains such species as Gryphaea newberryi 

Stanton, Metoicoceras whitei Hyatt, and Exqgyra columbella Meek. . 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 13t PLATE III 

Animas River, Colomdo Red Mesa quadrangle, Colorado San Juan River, 

New Mexico 'UpJ>er Chaco River, . New Mexico 

<.- .- -- 15 miles -----;:a. ~---- 30 miles------;;. 

6067. Jnocuranms sp., Ostrea sp., Cardium nff. C. speciosum, Tellina scitula 

10502. Inoceramus barabini, I"" ocuramus sagensis, ammonite fragment 

10501. Inoceramus baralnni 

10499. Inoceramus sagemis; Ostreasp., Tercdo?sp., PtychocllT08 erassum, Baculites compresBUS, Heteroceras nebrascense Sea,. t~s nodoBus var. quadrangu10563. Inoceramus sp., Fasciola· 

ria?sp.,Heteroceras nebrascens 

104!l8. Inoceramus barabinil I"" oceramus sagensis, Bautt ites 

ovattts? 

10500. Inoceramus sagensis 

10497. Inoceramus sagensis, Pte1'ia linguaqformis, Hyposcdon sp. 

10485. Cardium sp., Mactrafor- mosa, L!matia concinna?, f'ur-. 

ritella sp.,Cantharus? sp., Volutodermasp., Cinuliasp., shark teeth 

10432. Placonticeras intercalare 

10433. Mactra cf. M. holmesi 

]~ uw 

8539, 8542. Inoceramus barabini, Baculites sp.1 Helicoceras 

ef. H. fiiO'I"ton'l var. tenuistriatttm 

A 

8544, 85451 8546. Inoceram1UI 

baralnm, Ostrea Pf!llttcida, Ostrea sp. Sp_haeriola endotrachys, Cdraium sp., Callistadeweyi, LunatiaOccidentalis, Fasciolaria?sp., Acteon 

attenuatus, Anisomyoncf. A. 

shu1nardi, Baculites anceps var. obt'U8U8 

••~•-n .. oo~ ~H~~ __ _ 

9278. Serpula sp., Inoceramtis barcilnni, Cardium cf. C. speciosum Te£. 

lina scitula, Leptosole'li n. sp., Mactra 

gracilis}. Corbula sp., Odontcba.sis sp., TurriB!?)sp.,Acteonsp.,Hamineasp. 

10139. Serp1!-la sp., Inoceramus sj>., Ostrea sp., MO(tiolacf. M. meeki, Ci.Lrdiumcf. C. B]Jeciosum, Tellinascitula, 

Baroda sp., Leptosolen n. sp., Mactra . warrenana, Chemnitzia cerithifor- mis, Lunatia occidentalis, Turntella?sp., Anchurasp., Acteonsp., Ha,. 

minea subcylindnca, Cinulia n. sp. 

9273. Inoceramus baralnni, Placenti- ceras intercalare 

·9277, Pteria linguaeformis, Anomia sp., Lucina sp,, Lunatia sp., Baculites. sp. 

10140. Inoceramus baralnni, Cardium sp., Callista deweyi, Lunatia occidentalis 

A. Pierre fauna 

B. Eagle fauna 

9296. Leda sp.1 ~strea inornata, Syncylo- nema sp., !-Jihpistha undata, Cardium . speciosum, Lunatia sp., Placenticeras sp. 

9744 .. Yoldia evansi, Inoceramus baralnni, 

Pteria nebrascana, Ostrea sp. 1 Liopistha undata, Astarte? n. sp., Carotum n. sp., Tellina·n. sp.1 MactrajOrmosa, Mactrawar- renana, COroula n. sp., Chemnitzia?·ap., Morea? sp., Fmu8? sp., Acteon n. sp • 

9743. Yoldia evansi Inoceramus barabini, 

Pterianebrascana, Ostrea sp., Anomia n. sp., Astarte?n. sp., Cardiumsp. Tellina·n. sp., •lJona:& n. sp. Mactra formosa, Mactra war- rena~ C~la n. sp., Chemnitzia cerithi- formis., Solarium n. spri0tnatia concinna?, 

Lunatia w.bcrassa?, ~.TJJTodes aff. G. depressa, Anchurasp., Morea? sp., Volutoder- ma sp., Acteon n. ?,·, Ham mea subcylint~ 1:~:: c . A. shumardi, PlacenC. Telegraph Creek fauna 

D. Niobrara fauna 

E. Carlile fauna 

F. Greenhorn fauna 

12004. Inoceramus cf. I. lobatus, Inoceramus sagensis, Ostrea sp.1 Apon·hais biangulata, Baculites ova.tus, B. ova.tus var. haresi, Baculites aquila.ensts?, Baculites asper, Scaphitcs hippourepis, S. hippourepis var. crasBUS, Scaphites aquilaensis, S. aquilaensis var. nanus, Ei:hid1wcephalus? sp. 

12005A. Baculites asper, Placenticeras guadalupe 

12006. Baculites ovatus, B. ovatus var. haresi, Scaphites leei 

10143. Inoceramus barabini?, Ostrea sp., Anomia n.sp., Baculites sp. ---- r1043'L .ln~;m~ -;j;.~.;t;.~ - - ~:·~·\::.: Mancos - - -

conqesta var. ·. ·.-:- shale B · ___ 10142. Inoceramus cf. I. lobatus, Baculites ovatus, B. ovatus var. haresi, Baculites aquilacnsis '-...... var. distans, Puzosia (Latidorsella) mancosC?tBis, Scaphites stantoni, Scaphite.~ aquila- -- f10429. Inoceramus barabini, Ostrca sp., · /, 

Lucina sp., Baculites.ova.tus, Scaphites hippocrepis, H1JP.wdon radUitUll.ts / 

10430. Inoceramus sp., Ostrea congesta var. /'Y 

____ ~4~~~22: !_no_:e~~ ~:!... OE~ ~g_es~ !..ar..:... ____ , __ // 

10435. Inoceramus cf. I. lobatus 

10426. Baculites ova.tus?, Scaphites sp. C 

10434, 10484. Inoceramus cf. I. lobatus, Ostrea congesta var., ..,..-

- !!_~l~~·:_!~p~t~~~~-- ------- ___ .... ---

10505. Inoceramtts cf. I. acuteplicatus 

10504 Foraminifera (?),Inoceramus sp., Ostrea congesta, Baculites sp. 

10503. Foraminifera(?), Inoceramus cf. I. acuteplicatus, Ostrea 

congcsta, Scaphitcs vcntricosus, Ichthyodectes sp., Leuchichthys D 

vagans, Hypsodon audax 

10510. Inoceramus sp., Ostrea congesta 

10509. Inoceramus sp., Ostrea congcsta . 

= . -- · -io506./M"c;;:a,;;;;d,i;;rid'fus-;I~;:;.m~fra.gilii; i;wcero~ ~::--, Ostrea l:ztgttbris, V eniella sp., Baculites cf. B. gracilis, Scaphites E ', 

warren\ ' 

-- --- --. ---- -·-----------, ..,. 101>07. Inoceramus labiatus F ' - --- - - - - - --- - - - - ----- ' ' ' ' 

', "? 

' '? 

' 

Dakota 1.::.:.:.: 

!!Qndstone · · · · 

'.....,~.!,~6!!:!.~SJ:.!!!.~l!J?.is_! . .P.:..:..l!J!p!._~ ~~~~ __ ----__ 12005. Inoceramu.s sagensis, Cardium speciosum, Baculites ovatus, B. ova.ttts var. hm·esi, 

Scaphites bassleri 

10141. Inoceramus ·sp., Baculites ovattts?, Scaphites bassleri 

10144. Inoceramus sp., Lucina n.sp., Baculites sp. 

_1~~~~~~~8~------------------------~ 10145. Inoceramus undabundus, Inoceramus sp. 

12011. Inoceramus sp., Ostrea congesta, Scaphites ventricoBUS? 

12007, 12010, 12014. Inoceramus sp., Pteria qastrodes, Ostrea congesta, Lucina subundata, Cardium pauperculum, Pseudomelama? sp., Baculites sp., Scaphites vermiformis, Placenticeras sp. 

12012. Sauvagesia cf. S. austinensis 12008. Inoceramus sp., Pteria gastrodes, Ostrea congesta, Lucina subundata, Hamites? n.sp., Baculites asper, Scaphttes ventricoBUS, Scaphites vermiformis 

12009. Inoceranttts sp., Ostrea congesta, Baculites asper, Baculites cf. B. anceps, Scaphites vC?-miformiB 

12003. Inoceramus defOT1nis. Ostrea congesta 

12002. Inoceramus umbonat'Ud', Inoceramus sp., Ostrea congesta ( Tocit..o sandstone lentil) 

10368. Inciceramtts dimidius, Inoceramtts fragilis?, Inoceramus sp., Ostrea lugubris, Anchura? sp., Baculites cf. B. graciliB.r.. Scaphites warreni, Placenticeras sp., Prionocyclus wycr mingensis, Prionotropis cf. r. hyatti 

COLUMNAR LSECTTONS SHOWING THE FAUNAL ZONES OF THE MANCOS SHALE, MESAVERDE GROUP, LEWIS 

SHALE, AND PICTURED CLIFFS SANDSTONE OF THE WEST SIDE OF SAN JUAN .BASIN. 
MANCOS SHALE. 11 

Fossils of the Mancos shale. 

Greenhorn f~una. 

Inoceramus labiatus Schlotheim ___________________________________ ~ _______________________________ x 

Carlile fauna. 

Inocenunus dimidius \Vhite________ ___ _ __ __ __ _ ___ _ _ ___ _ __ __ _ _ ___ _ __ __ _ _ __ __ __ _ _ ___ _ _ _ __ __ _ _ _ x x x 

Inoceramus fragilis Meek and Hayden ____________ .:.._________________________________________ ? x 

Inoceramus sp_ _ _ ____ _ ___ _ __ __ _ ___ _ _ _ _ __ _ __ _ _ _ __ _ _ __ _ _ __ __ _ _ ___ _ _ _ __ _ _ ___ _ ____ _ _ _ _ __ _ _ _ _ _ x x Ostrea lugubris Conrad_____________________________________________________________________ x x x 

Veniella sp. undetermined__________________________________________________________________ x 

A.nchura? sp__ ____ _ _ _ __ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ __ _ _ _ __ _ _ _ __ _ _ __ __ __ __ _ _ ___ _ __ _ ___ _ _ _ _ _ _ _ x _____ _ 

Baculites cf. B. gracilis Shumard____________________________________________________________ x x ~-- _ Scaphites warreni Meek and Hayden ____________________ .: _____________________________________ x x __ _ Placenticeras? sp __ ._ ___________________________ -- ___________________ -- __ ---- _ --- __ -- __ ----- X 

Prionocyclus wyomingensis Meek___________________________________________________________ x 

Prionotropis cf. P. hyatti Stanton __________________________________________________________ x 

Prionotropis loewian us White______________________________________________________________ _ _ _ _ _ _ x 

Ptychodus SP----------------------------------------------------------------------------- --- --- X 

Niobrara fauna. 

~ 8 ~ 8 ~ s ~ ~. ~ ~ ~ s ~~~ ~ 8 

~ 

8 

~ 

8 

~ 

8 

~ 

~ ~ 8 

~ 

~ ~ § 

~ 

§ 

~ 

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 

---------------·----------- ------------------------------

Inoceramus undabundus Meek and Hayden ___________ x _________________________________________ _ Inoceramus cf. I. acutiplicatus Stanton _________________ x ___ x ________________________ · ________ _ Inoceramus umbonatus Meek and Hayden ______________________________ x _______________________ _ Inoceramus deformis Meek ________________________________________ --- ___ x _________ --- --- _____ _ Inoce1:amus sp.; very l~rg.e, thick-shelled __________________ x ___ x x x 1--- x 1 x ___ x x ___ x Ino~~Iamu_s. sp. undet~mnmed ______________________ x _______ :_ __________ 1 

_________ x x. --- _____ _ Ptena gastrodes Meek ____________________________ --- ________________________ x ___ x ---1--- x 

Ostrea congesta Conrad------------------------------ X X --- X X X X X X X X X --- X Lucina subundata Hall and Meek __________________ --- _________ ~-- ____________ x ______ --- ___ x 

Cardium pauperculum Meek------~----------------- ____________________________________ --- ___ x 

Sauvagesia cf. S. austinensis Roemer ________________________________________________________ x __ _ 

~S:~~~1t~~~?el~~li:~--s~~~-~~~========================== === === === === === === === === === -x- === === === === -~­

~:~~~lf~~: ~F~B~ !~l~~~s11I~~~~-~~ci~---~ ~= = = = = = =: =: = = =·= = = == = == = == = == = == = == = == = :: = == = -~ _ ~ ==: ==: ~=: ==: Baculites sp. undetermined _______________________________ x ____________ ---~--- x x Scaph~tes .ventr.icosu~ Meek and Hayden____________ _ _ _ x __ _ __ _ __ _ __ _ __ _ __ _ __ _ x __ _ __ _ 'l 

Scaplutes verm1form1s Meek and Hayden _______________________________________ x x x 

Placenticeras sp. undetermined _______________________________________________________ x ________ _ Ichthyodectes sp _____________________________________ x ___ ___ ___ ___ ___ ___ ___ ___ ___ _ __ _ 

Leuchichthyops vagans CockerelL _______ .____________ _ _ _ x -_. __________________________ --~---_______________ .-- ____ =_ =_ =_

1 

= ___ - __ - _= ____ - ____ -~ Hypsodon audax Leidy ________________________________ x 

'J;'elegraph Creek fauna. 

Inoceramus sagensis Owen _____________________________________ ~ _____________ === = =1-:-= 

Inoceramus cf. I. lobatus.Goldfuss _____________________________________________________ ·x x _____ _ Inoceramus sp. undetermmed ______________________________________________ x x _________________ _ Ostrea congesta Conrad, depauperate variety _______________________________________________ x _____ _ 

Lucina n. SP------------------------------------------------------------- ___ x _________________ _ Cardium speciosum Meek and Hayden ________________________________________________________ x __ _ Baculites ovatus Say ______________________________________________________ ? ___ ? _________ x __ _ 

Baculites ovatus Say var. haresi Reeside l\'lS _________________________________ --- --- --- ___ --- ___ 

1 

X ---

Baculi.tes sp. und.eterm~ned _________________________ ·-------'----------------- ___ x _________ x 

1 

_____ _ 

Scaplutes basslen Rees1de MS ______________________________________________ x ______ x ___ x x x 

Scaphites sp. undetern!ined _____________________________________________________ x _________ 1 _____ _ 
12 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Fossils of the Mancos shale-Continued. 

Eagle fauna. 

< ~ ~ ~ ~ ~ ~ ~ ~ 8~ 8~ 

§ ~ . ~ § § § § ! . ~ ~ 

::rin-o-ce_r_a_m_u_s_s_a_g_e_n_s-=-is--;O~w-e_n _____ -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_·-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_·1 -_-_-_ = = ~-= - - = x - - Inoceramus barabini Morton---------~----------------------------- ___ ? ______ x Inoceramus cf. I. lobatus Goldfuss ___________________________________ x ___ ___ ___ ___ _ __ x Inoceramus sp., thick-shelled form ____________________________________________ x ___ x x 

Inoceramus sp. undetermined _____________________________________________ X 

Ostrea congesta Conrad, depauperate variety ___________________________________ x ___ x x 

~~~:;;;, ~~~-e_t_~~~~~~~=~-~========·====================·============ === ~ ___ x __ _ Lucina sp. undetermined __________________________________________ _ 

Aporrhais biangulata Meek and Hayden _________________ ~------------ __ _ Baculites ovatus Say _____ ------___________________________________ x Baculites ovatus Say var. haresi Reeside MS _________________________ x Baculites aquilaensis var. distans Reeside MS___ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x 

X 

X 

Baculites asper Morton _______________________________ .: ___________ _ Baculites sp. undetermined ____________________________________________ x 

Puzosia (Latidorsella) mancosensis Reeside MS __________________________ x 

Scaphites hippocrepis (DeKay) ____________ ------------------------- Scaphites hippocrepis var. crassus Reeside MS _______________________ _ Scaphites aquilaensis Reeside MS _________________ ~ _______________ ..: __ x __ _ 

X 

X 

X 

X 

X 

? 

X 

X 

X 

X Scaphites aquilaensis var. nanus Reeside MS ______________________________ _ --- --- --- X Scaphites stantoni Reeside MS ________________________ ---------- __ _ _ _ x 

Scaphites leei Reeside MS _______________________________ ~ _____________ _ ___ , ___ --- ---

X 

Placenticeras guadalupe Roemer_____________________________________ ? --- --- --- X Echidnocephalus? sp ______________________________________________ _ X --- Holcolepis '? sp__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ x 

Hypsodon radiatulus CockerelL ______________________________________ x --- --- X 

Pierre fauna. 

X 

X 

X 

I~ 

. I~ Mactra cf. M. holmesi Meek ______________________________________________________________________ ~ 

10141. 1 mile north of Shiprock road, just west of Great Hogback, in sec. 32, T. 30 N., R. 16 W., San Juan County, N.Mex. Horizon 280 feet 

beneath top of Mancos shale. 

10142. 1 mile north of Shiprock road, just west of Great Hogback, in sec. 32, T. 30 N., R. 16 W., San Juan County, N. Mex. Horizon 160 feet 

beneath top of Mancos shale. . 10143. 1 mile north of Shiprock road, just west of Great Hogback, in sec. 32, T. 30 N., R. 16 W., San Juan County, N.Mex. Horizon 120 feet 

beneath top of Mancos shale. . 10144. 2~ miles north of Shiprock road, just west of Great Hogback, in sec. 20, T. 30 N., R. 16 W., San Juan County, N.Mex. Horizon 410 

feet below top of Mancos shale. · 10145. 2 miles north of Shiprock road, just west of Great Hogback, in sec. 29, T. 30 N., R. 16 W., San Juan County, N.Mex. Horizon 500 feet 

beneath top of Mancos shale. · · 10368. 14 miles S. 20° W. from Shiprock Peak, in sec. 5 or 8, T. 9 N., R. 4 W. Navajo meridian, San Juan County, N.Mex. Horizon about 

125 feet beneath the Tocito sandstone member of Mancos shale. 

10426. 1 mile west of Durango, Colo., in SW.l NW.l sec. 30, T. 35 N., R. 9 W. Horizon 850 feet above base of Mancos shale. 

10427. 1! miles west of Durango, Colo., at center of SE.l sec. 13, T. 35 N., R. 10 W. Horizon 950 feet above base of Mancos shale. 

1042b. 1! miles west of Durango, Colo., in NE. l SE. l SE.l sec. 24, T. 35 N., R. 10 W. Horizon 950 feet above base of Mancos shale. 

10429. Same locality as 10428. Horizon 1,000 feet above base of Mancos shale. 

10430. 2 miles west of Durango, Colo., at center of sec. 13, T. 35 N., R. 10 W. Horizon 970 feet above base of Mancos shale. 

10431. Same locality as 10430. Horizon-1,100 feet above base of Mancos shale. 

10433. At east edge of Durango, Colo., in NE. l SE. l sec. 29, T. 35 N., R. 9 W. Horizon 1,725 feet above base of Mancos shale. 

10434. 2 miles west of Durango, Colo., at center of sec. 13, T. 35 N., R. 10 W. Horizon 800 feet above base of Mancos shale. · 10435. Same locality as 10434. Horizon 900 feet above base of Mancos shale. 

10484. 1! miles west of Durango, Colo., in NW.l SE.l SE.l sec. 13, T. 35 N., R. 10 W. Horizon 800 feet above base of Mancos shale. 

10503. Animas River at mouth of Lightner Creek, Durango, Colo., in NE. l NE. l sec. 30, T. 35 N., R. 9 W. Horizon 600 feet above base o: Mancos shale. . 10504. Half a mile west of Durango, Colo., in SW.l SE.l sec. 19, T. 35 N., R. 9 W. Horizon 650 feet above base of Mancos shale. 

10505. Same locality as 10504. Horizon 700 feet above base of Mancos shale. 

10506. 1 mile northwest of Durango, Colo., in NW. l SE. l sec. 18, T. 35 N., R. 9 W. Horizon 300 feet above base of Mancos shale. 

10507. 1 mile northwest of Durango, Colo., in SW. l NE.l sec. 18, T. 35 N., R. 9 W. Horizon 150 feet above base of Mancos shale. 

10509. Half a mile northwest of Durango, Colo., in SW. l sec. 17, T. 35 N., R. 9 W. Horizon 300 to 350 feet above base of Mancos shale. 

10510. 1 mile northwest of Durango, Colo., in NE. l sec. 18, '.r. 35 N., R 9 W. ,Horizon 400 to 450 feet above base of Mancos shale. 

10644. 7 miles north of Bayfield, Colo., at center of sec. 5, T. 35 N, R. 6 W. Horizon 350 feet above base of Mancos shale. 

12002. One-fourth mile south of Chaco River, just west of Great Hogback, ncar center of sec. 19, T. 29 N., R. 16 W ., San Juan County, N. Mex. 

Horizon at top of Tocito sandstone. 

12003. Half a mile south of Chaco River, just west of Great Hogback, in SE. l NE. l sec. 24, T. 29 N., R. 17 W., San Juan County, N.Mex. 

Horizon 50-feet above the Tocito sandstone. . · 12004. 4milesnorth ofShiprockroad,justwest of Great Hogback, inSW.l NE.lsec. 20, T. 30N., R. 16 W., San Juan Cowity, N.Mex. Hori- zon 75 feet beneath top of Mancos shale. . 12005. Same locality as 12004. Horizon 190 feet beneath top of Mancos shale. 

12005 A. Same locality as 12004. Horizon 90 feet beneath top of Mancos shale. 

12006. Same locality as 12004. Horizon 115 feet beneath top of Mancos shale. 

12007. 1! miles north of Shiprock road, just west of Great Hogback, in NW. l SW.l sec. 25, T. 30 N., R. 17 W., San Juan County, N.Mex. 

Horizon 598 feet beneath top of Mancos shale. · 12008. Same locality as 12007. Horizon 698 feet beneath top of Mancos shale. 

12009. 2 miles north of Shiprock road, just west of Great Hogback, in NW. l NW. l sec. 31, T. 30 N., R. 16 W., San Juan County, N.Mex. 

Horizon 788 feet beneat.h top of Mancos shale. · 12010. Half a mile north of Shiprock road, just west of Great Hogback, in NW.} NW.l sec. 35, T. 30 N., R. 17 W., San Juan County, N.Mex .. Horizon 598 feet beneath top of Mancos shale. · 12011. H miles north of Shiprock road, just west of Great Hogback, in NW.l SW.l sec. 25, T. 30 N., R.17 W., San Juan County, N.Mex. Hori- zon 578 feet beneath top of Mancos shale. · . 12012. Same locality as 12011. Horizon 658 feet beneath top of Mancos shale. 

12013. 2 miles north of Shiprock road, just west of Great Hogback, in NE.l NE.l sec. 30, T. 30 N., R. 16 W., San•Juan County, N.Mex. Hori- zon 435 feet beneath top of Mancos shale. . 12014. 3 miles south of Chaco River, just west of Great Hogback, in SE.l SE.l sec. 34, T. 29 N., R. 17 W .. San Juan County, N.Mex. Hori·, wn 598 feet beneath top of Mancos shale. 
lVIEl::AVERDE GllOUP. 13 

Age and correlation.-The· Mancos shale at 

the type locality contains invertebrate faunas 

of Colorado age in the older part and Montana 

acre in the younger part ("upper few hundred 

f;et" 14). The collections made near San Juan 

River in San Juan County, N. Mex., and near 

Dura~go, Colo., agree in this respect with 

those reported from the typical Mancos shale. 

The lists given on page 11 sho~ the presence 

in both sections of faunas known In the western 

interior only in the Eagle sandston~ and .the 

Telegraph Creek formation and thmr equivalents at the base of the Montana group. The 

species collected beneath this fauna show that 

the principal faunal zones of the Colorado 

group of the region east of the Rock:f Mountains are all represented. The fossils show 

the presence of equivalents of ~he Graneros 

shale Greenhorn limestone, Carlile shale, and 

· Niob~·ara formation. (See Pl. III.) It is evident from the position of the basal Montana 

(Eagle) fauna that the Mancos shal~ includes 

younger beds on Animas River .~han on San 

Juan River, and that the form~twn, though a 

lithologic unit, does not everywhere represent 

the same time intervaL The Eagle fauna occupies a zone from 700 to 1,000 feet beneath 

the top of the Mt.tncos shale on Animas River 

but is immediately at the top of the shale on 

San Juan River. Farther southeast, as shown 

by collections made near Copper City, N. 

Mex., by J. ll. Gardner, it occurs in the·lower 

. part of the Mesaverde group, apparently the 

equivalent of the Point Lookout sandstone. 

In a sense the top of the Mancos shale is progressively older southward from Durango, 

Colo., across the San Juan Basin. Beds with 

the lithology of the Mesaverde group replace 

older and older marine shales of the Mancos. 

This .change continues ·beyond the San Juan 

Basin until eventually the wliole time interval 

of the typical Mancos shale is represented by 

rocks like those of the Mesaverde group, as, 

for exan1ple, the Miguel formation and the 

lower part of the Chamiso formation in Socorro 

County, N. Mex. The writer has not noted 

any specific· place in the field where a lateral 

transition of shale into sandstone can be 

traced, but it could hardly be possible that no 

such transition occurs. The Tocito sandstone 

lentil of the Mancos shale on San Juan River 

H Cross, Whitman, U. S. Ocol. Survey Ocol. Atlas, La Plata folio 

(No. GO), p. 4, 1899. 

represents a type of sedimentation lacking to 

the north but more and more abundant toward the south. 

The relation of the Mancos shale of the 

San Juan Basin to that of the more distant · 

areas in northern Colorado, Utah, and Arizona 

is not yet accurately known, though the time 

interval covered is certainly in large part the 

same wherever the name is in use. 

MESAVERDE GROUP. . 

Type locality and distribution.-The Mesaverde group was named by I-Iolmes 15 from 

the typical exposures in the Mesa Verde, in 

Montezuma County, southwestern Colorado. 

Holmes described three divisions-the ''lower 

escarpment sandstone," the "middle coal 

group," and the" upper escarpment sandstone." 

To these divisions Collier 16 gave the names 

Point Lookout sandstone, Menefee formation, 

and Cliff I-Iouse sandstone, respectively, all 

derived .from localities on or near Mesa Verde. 

The three formations of the group ~re not 

distinguished .at many localities, but the name 

~iesaverde as a designation for a coal-bearing 

series in the upper part of the Upper Cretaceous· 

has been very widely used-as far away from 

the type region as northern Wyoming. In the 

part of the San Juan Basin covered by this 

report the Mesaverde group forms a marked 

ridge or series of ridges, interrupted where 

the formation extends with low dip out into 

the Mesa Verde and where the rocks are 

gently inclined along the upper valley, of 

Chaco River. 

Lithologi.c character.-At the type locality 

the Point Lookout sandstone is a massive, 

cliff-forming gray to brown marine sandstone; 

the Menefee formation is a variable assemblage of sandstone and shale, with three groups 

of coal beds, and is of both marine and freshwater origin; and the Cliff House sandstone 

is variable in character though essentially 

a massive marine sandstone. This general 

description of the three lithologic units may 

be applied around the entire western side of 

the San Juan Basin, though the exposures 

on Anim~s and Florida ·rivers show the threefold division less clearly than those to the west. 

1o Holmes, W. 11., Geological report on the San Juan district: U. S 

Gcol. and Geog. Survey '.rerr. Ninth Ann. Rept., for 1875, pl. 35, 1877. 

16 Collier, A. J., Coal south of Mancos, l\1ontczuma County, Colo.: 

U.S. Oeol. Survey Bull. ()91, p. 29(), 1919. 
14 UPPER CRETACEOUS AND TERTIARY FQRMATIONS IN SAN JUAN BASIN. 

In Tps. 29 and 30 N., R. 16 W., just north 

of San Juan River, San .Juan County, N. Mex., 

where the writer examined the Mesaverde 

group in greater detail than elsewhere, the 

typical description applies, though the gross 

thickness there is much greater than in the 

Mesa Verde. The Point Lookout sandstone 

at this locality is a cream-colored to red-brown 

massive, cliff-forming marine sandstone that 

stands out prominently above the softer Mancos 

shale. The. Menefee formation is a group of 

gray to brown lenticular sandstones and gray 

to chocolate-brown and black carbonaceous 

shales and contains two groups of lenticular 

coal beds, one near the top and one near the 

base. The formation varies greatly along the 

strike and contains fossils indicating a fresh-

·water origin for some beds and a .marine origin 

for others. The Cliff House sandstone consists 

of a thick yellow to brown massive sandstone 

bed underlain and overlain by thin sandstones 

and shale, all of marine origin. 

South of San Juan River the forn1ations 

seem t'o have much the same con1position. 

The Cliff House sandstone, however, contains 

coal at some places:, notably along Chaco River 

near the mouths of Brimhall Wash and Pina 

Veta China Arroyo. On Meyers Creek the 

Cliff House sandstone has its normal marine 

character and though thinner than at San 

Juan River is a purer sandstone unit. 

The sections on pages 62-69 show in detail 

the lithologic character of the form.ations of 

the Mesaverde group. 

Thickness.-At the type locality the Point 

Lookout sandstone is 250 to 300 feet thick, the 

Menefee formation 400 feet thick, and the 

Cliff fiouse sandstone 400 feet thick, a total 

for the group of approximately 1,100 feet. 

On Florida River, Colo., the Mesaverde 

group was found by Gardner 17 to be 422 feet 

thick. In his section the Point Lookout sandstone is probably represented by massive gray 

sandstone forming the lower 60 feet, the Menefee formation by the shale and coal beds forming the middle 272 feet, and the CJiff House 

sandstone by sandstone and shale of the upper 

90 feet. In the Red Mesa quadrangle, Colo., 

Pishel 18 measured a section at a locality 20 

11 Gardner, J. H., in Lee, W. T., and Knowlton, F. H., Geology and 

paleontology of the Raton Mesa and other regions in Colorado and New 

Mexico: U.S. Geol. Survey Prof. Paper 101, p. 187, 1917. 

1s Pishel, M.A., unpublished data. 

miles southwest· of Durango in which the 

Mesaverde group was found to be 1,020 feet 

thick. The Point Lookout sandstone appears 

to be 270 feet thick, the Menefee formation 

340 feet, and the Cliff House sandstone 410 

feet. Near the Colorado-New Mexico boundary, in T. 32 N., R. 14 W., N. Mex., the group 

is 1,200 to 1,300 feet thick, the Point Lookout 

sandstone being about 225 feet thick, the 

Menefee formation 700 to 800 feet, and the 

Cliff House sandstone over 200 feet. The 

sections near San Juan River given on pages 

64-65, show the total thickness of the group 

to be over 2,100 feet and the thicknesses of the 

three formations in ascending 'order to be 

approximately 200 feet, 1,000 feet, and 7 50 

feet, respectively. Only parts of the group 

were measured in southern San Juan County. 

These measurements indicated a thinning of 

the Cliff House sandstone to 370 feet. On· 

Arroyo Torrejon Gardner 19 measured a section 

of the g:r:oup that shows a thickness of 1,300 

feet, of which the lower 70 feet may represent 

the Point Lookout sandstone, the middle 908 

feet the Menefee formation, and the upper 320 

feet the Cliff House sandstone. Lee's sections20 of rocks farther southeast assigned to the 

Mesaverde show much variation in thickness, 

from more than 300 feet to more than 1,800 

feet, due in part to erosion at the top of the 

form~tion and in part to uncertainty as to 

where the upper limit should be placed. In 

this area it is difficult to identify the three 

formations of the group. The Lewis shale is 

unidentified in the area, and likewise the 

Fruitland formation and Kirtland shale. In 

some sections the Mesaverde group as now 

conceived may include beds of the age of the 

Lewis, Fruitland, and Kirtland formations. 

In general th.e Mesaverde group may be 

said to thin eastward from the type locality 

and to thicken southward. 

Relation to adjacent formations.-The Mesaverde is conformable with the Mancos shale 

below and the Lewis shale above. It is separated from both by a zone of transition beds in 

which the formation boundary must be arbitrarily :fixed. 

19 Gardner, J. H., Coal field between San Mateo and Cuba, N.Mex.: 

U.S. Geol. Survey Bull. 381, p. 178, 1910. 

20 Lee, W. T., and Knowlton, F. H., Geology and paleontology of the 

Raton Mesa and other regions in Colorado and New Mexico: U.S. Geol. 

Survey Prof. Paper 101, pp. 171-222, 1917. 
MESA VERDE GROUP, '15 

Fossils.-Four collections were made from 

the Cliff I-Iouse. sandstone in New Mexico and 

four in Colorado. One collection (U. S. G. S. 

locality 10432) was made from the Point Lookout sandstone. The species included in these 

collections are shown in the list below and in 

Plate III. It is noteworthy that these collections, ·while containing a number of species 

that occur in the typical Montana faunas of 

the western interior province, contain also a 

nmnber that are not known in the typical· 

faunas but are closely related to species that 

are common in t4e faunas of the Coastal.Plain 

province. It would appear that some connection existed between the San Juan Basin area 

and the Coastal Plain which was not open to 

the other regions of the western interior. 

This feature was noted by Stanton 21 in the 

faunas of the Mesaverde group of the region 

southeast of the San Juan Basin. 

21 Stanton, T. W., in Lee, W. 'l'., and Knowlton, F. H., Geology and 

paleontology or the Raton lVIesa and other regions in Colorado and New 

ll'!exico: U.S. Gcol. Survey Prof. Paper 101, p. 218, 1917. 

Fossils of the JY.[ esaverd~ group. 

C'l <'-' ""' .... ..:> 00 I 

0 C'l .r,) 

~ ~ "'d" ......4 ....... ~ 

s ~ ~ I~· ~ ~ 

-----------------,---------------------1--l---l-------------- Micra bacia americana :Meek and Hayde_n _______________________________ --- ___ --- x ___ ---~--- _____ _ Yo.ldia evansi Meek and Hayden _______________________________________ ------------ X X ------ __ _ 

Inoceramus barabini Morton __________________________________________ x --- x --- x x x 

Inoceramus sp. undetermined---------------------·------------------------------ X ___ X •

1 

___ ------ Pteria nebrascana Evans and Shumard _______________ - __________ ------- X - _- __ - _ _ _ x __ - ________ _ 0strea p.ellucida Me?k and Hayden _______ , ____________________________ ------------------~------ __ _ Ostrea sp. undetermmed ______________________________________________ ------ x x x x ------ __ _ Anomia sp. undescribed _______________________________________________ ------------ x .---~--- ------

Liopistha undata Meek and Hayden--------------~-----------------------_------ x --- x 

1 

___ ------ Astarte? sp. undescribed ______________________________________________ X --------- x X ------ __ _ 

Sphaeriola cf. S. endotrachys Meek _____________________________________ ------------ ___ --------- __ _ 

Tancredia americana Meek and Hayden ___ ---------------------.-----·--- X --- --- x ___ ---1------ __ _ Cardium (Ethmocardium) sp. undescribed ________________________ · _______ --- X X X X X I X --- X 

Cyprimeria? sp. undescribed ____________ .:. ______________________________ X ------ x ------ ------ __ _ Callista deweyi Meek and Hayden _______________ :.. ______________________________________ - x _____ _ 

Tellina sp. undescribed---------------------------------:.-------------------------- X X!--------- Tellina equilateralis. Meek and Hayden _________________________________ --_------ x ------1------ __ _ Donax? sp. undescnbed ______ ----------------------------:-------------- --------- x. x ~--- ------ __ _ Mactra formosa Meek and Hayden _____________________________________ --------- x X X ------ x 

Mactra warrenana Meek and Hayden __________________________________ --------- ___ X X ------ __ _ 

~~·~)\~~: :g: l~~~1:st~:i ~~~~~::: = = = = = = = =: =:::::::::::::::::::::::: =:: =·:::: ::: ::: ::: ~ -x- -x- ::: ::: = = = Chemnitzia cerithiformis? Meek and Hayden ____________________________ --------- x x --------- __ _ Chemnitzia? sp. undetermined _________________________________________ --------- ___ --- X ---------

Pseudomelania? sp. undetermined--------------------------------~-------------- x --------------- Solarium sp. undescribed ______________________________________________ --------- ___ x ------ --- --- Lunatia occidentalis Meek and Hayden ____ -- ___________ --- __ ---_---- ______ -- _ x x ___ --- x --- __ _ Lunatia concinna? M.eek and Hayden ___________________________________ ------------ x --------- x 

Lunatia subcrassa? Meek and Hayden __________________________________ ---~----- ___ x --------- __ _ 

¥K::~i~~f~:~p.q;ri~~~~~.~~i~!ct~t~~l======================================== === === === === -~- === === === -x- Anchura 1iebrascensis? ;Meek and Hayden _______________________________ --------- x ___ --------- __ _ 

t{~~!~~?as~~·u~~~~~!~~~Yr~~~~~~======·============~======================= === === === === ~·-X-========= Cantharus? sp. undetermined---------------------------~----:..:.. ________ ------~--- ___ ------------ x 

Fusus cf. F. newberryi Meek and Hayden ___________________________________ --- ___ x ___ ------------ Fusus? sp. undetermined ________________________ . ______________________ ------~--- ___ --- X ------ ---

Pyrifusus sp. undetermined----,-------------.--------------------------- ·x ------------------------. · Fasciolaria'? sp. undetermined------------------------------------------------ X ___ --- --- --- --- --- Volutoderma, several undescrib~d species ________________________________ --------- x x ---~--- --- x 

Acteon attenuatus Meek and Hayden ______________________________________ --- x x ___ --- ___ --- __ _ Acteon sp. undescribed _______________________________ ,! _______________ --------- ___ x X ---------

Cinulia sp. undetermined--------------~---------------·--------------------- ______ ------------ X Haminea subcylindrica Meek and Hayden _______________________________ ------ ______ x ------------ Anisomyon cf. A. shumardi Meek and Hayden-___________________________ x ___ --- ___ x --- ________ _ Baculites anceps var. obtusus Meek ____________________________ ·-----'--- x x x x ___ ------------ Placenticeras intercalai'e Meek _________________________________________ ------ ______ x --- ___ x __ _ Shark teeth, undetermined ____________________________________________ ------ _________ --- ___ --- X 

8544. 4 miles north of Kline, Colo.,jn NW. t NW. tsec. 14, T. 34 N., R.12 W. Horizon in uppermost 100 feet of Cliff House sandstone. M.A. 

Pisbel, collector. · 8545. 4 miles northeast of Kline, Colo., in SE. t S\V. i sec. 7, T. 34 N., R. 11 W. Horizon in uppermost 100 feet or Cliff House sandstone. M. A. 

Pishel, collector. 

854(l. 2 miles west or Kline, Colo., in NW. t NE. t sec. 33, T. 34 N., R. 12 W. Horizon in uppermost 100 feet of Cliff House sandstone. 9742. Satans Pass, 18 miles north of Thoreau, N. Mex. Loose blocks or upper sandstone of Mesaverde group. 9743. 3 miles cast of Pueblo Bonito, N. l'v[ex., in sec. 19, 'l'. 2 N., R. 10 W. Horizon 40 feet above base or Cliff House sandstone, which is here 

nbout 350 ftlct thick. • 9744. Mouth or Escavada Wash, on Farmington-Pueblo Bonito road about 4 miles northwest of Pueblo Bonito, in sec. 27, T. 22 N., R. 11 W. 

Horizon 50 feet below top or Cliff House sandstone. . 10140. West side or NW. t sec. 23, '1'. 30 N., R. 16 W., 3 miles north of Liberty, N.Mex. Horizon 200 feet beneath top of Cliff House sandstone. 10432. Half a mile east of Durango, Colo., in NE. -t SE. t sec. 29, T. 35 N., R. 9 W. Horizon at extreme base of Mesaverde group. 10485. 1 mile south O! Durango, Colo., in NW. t SE. t sec. 32, 'l'. 35 N., R. 9 W. Horizon at extreme top of Mesaverde group. 
16 UPPER CRETACEOUS ANP TER.TIARY FORMATIONS IN SAN JUAN BASIN. 

Age and co_rrelation.-The Mesaverde group 

typically has a flora and inyertebrate faunas 

of Montana age. Although the writer collected 

practically no fossils from the Point Lookout 

and Menefee formations, the presence of Montana fossils beneath them in the Mancos shale 

and above them ~n the Cliff House sandstone 

shows that in the San Juan Basin also the whole 

group is of Montana age. The extreme variation in thickness frqm north to south, as shown 

in the· columnar sections on Plate II, and the 

difference in the position of the boundaries 

with reference to a faunal plane such as that 

Qf the basal Montana fauna occurring in the 

Mancos shale, or to a stratigraphic plane such 

as the top of the Pictured Cliffs sandstone, 

make it very improbable that the Mesaverde 

group of the San Juan Basin represents everywhere the same time interval within the 

Montana group. The writer believes that the 

Mesaverde group on San Juan River represents 

the time interval of part of the Mancos shale, 

the Mesaverde group, and much of the Lewis 

shale of the section on Animas River. South 

of San Juan River, where the Lewis shale 

becomes much thinner even than on San Juan 

River, the top of the Cliff House sandstone 

may represent practically the same time of 

deposition as the very top of the Lewis shale 

along the north side of the San Juan Basin. 

It seems very probable that the Point Lookout 

sandstone and the Cliff House sandstone are 

really aggregates . of successively overlapping 

beds which as a whole, with reference to a given 

chronologie plane, change their positions in the 

stratigraphic column from place to place. The 

Point Lookbut sandstone in its northern exposures is younger than in its southern exposures; 

the Cliff House sandstone in its northern 

exposures is older than in its southern exposures. 

The writer has not noted any locality in the 

field where such an overlap and passage from 

one lithologic phase to another is observable, 

but the exposures are in general inadequate. 

That such a phenomenon can be shown in 

other and more favorable regions is well known, 

and it is almost certain that something of the 

sort occurs here. 

The relations of the Mesaverde group to the 

beds so named south and east of the San Juan 

Basin are somewhat obscure. At some localities the zone of the basal Montana fauna is 

well known and occurs in either the top of the· 

Mancos shale or the base of the :Mesa verde 

group. The top of the formation, as noted on 

page 14, may, however, include beds as young 

as the Fruitland and Kirtland formations of the 

San Juan Basin. 

The relations of the :Mesaverde group to the 

beds similarly named in northern Colorado, 

Utah, and Wyoming are also not at all clear. 

Many more stratigraphic and faunal data are 

needed. In some parts of Wyoming the base of 

the :Montana group is definitely known and the 

general relations of the Mesaverde group of 

those regions to the typical. Mesaverde n1ay be 

deduced, but not enough is yet known to make 

detailed comparis.ons possible. At some places 

there are no· marine beds above the basal part 

of the Mesaverde, and most of the Mesaverde 

strata and the later beds are fresh-water 

deposits. It is quite likely that the Mesaverde 

at some of these localities is really nearer to 

the Fruitland and Kirtland formations in age 

than to the typical Mesaverde. 

LEWIS SHALE. 

Type locality and distribution.-The Lewis 

shale was named by Cross 22 from the exposures 

near the former Army post called Fort Lewis, 

in sec. 3, T. 34 N., R. 11 W., La Plata County, 

Colo. (See Pl. I.) The name has been used 

widely to designate the interval between those 

beds assigned tQ the Mesa verde and the fresh-. 

water deposits of post-Montana age-in fact, 

it has been applied in regions as far away as 

northern Wyoming. The Lewis shale may be 

traced continuously some distance north from 

the type locality and except for some interruptioJ;ls on the east ·side has been identified clear 

around the San Juan Basin. It has not been 

identified, if present, to the west, south, or east 

of the San Juan Basin. 

Lithologic character.-ThQ Lewis shale at 

the type locality is described by Cross as ''a 

body of more or less sandy shales and clays 

with occasional thin layers of impure limestone 

or of concretionary 1nasses at several different 

horizons." It maintains this character along 

the north side of the San Juan Basin, where it 

is a fairly homogeneous n1ass of dark-gray to 

greenish-gray shale, with some sandy layers, 

some limestone, and numerous calcareous concretions, some yellow and splintery,. others 

22 Cross, Whitman, U. S. Geol. Survey Geol. Atlas, La Plata folio 

(No. 60), p. 4, 1899. 
LEWIS SHALE. 17 

blue-gray, dense, and tough. In New Mexico 

the Lewis is sandier than in Colorado, though 

containing layers of impure brown limestone 

and yellow lin1estone concretions. 

Thiclcness.-Along the north side of the San 

Juan Basin the thickness ranges fron1 1,700 

feet near the type locality 23 to 1,600 feet on 

Animas River near Durango 2

'

1 and 2,290 feet 

near Pine River, and is said at other places to 

reach 2,500 feet. 25 In New Mexico it is 

thinner. It has a thickness of 1,100 feet near 

Navajo Springs, and 475 feet at San Juan Riyer 

and thins southward to· Coal Creek, where it 

is 76 feet thick. It increases somewhat on the 

south side of the 'basin and maintains a thickness of 100 to 150 feet at most localities. 

N enr Cuba it is said to be over 200 feet thick. 26 

These variations are shown graphically in the. 

23 Fishel, M.A., unpublished data. 

u Gnrdner, J. H., in Lee, W. '1'., and Knowlton, F. H., Geology.and 

paleontology of the Raton Mesa and other regions in Colorado and 

New 1\<lcxico: U. S. Geol. Survey Prof. Paper 101, p. 187, 1917. 

~~Schrader, F. C., 'l'he Durango-Gallup coal field of Colorado and 

New Mexico: U.S. Gcol. Survey Bull. 285, p. 242, 1906. 

2

6 Gardner, J. H., 'l'he coal field between Gallina and Raton Spring, 

N. 1\<fcx.: U.S. Gcol. Survey Bull. 341, p. 339, 1909. 

sections in Plate II. The Lewis shale seems 

to thin southward along the west side of the 

San Juan Basin in about th.e proportion .that 

the Mesaverde group thickens. 

Relation to adjacent formations.-The contact 

of the Lewis shale with both the Cliff llouse 

sandston~ and the Pictured Cliffs sandstone is 

one of gradual transition, and the fixing of· 

specific boundari'es -is entirely arbitrary. 

Fossils.-Bauer 27 obtained three collections 

of marine invertebrates from the Lewis shale. 

These and collections made by Lee, 28 Pishel, 

Gardner, and the writer at widely separated 

localities show that many characteristic Pierre 

species range through its entire thickness, notably species of Inoceramus and various cephalopods. The forms identified by T. W. Stanton 

in Bauer's and Pishel's collections and those 

collected by the writer are listed in the table 

below and in Plate III. 

n Bauer, C. M., Stratigraphy of a part of the Chaco River valley: 

U. S. Geol. Survey Prof. Paper 98, p. 273, 19Hi. 

28 Lei', W. T., and Knowlton, F. IT., Geology and paleontology of the 

Raton Mesa and other regions in Colorado and New Mexico: U. S. 

Geol. Survey Prof. Paper 101, pp. 190, 193, 1917. 

Fossils of the Lewis shale. 

I r- 0 f"'"'' I M ~ I ~ ~ ~ ~ ~ ~ ~ 0 0 ~ . 00 ~ 00 ~ ~ 

~ ~ ~ ~ ~ ~ f"'"'' ~ f"'"'' ~ f"'"'' ~ f"'"'' ~~~ f"'"'' f"'"'' 

-J-'_e_d_a_S_l_).-t-t_n_d-et_e_r_n-1i_n_e_d ____ -__ -_-_-__ -_-_--_-..1>-_-_-_-_-_-_-_-_-_-.:.-_ -_ -_ -__ -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_ l------1= ~ ~ -; = = ~ ~ = = 

Inoceramus barabini Morton ____________________________________ ---~ X X --------- X ------ X ---

~~~~~~~~~~~~~ :~~~~:~~~e~~:~'l,;~~c~=~-----~=-----~======================== === === === -?- === -~- -~- -~- -~- === -x- Pteria linguaeformis Evans and Shumard ___________________________________________ x ______________ _ 

Ostrea inornata Mee.k and Hayden ____________ .:. _________________ --~~--------- x ------------------ Ostrea sp. uncleternuned __________________________________________ ---·--- _______________ x ________ _ 

~~Liopistha ~~~;~1o~~)~n~ qnclata ~~~~e~~~~~~~;~.;i~l"ect_~~~~---=========================== Meek and Hayden __________________________________________ === === ===-~--X-================== x _________ --- _____ _ Lucina sp. undetermined _________________________________________________ x __________________ ·--- Cardium speciosum Meek and Hayden ____________________________________________________ --- _____ _ Teredo? sp. undetermined ___________________________________________________ x ______ X· --- ___ ---

Lunatia sp. undetermined ___________________________ . ____________________ x x _______________ X 

Fasciolaria.? sp: undetermined ___________________________________________________________________ _ Ptychoceras crassum ·whitfield _______________________________________________________ x "-- _____ _ Baculites ovatus Say __________ ,-------------------------------- ________________________ --- _____ _ 

~:~~~Ui~: ~~~ ~ir~·~~~~~l~~~ct:_----~==~========~===================== === -x- === -x- === === === -~- === === === Helicoceras cf. H. mortoni var. tenuistriatum Meek and Hayden ____ x ___ --- _________ --- ___ ------ x Hetm·oceras nebrascense Meek and Hayden_~--------------------- ______ --- ______ ------ x --------- Scaphites nodosus var. quadrangularis Meek ____________________________ --- ______ ------ x --- ___ --- Placenticeras intercalare Meek ________________________________________ x _______________ --- ___ ---

ii~~~~~i~~~r:;.sE,~ct~l~~~~[,~~~e_d __ :~=============================== === === ~== =~=-~--X- =·==I======;===== 

8539. 3 miles southeast of Kline, Colo., in sec. 18, T. 33 N., R. 11 W. Horizon a short distance above middle of Lewis shale, here 1, 700 feet thick. 

M.A. Pishcl, collector. · 8542. 7 miles south of Kline, Colo., in NE. t NW. t sec. 11, T. 32 N ., R. 12 W. Horizon a short distance above middle of Lewis shale,' here 1, 700 

feet thick. M. A. Pishel, collector. ' 

9273. 5 miles southeast of Liberty, N. Mex:. Horizon near top of Lewis shale .. Identified by T. W. Stanton. C. M. Bauer, collector. 

9277. South side of San Juan River, opposite Liberty, N.Mex. Horizon at middle of Lewis shale, here 475 feet thick. Identified by T. W 

Stanton. C. M. Bauer, collector. 

929G. 35 miles south of Farmington, N. Mox., at the mouth of Coal Creek. Horizon at middle of Lewis shale, here 76 feet thick. Identified by '1'. W. Stanton. C. M. Bauer, collector. 

10497. 2 miles south of Durango, Colo., at center of NW. t sec. 5, T. 34~ N., R. 9 W. Horizon 150 feet above base of Lewis shale. 

10•198. 2 miles south of Durango, Colo., in SE. i NE. t sec. 6, T. 34 N ., R. 9 W. Horizon 700 feet beneath top of Lewis shale. 

10499. 2 miles south of Durango, Colo. at center of sec. 6, T. 34 N ., R. 9 W. Horizon 300 feet beneath top of Lewis shale. 

10500. 4 miles southwest of Durango, Colo., in SE. t NW. t sec .. ll, T. 34 N., R.10 W. Horizon 800 feet beneath top of Lewis shale. 

10501. 3 miles cast of Durango, Colo., in SE. t NW. t sec. 23, T. 35 N., R. 9 W. Horizon at top of Lewis shale. 

10563. 2 miles south of Durango, Colo., in SW. t NE. t sec. 6, T. 34 N., R. 9 W. Horizon 400 feet beneath top of Lewis shale. 
18 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Age and correlation.-At a number of local- beneath them which the writer believes should 

ities the Lewis shale contains fossils of Montana be put with them. The original description 

age throughout .its thickness. Within the is as follows: 

San Juan Basin the thick Lewis shale of the Pictured Cliffs, 140 feet-40 feet of white sandstone; 

north side of San Juan Basin is probably, as· 60 to 80 feet yellowish-gray sandstone; beneath t'hese 

shown on page 16, essentially contemporan~ous 30 to .40 feet of brownish laminated sandstones. 

with the major upper part of the thick Mesa- A section measured by C. M. Bauer on the 

-verde group of the west and south sides; south side of the river several miles west of 

There is, however, probably some part of the I-Iolmes's locality is' given on page 63. It 

Mesaverde group that is older than any part of shows the formation to .include, besides the 

the Lewis shale, and likewise some part of the massive upper units, a lower part containing 

Lewis that is younger than any part of the much shale. The upper part of the formation 

Mesaverde, . but the time of deposition of consists of white to red-brown sandstone, 

much of the two formations was the same. It which forms a striking member of the stratiis probable that the top of the Lewis shale graphic series; the lower part is of yellow. to 

varies but little in age from place to place. brown sandstone interbedded with gray sandy 

The difference between the faunas of the shale; the whole is 281 feet thick. The PicMesaverde group and those of the Lewis may . tured Cliffs sandstone has been shov,rn to be 

be ef(plained as due to the difference in the ·present entirely around the San Juan Basin. 

sediments. In all the sections given by Lee,30 Schrader,31 

· The time interval of the typical Lewis shale and Gardner 32 it may be identified at the base 

is unquestionably represented outside of the of the so-called "Laran1ie" around the north 

San Juan Basin by sediments that cover wide and east sides of the basin. The writer has 

areas. It is impossible, however, to :fix upon traced it from a locality north of Pagosa 

'its equivalent exactly.. In a general way it is Junction, Colo., around the west and. south 

synchronous with some part of the middle and sides of the basin as far as the head of Chaco 

upper portions of the Pierre shhle east of the- River. 

Rocky Mountains, but. more exact correlation The Pictured Cliffs sandstone has not been 

must wait upon a more detailed knowledg~ of recognized outsicl.e of the San Juan Basin. 

the ranges of species within the Montana Lithologic character.-The lithologic characgroup. The so-called Lewis shale of various ter varies much in detail along the strike, 

parts of Wyoming certainly is not the same though as a whole it is fairly similar everyas the Lewis shale of the San Juan Basin. In where. At the type locality and to the north 

Wyoming at several localities the upper part it is a white to brown indurated conspicuous 

of the formation contains a true Fox Hills sandstone that forms a scarp where the dip is 

fauna, later than the fauna of any part of the low and a ridge where it is high. To the south 

Lewis shale or the Pictured Cliffs sandstone it is locally very light colored, with a rustyof the San Juan Basin, and it does not fit the brown crusty layer at the top, .and at many 

lithologic definition of the Lewis sh~le, because places is not well indurated. Near ·Escavada 

it contains at many places thick fresh-water Wash it is at most places a rather soft graydeposits with coal beds and heavy sandstones. white to yellow sandstone with dark-brown 

PICTURED CLIFFS SANDSTONE. platy concretions and is poorly exposed but is 

Type locality and distribution.-The name 

Pictured Cliffs. sandstone was first applied by 

Holmes 211 to the marine sandstone that crops 

out north of San Juan River a mile west of 

Fruitland, N. Mex. Holn1es evidently restricted the name to the massive ledges and 

excluded the interbedded shale and sandstones 

2o Holmes, W. H., Geology of the San Juan district: U. S. Geol. and 

Geog. Survey Terr. Ninth Ann. Rept., for 1875, pl. 35, p. 248, 1877. 

locally well indurated, red-brown, and cliff 

forming. In the Ignacio quadrangle east of 

Durango, Colo., it is at most places composed 

of two heavy beds of sandstone, separated 

30 Lee, W. T., and Knowlton, F. H., Geology and paleontology of the 

Raton Mesa and other regions in Colorado and New Mexico: U.S. Geol. 

Survey Prof. Paper 101, pp. 187, 191, 1917. 

31 Schrader, F. C., The Durango-Gallup coal field of Colorado and 

New Mexico: U.S. Geol. Survey Bull. 285, p. 242, 1905. 

32 Gardner, J. H., Coal field between San Mateo and Cuba, N.Mex.: 

U.S. Geol. Survey Bull. 381, p. 171, 1910. 
PICTURED CLIFFS SANDSTONE. 19 

locally by shale and coaL The formation is Fossils of the Pictured Cliffs sandstone. 

the highest marine deposit of the region.. J j 0> C'ol 

Thiclcness.-Near the type locality the ~ ~ ~ ~-

fornlation, including the interbedded sand- · ~-~-

stone and shale of the lower part not originally Serpula sp. undetermined ------------ ---· x x Inoceramus barabi~i Morton_--------\ X X X included by llolmes,. is 281 feet thick. Owing Inoceramus sagens1s Owen __________ :..------ x 

in part to the nature of the boundaries that Inoceramus sp. undetermined_------- --- --- x --- Ostrea sp. undetermined ________ ----- x --- X ---

rnust be drawn and in part to a real variation Modiola cf. M. meeki Evans and 

thel·e is little rebaularity in the thickness at Shumard ------------------------ ------ x --- Cardium aff. C. speciosum Meek and 

different places. In general the formation Hayden------------------------- x x x ---

d d h d f Tellina scitula Meek and Hayden _____ X J X X --- seen1s to thin eastwar an sout war rom Baroda sp. undetermined ____________ ------ x ---

Florida. River, Colo. It seen1s to be thin near Leptosolen n. sp _____ :... ______________ --- ? x ~---

pl.ne I:>l'ver·, thoubah the exposures are not good Mactra gracilis Meek and Hayden ---- --- X --- ---

·" Mactra warrenana? Meek and Hayden_ X --- and it rnay be considerably thicker than the Corbula sp. undetermined--------------- x 

100 feet that is visible. On the divid.e between Chemnitzia cerithiformis Meek and Hayden _______________________ · ___ ------ X ---

Pine· and Piedra rivers it is 125 feet thick, and Lunatia occidentalis Meek and Hayden_ x ---

on Cat Creek north of Pabaosa Junction 150 feet. Turritella sp. undetermined---------------- X --- Anchura sp. undetermined _______ - _- _ X ---

On the west 'side of the basin it decreases from Odontobasis? sp. undetermined------- x --- ---

394 feet on Florida River 33 to 240 feet in the Turris? sp. undeterm~ned ------------ --- X ? --- Acteon sp. undetermmed ________ - _- _ X . ---

Red Mesa quadrangle 34 southwest of Durango Haminea subcvlindrica Meek and HayIn New Mexico north of San Juan River it H~: l~~~-sp~-in-d-et~;~i~~d--~~======== === -x- -~- === 

varies between 150 and 225 feet. South of San Cinulia n. sp ----------------------- --- --- x ---

Juan River it decreases gradually until at the Ammonite fragment _________ .:. _______ --------- x 

n1outh of liunter Wash it is about 50 feet 

b 7 6067. 6 miles east of Durango, Colo., in sec. 17, T. 35 N., R. 8 W. thick. B~yond this point it varies etween 5 Horizon near top of Pictured Cliffs sandstone. J. H. Gardner, collector. 

l f rrh th' k h Identifications by '1'. w. Stanton. T anc 100 eet. ese IC~nesses ares own 9278 southbankofSanJuanRiverinSW.lSW.lsec.7,T.29N., 

R. 15 \v., San Juan County, N.Mex. Horizon 40 feet a~ove _base of graphically on Plate II. Pictured Cliffs sandstone. c. M. Bauer, collector. IdentificatiOnS by 

Relation to adjacent formations.-The Pic- Tiriii9~t~nl~Nes northwest of Fruitland,~- Mex., insec.19, T. 30 N., 

b · t' R. 15 W. Horizon near base of Pictured Cliffs sandstone. tured Cliffs sandstone passes Y trans1 IOn 10502. 2 miles east or Durango, Colo., in sw.t SE.l sec. 21, T. 35 N., 

·zones into both the Lewis shale below and the R. 9 w. Horizon at middle of Pictured Cliffs sandstone. 

Fruitland formation above. The determina- Age and correlation.-The Pictured Cliffs 

tion of the bounding planes is therefore purely sandstone contains, as shown by the list given 

arbitrary, though the lowest predominantly above, a littoral marine fauna of Montana 

sandy units and the highest marine beds have age. It includes species of Inoceramtts not 

furnished guides. known rn the latest Montana. fauna of other 

FossiZs.-Invertebrate fossils have been col- regions, such as that of the typical Fox Hills 

lected at several localities from the Pictured sandstone, and it completely lacks, so far as 

Cliffs sandstone, and the fucoid Halymenites now known, the typical Fox Hills forms 

major LesquermL'\: is abundant at all exposures There is no definite equivalent of the Pictured 

Iloln1es noted fossils at the type locality Cliffs sandstone known outside of the San Juan 

Other collections, made by Gardner, Bauer,35 Basin,· though the time interval 1s certainly 

and the writer, are listed in the following table represented by deposits at 1

nany places. The 

and in Plate III. Most of the specimens are writer believes the Pictured Cliffs sandstone 

casts or n1olds in a coai·se sandstone and pre- to vary but little in age throughout its known 

serve few of the sn1aller details. extent. It is relatively thin but essentially 

S3 Gardner, J. H., in Lee, w. 'r., and Knowlton, F. H., Geology and uniforn1 in lithology and easily recognized. It 

paleontology or the Raton Mesa and other regions in Colorado and therefore forms a valuable stratigraphic datum 

New Mexico: U.S. Gcol. Survey Prof. Paper 101, p. 187, 1917. 

u Fishel, M.A., unpublished data. . . and has been used as such by the writer m 84 Bauer, c. M., Stratigraphy of a part of the Chaco River valley: drawing up the sections on Plates II and III 

U.S. Gcol. Survey Prof. Paper 98, p. 274, 1916. 
• <. 

20 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

FRUITLAND FORMATION. and in New Mexico ·north of San Juan River it 

Type locality and distribution.-The Fruit- is consistently thicker. Only the basal part is 

land formation was named by Bauer 36 from the present on Cat Creek north of Pagosa Junction, 

settlement of that name on San Juan River, ·Colo., for the upper. part was removed by 

N. Mex. It includes the coal-bearing beds in erosion before the deposition of the Animas 

the lower part· of what was long designated" the formation. Between Piedra and Pine rivers 

Laramie formation" of the San Juan Basin, the thickness ranges from 350 to 400 feet . 

. and it has been shown by the various students In Gardner's section on Florida River 39 the 

o.f the region to extend entirely around the Fruitland formation is 438 feet thick. In the 

basin, though the outcrop is covered at some ~e.d Mesa quadrangle, 40 southwest of Durango, 

points by ·Tertiary sediments. It has not It Is 430 feet thick. On La Plata River near 

been recognized definitely outside of the basin· the New Mexico-Colorado boundary the FruitLithologic character.-The Fruitland forma- land beds are 530 feet thick, the greater thicktion, though extremely variable in details, ness being due perhaps to a local longer duracontains at all exposures the same sorts of tion of the deposition of sandy material, as 

rocks. It is of brackish and fresh water the lower part of the overlying Kirtland shale 

origin and is composed of gray to brown hard is relatively thin. The Fruitland is 425 feet 

sandstone, gray-white soft sandstone, gray, thick halfway between the State b~undary and 

brown, and black shale, and coal. In general San Juan River and ranges between 250 and 

it may be said that 325 feet at the river and south of it. A 

number of sections of the Fruitland formation 

the formation consists of sandstone, shale, and coal, 

very irregularly bedded. In constitution the various are shown on Plate II. 

beds range from shale to sandstone with every conceiv- Relation to adjacent formations.-The Fruitable intermediate phase of sandy shale and shaly sand- land formation passes into the underlying 

stone. The marked variation both laterally and verti- marine Pictured Cliffs sandstone by a zone 

cally is shown at many places by the unequal resistance of brackish-water sediments that contain 

to weathering and consequent production of fantastic 

assemblages of pillars, knobs, "mushroom rocks," and coal beds. The most convenient plane of 

other forms. This irregularity is most marked in the division is the top of the purely marine beds, 

gray-white sandstone and gray sandy shale, but it affects which also at many localities is practically the 

to some degree the coal beds also. * * * The coal base of the lowest coal bed. The Fruitland. 

beds are distributed throughout the formation, but are formation likewise grades upward continuously ~ore abundant and generally thicker :ln its lower portion. * * * The Fruitland formation is further character- into the overlying Kirtland shale. It may be 

ized by the presence of large concretions of iron car- distinguished in the aggregate from the Kirtbonate which weather dark brown or black. Many land shale in that it includes coal beds and inof these concretions have been converted by veins durated brown sandstone. Usually the highof crystallized barfte into large septaria.37 est of the sandstones has been ta.ken as the top 

The coal of the Fruitland formation in San of the Fruitland formation and the overlying 

Juan County, N. Mex., and many local details softer .rocks have been assigned to the I{irtof the stratigraphy are described in the paper land shale. Such an arbitrary separation unby Bauer and the writer.:18 The sections on doubtedly leads to the drawing of the bounding 

pages 55-70, taken largely from that paper, plane at slightly different positions stratishow the constitution of the formation at graphically at. different places and may account 

several localities. for some of the variation in thickness recorded. 

Thickness.-The Fruitland formation at the Fossils.-The Fruitland formation has 

type locality is 241 feet thick. In Colorado yielded many fossils. These have been de36 Bauer, C. M., Stratigraphy of a part of the Chaco River valley: 

U. S. Geol. Survey Prof. Paper 98, p. 274, 1916. 37 Bauer, C. M., and Reeside, J. B., jr., Coal in the middle and eastern parts of San Juan County, N.Mex.: U. S. Geol. Survey Bull. 716, 

p. 167, 1920. . 

38 Idem, pp. 155-237. 

scribed by Gilmore, Osborn, Stanton, and 

89 Gardner, J. H., in Lee, W. T., and Knowlton, F. H., Geology and 

paleontology of the Raton Mesa and other regions in Colorado and New 

Mexico: U. S. Geol. Survey Prof. Paper 101, p. 187, 1917. 

'o Pishel, M. A., unpublished data. 
KIRTLAND ·SHALE. 21 

ICnowlton. The vertebrates 41 include the'following: 

Dinosauria: 

Pentaceratops sterilbergii Osborn. 

Monoclonius? 

Carnivorous dinosaur. 

Chelonia: 

Adocus sp. 

Aspideretes sp. 

Baena nodosa? Gilmore. 

Pisces: 

Lepisosteus sp. 

The invertebrates 42 are of brackish and fresh 

water types, the former mainly from the lower 

beds. The invertebrate fauna includes 

Ostrea glabra Meek and Hayden. 

Anomia gryphorhynchus Meek. 

gryphaeiformis Stanton. 

Modiola laticostata (White). 

Unio holmesianus White. 

amarillensis Stanton. 

gardneri Stanton. 

reesidei Sta1iton. 

brachyopisthus White. 

baueri Stanton. 

brimhallensis Stanton. 

sp. cf. U. primaevus White. 

Corbicula cytheriformis (Meek and}Hayden). 

Corbula chacoensis Stanton. 

Panopea simulatrix 'Vhiteaves'? 

Salix baueri Knowlton. 

sp. a Knowlton. 

Quercus baueri Knowlton. 

Ficus baueri Knowlton. 

curta? Knowlton. 

praetrinervis Knowlton. 

leei Knowlton. 

praelatifolia Knowlton. 

sp. 

rhamoides Knowlton. 

squarrosa Knowlton. 

sp. 

eucalyptifolia? Knowlton. 

Laurus baueri Knowlton. 

coloradoensis Knowlton. 

Nelumbo sp. 

Heteranthera cretacea Knowlton. 

Pterospermites undulatus Knowlton. 

·neomexicanus Knowlton. 

Ribes neomexicana Knowlton. 

Carpites baueri Knowlton. 

Phyllites petiolatus I(nowlton. 

neomexicanus Knowlton. 

Unassigned plant. 

Age and correlation.-Owing to the similarity 

of the faunas and flora of the Fruitland formation to those of the overlying ICirtland 

shale the discussion of the age and correlation 

of the Fruitland forn1ation is united with that 

of the Kirtland shale on page 24. 

Teredina neomexicana Stanton. KIRTLAND .SHALE. 

Neritina baueri Stanton. : 

Neritina (Velatella) sp. Type locality and distribution.-The KirtCampeloma amarillensis Stanton. land shale was so named by Bauer 44 from a 

Tulotoma thompsoni White. 

Melania insculpta Meek? settlement on San Juan River, New Mexico, 

·Goniobasis? subtortuosa Meek and Hayden. situated on the formation. The typical exPhysa reesidei Stanton. posure extends up the _San J_uah from ICirtland 

Physa sp. to Farmington. Near Farmington the middle ' 

Planorbis (Bathyomphalus) chacoensis Stanton. ~-sandstone member of the Kirtland shale, deThe known flora 43 of the Fruitland forma- scribed below, is very well exposed. It was 

tion includes the following forms, beside much named by Bauer the Farmington sandstone 

unstudied silicified wood: member. The formation has been traced 

AI1emia hesperia Knowlton. 

Anemia sp. 

Sequoia reichenbachi (Geinitz) Heer. 

obovata? Knowlton. · 

Geinitzia formosa Heer. 

Sabal montana Knowlton. 

Sabal? sp. 

Myrica torreyi Lesquereux. 

u Gilmore, C. ,V., Hcptilian faunas of tho 'l'crrejon, Puet·co, and 

underlying Upper Cretaceous formations of San Juan County, N.Mex.: 

U. S. Gcol. Survey Prof. Paper 119, p. 8, 1919. Osborn, H. F., A new 

genus and species or Ccratopsia from Now Mexico, Pentaceratops sternbergii: Am. Mus. Nat. Hist. Novitatcs, No. 93, 1923. 41 Stanton, '1'. W ., Nonmarine Cretaceous invertebrates of the San 

Juan Basin: U.S. Goo!. Survey Prof. Paper 98, p. 310, 1916. 

n Knowlton, F. II., Flora of the Fruitland and Kirtland formations 

U.S. Goo!. Survey Prof. Paper 98, p. 330, 1916. 

around the west side of the San Juan Basrn but 

is overlapped on the north side by the Animas 

formation and on the south side by the Ojo 

Alamo sandstone. 'Whether it can be recognized on the east side 'of the basin the writer 

can not say. It has not been recognized 

definitely outside of the San Juan Basin, 

though there are certainly sediments of the 

same age over wide areas. 

Lithologic cha1'acte1·.-At the type locality the 

Kirtland shale may be divided into three 

groups of beds forming distinct members, all 

u Bauer, C. M., Stratigraphy of a part of the Chaco River valley: 

U.S. Geol. Survey Prof. Paper 98, p. 244, 1916. 
22 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

of fresh-water origin. The lower member the' dip of the beds is low and a ridge where the 

consists mainly of gray shale with some brown dip is high.-

and black carbonaceous layers and. a minor A section at the type locality, n1easured by 

amount of bluish, greenish, and yellow sandy the writer for Mr. Bauer 45 in 1915, is given on 

shale and of soft, easily weathered gray-white pages 62-63 and will serve to show the general 

sandstones, all irregularly bedd~d. The mid- character of the- formation, though the details 

dle member contains many irregular lenses of vary greatly in a short distance along the 

sandstone, soft, gray, and unresistant below strike. 

l;>ut hard, brown, and resistant above. ·This Thickness.-The Kirtland shale shows conmember was named the Farmington sandstone siderable variatio:t;1 in thiclmess. Except in 

member by Bauer. The upper inember, like the region near Durango, Colo.; the McDermott 

the lower member, consists of shale and soft formation seems to be. conformable with it and 

sandstone. would indicate that the variations shown 

Southward from the typical locality the between Ojo Alamo, N. Mex., and Florida 

Farmington sandstone member thins and is River, Colo., represent original diff~rences in 

completely replaced by soft beds between coal deposition. The thinning east of Ojo Alamo 

Creek and Kimbetoh Arroyo, the lower shale and east of Florida River is undoubtedly due 

member thickening at its expense, while the to erosion. The formation appears to be 630 

upper shale varies but little.. Northward feet thick at Durango, Colo./6 927 feet in the 

from San Juan Riyer the sandstone member Red Mesa quadrangle, southwest of Durango/7 

and the upper shale member vary irregularly 1,065 - feet at the New Mexico-Colorado 

in thickness, and the lower shale changes boundary, 1,120 feet halfway between the 

little. The lithologic constitution of these State boundary and San Juan River, 800 feet 

members remains the sarri.e as at the typical on San Juan River, then thickening gradually 

locality. to a maximum of 1,180 feet on Hunter Wash 

The· shaly parts of the Kirtland contain and thinning thence southeastward to 700 feet 

considerable barite in the form of small con- on Escavada Wash and 390 feet near Tucker's 

cretions and veins. Gypsum also is present as store, in sec. 20, T. 21 N., R. 7 W. Still farther 

sheets in joint- planes and as crystals, aragon- to the southeast, ··on Medio Arroyo, the Ojo 

ite in rounded brown fibrous concretions, and Alamo sandstone and the Puerco and Torrejon 

siderite in concretions. · Silicified wood is formations overlap it completely. 

common. The shales weather into rounded On San Juan River the lower shale men1ber 

billowy forms, and where erosion is rapid and is 271 feet thick, the Farmington sandstone 

the dip of the qeds ·l.ow they have formed member 459 feet, and the upper shale member 

' extensive badlands. Where the dip is high the 8.0 feet. Toward the south the lower shale 

shale members form marked valleys. ,.. member increases, in the sections measured, to 

The sandstones of the Farmington sandstone 368 feet, 550 feet, and 1,031 feet and then 

member are irregular, cross-bedded, and com- decreases to 975 and 830 feet. In the same 

posed almost invariably of two parts-a lower, sections the Farmington sandstone nlember 

soft, easily eroded yellow to white sandstone measures 432, 4.

50, 99, 87, and 20 feet. The 

containing clay pellets and locally sandstone 

upper shale member ranges from 12 to 44 feet 

balls of material like "the matrix and reaching in thickness. North of San Juan River the 

4 inches in diameter, and an upper hard sandstone which is fine grained, dark gray on a fresh lower shale member maintains at most places a 

surface and dark ferruginous brown on thickness of 300 to 350 feet. The Farmington 

weathered surfaces. These lenses are of small sandstone member, how.ever, ranges from 162 · 

lateral extent, not reaching more than several to 480 feet and. the upper shale member fron1 

hundred yards as a rule, and few of them 150 to 475 feet. These variations seem to 

exceed 20 feet in thickness. The writer has 

not anywhere found pebbles in the Farmington sandstone. The sandstones of the Farmington member make marked benches where 

u Bauer, C. M., unpublished data. 

46 Gardner, J. H., in Lee, W. T., and Knowlton, F. H., Geology and 

paleontology of the Raton Mesa and other regions in Colorado and New 

Mexico: U.S. Geol. Survey Prof. Paper 101, p. 187, 1917. 

11 Pishel, M. A., unpublishe9- data. 
KIHTLAND SHALE. 23 

indicate simply differences in sedimentation, . 

as the beds form every-where an unbroken 

sequence of deposits. 

The sections on Plate II show graphically 

the variations in the thiclmess of the Kirtland 

shale and its subdivisions. 

Relation to adjacent formations.-The contact of the Kirtland shale with the Fruitland 

formation is one of gradual transition. The 

character of the contact with the overlying 

McDermott formation, where that is present, 

is difficult to detern1ine. In the Red Mesa 

quadrangle 48 Pishel with good reason believed 

it to be one of conformity, and so far as local 

evidence goes the same n1ight well be true for 

the New Mexico area. At many localities it 

is difficult to find any but an arbitrary plane 

of separation. At others it is possible to draw 

a fairly plausible boundary, but one without 

any sign of an erosion intervaL At one locality 

on the north side of Pinyon Mesa, N. Mex., a 

pebble-bearing sandstone at the base of the 

McDer1nott formation rests with sharp contact on a considerable thickness of characteristic Kirtland shale, and at Oj o Alamo, N .. 

Mex., a coarse grit forms the base of the 

McDermott forn1ation. Near Durango, Colo., 

the McDermott forn1ation seems to rest on 

an eroded surface of Kirtland shale, with the 

contact sh~·ply defined by the change in color 

and in lithology. Gardner believed the contact 

on Florida River to show an angular discordance, but the writer doubts its presence and 

would interpret the· apparent difference as due 

to rapid change in the clip. As the McDermott 

formation contains in this region much very 

coarse anclesitic detritus, it is possible that 

the sharp contact represents the beginning of 

torrential deposits laid clown in connection 

with the volcanic eruptions, these deposits, 

though unconformable, being not very much 

later in age thu,n the underlying shales. The 

contact with the Oj o Alan1o sandstone on the 

south side of the basin and with the Animas 

formation on the north side, where the McDermott .formation is absent, is clearly an erosional unconfol·mity. 

Fossils.-The Kirtland shale has yielded a 

number of collections of fossils, nearly all from 

New Mexico. These have been described by 

4

8 Pishcl, lVL A., unpuhlishcd data. 

Gilmore, Stanton, and Knowlton. The fossils 

all indicate a fluviatile origin for the for1nation. 

The vertebrates 49 from the Kirtland shale 

include the following forms: 

Dinosauria: 

Kritosaurus sp. 

Crested trachodonts. 

Carnivorous dinosaurs. 

Ceratops? sp. 

Armored dinosaur (Scelidosauridae). 

Chelonia: 

Baena nodosa Gilmore. 

sp. undetermined. 

Neurankylus baueri Gilmore. 

Adocus bossi Gilmore. 

kirtlandius Gilmore. 

Plastomenus robustus Gilmore. 

sp. undetermined. 

Aspideretes sp. 

Crocodilia: 

Crocodylus sp. 

Brachychampsa sp. 

Pisces: 

Lepisosteus sp. 

Myledaphus sp. 

The invertebrates 50 include the following 

forms: 

Unio pyramidatoides Whitfield? 

baueri Stanton. 

sp. undetermined. 

Viviparus sp. 

The plants were described by Knowlton 51 

in 1916 and include the following forn1s: 

Geinitzia formosa Heer. 

Salix sp. 

Ficus praetrinervis? Knowlton. 

leei Knowlton. 

A collection made in 1921 from the Farmington sandstone at U. S. G. S. locality 7494, in 

the SE. ! SW. ! sec. 13, T. 35 N., R. 7 W., 5 

miles north of Bayfield,· Colo., and examined 

by Mr. Knowlton, contains the follmving 

spemes: 

Ficus curta Knowlton. 

Phyliites petiolatus? Knowlton. 

Several undescribed leaves. 

49 Gilmore, C. W., Reptilian faunas of the Torrejon, Pucrco, and 

underlying Upper Cretaceous formations of San Juan County, N. 

Mcx.: U.S. Geol. Survey Prof. Paper 119, p. 8, 1919. 'l'he list given in 

Gilmore's paper includes the faunas of both the Kirtland and 

McDermott formations. 

60 Stanton, T. W., Nonmarine Cretaceous invertebrates of the San 

Juan Basin: U.s·. Geol. Survey Prof. Paper 98, p. 310, 1916. 

61 Knowlton, F. H., Flora of the Fruitland and Kirtland formations: 

U.S. Geol. Survey Prof. Paper 98, p. 330, 1916. The list given in Knowl· 

ton's paper includes also species from the McDermott formation. 
24 UPPER CRET'ACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Age of Fruitland formation and Kirtland 

shale.-The Fruitland formation and ·Kirtland. 

shale contain very closely related floras and 

faunas .. Brown,52 on the basis of the vertebrates, considered his Ojo Alamo beds, mostly 

included in the Kirtland shale of this paper, 

"to be synchronous with the Judith (Belly 

River) formation." The vertebrate remains 

of the Fruitland, Kirtland, and Ojo Alamo 

formations are said by Gilmore 53 to show 

beyond all question that they pertain to a fauna or 

faunas distinctly older than that of the Lance, and 

that such evidence as there is contributes to the support of Brown's contention that the Ojo Alamo sandstone is synchronous with the Judith River and Belly 

River formations as found in areas to the north. 

Later, concerning other specimens collected 

from the Kirtland, Gilmore 54 says: 

They furnish corroborative evidence * * * that 

the Kirtland formation· is of Montana age. * * * 

These specimens show a stage of development reached 

only in the Judith River and Belly River ceratopsians. 

Osborn, 55 in interpreting the bearing of 

P entaceratops sternbergii on the age of the 

Fruitland formation, states that it is intermediate between the Judith River and Belly River 

beds on the one hand and the Lance formation 

on the other. 

The invertebrates are said by Stanton 56 

to favor the assignment of the Fruitland formation to 

an epoch considerably later than Mesaverde and Judith 

River and possibly somewhat earlier than Lance. 

* * * The sequence from the base of the Fruitland 

up to the top of the Ojo Alamo, which is conformable, 

according to Mr. Bauer, may include the equivalents 

of everything from the Fox Hills to the Lance, inclusive. 

The plant fossils are said by Knowlton 57 

to ·justify the conclusion "that the Fruitland 

and Kirtland formations are of Montana age" 

and are closely related to the floras of the Vermejo formation and Mesaverde group. 

62 Brown, Barnum, Cretaceous-Eocene correlation in New Mexico, 

Wyoming, Montana, and Alberta: Geol. Soc. America· Bull., vol. 25, p. 

380. 1914. 

53 Gilmore, C. W., Vertebrate faunas of the Ojo Alamo, Kirtland, and 

Fruitland formations: U.S. Geol. Survey Prof. Paper 98, p. 281, 1916 . 

. 6• Gilmore, C. W ., Reptilian faunas of the Torrejon, Puerco, and underlying Upper Cretaceous formations of San Juan County, N.Mex.: U.S. 

Geol. Survey Prof. Paper 119, p. 8, 1919. 65 Osborn, H. F., A new genus and species of Ceratopsia from New 

Mexico, Pentaceratops sternbergii: Am. Mus. Nat. Hist. Novitates, No. 

93, 1923. 

66 Stanton, T. W., Nonmarine Cretaceous invertebrates of the San 

Juan Basin: U. S. Geol. Survey Prof. Paper 98, p. 310, 1916. 67 Knowlton, F. H., Flora of the Fruitland and Kirtland formations: 

U.S. Geol. Survey Prof. Paper 98, p. 331, 1916. 

It seems most logical, in the light of present 

knowledge, to consider both the Fruitland 

formation and the Kirtland shale as of late 

Montana age, possibly equivalent to the latest 

part of the Pierre shale and part of the Fox 

Hills sandstone of the region east of the Rocky 

Mountains. The possible relations of these 

formations to the Laramie formation of the 

Denver Basin are discussed on page 28. 

McDERMOTT FORMATION. 

Definition, type locality, and distribution.-

The name McDermott formation is here introduced for a series of lentjcular sandstones, 

shales, and conglomerates containing rnuch 

andesitic debris and usually in part of purple 

color. The name is derived from McDern1ott 

Arroyo, in the Red Mesa quadrangle, southwestern La Plata County, Colo., and the exposures in sees. 18 and 19, T. 32 N., R. 11 W., 

adjacent to McDermott Arroyo, may be considered typical· of the formation. A section 

measured at this locality is given on page 57 

and shows the formation to be 328 feet thick. 

The formation appears .to be conformable on. 

the Kirtland shale and at the type locality is 

overlain unconformably by the Torrejon formation. 

The McDermott formation may be traced 

from the type locality northeastward to the 

divide between Florida and Pine rivers, except 

in Bridge Timber Mountain, .where it is covered by overlap of later beds. Farther east it 

was removed by erosion before the deposition 

of the Animas formation. Southward from the 

typ~ locality the formation may be traced to 

a locality some miles beyond Ojo Alamo, N. 

Mex. Beyond this place it seems to have 

been eroded away during the interval preceding 

the deposition of the Ojo Alamo sandstone. 

The outcrop, therefore, extends virtually 

around the western half of the San Juan 

Basin. 

The formation defined above is the lower 

part of the unit described by Cross 58 in 1892 

from observations made by T. W. Stanton as 

the '' andesitic beds on Animas River'' and 

in 1896 from his own observations 59 as the 

"Animas River beds." It is the same unit as 

5~ Cross, Whitman, Post-Laramie deposits of Colorado: Am. Jour. 

Sci., 3d ser., vol. 44, pp. 25-27, 1892. · 

59 Emmons, S. F., Cross, Whitman, and Eldridge, G. H., Geology of 

the Denver Basin in Colorado: U. S. Geol. Survey Mon. 27, pp. 217-

219, 1896. 
lv.IcDERMOTT FORMATION. 25 

the Aninuts fonnation of Shaler 60 (1907) and Mexico, though sandstone, shale, and conGardnm·61 (1909). It forms the basal part of glomei~ate with a notable amount of andesitic 

the Aniinas formation as later conceived by material in them mark the McDermott forGardner.62 It is included in the upper part of mation clearly in the region north of San Juan 

theOjo Alan1o beds of Brown 63 (1910), in the up- River. At San Juan River the McDermott 

permost part of the IGrtland shale-of Bauer 64 formation is represented by thin irregular 

(1916), and in the Ojo Alamo sandstone in lenses of fine purple and green tuffaceous sandpart (north of Pinyon Mesa, N. Mex.) and the stone, coarse white sandstone with clay pelKirtland shale in part (south of Pinyon Mesa) lets, and purple aU:d gray shale forming 30 feet 

of Bt1uer and Reeside65 (1921). . of beds just beneath the Ojo Alamo sandstone. 

The NlcDern1ott formation has· not been South of Sari Juan River the McDermott for-. 

recognized outside of the San Juan Basin. mation is a thin assemblage of brown sandLithologic chaTacte1·.-At the type locality the stone and grit, gray-whi~e sandstone, and 

McDern1ott formation consists of an irregular purple and gray shale just beneath the Ojo 

assmnblage of brown to yellow soft sandstone; Alamo sandstone. Except for the purple 

gray-white coarse tuffaceous sandstone; purple, color of some of the beds this assemblage does 

yelio"'r, and bluish-gray tuffaceous shale; green not look greatly l{ke the McDermott formato drab coarse conglomerate with matrix mation in .Colorado. These beds, however, 

almost entirely of andesitic debris and pebbles contain detritus from andesites. 

and cobbles nearly all of weathered andesite; The constitution of the McDermott formain the upper part of the formation conglomer- tion at a number of localities is shown by the 

ate with rusty brown matrix and pebbles nearly sections on pages 56-62. 

all of siliceous, resistant rocks, such as quartz, Thiclcness.-The thickness of the McDermott 

quartzite, and chert. These pebbles are much formation is highly variable, owing in part to 

like those in the Ojo Alamo sandstone described the arbitrary placing of the lower boundary 

on page 29. Nearly all the finer-grained parts at many localities, in part to erosion of the 

of the formation contain some volcanic debris, upper surfaee, and in part to a variation in 

the purple shale particularly. Northward from the original thickness. In Colorado it .is 200 

the type locality the proportion of andesitic to 400 feet thick at most localities. In northmaterial in the formation increases. On ern Sari Juan County, N. Mex., it is thinner, 

Anin1as River it is composed of fairly pure ranging between 150 and 200 feet. It thins 

and little weathered andesitic debris, pre- still more southward and is from 30 to 50 feet 

dmninantly purple. Some beds of it are very thick in the region south of San Juan River. 

coarse indeed, masses several feet in diameter Some of these variations· are shown graphically 

being common. East of Animas River notable in Plate II. 

beds of siliceous pebbles are present in the Relation to adjacentjoTmations.-The contact 

lower part of the formation, associated 1vith of the McDermott formation with the Kirtyellow sandstone. Southward from the type land shale is discussed on .P.age. 23. It ~s 

locality the proportion of volcanic matter de- conformable at many locah.tles, though It 

creases. · Beds of purely andesitic debris do seems to be uncon~or.mable locall:y. Over 

not occur west of La Plata River in New most of the .exposure Ill the IgnaciO quad60 Shaler, M. K., A reconnaissance survey of the western part of the 

Durango-Gallup coal field of Colorado and New Mexico: U. S. Geol. 

Survey Bull. 316, pp. 322-323, 1907. -

61 Gardner, J. H., The coal field between Durango, Colo., and 1\'Ionero, 

N.Mex.; U. S. Gcol. Survey Bull. 341, pp, 352-353, 1909. 

Oi Gm·duer, J. H., section on Florida River published in Lee, W. T., 

Stratigrnphy of the coal fields of northern central New Mexico: Geol 

Soc. America Bull., vol. 23, p. 585, 1912. · 

63 Brown, Barnum, Tho Cretaceous Ojo Alamo beds of New Mexico, 

with description of the new dinosaur genus Kritosaurus: Am·. Mus. 

Nat. Hist. Bull., vol. 28, pp. 267-268, 1910. 

64 Bauer, C: M., Stratigraphy of a part or the Chaco River valley: 

U. S. Geol. Survey Prof. Paper 98, p. 275, 1916. 

6o Bauer, C. M., and Reeside, J. B., jr., Coal in the middle and eastern 

parts or San Juan County, N. Mex.: U.S. Gcol. Survey Bull. 716, pp 

162, 172, 1921. • 

rangle- that is, from Bridge Timber Mountain 

to the divide between Florida and Pine 

rivers-the' McDermott formation is overlain 

by the Animas formation. On Animas River 

the contact is marked by an a'hgular discordance and a sharp color contrast between 

the purple Mc:Permott formation and the 

greenish to brown Ani:J;nas formation. At 

most other localities the sharp change in color 

is· evident though a discordance in dip or 

local evidence of erosion has ·not been detected. 

The lower beds of the Animas formation are 
26 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

usually coarse and composed largely of Southeastward fron1 Oj o Alamo the Oj o 

andesitic debris, but 'they differ from the Alamo sandstone very clearly transgresses 

McDermott formation in containing much across the McDermott formation (see Pl. II), 

more weathered detritus and more non- and the evidence of erosion before Ojo Alamo 

volcanic material. Eastward from the divide time is· plain. It is therefore likely that 

between Pine River and Piedra River the there is a hiatus between the McDennott 

Animasformationis in contact with successively formation and the Ojo Alamo sandstone 

lower beds of the McDermott formation, the wherever they are in contact. Not enough 

Kirtland shale, and part of the Fruitland is yet known of the Ojo Alamo fauna, as shown 

formation, and the evidence of pre-Animas on page 31, to determine whether it is very 

erosion is very clear. It is the writer's belief different from that of the McDermott, ·but 

that the Animas formatio:p. is everywhere the writer believes that there is a difference 

unconformable upon the McDermott formation which will be established with further coland that there is, in fact, a notable gap at- this lecting. 

contact. In Bridge Timber Mountain the The beds of silicequs pebbles in the McDerbasal Wasatch beds ("Tiffany beds" of mott formation present a special problem. 

Granger) overlap the McDermott formation No pebbles of any kind have been found in the 

and the Kirtland shale. Southwest of Bridge formations between the Tocito sandstone 

Timber Mountain a narrow strip of Animas lentil of the Mancos shale and the McDermott 

formation is present between the outcrops of formation. Clay pellets and "mud balls" 

the M~Dermott formation and t.he "Tiffany" are common in some of the beds but no pebbles. 

zone of the Wasatch and Torrejon formations, The siliceous pebbles, therefore, appear very 

but it thins out within a few miles, and in suddenly in the. succession of strata. Their 

sec. 5, T. 32 N., R. 11 W., the Torrejon ·source has not l;>een traced. Among them 

formation rests directly on the McDermott rocks probably as old as pre-Cambrian are 

formation. The basal part of the Torrejon represented and certainly as ·old as Carbonihere consists of light and dark gray shale with ferous. Whether the rocks forming the pebsome ,thin, platy green sandstone and son1e bles had been uncovered by erosion on some 

thin brown sandstone. The lithologic contrast land mass during a long period of time, perhaps 

with the conglomerates, ·soft yellow· sandy all of Cretaceous time o;r longer, and only 

beds, and purple layers of the McDermott fine debris was transported until some change, 

formation. permits a ready separation. The with which the volcanic eruption is possibly 

effect of erosion is not very evident, but as the to be connected also, increased the power of 

Animas and Ojo Alamo formations are un- the streams to can·y debris, or whether the 

represented the Torn'jon is unconformable uncovering and transportation of the mate1·ial 

on the McDermott formation. On Barker occurred between Kirtland and McDermott 

Arroyo, in New Mexico, the Ojo Alamo time·, must be determined indirectly. The 

sandstone appears between the Tortejon form- latter alternative would necessitate a great 

ation and the McDermott formation and is hiatus between Kirtland and McDern1ott 

the overlying unit as far south as the Me- time, which is not shown either by the fossils 

Dermott formation occurs. The contact is or by the structural relations of the formations. 

one of erosional unconformity. Angular dis- The writer believes that the presence of the 

cordance has not. been noted ·anywhere, and siliceous pebbles requires some other explanaat some localities, owing perhaps to a re- tion than that of a hiatus. 

working of )v.fcDermott materials, it is difficult Fossils.-Near the type locality of the Meto determine logically a plane of division Dermott formation indeterminable bones of 

between the two formations. At many dinosaurs, fragments of turtle bone, and fossil 

localities, however, the contact is a clean-cut wood have been collected at· a number of 

line between pebble-bearing sandstone and localities, but no other fossils, In the Durango 

shale without great irregularities, and at region several lots of plants have been collecte~; 

still other localities it is at the base of a and south of San Juan River in New Mexico 

conspicuous coarse basal conglomerate in the both plants and reptilian remains have been 

Ojo Alamo sandstone and is very sinuous. found. 
McDERMOTT FORMATION. 27 

The vertebrate fauna has been listed by 

Gihnore 66 and includes the following forms, 

all fr01n New Mexico : 

Dinosauria. 

Kritosaurus navajovius Brown.67 

Monoclonius sp. 67 

Armored dinosaur (Scelidosauridae). · 

Carnivorous dinosaur suggesting Dryptosaurus and Dynamosaurus. 

Chelonia: · 

Baena nodosa Gilmore. 

Pisces: 

Lepisosteus sp. 

From the same region as the vertebrates just 

listed two lots of fossil plants were· collected by 

Bauer. These were examined by Knowlton 

and the species described. 68 The species in the 

two lots are as follo·ws: 

6965. 1 mile east and a quarter of a mile north from 

Pina Veta China, N. Mex.: 

Pistia corrugata Lesquereux. 

Ficus leei? Knowlton. . 

Fragments of a large leaf, prqbably Ficus sp. 

Unassigned plant suggesting Selaginella. 

6966. 1 mile east and three-quarters of a mile north 

from Pina Veta China, N. Mex.; horizon at very top of 

McDermott formation: 

Palm (genus and species?). 

Onoclea neomexicana Knowlton. 

Asplenium neomexicanum Knowlton. 

Ficus leei Knowlton. 

Myrica? neomexicana Knowlton. 

Leguminosites? neomexicana Knowlton. 

Pterospermites sp. 

Plants have been collected from four localities 1n the Durango region and have been 

examined by Knowlton, who finds the following species present: 

Florida River, Colo.; horizon 211 feet above base of 

McDermott formation; J. H. Gardner, collector: 

Ficus planicostata Lesquereux. 

West side of Animas River below Durango, Colo.; 

Whitman Cross and A. C. Spencer, collectors: 

Fern, new, genus? 

Sabalites sp.? 

Cyperacites sp. 

ll'icus eucalyptifolia Knowlton. 

den veriana? Cockerell. 

Quercus preangustiloba Knowlton. 

Grewiopsis sp. 

Cissus coloradoensis? Knowlton and Cockerell. 

Rhamnus cf. R. cleburni Lesquereux. 

60 Gilmore, C. W., Reptilian faunas of the Torrejon, Puerco, and 

underlying Upper Cretaceous formations of San Juan County, N.Mex.: 

U. S. Goo!. Survey Prof. Paper 119, p. 8, 1919. The list given by Gilmore includes the McDermott fauna with tho Kirtland fauna. 67 Cited by Brown in his Ojo Alamo beds, but really coming from the 

present McDermott formation. 

os Knowlton, F. H., Flora of.tho Fruitland and Kirtland formations: 

U.S. Goo!. Survey Prof. Paper 98, p. 330, 1916. The list given includes 

tho plants of the McDermott formation with those of the Kirtland 

shale. 

19()4. East of ridge west of Animas River about 3 

miles· below Durango, Colo.; base of beds· containing 

eruptive.debris; Whitman Cross and A. C. Spencer, 

collectors: 

Cyperacites, sp. 

Canna? magnifolia Knowlton. 

Laurus socialis Lesquereux. 

Cinnamomum linifolium? Knowlton. 

Sequoia acuminata? Lesquereux. · 

7457. 4 miles south of Durango, Colo., in NW. i 

SE. i sec. 11, T. 34 N., R. 10 W., near base of McDermott formation; J. B. Reeside, collector: · 

Salpichlaena sp. probably new but close to S. 

anceps (Lesquereux) Knowlton. 

Ficus sp. 

Laurus sp. 

Fragments of two or three other dicotyledons. 

Age and correlation.---:The dinosaur fauna 

listed above contains only forms considered 

to be of Montana age. Kritosaurus occurs -

in the Kirtland formation and is known elsewhere only in the Belly River formation. 

Monoclonius is not known in later beds than 

those of Montana age. The specimen of 

carnivorous dinosaur is most like a form from 

the Edmonton formation. Baena nodosa occurs also in the Kirtland and Fruitland formations. The assemblage is therefore said by 

Gilmore 69 (see p. 24), following Brown, to 

indicate Montana age for the inclosing beds, 

or at least an earlier age than that·of any beds 

with Triceratops, such as the Denver formation and the Lance forn1ation. The fauna is 

certainly much like that of the Fruitland and 

Kirtland formations. Concerning. the plants 

listed above, Knowlton says (see p. 77 of this 

volume): 

The bearing of this flora on the question of age 

is difficult of satisfactory or conclusive evaluation. * * * As the matter now rests, the plants 

undoubtedly favor placing the McDermott formation 

in the Cretaceous, but they are not conclusive. 

The paleontologic evidence as to age is there'7 

fore somewhat conflicting, though n1ore favorable to an association of the McDermott 

formation with the underlying beds than with 

later deposits. The ~1:cDermott formation is 

continuous between the Colorado area and the 

New ~1exico area and is everywhere terminated 

by an erosion surface. The base, on the con-· 

trary, is a much less definite plane of separation. It seems to the writer, therefore, that 

the McDermott formation has much closer 

69 Gilmore, C. W., Vertebrate faunas of the Ojo Alamo, Kirtland, and · 

Fruitland formations: U. S. Geol. Survey Prof. Paper 98, pp. 28Q-281, 

1916. 
28 UPPER CRETACEOUS J\.ND !ERTIARY FORMATIONS IN SAN JUAN BASIN. 

relations to the underlying than the overlying 

beds, and that it should be placed in the Cretaceovs. However, in view ·of the doubt that 

exists regarding its age this assignment is made 

with question in this paper. 

The McDermott formation being, in the 

_ opinion just expressed, probably the highest 

conformable Cretaceous ·formation of the San 

Juan Basin, its relation to the Laramie formation of the Denver Basin comes into question. 

The Laramie formation is universally accepted 

as of post- Montana age, as it follows the Fox 

Hills sandstone, which by definition of the 

Montana group is the highest Montana formation. The highest marine beds of the Sail 

Juan Basin, those of the Pictured Cliffs sandstone, contain a fauna some~hat older than 

that of the Fox Hills sandstone. The beds 

above the Pictured Cliffs sandstone therefore 

must represent the time of possibly a small part 

of the Pierre shale and certainly the Fox Hills 

sandstone. Whether they include any deposits 

as late in time as the Laramie of the Denver 

Basin can be determined only by comparison 

of the respective faunas and floras. It has 

been stated on page 24 that the vertebrate 

fauna and the flora of the Fruitland and Kirtland formations are agreed as to the Montana 

age of the beds, and that the invertebrate fauna 

is less positive in its testimony, for though the 

fauna may be as old as Fox Hills it has much in 

common with that of the Laramie. The 

Laramie .formation has yielded no determinable reptilian fossils, and the McDermott formation no invertebrates, so that a direct comparison can be based only on the floras. These 

have little in common and deny rather than 

affirm a close relationship, though the evidence 

is admittedly not conclusive. Unless in Laramie time dissimilar plants lived simultaneously 

in northeastern and southwestern Colorado the 

·beds are not of the same age. If the evidence 

of the vertebrates of the McDermott formation 

and that of the p1ants are taken together it 

must be. said that they lend some support to 

placing the McDermott formation even as low 

.in the series as the Montana group, and that 

there is not now in hand any clear evidence of 

the presence in the San Juan Basin of an equivalent of the Laramie formation of the Denver 

~asin nor any evidence that it was ever present 

1n the past. It seems much more likely that 

the post- McDermott hiatus represents all of 

Laramie time and the interval of· the postLaramie hiatus in the Denver Basin. 

OJO ALAMO SANDSTONE. 

Type locality and distribution.-The histor"y 

of Ojo Alamo as a formation narne has been 

t~aced in detail by Bauer.70 It was first 

applied by Brown 71 to a reptile-bearing shale 

below ·a conglomerate on Ojo Alamo Arroyo 

near Ojo Alamo, N. Mex. Later Sinclair 

and Granger 72 found that at the same locality 

there were two conglomerates inclosing between 

them a shale with reptilian remains resembling 

those in the shale beneath the conglomerate. 

They considered the lower conglomerate to 

split the original shale of Brown into two parts; 

the upper inclosed between the lower conglomerate and a higher conglomeratic sandstone and the lower extending downward for 

an unknown but considerable thickness. They 

applied the name to the whole mass of sandstones, conglomerates, and shales. Bauer 73 

showed that the lower conglomeratic sandstone of Sincl~ir and Granger when traced 

laterally became continuous with the upper 

by the pinching out of the included shale 

member and proposed to restrict the name 

Ojo Alamo to these conglomeratic beds and 

the shale between them, inasmuch as the 

trading post Ojo Alamo is situated on them, 

and to use the name Kirt~and for the lower 

shal-e .. It is in the· sense proposed by Bauer 

that the name Ojo Alamo is used in this 

paper. 

The Ojo Alamo sandstone may be defined 

as a conglomeratic sandstone containing one 

or more lenses of variegated shale and soft 

sandstone-bounded below by an unconformable 

contact with the McDermott formation and 

above at the type locality by a~ ~conformable 

contact with the Puerco formation. The section at the type locality given on page 68 

shows it to be 86 feet thick. 

The Ojo Alamo sandstone, so far as no'w 

known, is confined to New Mexico. It extends as the cap- rock of a continuo~s ridge 

70 Bauer, C. M., Stratigraphy of a part of the Chaco River valley: 

U.S. Geol. Survey Prof. Paper 98, pp. 274-276, 1916. 

71 Brown, Barnum, The Cretaceous Ojo Alamo beds of New Mexico 

with description of the new dinosaur genus Kritosaurus: Am. Mu~. 

Nat. Hist. Bull., vol. 28, pp. 267-274, 1910. _ 

73 Sinclair, W. J., and Granger, W. J., Paleocene deposits of San Juan 

Basin, N.Mex.: Am. Mus. Nat. Hist. Bull., vol. 33, pp. 30Q-304, 1914. 

73 Bauer, C. M., Stratigraphy of a part of the Chaco River valley: 

U. S. Geol. Survey Prof. Paper 98, pp. 275-276, 1916. 
O.JO ALAMO SANDSTONE. ~9 

fron1 Pinyon Mesa, a few miles north of San. 

Juan River, around the west and south sides 

of the- San Juan Basin. It· is concealed for 

so.me miles north of Pina Veta· China but forms 

the cliff at the top of the bluffs near San Juan 

River, along the lower part of La Plata River, 

and it is the cap rock of Pinyon Mesa.' A 

small ren1nant is present east of Barker Arroyo, 

but north of that locality it is cut out by the 

ov~1·Iapping Torrejon ~ormation~ (See Pl. I.) 

The pebbles contained in the conglomeratic 

portions of the Ojo .Alan1o sandstone are similar to those found in certain beds of the McDermott and Animas formations and include 

a highly varied assortment of resista~t siliceous 

materials. Perhaps two-thirds are of j aspery 

quartz of a striking, brilliant red color; chert 

of various shades of brown, gray, and black; 

vein quartz; pink, \~hite, and rately· gray 

quartzite, and hard brown sandstone. The 

Shaler, 1907, Brown, Sinclair · Bauer, 1916, 

This paper 

Torre jon 

and Puerco 

formations 

Ojo 

Alamo 

sandstone 

Upper 

conglomerate 

Shale 

member 

. Lower 

McDermott 

formation 

Farmington 

sandstone 

member 

Kirtland 1--:----~~:::r 

shale 

and 

Gardner, 1910 · 

--? --

l>uerco 

marl 

1910 and Granger, 

1914 

---?---

Torre jon 

formation 

Puerco 

formation 

Puerco 

formation 

Unnamed 

conglomerate 

-----

Ojo 

Alamo 

beds · 

Ojo 

Alamo 

beds 

---?--- ----?---

and Bauer and 

Reeside, 1921 

Torrejon 

and Puerco 

formations 

Ojo 

Alamo 

· sandstone 

Kirtland 

shale 

FIOUI~E 2.-Diagnun showing the differences ·in naming of beds exposed near Ojo Alamo, N.Mex. 

Lithologic character.-The Ojo Alamo sand- remaining third includes silicified rhyolite, anstone is a white, gray, and brown resistant desite, and other porphyries and. rarely gran-

~andstone :frmn medium to coarse-grained, con- ite, gneiss,. and schist. · The pebbles are all 

tn,ining lenses of well-rounded pebbles of vari- \veil rounded, and- many ·of then1 are·chatterous resistant siliceous materials and lenses of marked. They attain as great a size ·as 6 

gray, greenish, and very rarely reddish shale inches in. diameter, though usually from 1 to 

interfingering with soft gray-\vhite sandstone. 3 inches. Their source is as yet unknown, 

Silicified logs are abundant locally, and. the· though possibly they came from the east or 

formation contains a few concretions of dark south rather than the north, for the types of 

ferruginous sandstone.· , rock abundant in the present-day river gravels 

82587-24t--3 
30 UPPER CRETACEOUS AND TERTIARY FOR.MATIONS IN SAN JUAN BASIN. 

derived from the north are lacking in the Ojo . Plata River, the thickness ·decreases to 200 

Alamo sandstone. · feet, and within 5 miles to the northeast it is 

. Sections at a number of localities are given reduced to a vanishing edge between the Meon pages 61-70 and show the constitution of the Dermott formation and the overlying beds 

formation in detail. referred in this paper to the Torrejon formaThickness.-N ear· the type locality the for- tion. (See p. 36.) Still farther north thin 

mation is from 60 to 80 feet thick. To the beds of conglomerate composed of pebbles like 

south it increases somewhat in thickness those of the Ojo Alamo sandstone occur in the 

locally; reaching 125 fe'et on Escavada Wash. upper part of the McDermott formation and 

A section at Tucker's store, 12 miles southeast appear like a· continuation of the Ojo AlQ.mo 

of the locality on Escavada Wash, shows the sandstone. They occur, however, in an enthickness to be 75 feet. The Ojo Alamo tirely distinct matrix and have been traced 

sandstone may be traced eastward from into beds of conglomerate that on Barker 

Tucker's store as a nearly continuous sand- Arroyo lie beneath the thinning wedge of Ojo 

stone ridge just benet;tth the beds assigned to Alamo sandstone and are distinctly not a part 

the Puerco formation and overlapping with it of it. 'l~he Ojo. Alamo sandstone. thus thins, 

across the Kirtland, Fruitland, Pictured Cliffs, perhaps by erosion rather than by nondeposi-

·and Lewis formations. It appears to vary tion, and in the region northeast of Barker 

little from its thickness at Tucker's store, Arroyo; which j'oins La Plata River about 9 

though no careful measurements were made. miles north of Farmington, N. Mex., it disTo the north of the type locality the formation appears from the succession of rocks·bordering 

increases but little in thickness as far as :Pina the west of San Juan Basin. 

Veta China, where it is 91 feet thick. On the Relation to adjacent formations.-The lower 

. western slope of the Chaco-Gallego divide contact of the Ojo Alamo sandstone has been 

thm~e are so few exposures between Pina Veta described on pages 23 and 26; It is one of 

China and the bluffs south of San Juan River, erosional unconformity without notable disa dista~ce of 11· miles, that little can be deter- cordance of clip except where it overlaps ~he 

mined. Along West Gallego Arroyo .. how- older .beds, as on Medio Arroyo. Gardner 7

'

1 

ever, exposures of the Ojo Alamo sandstone has described the overlap at this place, though 

occur at many places from the head. of the not differentiating the basal ·sandstone now 

arroyo to· its .. junction with the main arroyo known to be Ojo Alamo. Th~ Ojo Alamo and 

and on clown to San Juan River, where they overlying beds rest on the Fruitland and older 

are continuous with the exposures on that formations with a difference in strike of nearly 

, river. The exposures are so situated that the 90°. The· clip is nearly the san1e for both 

writer has no doubt of the continuity of the formation!', about 4 °. · 

Ojo Alamo sandstone through the Chaco- The upper contact of the Ojo .. Almuo is also 

G~llego divide from Pina Veta China to San an erosional unconformity. This is shown by 

Juan River. The fine exposm·es along this a sinuous line of contn,ct, sharply clefiriecl, a 

stream ai1cl its tributaries show a large increase lithologic change from the conglon1eratic sanclin the thickness of the formation. In the stone of the Oj o Alamo sandstone to the varietriangular ~rea bet\veen Animas and San Juan gated shale of the Puerco and Torrejon farinarivers the sandstone and its included shale tions, and, as will be shown later, a complete 

units measure 400 feet in thickness. The change of fauna in passing from the Ojo Alamo 

lithologic constitution of this thicker phase of sandstone to the Puei·co formation. 

the formation differs from that of the typical Fossils.-The Ojo Aln,mo sandstone has afphase only in the greater number of alterna- forded abundant but fragmentary remains of 

tions of shale and· conglomeratic sandstone, reptiles and a few poorly preserved remains 

·and although the increase in thickness is of plants. 

SUrprisingly great there is little room for doubt _1l_G_a1-·d-ne-·r,-J-. ....,..H-: .-, -T-he-eo-al-fie-ld-be-t.,.,-·e_e_n_S-an_M_a-te_o_a-nc_l_C_u_ba, 

aS to the identity of the formation. with that N.Mex.: U.S. Geol. Survey Dull. 381, p. 171, 1910; 'l'he PUCI'CO and 

Torrejon formations of the Kacimiento group: Jour. Geology, vol. 18, 

at Ojo Alamo. In Pinyon Mesa, west of La p. 122, 1910. 
OJO ALAMO SANDSTONE. 31 

'l'he Yertebrates described in t4e literature· that "even generic determination of isolated 

as deriYed fron1 the Ojo Alamo sandstone have dinosaur teeth and bones must be considered a 

been listed by Gilmore 75 as follows: provisional reference," it seems fair to ask 

Dinosauria: · 

l\ritosaurus·navajovius Brown. 

Monoclonius sp. 

Armored dinosaur (Scelidosauridae). 

Deinodon? 

Chelonia: 

Basilemys nobilis Hay. 

Adocus vigoratus Hay. 

Aspideretes vorax Hay. 

fontanus Hay. 

austerus Hay. 

Thescelus rapiens Hay. 

Compsemys sp. · 

Crocodilia: 

Crocodylus sp. 

Pisces: 

Lepisosteus sp. 

AU the collections made up to the present 

time have come fron1 places near the type locality, Ojo Almno. '"!~he. specifically identified 

:fonns, except J(ritosaurus navajovius; were all 

coHected by Brown in 1904 and by Gardner and 

Gidley 70 in 1908 near the type locality.· The 

nwst significant species are Jfonoclonius sp. 

and J(?·itosauTus navajovius. Jfonoclonius sp. is 

cited on the evidence of a horn core collected 

by Brown. At the tin1e of collecting the specinlen Brown was applying the name Ojo Alan1o 

to the shale (McDermott and Kirtland) beneath the congl01nerates. Specin1ens representing primitive ceratopsian dinosaurs are 

known fr01n four or five localities in the IGrt1and shale, and Brown's own staten1ent 77 of 

the occurrence of his 1naterials is that "the 

vertebrate ren1ains were nun1erous in severj.tl 

places :fron1 30 to 100 feet below the conglonlerate." It is :fairly open to question, therefore, 

whether the horn core came fron1 the Ojo 

Alamo sandstone or older beds. f(Titosau?'US 

navajovius is cited on the evidence of material 

collected by Sinclair and Granger 78 and identified by Brown. This n1aterial consisted of 

part of a trachodont Inaxillary and fragn1ents 

of the skull. InasnniCh as Brown hi1nself. says 

n Gilmore, C. W ., Hoptilian faunas of tho 'l'orrojon, .Puoroo, and 

underlying Cretaceous formations of San Juan County, N. l\1:cx.: U, S. 

Gcol. Survey Pro"r. Paper 119, p. 9, 1919. 70 Gilmore, C. \V., Vertebrate faunas of the Ojo Alamo, Kirtland, and 

Fruitland formations: U.S. Gcol. Survey Prof. Paper 98, p. 279, 1916. 77 Brown, Barnum, Tho Cretaceous Ojo Alamo beds of New Mexico, 

with a description of tho new dinosaur genus Kritosamus: Am. Mus. 

Nat. Hist. Bull., vol. 28, p. 268, 1910. · 75 Sinclair, W. J., and Granger, Walter, Paleocene deposits of tho San 

Juan Basin, N. Mcx.: Am. Mus. Nat. Hist. Bull., vol. 23, p. 302, 1914. 

whether this material is determinable with cer-

. tainty. or should be referred merely to the 

trachodont dinosaurs until more material is 

available. The age assignment of the formation must rest in part on the dinosaur fauna, 

m:td the inclusion of determinations that are· 

not surely founded is .apt to lead to confusion. 

The remaining specimens now known whose 

stratigraphic position is unquestioned are 

mostly fragmentary, and though suggesting 

a varied fauna, are not sufficient for such 

definite· assig1unent as should be used in correlation. These spe"cimens include teeth of 

Deinodon?)· dern1al ·plates and a scapula of an 

arn1ored dinosaur; part of the frill of a ceratopsian distinct from Triceratops, Oeratops, or 

Jfonoclonius.; 79 Yerte brae of a Yery large carnivorous dinosaur of the proportions of TyTannosau?'Us)· and a scapula and ischiu1n of the 

large sauropod dinosaur AlamosauTus sanjuanensis Gilmore. 80 The last three were not included by· Gilmore i1i the list given above. 

Away fron1 the type locality little Yertebrate 

n1aterial has been found. A few ·poorly presen•ed dinosaur bones were seen by the writer 

near Kimbetoh Arroyo and a few scraps of 

turtle carapace near San Juan River. 

Sevetal small lots of fragmentary plants have 

been collected fron1 the Ojo Alarno sandstone. 

These have been e·xamined by F. H. I\:nowlton, 

who reports as follows: · 

6951. ·3! 1hiles south of Pina Veta China, N. Mex.; 

l1orizon near base of Ojo Alamo sandstone: Material 

is a very hard fine-grained sandstone. Plants very 

fragmentary. There are two species with rather hirge 

leaves and a small, narrow Salix-like leaf. One of the 

large leaves is either a Platamts or an Aralia. If the 

former it might well be Platan'us aceroides Goeppert or 

Platamts raynoldsii Newberry, but it is impossible to 

be certain. Both these are well-known Eocene (Fort 

·Union, Denver, Raton, etc,) species. The other things 

can not be identified. 

7373. 2 miles south of Farmington, N. Mex.; horizon 25 feet above the base of the Ojo Alamo sandstone, 

asso<:iated with a lens of impure lignite. 'J;'his material 

is a soft clay shale well fitted to retain plant remains, 

and in fact the plants present are in the main beautifully preserved, but unfortunately they were so much 

79 Gilmore, C. W., H.eptilian faunas of the 'l'orrojon; Puorco, and 

underlying Upper Cretaceous formations of San Juan County, N. Mox.: 

U.S. Goo!. Survey Prof. Paper 119, pp. 65, 67, 1919. 

so Gilmore, C. \V., A now sauropod dinosaur from tho Ojo Alamo 

formation of New Mexico: Smithsonian Misc. Coil., vol. 72, No. 14, 1922. 
32 UPPER CRETACEOUS AND TERTIARY l!"OR.l\1ATIONS IN S~N JUAN BASIN. 

broken up before fossilization that it is now impossible 

to identify them with any degree of cer-tainty. I note 

the presence of a peculiar fern that is probably an 

Anemia, but.it can not be fixed with certainty. There 

are also at least two types of dicotyledonous leaves, a 

small one that seems to be a Sapind1ts of the type of 

Sapindus affinis Newberry (a Fort Union species) and 

a larger . 0~1e that strongly suggests an undescribed 

species of Fiws from the Dawson ark.ose of Colorado. 

Mr. Knowlton examined another collection 

made by Bauer from a locality very close . to· 

locality 7373, and his report on it 81 is repeated 

below: · 

This material is very fragmentary. It includes, apparently, two ferns, one Pteris-like and the other 

Anemia-like, but neither is sufficiently well preserved 

to be identified. There is also a monocotyledon that 

· may be a palm ray or a large. leaf of a sedge. The 

only dicotyledon present is a Sapind1ts not unlike a 

large leaflet of S. angustifolia Lesquereux, a Green 

River species. This lot appears to be Tertiary, but it 

is too fragmentary to place positively. 

Alamo deposits ·and the Ojo Alan1o sandstone. 

The similar position in the stratigraphic succession of the Ojo Alamo sandstone and the 

Animas· formation (as shown on p. 25) and the· 

fact that each formation in its area of occurrence car~ies the latest dinosaur remains known 

suggest that they are of very nearly the sarne 

age, or perhaps better that the lower part of 

the Animas formation and the Ojo Alamo 

sandstone are of ·the same age. The relations 

between the Ojo Alamo and Animas are treated 

more fully on page 34. The writer believes 

that both of these formations are later· than 

Montana and Laramie and that botl1 are 

equivalent to some part of the Denver, Raton, 

and Lance forn1ations, the Anin1as forn1ation, 

however, r~epresenting a longer tim!3 interval 

than the Ojo Alamo sandstone. In view of 

the wide differences in opinion expressed by 

various students as to the correct as$ignn1ent 

of this whole group of related formations, the 

Ojo Alamo sandstone ·and Animas· forn1ation 

are herein classified as Tertiary (~). 

ANIMAS FORMATION (RESTRICTED). 

Type locality and distribution.-The 'vriter 

here ·applies the name Animas to the greenishgray and tan beds with much andesitic debris 

that on Ani1nas River in the Ignacio quadrangle, Colo., lie unconformD.bly· upon the purple beds assigned t·o the McDermott formation . 

and tinconforn1ably below the Torrejon formation. Andesitic beds on Anin1as River near 

Durango, Colo., were described ·without a 

specific name in 1892 by Cross, 83 quoting· field 

o.bservations by T. . W. Stanton. He de-

·scribed the deposits at greater length in 1896, 

naming thern the "Animas River beds " 84 and 

·including the. McDermott. formation and part 

of the Anirnas formation as here distinguished. 

A complete section through both the McDermott and Animas forn1ations was measured on 

Florida River by Gardner 8

" in his work on the 

Ignacio qu.adrangle, though both were included 

under the designation Animas formation. 

83 Cross, Whitman, Post-Laramie deposits of Colorado: Am, Jour. 

Sci., 3d ser., ,vol. 44, pp. 25-27, 1892. 

81 Emmons, S. F., Cross, Whitman, and Elqridgc, G. H., Geology of 

the Denver ·Basin in Colorado: U. S. Geol. Survey Mon. 27, pp. 217-

219, 1896 .. 

85 nardner, J. H., in Lee, W. T., Stratigraphy of the coal fields of 

northern central New Mexico: Geol. Soc. America Bull., vol. 23,. pp. 

81 Bau.er, c. M., Stratigraphy of a part of the Chaco Hiver valley: 1584-587, 1912; also in Lee, W. 'l' .. • and Knowlton.' F. !'f·• Geology and 

u. s. Geol. Survey Prof. Paper 98, p. 278, 1916. · paleontology of the Raton ~1esa and other regwns m Colorado and 

82 Idem, p. 275. . . New Mexico: U.S. Geol. SurveiProf: Paper 101, pp. 185-186, 192, 1917. 

Age and correlation.-The Ojo Alamo sandstone, as noted above, has yielded a .very .imperfectly known fauna and a very small flora. 

The fauna has been correlated by. Brown and 

by Gllmore with the Judith River and Belly 

River formations, of middle Montana age. 

(See. p. 24.) The writer believes that of the 

two :inost significant forms cited as members 

of the .fauna· one probably came from older 

beds and the other is probably not determinable closely e.nough to afford a sure correlation~ 

The remainder ·of the fauna is either entirely 

new or too fragmentary for precise identification. The known flora suggests Tertiary, 

ratp.er than Montana age, but is, like the 

fauna, too meager to permit even a comparison. 

In short,· the paleontologic data now available 

are entirely inconclusive as to the age of the 

beds. Bauer 82 in 1916 accepted' as actual the· 

apparent conformity of the Ojo Alamo sandstone on the older beds in the area he studied 

and assigned the Ojo Alamo to the Cretaceous 

systen1. The presence· of an overlap of Ojo 

Alamo across older beds and structural 'discordance near 'Medio Arroyo, the sharp change 

in. lithology from the McDermott formation to 

the Ojo Alamo sandstone, and local evidence 

of erosion, even where there is no. evidence of 

.discordance otherwise, show the presence of 

. an impor;tant hiatus between the pre-Ojo 
r\NIMAS FORMATION (RESTRICTED) .• · 

The Animas formn.ticm is confined, so far as 

now known, to the northern. ·ri1n of the San 

Juan Ba.sin.. The writer ha.s traced it,s outcrop .frmn the type locality southwestwaiCl into 

the Heel ~~esa, qua,drangle, a, few m.iles southwest of Durango, Colo., where the for1nation 

wedges out. lie ha,·s .tra,ced it also eastward to 

Pagosa Junction. Beds with andesitic debris 

are reported well beyond that locality and 

,~ery likely are part of the Anin~as fonnation. 

Lee 80 :found such beds at Dulce, N. Me:x., and 

they a;.re undoubtedly present at other localities. 

Litholog.ic chnracter.-'l'he lower 300 feet of 

the Animas for1nation contains coarse co.ncrlonl- o 

crates separa,ted 'by shale and sandstone. 

. All these beds are greenish gray -to tan and 

contttin n1uch weathered andesitic n1ateria.l. 

The conglmnerates conta,in 1nany pebbles of 

quartz, quartzite, a,nd chert and a, few ~of nonandesitic igneous rocks, similar to those of the 

Ojo Aln.mo conglmnerates, but consist predonlinn.ntly of andesite .. Above this ·300-foot 

zone g,reenish-gray to tan shale and sandstone 

. ttre the predominant rocks, though la,yers of 

fine conglmnerate a,re also fairly conunon. All 

this upper pm·t of"the fonnation conta,ins nn1Ch · 

andesiti~ detritus. Heddish bands occur 

locally. but are not a conunon feature. The 

Anin1n.s fornuttion contains. throughout so1ne 

vegetable debris, locally enough· to forn1 thin 

~oal beds. This feature becomes more pronounced eastwa,rd fron1 the type locality. On 

Cat Creek, n~ar Pagosa .Junction, a nuinber of 

thin lenticula,r coa,l beds. are .present and fossil 

pla,nts occur a,bundantly at· 1nany horizons. 

Sections of the Ani1nas forn1ation · a,t sev·eral 

loc~Llities are given on pages 55-56. 

Thiclcness .-On Anin1as River the forn1ation 

is about 1,100 feet thick, though cut off above, 

as indeed it is everywhere else, by an unconforJnity, owing to the r01noval of an unknown 

mnount of the original thickness. The section 

mea,sured by Gardner on Florida River, refen·ed to on page 3~, shows a thickness of 1,800 

feet for the fonnation-that is, exclusive of 

the part of his section assigned in this paper 

to the ~1cDm·n1ott forn1ation. The next conlplete section available is on the divide between 

Pine Hivei· and Piedra River in sees. 31 and 

32, 'I'. 35 N., R. 5 W., where. the Anin1as 

86 Lee, W. 1'. and Knowito;1, F. H., Geology and paleontoiogy of the 

Hnton :Mesa and other regions in Coloi·acto and New :Mexico: U.S. Geol. 

Survey Prof. Paper 101, pp. 19Q-191, 19li. 

forn1ation is. 2,670 feet thick. On Cat Creek, 

near Pagosa Junction, the Animas fonnation 

is 1,840 feet thick.· West ward fr01n the type 

locality the overlap of the Torrejon and Wasatch ("Tiffany" zone) for1nations gradually 

reduces the thickness of 'the part of the fornlation exposed until all is covered under Bridge 

Timber ~1ountain. In the Red ~1esa quadrangle, a few 1niles to the west, scarcely 100 

feet of the basal zon'e of the Anin1as forn1atio~ 

is present. These thicknesses are shown 

graphically on Plato IL · 

Relati()n ·to adjacent formations.-The Animas formation is unconfonnable upon the :McDennott fonnation. On Animas River there 

is angular discord.ance and a sharp color change . 

Elsewhere the color change is pro1ninent, but 

no discordance has been noted. 'I'he Ani1nas 

formation· furthennore overlaps successively 

the ~1cDennott forn1ation, the Kirtland shale, 

and part of the Fruitland forn1ation in the 

region between the Florida River-Pine River 

divide and Cat Creek, north of Pagosa Junction. Farther east beds with andesitic debris 

that are lithologically like the A.nin1as fornl.ation ·are reported 87 to rest on still older rocks. 

It is highly probable that the base of the 

Animas is everywhere unqonfonnable. 'l''he 

top of the Anin1as fonnation as now pres01;ved 

js an extremely variable surface. N ea.r Anin1a~ 

River the overlapping. Torrejon formation 

covers up a large part of the forn1ation and 

the Wasatch beds ("Tiffany" zone) cover the 

rest. There is no· sign of interfingm·jng. or 

lateral gradation of Torrejon beds into AniJnas 

beds. East of Anilnas River the widespread 

Quaternary deposits in Florida Mesa and Oxford Mesa hide the older rocks over large areas 

but such exposures as are a\7 ailable. show that 

the b~sal Wasatch beds ("Tiffany. beds" of 

Granger) directly overlie: the Ani1nas forination, with a hiatus between representing at 

least the Torrejon formation. The contact is 

marked by a lithologic change without any 

1narked local evidence of erosion. The greoriish-gray shales and sandstones of the Aninias 

for.ma,tion a1~e succeeded by a series of variegated shales . and coarse · ~u·koses with pink 

f.eldspars that has a distinctly different aspect. 

87Lee, W. '1:., and Knowlton, :F. H., Geology and paleontology of the 

Raton Mesa and other regiom in Colora:lo and New l'viexieo: U. S .. 

Geol. Survey Prof. Paper 101, pr). 190-l!H, 19Ii, 
34 :UPPER CRETACEO~S AND TEi{TIARY FORMATIONS IN SAN juAN BASIN. 

Fossils.:__The Ani1nas formation has yielded tains the latest known dinosaur rep1ains, each 

fragn1entary and· indetenninable dinosaur succeeds the l\1cDermott formation unconbones at several localities·. A con1plete but formably, each overlaps the preceding formaindetenninable dinosaurian lin1b bone was re- tions eastward along the outcrop, and each 

ported 88 fr01n. the .ba.sal part of the formation contains beds of siliceous pebbles of simjlar 

near the divide between Pine and Piedra but peculiar constitution. (See p. 29.) The 

rivers. andesitic material of the Animas formation 

Fossil plants have long been· known-in appears to have been derived from the north, 

fact, since the. first recognition of the fonna~· the site of the present mountains. The silition. Practically all the ·known collections ceous materials of both Animas and Ojo 

frmn the Animas formation have been in .the Alamo formations are unlike the rocks occurring 

hands of F. H. Knowlton. The results of his in the present mountains and the debris 

study are contained in a paper describing the brought down by the :r:ecent ~treams and must 

flora and discussing its relations to other have been derived from some otlier source, 

floras, which fonns ·a part of this volume (pp. possibly east or south of the San Juan Basin. 

77-115). Thus there probably were sediments coming · 

Age and correlation.-The j\..nimas formation in from two directions. In the south little . 

must be correlated chiefly on the basis of its andesitic debris reached the site of the present 

plant fossils, though the relations to adjacent Ojo .Alamo sandstone, a:rid the deposits consist 

forn1ations and its lithologic constitution offer chiefly of sand, clay, and the siliceous pebbles. 

some aid. Knowlton says of the flora: In the north much the greater part of the 

On combining the Animas species found in the material is andesitic debris, but some of the 

Denver, Raton, and Wilcox it appears that 33 species, s~liceous material also reached the area during 

or over 90 per cent of those having an outside distribu- the early part of Animas time and is mixed 

tion, are held in common and the conclusion is reached 

that the Animas formation· is of the same age namely, with the andesitic matter in the lower beds 

. Eocene Tertiary. of the Animas formation. - The presence of 

The similarity in lithology of the Animas such bed's of pebbles has been used in other 

and Denver formations led, as long ago as the . regions as an argurriep.t for a lapse of much time 

time of first .recognition of the formation, to a in phe interval .preceding their deposition. 

tentative cm;-relation between them, though This argument is· weak when applied to the 

the later establishment of the occurrence in San Juan Basin, because of the presence of 

the Rocky Mountain regi<;>n of beds of andesitiG identical beds in the McDermott formation, 

debris in rocks of Montana age weakens the which also carries Cretaceous· dinosaurs and 

force of such correlations ·unless they are sup- plants. Possibly the Puerco formation also is 

ported by other evidence: . The Animas .forma- equivalent in age to some of the upper beds 

tion is· unquestionably unconformable on the of the Animas. formation. The small flora ·of 

McDermott formation and on the older .beds the Puerco (see p. 75) seems to support this 

and is separated from them, in the writer's view, but the very narrow distribution of the 

belief, by a notable hiatus. It is overlain Puerco formation and the entire absence from 

unconformably by the Torrejon formation the Animas formation of mammals, so far as 

and therefore must precede it in time. The present knowledge goes, renders such a correlarelations between the Animas formation and tion uncertain, though the writer has considered 

the Ojo Alamo sandstone and the Puerco it (see p. 43) the best interpretation of the 

formation are not so clear. The Animas and data now in hand. 

the Ojo Alamo are nowhere in contact, their It is the writer's belief, in short, that 

nearest outcrops being about 12 miles apart. present evidence shows the Anirnas fonnation 

The dinosaur fauna of the Animas and the to be equivalent in time to some par"t of the 

flora of the Ojo Alamo are virtually unknown,·. Denver, Raton, and Lance formations outside 

and no paleontologic comparison can be made. of the San Juan Basin and to the Ojo Alamo 

Yet it is significant that each in its area con- s~ndstone and probably the Puerco formation 

- within it. · ss Gardner, J. H., unpublished data. 

Q 
• 

NACIMIENTO GROUP. 35 

In ~iew of the difference of opillion expressed 

bv .various writers us to the correct assign1nent 

of this whole group of related formations, the 

Ani1nas forrnation is herein classified as Tertiary(~). 

NACIMIENTO GROUP. 

The his tory of the ruunes. Puerco and Torrejon has been traced. in detail by Gardner 80 and 

Bauer.00 The naJne Puerco was applied by 

Cope 01 in 1875 to the entire sei·ies of beds on 

Puerco River, now supposed to include both 

the Puerco and 'I'orrejon forrnations. I:Ie did 

· not at th~tt tirne have fossils frorn these beds· 

(nor have rmy been . collected since). Later 

nurnerous fossils were found in the region west 

of Puerco River which were believed by Cope 

to have con1e frorn the equivalent of his Puerco 

beds and were described by hun as the Puerco 

fauna. These fossils were later separated· by 

vVortrnan °2 into two quite distin.ct faunas. 

For the beds yielding the younger fauna he 

proposed the nn.n').e Torrejon.frorn the exposures 

on Arroyo Torrejon, Sandoval County, N.Mex., 

retairiing Cope's naJne Puerco for the beds 

yielding the older fauna. In these ·senses the 

· nmnes have been gerierally accepted since that 

tin1e. 

The Torrejon fauna is interpreted by Inost 

students of ·v-ertebrate paleontology to be a 

direct descendant of the Puerco fauna but is 

sufficiently different to demand the lapse of a 

long mterval of tune. As, in addition, the two 

faunal zones appear to be relatively close 

to()'ether strati()'raphically at some localities and b b . 

widely separated at others and as the area 

yielding the Torrejon fauna is rnuch greater in 

extent than that yielding the Puerco fauna, it 

would seem necessary to assurne the presence 

of a hiatus. I-Iowev-er, owing to the great 

siJnilarity in ~ithology and the restriction of the 

fossils to relatively narrow zones with a barren 

in ter\Tal between, no break has been recognized 

in the field in the ~eries of beds, even at the 

localities where both fonnations are ]mown. to 

be present. 

so Gardner, J. H., 'l'he Puerco and 'l'orrejon formations of the Naci. 

miento group: Jour. Geology, vol. 18, pp. 702-713, 1910. 

oo Bauer, C. M., Stratigraphy of a part. of the Chaco River valley: 

U. S. Oeol. Smvey Prof. Paper 98, 276-27i, 1916. 

ot. Cope, E'. D., Report on the geology of that part of northwestern 

Now M·oxico examined during tho field season of 1784: Chief Eng. Ann. 

Ropt. for 1875, pt. 2, appon(lix G1, pp. 1008-1017, 1875c 

n Wortman, J. L., and Matthew, \V. D., A revision of. the Puet·co 

nuna: Am. l\1"tts. Nat. Ilist. Httll. vol. 9, p. 260, 1897. 

Gardner 93 proposed to use the narne N aci- · 

miento, frorn the town of that narne (better 

known as Cuba), as a group tenn to include 

the Puerco and Torrejon forn1ations. It is a 

conv-enience wher·e the two formations are not 

distinguished on 1naps and in discussions, and 

for that reason it is now retained, but as the 

two forn1ations are almost entirely distinct in· 

fauna and, as stated above, possibly separated 

by a hiatus, Sinclair and Grang.er 91 did not use 

the grolip tenn. 

Inas1nuch as the forn1ations are not separated 

on the maps and other illustrations accompanying this paper, and as such a separation would 

be worth little if made, it may seem unnecessary 

to discuss the;m separately. However, for 

future convenience it has seen1ed worth while 

in the following description to assen1ble as far 

as possible the data for each formation by 

itself. 

PUERCO FORMATION. 

Distribution.-The Puerco :forn~ation ·as defined by its fauna is now known only in a small . 

area extending fron1 Escav-ada \?V ash to the. 

head of the west fork of Gallego Arroyo, in 

southeastern· .San Juan County, N. Mex. 

The distance along the outcrop is about 35 

1niles. No fossils are known frorn· the section 

on Puerco River near Cuba, whence the forrnation nmne was derived, and only Torrejon 

fossils frorn the beds on Arroyo Torrejon. 

In fact, as the Puerco forrnation is characterized only by its fossils, it is v-ery doubtful 

whether or not the formation is really present 

at either of these localities. It is purely an 

assumption to apply either Puerco or Torrejon 

to the barren interval between the fossiliferous 

zones of the Puerco and Torrej on or to the 

lateral ·extension of the beds in this interval 

into localities where Puerco "fossils . are not 

known. The barren . interval is rather thin 

on both Arroyo Torrejon and Puerco River, 

as shown by Sinclair and Granger, 95. Inodifying Gardner's sections, and 1nay be later 

than the fossiliferous · Puerco. . North of th~ 

head of West Gallego· Arroyo beds that seen1 

in lithology and stratigraphic position to be 

93 Gardner, J. H., 'l'he Puerco and 'l'orrejon formations of the Nacimiento group: Jour. Geology, vol. 18, p. 714, 1910. 

of Sinclair, W. J., and Granger, Walter, Paleocene deposits of the San 

Juan Basin: Am. Mus. Nat. llist. Bull .. , vol. 33, p. 313, 1914. 

oo Iclem, fig. 2. 
36 _UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN .. 

·the continuation of the fossiliferous Puerco L1~thology arid thickness.-On Escavada Wash 

beds are present in the divide between Chaco and its branches the lowet 250 feet of the. 

River and Gallego Arroyo as far as Pina Veta series -of beds which include the Puerco and 

China, though no fossils have yet been found Torrejon formations consists of a rathei· dark 

to sho"\'v that these beds are really the Pue1·co mass of lenticular light and dark gray shale 

fonnation. On San Juan and Animas rivers with· bands of purplish, ·bluish, black,_ and 

the beds just above the Ojo Alarno sau_dstone rarely red shale, intenningled with soft gray..: 

are not at· all like the typical Puerc9 and have white sandstone. Concretions and layers .of 

not yielded any. mammalian fossils. There is blue-black manganitic sandstone and veins · 

a ·Jong interval without outcrops between and . concretions of barite occur con1monly. 

Escavada Wash and Arroyo Torrejon and a The upper half of the lowerniost 50 feet of 

sin1ilar lack of exposures between th(3 head of these beds contains Puerco fossils, and tllis is 

·'Vest Gallego Arroyo and Pina Veta China· .the most southerly occurrence of the fauna. 

and. between Pina Veta China and San Juan There is no consistent lithologic difference to 

River. The lateni1 relation of the beds im- . separate the fossil zone fron1 the adjacent beds. 

n1ediately above the Ojo Ala1no sandstone The ~ext higher 500 feet· consists of creambeyond these covered intervals to the known colored to yellow and browri, fairly well inPuerco beds is therefore a matter of inferenc·e. durated sandstone with reddish-brown conIt is possible that the Torrejon formation cretjons, the sandstone in layers 30 to 40 feet 

overlaps and conceals the Puerco formation thick separated by greenish-gray· and lead7" 

over. 1nost of the San Juan Basin. This idea gray shale and son1e soft white sancl~tone. 

is suggested by the scanty distribution of the These beds have yielded no fossils but were 

knowri Puerco beds and the demonstrated placed arbitrarily in the Pue1·co forn1ation by 

overlap ~orti1ward of upper Torrejon over Sinclair and Granger. 96 The next higher 459 

the lower Torrejon beds on Animas River, for feet includes much very dark slate-colored 

if the ove~lap was progressive and began shale. witl:i t-wo prominent and several fainter. 

earlier in the south, the lower Torrejon beds reel bands. The lowest Torrejon fossils yet 

south of San Juan River may have covered collected came from a horizon 75 feet above 

up the Pu.erco beds and were then them- the base of this .unit. There are therefore 

selves covered. (See p. 39.) It n1ust be ad- only 50 feet of proved· Puerco beds in this 

1nitted that the presence of a barren zone as section, though above these beds are some 

thick as the known Puerco fossiliferous zone 77 5 feet of barren beds before the lowest 

at the. base of some of the sections offers a horizon of Torrejon fossils is reached. The 

possibility that in the future the Puerco fauna barren beds may equally well be Puerco or 

will be found of greater e_xtent tl.lan is now Torrejon. 

known, though the differences in lithology Near Ojo Alamo the lower 150 feet of beds 

and the fact that no fossils were found, even comprising the Puerco and Torrejon forn1ations 

after careful search. for thenl, make such an is a rather dark mass of shale and soft sandoutconle seem unlikely now. The writer has stone (see section 011 p. 67) 111uch like the 

preferred as a working hypothesis to consider lowest beds on Escavada Wash. The lowerthe present a~ailable evidence as indicating most 90 feet of this mass contains Puerco 

an overlap of the Torrejon formation and a 

restriction of the Puerco formation practically fossils. The next higher 240 feet consists of 

to the area in which Puerco fossils. are now lighter-gray shale with bands of brown, olive, 

known. Whether the Puerco formation, as and some dark shale, soft gray-,vhite sandstone, 

limited by· this hypothesis, was once much and a few l~yers of yellow and brown resistant 

inore widespread .than the existing exposures sandstone .. Torrejon fossils occur about 50 

. there is little to indicate. If there really is a feet above the base of this. unit. The proved 

post-Puerco hiatus, the possibility of con- Puerco beds in this section are therefore only 

siderable erosion during the time represented 90- feet thick and are succeeded by a barren 

by the break renders it likely that Puerco interval of about 110 feet. . 

beds once covered a much larger area than at 

present. 96 Sinclair, W. J., and Granger, Walter, Paleocene deposits of the San 

Juan Basin: Am. Mus. Nat. Hist. Bull., vol. 33, pp. 297-316, 1914. 
NACIMIENTO GROUP. 37 

At· the head of the west fork of Ga1lego eYen shaly strata of the Puerco. E.Yen whei·e 

Ari·oyo only .a partial section is exposed. Dark the beds of cloubtf:ul age that succeed the Ojo 

yariegatecl shale,· containing ~he northern- Alamo sandstone contain conglmneratic beds 

1nost occurrence of the Puerco fauna, rests on they differ fron1 the Ojo Alamo sandstone in 

Ojo AlanlC) sandstone but is cut off aboYe by lacking ·the abundant red elmnents present in 

recent erosion.· · the conglomerates of the older forn1ation and 

On Arroyo Torrejon the beds beneath the also the yariecl igneous constituents. 

lowest Torrejon fossils and aboYe the Ojo The contact of the Puerco formation with 

Almno sandstone are yellowish and clark-gray the Torrejon formation is obscure. Each of 

sanely shale, Yariegatecl reel, purple, drab, and these formations shows considerable variation 

white shale, ancl1nassiYe coarse tan sanclstone. 07 in gross lithology when traced along the strike 

They are 110 feet thick and haYe yielcl9d no and is likewise highly Yariable in details. 

fossils. On Puerco River the beds. beneath Nearly all the indiYidual 'beds are lenticular 

·the horizou equiYalent· to that of the lowest and can be traced for .oniy short distances, 

Torrejon fossils on Arroyo Torrejon, as deter- eYen in continuous exposures. Beds. Yery 

1nined by Sinclair and Granger, are ·179 feet similar in lithology occur in both formations, 

thick. Th.ey are cmnposed of massiYe coarse- and isolated outcrops that afford only lithologic 

grained brown sandstone, gray shale, and criteria can not b.e assigned with confidence. 

soft gray and tan sandstone 08 and haYe yielded It is therefore impracticable, if not impossible, 

no fossils. These barren beds may be Puerco to designate on lithologic grounds any giYen 

in age 'but ·in this paper are ·considered as horizon as the diviclin·g plane between the 

belonging to the Torrejon formation. · Puerco and Torrejon formations. The fossils, 

Near Pina Veta China a considerable ex- as stated aboYe, giYe some reason to believe 

posure of Yariegatecl shale and soft sandstone that there is a time interYal1mrepresented by 

very nn1eh like the fossiliferous beds at the sediments between the formations. The inhead of Yv est Gallego Arroyo and resting terYal between the fossil zones is Yery much 

clirectly on the Ojo Almno sandstone n1ay be thicker on ·EscaYada Wash than it is near Ojo 

of Puerco age, but the beds haYe yielded no Alamo and if it ·could be shown to constitute 

fossils to confirn1 such an assignment.· part of the Puerco formation would· lend· 

Near San Juan and Anin1as rivers the beds strong support to the supposition of a postbeneath the lowest leYel of Torrejon fossils are Puerco erosion interval. As its· age is, for the 

soft white to buff or brown pebble-l?earing present at least, indeterminate, the eYidence 

sandstones, separated by gray, oliYe, and for such an interval must come largely from 

brown shales. The pebbles of the sandstone the faunal relations. Along Animas RiYer in· 

beds are chiefly gray chert and quartz. Thes~ Colorado beds that rest unconformably upon the Animas formation have been traced by beds are about 150 feet thick and have yielded only a· few scraps of turtles and a few poorly continuous exposures southward to. the fossiliferous Torrejon beds near Cedar Hill, N. pr~serYecl plants. The lithology of these beds Mex. They are clearly the upper beds of the 

is quite different fron1 that of the proYed Torrejon and haYe therefore overlapped the 

Puerco beds and that of the exposure near remainder of the Torrej on formation, which 

Pina Veta China. They n1ay be of Puerco is .P:r:esent on Animas River below Cedar Hill. 

age but in this paper are included in. the It may be. legiti~ately inferred that still 

Torrejon-formation. farther south the lower Torrejon overlapped 

Relation to adjacent formations.-The lower the Pu·erco beds and that -the lack of Puerco 

contact of the Pue1~co fm:mation, with the fossils· in the region ·between Aztec, N. Mex., 

Ojo Almno sandstone, is one of lithologic and Pina Veta China or perhaps eYen the head 

contrast and erosional unconformity without of the west fork o~ Gallego Arroyo is really 

discordance of clip. The conglomeratic sand- due to the absence of Puerco beds. There are 

stone of the older fonnation has an irregular at present no direct obserYations to support 

upper surface upon which were laid the more such a deduction except perhaps the difference in lithology between the beds that fol- 97 Gardner, J. H., Thq Pucrco and Torrejon formations of.the Naci-llow the OJ"o Alamo on San Juan and. Anima 

mionto group: Jour. Geology, vol. 18, p. 724, 1910. S 

os Idem, p. ·717. -rivers and the Puerco beds farther south. 

82587-24t-4 
UPPER CRETACEOUS AND TE~TIARY FOR.MATIONS IN SAN JUAN BASIN. 

Fossils.-The Pum·co formation contains a 

large vertebrate fauna. The latest full list of 

the mammals is that given by Matthew 99 in 

1914, though a number of changes have been 

proposed since that date, chiefly in the publi-

. cations of the American Museum of Natural 

I-Iistm:y. The latest full list of the reptiles is 

that by .Gilmore/ published in 1919. These. 

lists in condensed form but without any· essential change are given below. The abundance 

of mammals and the complete absence of 

.dinosaurs are the distinguishing features. 

Puerco mammals: 

"N eoplagiaulax" american us Cope. 

Polymastodon taoensis Cope. 

attenuatus Cppe. 

Catopsalis foliatus Cope. 

Claenodon? protogonioides? Cope .. 

Triisodon quivirensis Cope. 

heilprinianus Cope. 

gaudrianus Cope. 

Oxyclaenus cuspidatus Cope. 

simplex Cope. . 

Loxolophus hyattiant1s Cope. 

priscus Cope. 

attenuatus Osborn and Earle. 

Carcinodon filholianus Cope. 

Paradoxodon rutimeyeranus Cope. 

Protogonodon pentacus Cope. 

W ortmania otariidens Cope. 

Onychodectes tisonensis Cope: 

rarus Osborn and Earle_. 

Mioclaenus turgidunculus Cope. 

Oxyacodon agapetillus Cope. 

Periptychus coarctatus Cope. 

Ectoconus ditrigonus Cope. 

· Conacodon entoconus Cope. 

cophater Cope. 

Hemithlaeus kowalevskianus Cope. 

Anisonchus gillianus Cope. 

Puerco reptiles and fish: 

Chelonia: 

Compsemys parva Hay. 

vafer Hay. 

puercensis Gilmore. 

Baena sp. 

Adocus hesperius Gilmore. 

Hoplochelys crassa (Cope). 

bicarinata Hay. 

laqueta Gilmore. 

Plastomen us sp. 

gg Matthew, \V, D., Evidence ·of the Paleocene vertebrate fauna on 

the Cretaceous-'l'ertiary problem: Geol. Soc. America Bull., vol. 25, 

pp. 383-385, 1914. 

t Gilmore, C. w.,. Reptilian faunas of the Torrejon, Puerco, and und~rlying Upper Cretaceous formations of San Juan County, N. Mex.: 

U.S. Geol. Survey Prof. Paper 119, pp. 9, 10, 1919. 

Puerco reptiles and fish-Continued. 

Chelonia-Continued. 

Aspideretes sagatus Hay. 

· puercensis Hay. 

reesidei Gilmore. 

vegetus Gilmore . 

quadratus Gilmore. 

perplexus Gilmore·. 

Co1iochelys admirabilis Hay. 

Rhynchocephalia: 

Champsosaurus australis Cope. 

saponensis Cope. 

Loricata: 

Crocodylus stavelfanus Cope. 

Pisces: 

Lepisosteus sp. 

In a late paper :Matthew 2 says of the Pum·co 

fauna: 

It contains a large mammal fauna which is wholly 

unknown elsewhere. Multituberculates fonn a considerable element, but the major part is archaic placentals. There are no dinosaurs, but the crocodiles, 

rhynchocephalians, and turtles are of tlie same groups 

as those of the Judith and Lance and not perceptibly 

more advanced. 

Plants are represented in the Puerco forination by fossil wood and by rather rare leaf inlptessions. One collection of leaves was made 

by ·Sinclair and Granger on Barrel Sp~·ing 

Arroyo and studied by F. I-I. ICnowlton, who 

made the following report: 3 

. With a fair degree of probability I am able to identify the following species: 

Ficus occidentalis Lesquereux. 

Artocarpus sp. ined. 

Paliurus zizyphoides Lesquereux. 

Viburnum lakesii? Lesquereux. 

Platanus sp. cf. P. haydenii Newberry.· 

Populus sp.- cf. P. cuneata Newberry. 

Viburnum sp.? 

Fragments. 

The Ficu,s, Paliunts, and Vib1trwum lakesii are 

species of the Denver and Raton formations. The 

Artocarpus is the same, apparently, as an undescribed 

species from the Raton formation, while the others, if 

correctly identified, should indicate Fort Union. 

While I am not positive about it, so far. as I can 

determine from the imperfect material available, the 

age ·indicated is that of the Denver or perhaps as late 

as Fort Union. 

2 Matthew, W. D., Fossil vertebrates and the Oretaceous-'l'ertiary 

problem: Am. Jour. Sci., 5th ser., vol. 2, p. 218, 1921. 

a Sinclair, W. J., and Granger, \Valter, Paleocene deposits of the San 

Juan Basin.: Am. Mus. Nat. Hist. Bull., vol. 33, p. 306, 1914. 
NACIMIENTO GROUP. 39 

A second collection was made by the writer 

from beds at the smne horizon as that just 

described and at Yery nearly the same locality. 

This locality is 1 n1ile northeast of Ojo Alan1o, 

N. ~1ex., and is almost at the top o:f the 

Puerco beds as here limited (U. S. G. S. -plant 

locality 7495). ~1r. ICnowlton has examined 

this collection also (see p. 75) and concludes 

thn,t "on the basis of ·the plants the Puerco 

formation :is of Tertiary age ariel in the approxiInn,te position of the DenYer, Raton, and 'i\Tilcox beds.'' 

.Age (tnd correlation.-The age and correlation of the Puerco and Torrejon fonnation·s are 

set fo:~·th on page 43. 

TORREJON FORMATION. 

Dist'rib1.dion.-The 'rorrejon formation, as 

defined by its fauna, is known to extend fr01n 

Arroyo Torrejon in SandoYal County, N. ~1ex., 

across the southern and western parts of the 

San Juan Basin ahnost to the Colorado-New 

Mexico boundn.ry. The beds that contain the 

the fossils near Cedar I:-Iill, in northern San 

Juan Count:y, N. ~1ex., ·have been traced by 

continuous exposures along the Animas- Valley 

about 12 1niles into Colontclo, where they rest 

cli_l'ectly upon the Aniinfts formation. They represent, howeYer, only the upper 300 to 400 

feet of the Torrejon fonnation n.s fully exposed 

:in New Mexico, these upper beds hn,Ying oYerlapped the lower beds, which n.long Animn,s 

H.iver below Cedar I:fill nre about 1,000 feet 

thick. The Torrejon formation has been 

tritced also fr01n. New ~1exico into the Yalley 

of ~1cDern1ott Anoyo, in the southern pa1;t of 

tho Red ~~[esa quadrangle, 8 or 10 1niles west of 

Anin1as River. ~1amn1alian fossils haYe not 

yet been found in the Torrejon formation in 

Colorado and its identification is dependent 

chiefly on the unquestioned tracing of continous outcrops. En.stwm;d fron1 Arroyo Torrejon the Torrejon formation has been followed 

by Gardner and by Sinclair and Granger to and 

beyond Puerco RiYer. 

Lithology and thickness.-At the type locality 

of the Torrejon formation the constituent heels 

are described by Gardner 4 as drab, gray, reeldish, black, and yellow shale and soft gray and 

tan sanclstolle. Gardner's section, n1oclified by --~----'------ -------

Sinclair and Granger, 5 shows the thickness of 

the beds present between -the Wasatch formation and the base of the lowest beds contain-:-

ing T()rrejon fossils to· be .240 feet. Beneath 

these beds is a barren zone 110 feet thick, 

which in turn rests on the Ojo Alan1o sancl-

.stone. The horizon of the lo·west fossil zone 

has been traced by nearly continuous exposures to Puerco River. 6 The beds above it 

there are described by Gardner 7 as including 

-variegated shale; gray, yellmvish, and dark 

shale; soft gray sandstone; and massiYe 

coarse brown sandstone. They are said by 

Sinclair and Granger, modifying Gardner's 

section, to be 660 feet thiok, with :1 barren 

zone 179. feet thick beneath then1. The 

barren basal zone is in this paper considered 

of Torrejon age. 

"'On Esca-vada 'iV ash and its branches, aboYe 

the thick barren zone that succeeds the zone 

of Puerco fossils, a- series of beds containing 

much Yery dark slate-colored shale with two 

prominent and several fainter reel b<l.llds, 

lenses of soft gray-white sandstone, and some 

lenses of indurated brown sandstone, attains 

a thickness of 450 feet. Black, probably nlang'anitic sandstone concretions and barite in 

-veins and concretions, occur throughout but 

are Inore common in the lovl'er part. A peculiar dense quartzitic sandstone with many 

in1pressions of plant sten1s occurs at n1any 

horizons. The lowest Torrejon fossils were 

founcl 7 5 feet aboYe the base of this unit, and 

the highest near its top. 

Above the dark shale on Esc a vada 'iV ash is a 

·group of beds that seem to lie upon the sllale 

with sharp erosional contact. These beds, 

250 feet thick, consist of dove-colored shale, 

lighter-gray sanely shale, ·and soft white sandstone. A few reddish bands occur near the 

top, and son1e nearly black bands· are present. 

Lenses of resistant light-gray sandstone 'with 

scattered pebbles of clark chert and quartz 

were seen here and there. The series as a 

whole shows marked banding and is -very distinct in its generaf light· color from the underlying beds. The sharp basal contact has been 

traced beyond Alamo AITO}TO on the south 

5 Sinclair, W. J ., nnd Granger, Walter, Paleocene deposits of the San 

Juan Basin: Am. :Mus .. Nat. Ilist. Bull., Yo!. 33, fig. 2, 1914. 

o Idem, fig. 2. 4 Gardner, J. H., The Puerco and 'l'orrejon formations of the Naeimi- 7 Gardner, J. H., 'l'hc Puet·co and Torrcjon formations of the Nacimiento group: Jour. Geology, vol. 18, p. 724, 1910. , ento group: Jour. Geology, vol. 18, p. 717. 1910. 
40 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

and beyond Ojq Alamo on the north, a dis- gray quartzitic sandstone. These beds a.re 

tance. of some 30 miles in an air line. How- 600 to 700 feet thick. In their upper part are 

, ever, as the beds are very similar· to beds some indurated brown sandstones and a few 

f3;.rther north known·. to contain · Torrejon reddish bands. ·These beds are succeeded by 

fossils and· as they seem to be no higher in an equal thickness of beds in ''.rhich indurated 

the section than the exposures that contain brown lenticular sandstones are abundant and 

Torrejon fossils ·near ·Angel Peak, they have are separated by gray shale, red and purple· 

been in this paper included in the Torrejon shale, :and soft gray-white sandstone. The 

formation. Future paleontologic or other evi- red shale is gr.eater in proportionate· amounts 

dence may warrai1t a different assignment. in the _higher part. Near San Juan River the 

It is possible that they represent the "Tiffany only fossils found i.n · this whole series 10 are 

beds" of Granger, a faunal zone in the basal Torre jon fossils from horizons high up in the 

part of the Wasatch fm"mation in Colorado series. Along Animas River, however, Tor-

(see p. 44), or that they ~re part of the rejon fossils fron1 the exposures below and 

typical Wasatch formation of' the region, above A_ztec, N. Mex.,. show that the beds 

though. their absence beneath the massive above the lower 150 feet, approximat~ly, of 

sandstones of the Wasatch farther east renders .the series are of Torrejon age. The lower 

. the latter possibility very unlikely. In the beds have not yielded mammalian fossils but 

absence of ·fossils their· assignment to tl!e in this paper are also included in the Torre jon 

Torrejon is as reasonable as any other that· formation. 

can be made. · Iu the Pruett Pastures, east of. La, Plata, 

Near Ojo Alamo the barren interval above N. Mex., the lower half of the series of beds . 

the Puerco fossiliferous zone is followed by 240 assigned to the Torrejon formation lacks the 

feet of beds that consist of gray shale with olive shale shown on Animas River and has· 

bands of brown, olive, and some very dark less soft yellow heavy-bedded sandstone. The 

shale; soft gray-white sandstone; and .a few general effect to the eye. is that of a n1ore 

layers of brown resistant sandstone containing 1narked banding of light and dark gray shaly· 

rather nire pebbles of . chert and quartz. beds. The upper half consists of brown 

(See section on p. 67 .) . Torre jon fossils are sandstqne and gray and red shale like that on · 

found in a thin zone 50 feet above the base of Animas River. No fossils have been collected 

this unit: These beds contain also some dark, except ind.etenginate scraps of turtles, but by 

probably manganitic sandstone in layers and tracing around fron1 Animas Valley it has been 

concretions, gray dense quartzitic sandstone shown that the section contains the smne beds 

with impressions. of plant stems, and barite as are present in Animas Valley . 

. in veins and concretions. Above these beds The beds ·exposed on Animas River near 

lie the light-colored ·beds which ha~e been Cedar I-Iill, N. 11ex., which· are fossiliferous, 

traced from Escavada Wash (see · p. 39) 1 i·epresent approxi1i1ately the uppennost 300 

attaining here a thickness of 186 feet, though feet of. the Torrejon formation and consist of 

cut off above by recent erosion. At this brown lenticular sandstone and variegated 

locality· these uppermost ·beds were 1e"ft un- shale. The beds above them, identified in 

assigned by· Sinclair and Granger 8 but were this paper as the "Tiffany beds'' of Granger, 

assig:ned to the Wasatch formation by Bauer.O are very si1nilar, but the sandstones are perOn San Juan and Animas rivers the Ojo sis tent, . especially the basal sandstone. The 

Alamo sandstone is immediately ovedain by uppennost Torrejon beds and the "Tiffany" 

a succession 9f rather soft white to buff, in zone have been traced continuously northward 

places rusty-brown ·conglomeratic sandstones along Anin1a.s River to a point beyond the · 

separated by light-gray, dark-gray, olive, mid mouth ·of Florida River.· Here, however, a 

brown shales, with which are associated some change takes place, the indurated sandthin beds of fine-grained green sandstone and stone being replaced by soft sandstone and 

s Sinclair, W. J., and Granger, Walter, Paleocene deposi~s ·of the 

San Juan Basin: Am. Mus. Nat. llist. Bull., vol. 33, p. 312, 1914. 10 Granger, Walter, Notes ori. Paleocene and lower Eocene mammal 

9 Bauer, C. M., Stratigraphy of a part of the Chaco River valley .horizons of northern New Mexico and southern Colorado: Am. Mus. 

U.S. Gcol. Survey Prof. Paper 98, p. 65, 1916. : Nat. llist. Bull., Yo!. 37, pp. 823-826, 1917. 
·. 

NACIMIENTO GROUP. 41 

shale. . It is very difficult to ·locate exactly 

in this n1ass o:f soft, variable rocks the accepted 

dividing plane between the Torrejon and the 

"Tiffn,ny" zone, though its appro~in1ate position 1nay be traced. The exposures are good 

enough to show the pinching out of the individual inclurn.ted sandstone beds, so that no 

doubt exists as to the change in lithology. 

Relation to adjacent fonn,ations.-The contact of the Torrejon fonnation with the Puerco,. 

as shown on page 37, is indefinite but is probably unconfonnable. Where ·the Puerco is 

prestnnn.bly absent the lower contact of the 

·To:n'ejon .:fonnation is one of lithologic change 

and. erosional unconfonnity without n1arked 

cliscordance of clip. The upper contact, with 

vVn,satch sandstone; is in the southern part of 

·Sn,n J·un.n Basin also one ·of lithologic. change 

and, locftlly, of distinct erosion but without 

notable discordance of dip. The soft beds 

assigned to the 1'orrejon are directly followed 

by the basal cliff-form.ing sandstone of the 

Wasatch. 1'o the southeast, however, near 

Cuba, N. Mex., the W:asatch fonnation overlaps the Torrejon and Puerco fonnations and. 

rests upon t11em and older rocks with nlarked 

disc01·dance.U The contact betwe(:'ln the Torrejon fonnation and the overlying beds has 

been followed by the writer in very rapid 

reconnaissance between the head of Ki1nbetoh 

Arroyo, near the southeast corner of T .. · 24 N., 

R. 8 W., and the divide between San Juan and 

Ani1nas rivers. It is 1nuch less distinct toward 

the north owing to the appearance in the 

upper .Torrejon of i~du~·ated brown sandstones 

resmnbling tlH~ overlying fonnation, and in 

fact near the State boundary a separation is 

very difficult. So far as is now known, only 

the true Wasatch fauna (with Eohippus, 

Phencteodus, Ooryphodon, Pachyaena, etc.)· is 

·present in the southern part of the San Juan 

· Basin. In Colorado the ·earlier "Tiffany" 

fauna (see p. 46) is present east of Pine River, 

and the lithologic zone containing it has been 

traced we!?tward into· the beds just above the 

Torrejon fonnation on Anin1as Riv.er. The 

presence of these beds with the cr Tiffany" 

fauna, intennediate betw(:'len that of· the 

Torrejon formation and the Wasatch, their 

lithologic sin1ilarity to the Torrejon formation, and the apparent continuity of the s.trata, 

11 Gardner, J. H., 'l'ho Puerco and Torrejon formations of the Nacimiento group: Jour. Geology, vol. 18, pp .. 717, 721; 1910. 

strongly suggest that sedin1entation in the 

northern part of the bl:!-_sin was continuous 

from Torrejon ti1ne into Wasatch tin1e and 

that· there is no such break in the series as is 

apparently present in the southern pn.rt of 

the basin. · 

Fossils.__:_The Torrejon fonnation contains 

a large vertebrate fauna. The 1nannnals were -

listed in 1914 by Matthew 12 and the reptiles 

in 1919 by Gihnore. 13 These lists are given 

below witliout. change, though a number of 

changes have been proposed since 1914 in the 

list of n1ammals. 

Torrejon mammals: 

"N eoplagiaulax '' molest us Cope. 

Ptilodus mediavus Cope. 

. trovessartianus Cope. 

Polyn:~astodon fissidens Cope? 

Didymictis haydenianus Cope. 

Claenodon corrugatus Cope. 

ferox Cope.· 

protogonioides Cope .. 

Sarcothraustes antiquus Cope. 

Goniacodon levisanus Cope. 

Microclaenodon assurgens Cope. 

Dissacus saurognathus Wortman. 

· navajovius Cope. 

· Chriacus pelvidens Cope. 

truncatus Cope. 

baldwini Cope .. 

schlosserianus Cope·. 

Tricentes subtrigonus Cope. 

crassicollidens Cope. 

Deltatherium ftindaminis Cope. 

Palaeoryctes puercensis Matthew. 

Pentacodon inversus Cope. 

Mixodectes pungens Cope. 

crassiusculus Cope. 

lndrodon malaris Cope. 

Psittacotherium multifragum Cope. 

Conoryctes comma Cope. 

Tetraclam1odon puercensis Cope. 

minor Matthew. 

Mioclaenus turgidus Cope. 

lydekkerianus Cope. -

lemuroides Matthew. 

acolytus Cope. 

inaequ.idens Cope. 

Protoselene opisthacus Cope. 

Periptychus carinidens Cope. 

rha.bdodon Cope. 

Anisonchus sectorius Cope. 

Haploconus lineatus Cope. 

corniculatus ·cope. 

Pantolambda bathmoclon Cope. 

cavirictus Cope. 

12 Matthew, W. D., Evidence of the Paleocene v.ertebrate fauna on 

the Cretaceous-'l'ertiary problem: Geol. Soc. America Bull., vol. 25, 

pp. 383-385, 1914. 

13 Gilmore, C. W., Reptilian ·faunas of the Torrejon, Puerco, and 

underlying Cretaceous formations of San Juan County, N.Mex.: U.S. 

Geol. ·survey Prof. Paper 119, pp. 9, 10, 1919. 
42 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Torrejon reptiles and fish: 

Chelonia: 

Compsemys torrejonensis Gilmore. 

parva? Hay. 

Baena escavada Hay. 

sp. undetermined. 

Adocus substrictus, (Hay). 

onerosus Gilmore. 

annexus (Hay). 

Hoplochelys saliens Hay. 

paludosa Hay. 

elongata Gilmore. . 

Plastomerius acupictus Hay. 

n. sp. ? undet. 

sp. 

Aspideretes singularis Hay. 

sp. 

. Platypeltis antiqua Hay. 

Amyda eloisae Gilmore; 

Serpentes: . 

Helagras prisciformis Cope. 

Rhynchocephalia: 

Champsosaurus puercensis Cope. 

Loricata: 

Crocodylus sp. 

Pisces: · 

Lepisosteus sp. 

Torrejon formation, the results of the exainination of these collections by F. II. l{nowlton 

are given here. 

7371. 3 miles 'south of Farmington, N. Mex.; horizon about 50 feet above the OjQ Alamo sandstone: 

Atrocarpus pungens (Lesquereux) Hollick. 

Rhamnus goldianus? Lesquereux. 

Platanus aceroides Goeppert. 

Paliurus zizyphoides? Lesquereux. 

Liquidambar? cucharas? Knowlton, but much 

smaller. 

Dombeyopsis obtusa? Lesquereux. 

Quercus sp. 

Fragments of several types of dicotyledons. 

This material is very difficult and unsatisfactory to 

study, for although in the individual spe'cimens the 

outline and nervation are well preserved the specimens 

are so fragmentary that it is impossible to make the 

identifications positive. So far as the fragments go 

they cou~d be referred to the species indicated with 

reasonableness, but without the whole or the major 

portion of a leaf it is unwise or at least unsafe to make 

positive determinations. I believe, however, that 

these remains have been allocated with a reasonable 

degree of ·certainty,· and therefore they indicate undoubted Tertiary age and the approximate position 

In a late paper Matthew 14 says of the of the Denver and Raton formations. 

The previously known position and distribution· of Torrejon fauna: the forms listed is as follows: Artocarpus p1mgens was 

The Torrejon overlies the Puerco conformably ·and described from specimens collected from the Denver 

contains the same and some additional families of formation at Golden, Colo., and has been found in 

archaic mammals, both . multituberculates and placentals. Some of the Puerco phyla can be followed 

through, apparently as direct descendents, and in 

these there is evidence of considerable evolutionary 

change, representing a considerable lapse of time. 

Poorly preserved invertebrates have been 

reported from the Torrejon formation/ 5 but 

the only species that have been studied are 

those described by White 16 under the following 

nan1es: 

Unio rectoides White? 

Helix nacimientensis White. 

adapis White. 

Pupa ieidyi Meek? 

Several lots of poorly preserved plants 

were collected by the writer from the indeterminate zone beneath the lowest horizon 

of Torrejon ma1nmals in the region adj·acent 

to San Juan and Animas rivers. As these 

beds ate· treated in this paper as part of the 

14 Matthew, W. D., Fossil vertebrates and the Cretaceous-Tertiary 

problem: Am. Jour. Sci., 5th ser., vol. 2, p. 218, 1921. 

15 Sinclair, W. J., and Granger, Walter, Paleocene deposits of the 

San Juan Basin, New Mexico: Am. Mus. Nat. Hist. Bull., vol. 33, 

p. 313, 1914. 

16 White, C. A., On the relation of the Laramie molluscan fauna to 

that of the succeeding fresh-water Eocene and other groups:· U.S. Geol. 

Survey Bull. 34, pp. 11, 12, 1886. 

the 'Vilcox deposits of Mississippi, Arkansas, and 

Louisiana. It occurs in the San Juan Basin in the 

Animas formation and probably iri the. Puerco formation. Rhamnus goldianus is a very abundant form 

in the Denver and has been reported in beds presumed 

to be of similar age at Silver Cliff, Colo.· It is also foun_d 

in the Raton formation Qf southeastern Colorado and 

questionably in the Laramie at Marshall, Colo., where 

it occurs in the highest beds referred to the Laramie. 

Platanus aceroides has a very wide distribution in the 

Tertiary and is not now recognized as occurring in 

older becl.s. It occurs in the San Juan Basin in the 

Animas formation. Paliurus zizyphoides was de-

-scribed from specimens found at Black Buttes, 'Wyo., 

in .beds believed to be of post-Laramie age and was 

subsequently identified in the Denver at Golden, in 

the Raton of southern Colorado, and doubtfully in. 

the Laramie at Erie, ·Colo. It occurs in the Puerco 

formation of the San Juan Basin. The identification 

of Liquidambar? ~ucharas is not very certain. It is· 

based on one side of a leaf that is much smaller than 

tl{e type of the species, which came from the Raton 

formation of southern Colorado. The form assigned 

to Dombeyopsis obtusa is also unsatisfactory. The 

type locality of this species is the Laramie of Colorado 

Springs, Colo. It was found later at several places in 

'the Laramie, in the Denver at Golden and Sedali~, 

Colo., and in the Dawson near Colorado Springs. 

7437. Near the center of sec.· 18, T. 30 N., R. 12 vV., 

about 7 miles northeast of Farmington, N. Mex.; 

horizon 100 feet above the top of the Ojo Alamo 
NACIMIENTO GHOUP •. 43 

sandstone. This material is very fragmentary, yet it 

obviously contains a number of very distinct types. 

There is, for instance, what appears to have been a 

large leaf with a very thick midrib and thin remote 

secondaries. It suggests a Fict~s, but there is no 

margin preserved. There is a small ovate-lanceolate, 

entire-margined leaf that has the size and shape of 

Jt(,glans schim7Je1·i Lesquereux, a Green River species, 

but it has a different secondary nervation. There is. 

also a small ovate, long-pointed leaf with a sharply 

serrate margin and three ribs from the base of the 

blade th[l.t might well be Zizyphus meigsii (Lesquereux) 

Berry, a. well-known species in the ·wilcox and Raton 

formations. · If this material had been submitted 

without stratigraphic data I should 'not have hesitated 

to place it in the Tertiary, but. beyond tha.t it would be 

lutza.rdous to venture a.n opinion. 

Age c~rul con·elation of the P1..terco and Torrejon 

fonnations.-The Puerco formation is distinctly later than the Ojo Alan1o sandstone, as 

shown ·by the erosion interval between them 

and the nearly con1plete change in lithology 

and· fauna. Its relation to the Animas fornlation is not so clear, as the two forn1ations are 

widely separated geographically and as the 

Aninuts fonnation has yielded no n1ammals 

and the flora of the Puerco formation is very 

s1nall. Fortunately the flora of the Puerco 

fonnation; even though sn1all, contains enough 

confidently identified species to link it closely 

with the Animas flora and no contradictory 

species at all. Unless the flora of the Animas 

for1nation consists of long-lived, persistent 

species, it is probable that there is little difference in age. between the upper part of the 

Anin1ns fonnation and the Puerco formation. 

A suggestion that the Animas.f-lora contains at 

least some long-ranging species is contained in 

the character of the flora of the beds near 

Ani1nas and San Juan rivers interpreted in this 

paper to be basal Torrejon, m).d in the small 

flora collected from the "Tiffany beds'' (the 

base of the Wasatch formation). The Puerco 

for1nation 1nay thei·efore be later than the 

Animas formation. I-Io\vever, the ·probable 

unconforn1ity of the Torrejon on the Puerco and 

the den1onstrated unconforn1ity of the Torrejon 

upon the Animas lend support to the flora in 

indicating that .the upper part of .the Animas 

and the Puerco are close together in age. An 

exact correlation 1nust await further data. 

The 'l'orrejon formation is probably unconformable upon the Pum·co and is certainly 

unconfor1nable upon. the Anin1as formation. 

It is therefore later in tin1e than either of them. 

The Pum·co and Torrejon forn1ations have 

both bee.n almost universally regarded as of 

early Tertiary age; though it has been proposed 

at various times to include them in the Upper 

Cretticeous. The small flora of the Puerco 

formation is interpreted as ·indicating the age 

to be that of the Raton, Denver, and vVilcox 

formations,. all accepted as Eocene. The 

faunas of the Puerco and Torrejon are marked 

by the abundance of primitive man1mals, turtles, and. crocodiles and by the absence of cllnosaurs. Matthew 17 in 1914 compared the 

early 1nammalian faunas known in the Edmonton, Paskapoo, Lance, and Fort Union fornlations ·with those of the Pum·co and Torrejon. 

At that time he presented the classic view that' 

the Ednwnton beds were the oldest and intermediate in age between Judith River and 

Lance; .the Paskapoo and Lance nearly the 

same in age and still Cretaceous; the Puerco 

.beds younger than.Lance but older than Torrejon and Fort Union and of earliest Tertiary age. 

In a brief review in 1921 Matthew 18 changes 

his views somewhat, stating that 

The Puerco "Lower Paleocene" * * * may be. 

as old as the Lance or older, although usually regarded 

as later. The Torrejon and Fo'rt Union fa.unas, Upper 

Paleocene, are not much later than the Lance, and the 

phyletic evolution indicates that they Me considerably 

later than the Puerco. The Tiffany and Cernaysian 

faunas show a still later stage of the Paleocene faunas. 

In a more extended discussion published.a few 

nwnths later Matthew 19 says: 

The Torrejon a.nd Fort Union are Upper Paleocene, 

correlated by the paleobotanists with the lower 

Thanetian of Europe (Gelinden and Sezanne). 

The Puerco, ·Lower Paleocene, is post-Senonia.n but 

may be as old as the La.nce or older. 'J;'he fauna shows 

it to be considerably earlier than the Torrejon-Fort 

Union, and the.near rela.tions in stratigraphy and flora 

between Lance and Fort Union are strongly against 

intercalating between them the very wide time gap 

which is involved by placing the Puerco as later than 

the Lance. If so, we must conclude tha.t the latest 

dinosaur fa.unas were contemporary with the older 

Paleocene il1ammalian fauna., and that it is owing to 

some imperfectly known differences in facies that they 

are not found associated. Some indirect evidence in 

support of this view is afforded by the Paskapoo,· in 

which Lance mammals and Paleocene placentals are 

found associated. 

t; :Matthew, W. D., Evidence of the Paleocene vertebrate fauna on the 

Cretaceous-Tertiary problem: Geol. Soc. America Bull., vol. 25, pp. 381-

402, 1914. 

ts Matthew, 'vV. D., The Cannonball Lance formation: Science, n. ser. 

vol. 54, pp. 27-29, 1921. 

t9 l\'Intthew, W. D., Fossil vertebrates and the Cretaceous-Tertiary 

problem: 1\.m. Jour. Sci., 5th scr., vol. 2,' p. 220, 1921 
44 UPPER CRETACEOUS AND· TERTIARY FORMATIONS IN SAN JUAN BASIN. 

·In these later papers :Matthew is in favor of WASATCH FORMATION. 

assigning the Puerco and Torrejon. together Identification and dist~ibution in San Juan . WI. th the · succeeding '' Tiff any beds'' to the B · I s J n County N Mex the as~n.- n an ua , . . ., · Cretaceous, though. frankly stating that the hase of the Wasatch formation formed the 

opinions of other vertebrate paleontologists upper boundary of the writer's field work. It 

are not fully in accord with his. l-Ie cites was mapped only in the extren1e southern and 

H. F. Osborn as adhering to the older view northern parts of the county, the region 

that the extinction of the dinosaurs, presuma~ between having been examined only. in rapid 

lily at the end of the Lance, marks the end of reconnaissance without mapping except for 

Cretaceous time,. and he also cites. J. · W. approximate locations on a very gen·eralized 

-·Gidley as accepting the view advocated by the topographic map. In Colorado all of the 

paleobotanists that Tertiary· time began with formation. present in. the Ignacio quadrangle 

the deposits containing the related Fort was examined. Few details are available 

Union, Lance, Denver, and Raton floras and reO'arding the formatimi in New Mexico. It 

their equivalents in other regi?nS. . w:s first noted as such by Cope 20 in 1874. 

· It seems to the writer that in a genei'al way Collections made by Cope and others brought 

the time interval represented by the sediments into his hands representatives of 20 genera of 

of the Ojo Alamo sandstone and the Animas Wasatch fossils from the San Juan ·Basin.21 

formation, the Puerco formation, and the Cope estimated the .thickness of the Wasatch 

Torrejon formation of the San Juan Basin is formation of New Mexico as 2,500· feet. 

equivalent to that of the Raton. formation of Granger in 1912 examined the formation near 

northeastern New Mexico and southeastern Gallina and Cuba, N. Mex., and made collecColorado, to that of the Arapahoe and Denver tiOns ·of fossils. On the basi~ of this work he 

formations of the Denver Basin, and to that estimated ·the total thickness ·as 1,QOO feet and 

of the Lance and Fort union formations of reCOO'nized two faunal divisions, a lower cliviWyoming,· Montana, and the Dakotas. In · sion~ called the "Almagre beds," containing 

the San Juan Basin the first and most notable Eohippus and Anacodon and consisting of red, 

break in the stratigraphic and biologic succes- gray, and ocherous shale and sandstone, and an 

sion comes at· the base of the Animas and Ojo upper division, called the "Largo beds," conAlamo formations and affords a suitable place · taining Eohippus, Meniscotherium, and· Amto draw a systemic boundary. Whether this bloctonus and consisting of lithologic 1naterials 

horizon can be recognized and is the best pla~e similar to those of the lower unit but with more 

to draw . the boundary in· other regions de- red coloring. Most of the fossils recorded fro~ 

pends on the· pr,emises accep~ed a~. the .ba~is the Wasatch formation of the San Juan Basin 

for a judgment, and the verdict will be quite ·seem to have .co~:te from the southeastern part 

different as rendered by different individuals of the basin. In Colorado, between Los Pinos 

honestly weighing the· same data. The writer and Piedra rivers in southeastern La Plata 

has not presumed to pass judgment on t~e County, beds near the base of t_he Was~tch 

widely varying opinions expressed by differ- forii.lation containing a fauna Intermediate. 

ent authorities as to the proper location of the between that of the· Torrejon and Wasatch 

Cretaceous-Tertiary boundary in the Interior· formations were noted by Gidley and Gardprovince of North America but has indicated ner. 22 These beds have since been called by 

the conflict in interpretation of the data by Granger 23 the "Tiffany beds." They are 

questioning the assignment of the Ojo Ala~o lO Cope, E. D., Hcport on the geology of that part o~northwcstern New 

and Animas formations· to the Eocene,_· while. Mexico examined during the field season of 1874: Ch1ef Eng. Ann. Hept. 

for 1875, pt. 2, appendix G 1, pp. 1008-1017. . . . r • 

at the same time COrrelating them With the 21 Granger, Walter, Lower Eocene of New MeXICO and '' yommg: 

Am Mus. Nat. Hist. Bull., vol. 33, pp. 201-207, 1914. Raton and Denver formations, whose age has 22 ·Gidley, J. w., in Wegemann, c. H., wasatch fossils. in so-.callecl 

been . accepted by most. writers as Eocene, an_ d Fort Union beds of the Powder River basin, Wyo., and thmr bcarmg on 

the stratigraphy of the region: U. S. Geol. Survey Prof. Paper 108, p. with the Lance, variously placed in the Ore- 59, 1918. . .. 

1 h U · d St t 2a Granger, Walt(3r, Notes on Paleocene and lower Eocene mamma taceous and Tertiary and by t e nite . a es horizons of northern New Mexico and southern Colorado: Am. Mus .. 

Geological Survey doubtfully_ in the Tertiary .. Nat. Hist. Bull., vol. 37, p. 829, 1917. 

. . 
W ASATCFI FORMATION. 45 

treated in this paper as a faunal zone of the lower 300 feet or so seems to be one continuous 

W asntch forn1ation, ·as they are not {lifferent sandstone bed. · Else~vhere. the~e is a succesin lithology from the beds above ap.cl in fact are sion of sandstone and shale beds, the sandstones 

separable only by the1r fauna. This· zone has mostly red-brown and resistant, the shales 

been traced northward fron1 the type locality gray and reel with layer_s of soft white sandin sec. 20, T. 33 N., H. 6 W., to the southern stone irregula1~ly intermingled. 

part ofT. 35 N., H. 6 W., and eastward as far On the divide between San Juan and Animas 

as Pngosa Junction. It undoubtedly ·extends rivers the Wasatch formation consists of a 

beyond that locnlity, but how fa-r has not been succession of sandstone and shale beds; the 

detm~mined. In all this region it may be iden- sandstone gray-white to copper-red, rather 

tified by its fossils as well as by t1~acing the coarse, containing small pebbles of chert and 

beds.· · \Vestward frmn the type locality it has quartz; and the shale variegated, purple and 

been traced by following the beds to the· divide gray, with intermingled soft white sandstone. 

between Animas and La. Plata rivers and The lower layers of sandstone are heavier and 

southward for smne n1iles into New Mexico. more massive than the higher layers. Near 

It has not, however, yielded fossils west or ·cedar Hill, N. Mex., the lower 700 feet of the 

sout_h of thQ type locality, and the identification Wasatch. formation is exposed, and higher beds _ 

has depended entirely on tracing 'outcrops and are visible off to the east. 

on lithologic comparisons. In the ·southern In Colorado the phase of the Wasatch :fonnapart of the San Juan Basin this faunal zone is tion consisting of brown indurated sandstone 

. apparently absent, and beds with only the and variegated shale persists for a few miles 

typical Wasatch fauna have been observed. north of the State boundary. It passes then 

Just where between northern and southern San into soft, fine conglon1erate, soft sandstone, 

Juan County this zone wedg~s out has not been usl~ally arkosic, and variegated shale. The 

deter1nined. In this r~gion, the -location of mass viewed from a distance is of a rather even· 

Newberry's" Canyon Largo series," the forma- clove-gray color, but closer inspection shows 

tion is very clearly displayed in Canyon red, greenish, and gray tones in about equal 

Blanco and Canyon Largo, but little detailed- an1ouilt. This n1aterial weathers into slopes 

infornuttion regarding it is available. The as if it were all shale·. This softer phase of 

vVasatch for1nation occupies the central part the Wasatch. formation has been traced eastand nulCh of the _eastern part of the basin, for it ward across the Ignacio quadrangle to the 

is· reported to overlap .the older beds at n1any fi-:D Hills, which extend from H. 6 W. to 

points along the eastern border. It is, so far as Piedra Hiver. flere the lower 400 feet of the 

known and with the exception of much later Wasatch fornuttion, containing near the base 

gravels, the latest formation now present in the the "1'iffany-" fau_na; consists chiefly of varieSan Jua.n Bn,sin. . ·gated green, reel, and gray shale with a minor 

Lithologic character and thickness.-In south- amount of fairly well indurated arkose. The 

on,stern San Juan County the part of the arkose contains pebbles of pink feldspar as 

Wasatch formation seen comprises a ~assive, much as three-fourths of an inch in dian1eter 

cliff-fonning basal coarse sandstone, 50 feet in a matrix of fine-grained greenish material. 

thick, of- copper-red color, .containing lenses of The higher beds consist of gray shale with 

pebbles o:f chert and quartz; overlain by 150 some red ·bands, soft sandstone, and son1e 

feet o:f light-gray and red shale and soft .white rusty-brown indurated sandstone. and arkosic 

sandstone, overlain in turn by another sand- conglon1erate. Gardner's section 24 of the forstone very n1uch like the first. Higher than mation describes the lithology well, ·though 

these beds, but smne distance· back from their the writer is not certain whether the b_ase of 

outcrop, are similar shales and sandstones. the section coincides with the ba,se as chawn 

The basal contact o:f the lower sandstone is in this paper. N 0 mention is made by Ga1:dner 

·:not conspicuously irregular at most places, of the prominent arkoses which tha writer 

though locally it shows erosion. The lithologic places in the lower part of the W asat<?h formacontrast is sharp. 1 

AlonO' Blanco and lower Largo canyons the-- 21 Gardner, J. H., in Lee, w. T., aad Knowlton, F. H., Geology and 

b . paleontology of the Raton Mesa and other regions in Colorado and New 

-Wasatch IS excellently exposed. Locally the Mexico: u.s. Geol. Survey Prof. Paper 101, p.IS5, I9Ii. . / 
46 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

tion, and these may lie below the beds measured by Gardner. The thickness is certainly 

as great as that given in _his section. Partial 

sections at several places are given on pages 

55-58. 

Relation to adjacent formations.-In southern San Juan County there is a sharp lithologic 

change from Torrejon to Wasatch and near 

the Nacimiento Mountains an overlap of the 

Wasatch and an angular discordance. 

The -uppern1ost Torrejon in southern San 

Jua1~ County contains little brown resistant 

sandstone, but toward the north n1ore and more 

of such rock appears until the gross lithology 

is n1uch like· that of the overlying Wasatch 

fonnation. The Torrejon sandstones ~re thin~ 

ner, shorter lenses and do not form as much of 

the bulk of the formation as those of the overlying beds. This hazy distinction has been 

used in mapping the base of the Wasatch formation in northern San Juan County. · Th~re is 

no sign of an erosion interval or .discordance in 

clip. Even this lithologic distinction clisappe~rs 

a few 1niles north of the State line i1i Colorado, 

for the whole series present above the Anin;-as 

fonnation passes laterally into soft 1naterials in 

which no breaks have been discerned. 

.The Wasatch formation, therefore, appears 

to be confonnable on the Torrejon formation 

in the northern part of the San Juan Basin and 

unconformable -in the southern part. 

Fossils.~The latest list of Wasatch fossils 

· from. the- San Juan Basin is that given by 

Ma'tthew 25 in 1909. It does not include the 

"Tiffany" fauna. Mat'thew's list is repeated 

belmv without any of the later changes or 

additions: 

Pelycodus jarrovii Cope. 

tutus Cope. 

frugivonts Cope. 

· Cynodontomys angulatus (Cope). 

Didymictis pretenus (Cope). -

leptomylus Cope. 

Vulpavus sp. · 

Ambloctonus sinosus Cope. 

Oxyaena lupina Cope. 

forcipata Cope. 

morsitaris Cope. 

Sinopa viverrina. (Cope) . 

. strenua (Cope). 

· multicuspis (Cope). 

hians (Cope). 

25 Matthew, W. D., Faunal lists of the 'l'ertiary l'viammalia of the 

'V ~st, in Osborn, H. F., Cenozoic mammal horizons of western North 

America: U. S. Geol. Survey Bull. 361, pp. 92-95, 1909 

Pachyaena ossi{raga Cope. 

Hyopsodus miticulus (Cope). 

Diacodon alticuspis Cope. 

celatus Cope. 

Esthonyx burmeisteri Cope. 

acer Cope. 

bisulcatus Cope. 

spatularia Cope. 

?Sciuravus buccatus (Cope). 

Calamodon simplex ·Cope. 

arcamoenus Cope. 

novomehicanus Cope. 

Ectoganus gliriformis Cope. 

Phenacodus primaevus Cope. 

astutus (Cope). 

fiagrans (Cope). 

?stilcatus Cope. 

Meniscotherium terraerubrae Cope. 

chamense Cope. 

tapiacitis Cope. 

Coryphodon lobatus Cope. 

elephantop~ls Cope. 

Iatidens Cope. 

Heptodon singularis (Cope). 

Systemodon tapirinus (Cope). 

Eohippus validus Marsh. 

angustidens (Cope). 

cuspidatus (Cope). 

cristonensis (Cope). 

Trigonolestes chacensis (Cope). 

The "Tiffany" zone has yielded a fauna as 

yet only partly described. The specimens collected by Gidley and Gardner 26 in 1909 were 

listed by Gidley as follo,vs: 

Coryphodon sp. 

Phenacodont intermediate between Phenacodus 

and Euprotogonia. 

Hemiacodon (? n. sp.). 

N othodectes sp. 

Miscellaneous unidentified teeth. 

The species collected by Granger 27 in 1916, 

as given in a preliminary report, included 

Periptychus n. sp. 

Phenacodonts, 3 species. 

?Dissacus. 

?Chriacus. 

N othodectes sp. 

Many undetermined small mammals. 

The writer made two collections in 1921 

from the "Tiffany" zone~ These have been 

examined by Mr. Gidley, and his report is as 

follows: 

26 Gidley, J. ,V., in. Wegemann, C. H., Wasatch fossils in so-called 

Fort Union beds of the Powder River basin, Wyo., and their bearing on 

the stratigraphy of the region: U. S. Geol. Survey Prof. Paper 108, 

p. 59, 1918. 

21 Granger, ·walter, Notes on Paleocene and lower Eocene mammal 

horizons of northern New l\1:exico and southern Colorado: Am. Mus. 

Nat. Hist.. Bull., vol. 37, p. 828, 1917. 
WASATCH FOR:MATION .. 47 

Near head of Cro~vbar Creek, 5~ miles east of Bay-· 

field, Colo., in sec. 11, T. 34 N.,· R. 6 W.; horizon in 

lower 100 feet of "Tiffany" zone of ·wasatch formation: , 

Psittacotherium sp., portion of anterior tooth 

(canine'?). 

Tetracln,euodon or Phenacodus, lower molar in 

fragment of jaw. · 

Cf. Tricentes sp., two moiars in portion of a 

lower jaw. 

These fossils are not sufficiently complete nor characteristic enough to make positive the determin·ation 

of the horizon. Psittacothcri1tm, Tricentes, and Teti·aclaenodon are Torrejon genera, the first never having 

been reported outside this horizon. However, the 

phenacodont tooth so closely resembles a corresponding 

one in our collection from the "Tiffany beds" as to 

lead me to' believe that the species from this l~cality 

represent this horizon. 

One mile west of Carracas station, Colo., on the 

Denver & Rio Grande Western Railroad, at the edge 

of the hills north of the railroad; horiz01i in the lower 

100 feet of the "Tiffany beds": 

Tetraclaenodon cf. T. puercensis (Cope). Three 

teeth, p 4, m 1, and m 2 (broken), in a portion of a left lower jaw; a first left lower 

molar in a fragment of jaw; a left lower molar 

crown but little worn; a right lower premolar, 

p 3. 

Tetraclaenodon cf. T. minor (Matthew). Two 

right lower molars, m 2 and m 3. 

Phenacodus cf. P. primaevus Cope. A left first 

lower molar in portion of jaw containing roots 

of p 3 and p 4. 

Nothodectes cf. N. gidleyi or new species.· A 

left upper incisor larger than' Matthew's type; 

Creodont of the Claenodon type, genus and 

species not determined but probably new. 

A last right lower mohu: in portion of jaw. 

The fragmentary condition of most of the specin\ens 

of this lot is such that absolute dependence can not 

be placed on the .above identifications. However, 

there seems to be here a rather unexpectedly mixed 

fauna of \Vasatch, Torrejon, and "Tiffany" species. 

This assemblage of species docs not exactly agree with 

our former conception of the ''Tiffany" fauna as known 

from the type locality, and this interniingling of true 

Wasatch and Torrejon species, if substantiated by 

larger collections, may modify our idea. of a considCI'ablc time interval between these two horizons. 

Smne of the n1aterial .collected by Granger 

in 1916 and not identified at the time of his 

preliminary report (see footnote, p. 46) hns 

since been studied and described.28 These 

species include the following: 

Zanyctcris paleocenus Matthew. 

N ot)wclectes gidlcyi lVIatthew: 

2s lVI:ntthew, W. D., A Paleocene bt1t: Am. l\{us. Nat. Hist. Bull., 

\'ol. 37, pp. 5G!l-571, l!ll7; ~L'he dentition of Nothodectes: Am. l\h1s. Nat. 

Hist;. Bull., vol. 37, pp. 831-839, 19li. Matthew, vV. D., and Granger, 

Wnlter, New genera of Paleocene mammals: Am. Mus. Nat. Hist. 

Novit~tcs, No. 13, l!l21. 

Ectypodus muscblus Matthew and Granger. 

Peradectes elegans Matthew and Granger. 

Leptacodon tenor Matthew and Granger. 

Xen[tcodon mutil_atus Matthew and Granger. 

Labidolemur soricoides Matthew and Granger. 

Ignacius frugivorus Matthew and Granger. 

N:avajovius kohlhaasae Matthew and Granger. 

Carpodaptes aulacodon Matthew and Granger. 

Two collections of fossil plants were n1ade 

from the "Tiffany" zone of the Wasatch 

fonnation. These were examined by F. I-I._ 

l(nowlton, w}1o identified the following forms: 

7454. 5 miles east of Ignacio, Colo.;· in the 

center of the NE. t sec. 19, T. 33 N., R. 6 W.; 

near base .of "Tiffany" zone of the Wasatch 

forn1ation: 

Aralia'? sp. 

Ficus sp. 

Celastrinites cf. C. artocarpidioides Lesquereux, 

a Denver species.· 

Fragments of dicotyledons. 

74.55. At milestone 436, 1 n1ile south of 

Florida station on Denver & Rio Grande 

Western Railroad; near base of "Tiffany" 

zone of the wasatch formation: 

Ficus planicostata Lesquereux. 

cf. F. denveriana Cockerell. 

cf. F. schimperi ·Lesquereux. 

Fragmentary dicotyledons. 

Ficus zJlanicostata has been reported both 

from the Laramie and from late~ beds; Ficus 

schimperi and Ficus denveria:na from the Raton 

and vVilcox fonnations, the last from the 

Animas formation also. Mr. Knowlton (p. 76) 

says of these collections: 

This material is so poorly identified that little can be 

said as to age determination. If the suggested identi-

·fications were authenicated there would be no hesitation in regarding it as approximating in age the Denver 

and Raton formations, and there is nothing in the collections that in any way militates against this conclusion. 

Age and ~orrelation.~ The Wasatch forma-

.tion of the San Juan Basin contains in the· 

higher beds the fauna th~t in the stricter sense 

of the name is considered characteristic-that 

with ''Eohippus. and its associated forms, 

which include lemuroids, ·rodents, and artiodactyls."20 It contains also in 'the basal 

"Tiffany" zone a fauna intermediate between 

that of the Torrejon- and that of the younger 

Wasatch beds-intern1ediate in the sense that 

~g Granger, 'Valter, Notes on Paleocene and lower Eocene mammal 

horizons of northern New 1\•Iexico and southern Colorado: Am .. Mus. 

Nat. Uist. Bt1ll., vol. ~7. pp. 829-830. 19li. 
. . 

48 . UPPER CRETACEOUS AND TERTlARY :F'ORMATIONS IN SAN J·UAN BASIN . 

it associates genera known in the typical 

Torrejon but not in the typical Wasatch 

faunas and genera known in the typical 

Wasatch but not in the typical Torrejon. The 

typical Wasatch fauna is widespread in the 

Rocky Mountain region, and the beds that 

· contain it are u·sually designated the Wasatch 

formation, though locally numerous names 

distinctive of faunal zones within the forma-

_tion have been applied·. The "Tiffany" fauna 

is kn.own in the "Clark Fork beds" of the 

Wasatch fo1~matio:o. in northwestern Wyoming. 

Matthew 30 says that ~he "Tiffany" zone 

is still faunally Paleocene, the mammals archaic 

placentals. The phyla that can be· traced through 

show in some instances a considerable advance beyond 

the Torrejon, indicating considerable." lapse of time, 

and are very close to the succeeding Wasatch horizons 

of the true Eocene. Bi.tt in the Tiffany, as in the 

Torrejon, the modernized placental mammals, abt:mdant 

in the overlying horizons of the ··wasatch, are almost 

wholly absent. There is between Tl.ffany and true 

Eocene very little lapse of time but a great change of 

fauna. For various reasons impossible to present here 

I hold that the change is not explainable as due in 

. any degree to .difference in facies but must be due to 

migration. 

The assignment of the typical Wasatch to 

the Eocene has never been questionecJ.. 

Granger likewise placed his ''Tiffany beds" in 

the Eocene, but 11atthew, because of their 

relations to the Torrejon faunally, proposes to 

place th~m \Yith the Torrejon, in the· Cretaceous system. 

FIGURE 3 . .:....Diagram showing the relations of the formations along tho 

west side of the San Juan Basin: 

~o Matthew, W. D., Fossil vertebrates and the Cretaceous-Tertiary 

problem: Am. Jour. Sci., 5th ser., vol. 2, p. 218, 1921. 

. SUMMARY OF THE RELATIONS OF THE FORMATIONS 

WITHIN AND WITHOUT THE SAN JUAN BASIN. 

The relations of the formations within the 

San Juan ·:Basin to one another have been giveri 

in the descriptions of the individual tmits. 

These are summarized graphically in Figures 3 

and 4. Figure 3 sets forth the relations as shown 

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U. S. GEOLOGICAL SURVEY 

San Juan Basin,<' 

Colorado and 

New Mexico 

Animas 

fonnation 

restricted 

Hiatus 

McDermott formation 

Kirtland formation 

Fruitland formation 

Pictured Cliffs 

sandstone 

:::s: p 

tMancos shale 

Dakota sandstone 

Raton region,~ 

Coloraao and 

New Mexico 

.-----? 

Poison Canyon t 

formation 

Hiatus_ ? ------, 

Raton formation 

Hiatus 

V ermejo formation' 

? 

Trinidad sandstone· 

Pierre shale 

Niobrara formation 

Benton formation 

Dakota sandstone 

Denver region, c 

Colorado 

Hiatus 

Denverfonnat~ Hiatus 

[AiiPa!We form-at:"P'w-n---,1 

Hiatus 

Laramie formation 

fox Hills sandstone 

Pierre shale 

Niobrara formation 

Benton formation 

D.akota formation 

Hanna Basin, d 

Wyoming 

Hanna formation 

Hiatus 

Ferris formation 

Medicine Bow 

formation 

Lewis shale 

Mesaverde formation 

Steele shale 

Niobrara formation 

Carlile shale· 

Frontier formation 

Mowry shale 

Thermopolis shale 

Gloverly formation 

1 

Central Wyominge 

Wind River formation 

Hiatus 

Fort Union formation 

[Hiatus] 

Lance formation 

["] 

Lewis shale 

Mesaverde formation 

Steele shale 

Niobrara formation 

Carlile shale 

Frontier formation 

Mowrv shale 

T-hermopolis shale 

Dakota sandstone 

Lower Cretaceous 

? 

B~ Ho~n Basin, I 

yommg 

Wasatch formation 

Hiatus 

Fort Union formation 

Hiatus 

Lance ( "Ilo") 

formation 

["] 

Meeteetse formation 

? 

Mesaverde formation 

Cody shale 

Frontier formation 

Mowry shale 

Thermopolis shale· 

Cloverly formation 

? 

Black Hills region and 

eastern Wyomingu 

Wasatch formationm 

·Hiatus 

Fort Union formation 

Lance formation 

["] 

.Fox Hills sandstone 

Pierre shale 

Niobrara formation 

Carlile shale 

Greenhorn limestone 

Graneros shale 

Dakota sandstone 

Fuson formation 

Lakota sandstone 

Southern North Dakota and 

northern South Dakotah 

Hiatus 

Fort Union formation 

Lance 

formaLudlow lignitic ICann_onball 

member manne member 

tion Nonlignitic beds 

Fox Hills sandstone 

Pierre shale 

Not exposed 

Southern Montana i 

Hiatus 

Fort Union formation 

Lance formation. 

["] 

Bearpaw shale. 

Parkman sandstone 

Claggett formation 

Eagle sandstone 

Telegraph Creek 

formation 

Niobrara shale 

Carlile shale 

Frontier formation 

Mowry shale 

Thermopolis shale 

Cloverly formation 

? 

PROFESSIONAL PAPER 134 PLATE IV 

Central Montana; Northwestern· 

Montanak 

Hiatus 

? ? 

Fort Union formation Willow Creek 

formation 

? 

Lance formation St. Mary River 

formation 

[n] [n] 

Lennep Bear- sandstone paw 

shale 

. Horsethief sandstone 

Bearpaw shale Bearpaw shale 

Judith Riverformation 

Claggett shale 

'Two Medicine 

formation 

Eagle sandstone 

Virgelle sandstone 

Colorado shale Colorado shale 

'? ? 

Kootenai formation Kootenai formation 

DIAGRAM SHOWING THE APPROXIMATE CORRELATION OF THE FORMATIONS OF SAN JUAN BASIN WITH THOSE OF OTHER REGIONS IN THE WESTERN INTERIOR. 

a This paper. b Adapted from I,ee, W. T ., and Knowlton, F. H., Geology and paleont{)logy of the Raton Mesa and 

other regions in Colorado and New Mexico: U.S. Geol. Survey Prof. Paper 101, 1917. • c Adapted from Emmons, S. F., Cross, Whitman, and Eldridge, G. H., Geology of the Denver Basin m Colorado: U.S. Geol. Survey Mon. 'rl, 1896. d Adapted from Bowen, C. F .• Stratigraphy oftbe Hanna Basin, Wyo.: U.S. Geol. Survey Prof. Paper lOll, pp. 227-241, 1918. e Adapted from Hares, C. J., Antfcl.ilw; in central Wyoming: U. S. Geol. Survey Bnll. 641, pp. 233-

279, 1916. 

As interpreted by John B. Reeside, jr. 

I Adapted from Hewett, D. F., and Lupton, C. T., Anticlines in tbe southern part of the Bighorn Basin, 

Wyo.: U.S. Geol. Survey BuD. 656, 1917. g Adapted from various pnbllcatfons • h Adapted from Lloyd, E R.,and Ilares, C.1.,1our. Geologyjvol. 23, pp. 524-M7,1915; and Winchester, 

D. E.t Hares, C. 1., Lloyd, E. R., and Parks, E. M., U.S. Geo. Survey Bull. 6'rl, p. 16,1916. i Aaapted from Tbom, W. T ., jr., 00 prospects in and near the Crow Indian Reservation, Mont.: 

U. S. Geol. Survey Bull. 736, pp. 35-53, 1922. J Adapted from various publications. "Adapted from Stebinger, Eugene, The Montana group of northwestern Montana: U. B. Geol. Survey Prof. Paper 90, pp. 61~, 19U. 

I Tbe Polson Canyon and Raton formations may clliier bu' little in age and may be simply varying phases of sedimentation: Lee, W. T ., and Knowlton, F. H., op. cit., p. 61. m Not present east of Salt Creek and Powder River fields of east-central Wyoming. n Most geologists, fnclndlng the authors clted1 ~ho have examined the fonnations of this region consider 

that no hiatus exists at this horizon. Others Deiieve tbe absence of beds containing tbe Laramie flora to indicate a break in sedimentation. The writer can not account for the absence of such beds hut 

nevertheless believes tbe evidence now avaflable to show a transition without hiatus from pre-Lance to Lance deposition. 
P:HYSJCAL HISTORY 01!"' WESTEHN PART OF SAN JUAN BASIN.: 49 

along the outcrop and as infened from other 

data. 

The relations of the forn1at~ons of San Juan 

Basin to those of son1e of the other parts of the 

vVestern Interior· are show1i in Plate IV. Most 

ofl th:e correlations shown in this diagram are 

of ·long standing and need no special discussion. 

A tentative correlation with the European 

time~scale is given in Figure 5. The eorrelaSan Juan Basin, Colorado and New Mexico 

Wasatch formation 

~ 

Torrejon formation 

. ;_.-----

Puoreof. I~ 

~ 

o·o Hiatus 1\.nimas 

ormation 

Hiatu~ 

McDermott formation 

Kirtland shale 

Fruitland formation 

Pictured Cliffs sandstone 

t:s:: p 

r-- r- - Eaglofauna 

r--=----- Telegraph 

Creek fauna 

-------

Niobrara fauna 

1-------- Mancos 

Carlile fa una 

shale f--------

Greenhorn fauna 

t--------

Dakota sandstone 

European 

time scale 

Ypresian 

Spamacian 

(Cemaysian) 

Thanetian 

Montian 

Danian 

Maestrichtian 

Campanian 

Santonian 

Coniacian 

Turonian 

Cenomanian ? 

I 

FJGUHJ' 5.-Tontntivo corrolation of t.ho formations of tho San Juan 

Basin with tho. European time scale. 

tion of the Tertiary part of the section is based 

chie:f:ly . on the published correlations of the 

vertebrate paieontologists. The c'orrelation. of 

the Cretaceous part of the section is in large 

part of long standing. 

PHYSICAL HISTORY OF THE WESTERN PART 

OF THE SAN JUAN BASIN FROM MANCOS 

TIME TO WASATCH TIME. 

deposited were chiefly muds. The nearest 

shore of this sea seems to have been off to the 

southwest, in Arizona. Into the San Juan 

Basin itself little sand was bratight except in 

the very early stages and at the tini.e of depositimi of the Tocito sandstone. In~ adjoining 

areas nearer to the shore, however, some beds 

of sand accun1ulated, especially south o£ San 

Juan County, and at some places there was. 

even n1ore sand than mud. These n1uds and 

sands are now represented by shales and sandstones containing· marine fossils. The similarity of the fossils of this se·a of Mancos time 

to those _present in deposits within and east 

of the present Rocky Mountain.s and in deposits 

in the present Gulf coastal region indicate that 

the sea extended over the site of the present 

mountains and far beyond and ·was connected 

on the south with the waters in which the 

Cretaceous deposits of the Gulf region were 

being laid down. 

Toward the end of Manco~ time the sea 

. began to \Vithdraw from the area, probably 

toward the northeast. The sea in the south 

became shallower as the shore line approached, 

·and more and more sand \vas deposited there 

until the deposits were all sand-the present 

Point Lo9kout sandstone. This set of conditio.ns moved only gradually northward, and 

muds were still being deposited on the site of the 

north side. of the present basin long aftei.' the 

sandy type of sedimentation had begun at the 

site 9f the south.side of the basin, as is shown 

by the position. of the fossil zones with reference to the change in lithology. 

However, the conditions producing the sand}; 

marine sediments did not persist long at any 

one place, for they were succeeded quiekly 

from place to place by conditions of relative instability. The shallow waters in which the 

Point Lookout sandstone was deposited became 

shallower still, and a period began during 

which there were constantly changing swamps 

and lagoons-that is, actual shore conditions 

with the sea very near at hand. Muds and sand 

accunn1lated~ At times only .. fresh water 

flooded the swamps and 'lagoons; at other 

times, n1arine waters. Around and in the 

swampy areas lived plants of many kinds, 

whose 1·emains now form beds of coal and im- . 

During Mancos time the San Juan, Basin pressions of whose leaves occur in the sandand tho adj9ining country were occupied by a stones. The beds formed when the water was 

sea in which the sediments that were being fresh contain the remains of fresh-water 
50 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

animals.; the beds formed when the sea caine divisions, Point Lookout, Menefee, and Cliff 

in contain. the remains of marine animals. House, constitutes the Mesaverde group of 

This mass of coal and hardened muds and sediments. 

sands, with both fresh-water and marine fos~ils, After a time the sea became shallow again, 

is the Menefee formation, evidently laid down the waters apparently withdrawing quickly 

near tide level. from the whole area and leaving as they.went 

This unstable period in the north was not a relatively .thin but. widespread mantle of 

very long relatively, for the sea ceased its sand containing theremains of marine ~nin1als. 

-retreat and began to return to the area it ·had This near-shore deposit of sand formed the 

previously occupied. There was again at each Pictured . Cliffs sandstone, the last purely 

place, as the sea moved gradually southeast- marine formation. of the region, though a few 

·ward, shallow water in which marine sands later incursions of sea water during the depwere laid down. These sands formed the osition of the next higher format ion are 

Cliff I-Iouse sandstone of to-day; which , is shown by the pre~ence of shells of brackishtherefore considerably younger in the south wat.er animals. 

than in the north, and the conditions of the The deposition of the Pictured Cliffs sandMenefee deposits persisted in· the south long stone was followed by a relatively short period 

after the sea had returned to the northern part of unstable conditions like those represented 

of the area. At this time also the sea must by the Menefee formation. Swamps in which 

still have covered a great area, for the same vegetable debris accumulated, occasional incurspecies of fossils occur both in and far beyond sioris of salt water which permitted oysters 

the San Juan Basin. Some of these fossils and brackish-water animals to thrive, and 

occur elsewhere only in the region east of the .bodies of fresh water in which fresh-water 

Rocky Mountains and in the basins now animals lived are clearly recorded ,in the sediinclosed by the mountains, and other species ments and indicate a low, poorly drained 

have their nearest relatives in the Gulf coastal coastal region. The shore line seems then to. 

region. have p~ssed on toward the east, for no nwre 

The shallow sea in which the sands of the salt water reached the region, and rivers were 

Cliff House sandstone were accumulated be- the chief depositing agency. I-Iighly ·variable 

came deeper as the shore line moved farther beds of sand, sandy mud, and clay that show 

away to the southwest, and then muds chiefly every indication of being flood-plain deposits 

were· deposited. These muds were, of course, were formed. · For the first time since the 

muc11 thicker !n. the northern part of the basin beginning of the Upper Cretaceous, so far as 

than in · the southern part, and indeed so present knowledge extends, dinosaurs became 

gradual was the movenlent of the shore line abundant in the region, and river tm'tles 

that a considerable thickness of mud was flourished. The COnlplex of fresh and brackisll 

formed in the north while Menefee and Cliff 'vater sht).les, sandstones, and coal beds conI-louse sediments were still forming in the south. taining a varied array of fossils, which now 

There was in fact but little mud deposited in represents the muds and other deposits, is the 

the south and practically no change in condi- Fruitland formation. 

tions from those of the Cliff House sandstone. The deposition of the Fruitland formation 

The muds of these deeper waters formed the was followed without interruption by that of 

Lewis shale of to-day. a thick series of clays and sandy muds, which 

There is, then, owing to this retreat. and ad- are now the Kirtland shale. In the south few 

vance of the sea, a great wedge-shaped mass, layers of purer sand ·were deposited, but in the 

chiefly of sandy rocks, whose thinner edge north the middle part of the series contains 

projects northeastward between the Mancos n1any lenses of sand, which now, hardened into 

shale below and the Lewis shale above. The sandstone, make up the Farmington sandstone 

thick side of this wedge was being ·formed member of the Kirtland shale. The forn1ation 

during the same time that the upper part of shows many features to indicate that it was 

the Mancos shale, the thin part of the wedge, laid down on a river flood plain. The sediand practically all of the Lewis shale were ments suggest sluggish streams and a source 

forming. · The wedge, made up of the three that was not high enough to supply coarse 
PJIYSICAL HISTORY 01!"' WESTERN PART OF SAN JUAN BASIN. 51 

mn.tcrials. They contn.in pla,nt fossils in the 

for:rn of ]ea,f impressions a,nd logs, shells of 

fresh-w11te.r nnimals, and remains of fish, river 

turtles, a,nd dinosmU's. 

Upm~ the Kirtland shale wa,s deposited a 

rfl.ther peculiar mass of sediments now included 

in the ~1cDennott form11tion, an explanation 

of whose origin is perplexing. On the north 

side of the present basin this material consists 

la,rgely of debris derived from eruptions of 

andesitic lava and ash, n1ost of it of purplish 

color and little wefl.thered .. It contains beds 

of cobbles and boulders of andesite that must 

have roqui1:edlarge, rapidly moving strean1s to 

trnnspott thmn. At n1any localities there are 

also thin beds of pebbles of many sorts of 

hard, resistfl.nt siliceous rocks and beds of 

sanely and clayey .n1atter n.ssociated with the 

. beds of findesitic debris. The proportion of 

anclesitic 1natter in the formation decreases 

southward in a very n1m·ked fashion, though 

some is present everywhere, and it seen1s quite 

clear thn.t the andesitic debris cmne from the 

north, frmn son1e part of the region covered by 

the Sari J·uan Mountfiins. The so1.u·ces of' the 

siliceous pebbles are unknown, though they 

can hardly be the san1e areas as those which 

yielded the andesitic debris: nncl n1ot·eover 

:most of the rocks ·represented iunong the 

pebbles are not known in the present mountain 

region north of the San Juan Basin. We may 

conjecture witi1 son1e reason that -the land 

fron1 which the pebbles were dedved lay to the 

south or east rfl.ther than to the west, but at 

present there is little basis for a definite assertion as to its position or extent. 

The sudden appearance of these beds of 

n.ndesitic debris and of siliceous pebbles .raises 

1nany questions. I:f they can1e from the same 

land 1nasses that yielded the material of the 

pre-:McDennott deposits .why are they absent 

frmn these deposits and why do they appear 

suddenly~ The silnilarity of the plant and 

aninu\1 :fossils of the ~1cDermott and Kil·tland 

fonnations and the lack of any recognizable 

widespread break in the series of deposits constitute s.trong arguments against the assumption of fi tune interval between the fonnations. 

Yet the andesitic lava n.nd ash had to be availn.ble for e1:osion, and., as the siliceo~s pebbles 

include rocks certainly as old as Carboniferous, 

n.nd probably as old as pre-Cambrian, theil· 

sources had to be exposed and subject to 

erosion before the deposition of the ~1cDermott for:p1ation began. If a long time had 

elapsed be.tween the deposition of the Kil·tland 

shale and that of the ~1cDern1ott formation, 

there would have been time in this interval 

for the eruption, erosion, and transportation 

of the andesitic debris and for the uncovering, 

erosion, and transportatio:n. of the siliceous 

constituents. Such an interval would be a · 

very logical find .consistent explanation of 

most of the facts that have been observed. 

However, as neither the fossils nor the appar .. 

ent p~ysical features of the contact of the 

deposits warrant the deduction that any considerable tin1e !Jiterval is represented, some 

other explanation must be offered. 

Probably there were, near the end of ICirtland 

time, outbursts of andesitic lava and ash smnewhere in the region to the north. With these 

eruptions came heavy rains that s·upplied the 

vohune of water necessary to move the coarse 

materials now seen in the ~1cDermottforn1ation. 

.The rapidity with whiqh erosion and transportation followed the eruption of the n1aterial 

would account for its sudden appearance in 

the series of deposits and its relative freshness. 

There n1ay have been going on some general 

change in the attitude of the land surfacesome uplift or premonitory symptom of the 

period of mountain building that was to follow, 

of which the volcanic eruptions were one phase. 

That there is nothing unreasonable about the 

presence of andesitic outbursts in the Rocky 

Mountain region as early as this time is shown 

by the still older and even more extensive deposits of andesl.tic debris in the Livingston formation of the Livingston region, Montana. 

The supposition of some general change, furthei·:tllore, helps to explain the appearance of 

the siliceous· p.eb bles. . They could very well 

have been forming for a considerable period on 

a ln,nd mass not covered by Cretaceous serlin1ents, or at least not cove1~ecl at the end of 

Montana time and drained by streams that 

could not carry the pebbles as far as the San 

Juan Basin. Then, through the quickening of 

the streams by the volcanic rains or by the accumulated change in the attitude of the land, 

they were Cttrried to their present locations at 

about the same time as the·volc~nic products 

reached the basin. The pebbles would easily 

have withstood long weathering and transportation. I-Iowever it may have happened,. the 
52 UPPER CRETAC:EOUS ~ND TERTIARY FORMATIONB IN. SAN JUAN BASIN. 

net result of the activities of McDermott time erosion had not produced any large irregulariw~s the ·formation of a· blanket of s~diments, ties of the surface and the new n1aterials lie so 

coarser and consisting chiefly of and.esitic de- evenly upon the old that there is little local 

tritus on the site of the north side of the evidence of the interval represented at their. 

present San Juan Basin, and finer and. with contact. . During the early part of the time 

less volcanic matter southward until at its when the beds of andesitic debris were fonning 

southernmost occurrence it is not strikingly other materials, largely nonvolcanic, were 

different (rom the Kirtland shale, except for comirig into the San Juan Basin frorn son1e 

the purplish color of some. beds. Plants con- other direction, through the action of strearns. 

tin.ued to live in the region during McDermott These materials were lai·gely in the form of 

.time, and ·also dinosaurs, .turtles, and croco- sand, but at tin1es the currents were ·strong 

diles. enougP. to transp~rt la~ge pebbles and cobbles, 

There is no important break in the series of which are of siliceous composition and· very 

deposits included in the Mancos shale and like the pebbles of the McDermott formation. 

later formations up to the top of the MeDer- Some .material. of this sort is present- in the 

mott formation. The formations pass each .1\.:~imas formation, but n1ost of _the sand and 

. one into the. next- by a continuous gradation conglomerate beds formed fron1 these nonvolof shale into sandstone or sandst.one into shale, canic materials are in the Ojo Alamo formation. 

except for the local erosion at the base of the ·The Ojo Alan1o is not . known _anywhere 

·McDermott formation. All the changes in ·to come into direct· contact with the Anin1as 

the marine beds were caused by a shift of the formation, the areas of deposition not over-

. shore line that brought the sandier near-shore lapping so far as now known, though of course 

sediments closer or placed them farther away. we do not know what is present under the cover 

The cause of such shifts 'is open to dispute; it of later beds· in th_e center of San Juan Basin. 

may possibly have been a worldwide rise or Whether these non volcanic n1aterials were ·laid 

fall of the sea level, a rise or fall of the land in bare on an old land mass during a long period 

certain regions without material alteration of preceding their deposition or whether this 

the general sea level, or the filling. arid sinking erosion of a great thickness of rock occurred 

irregularly of the area that was receiving the mostly during the interval following the deposediments. The river-made sediments vary sition of the McDermott formation is not 

but little iri general composition. · The changes definitely known. ThB very similar rnaterial 

before the end of McDermott time seem to present in the l\1cDermott formation suggests 

have occu~red without sharp loc"al disturb- that .the sourc~s were the same and that eroances. The deposition of the McDermott sion had proceeded far at the sources, even in 

formation, however, ended with a change of McDermott tin1e. If this is true, not so long 

·considerable importance. The sediments of a· time interval between the McDermott forthe San Juan Basin were uplifted enough to mation and the succeeding beds is required as 

cause erosion .to begin, and locally there was there would be if the erosion of the regions. 

folding that tilted the beds. · The folds that outside of the San Juari Basin contributing the 

now delimit the north and west sides of the sedimentary materials all took place in postbasin ·probably began to form at this time, McDermott time. The erosion shown within 

though the movement continued at later times. the San Ju:an Basin and the change in flora 

After the uplift and erosio~. that carried from the McDermott to the Animas tend to 

away parts of the older beds, volcanic outbursts show, however, ·that a fairly long period 

to the north of the San Juan Basin again elapsed between Animas (and Ojo Alan1o) and 

poured out andesitic lava and ash. There was McDermott time. The Ojo Alamo sandstone, 

·apparently time for some weathering, and then like the Animas formation, was at many places 

a considerable thickness of this material, laid down on a surface with·few irregularities 

greenish gray in color~ was brought southward and gives little evidence of any gap in sediby streams and spread out t<? form what we mentation at its base. In the southeastern 

now call the Animas formation. In some part of the San Juan Basin it_ was deposited 

places it lies across the uplifted and eroded across the eroded edges of the older rocks. J n 

edges of the older formation. In others the region covered by the Ojo Alarno sand-
.PHYSICAL HISTORY Ol!"' .WESTERN PART OF SAN JUAN BASIN. 53 

stone dinosaurs were ntunerous and varied in rejon beds rest on the Puerco beds without a 

type. They were present also in the region conspicuous break-in fact, they are not sepacoverecl by the Ani1nas beds in early Animas rable by any recognizable difference in litholtinle, but little else is known of thmn there. ogy or structure. This feature is made more 

A variety of plants is known from the whole pronounced by the presence of a doubtful zone 

of the Ani1nas fonnation, which shows that the of sedin1ents that n1ay be either Puerco or 

flora was n1uch like that occurring in the simi-. Torrejon. There is reason, however, to belar deposits ·on the east side of tP,e present lieve that an interval not represented by sediRocky ~fountains. ments separated Puerco ·and Torrejon time. 

The deposition of the Anin1as and. Ojo The Torrejon deposits in the present Ani1nas 

Almno :formations was followed by another ·valley in· Colorado were laid directly on the 

period of locn.l folding nncl erosion. Upon the Animas beds, nnd it is possible, though indisur:face thus forn1ecl were laid down by rivers catecl only by negatjve evidence, that they re~.t 

the .n1ucl and sand thnt now constitute the at other places directly on the Ojo Alan1o 

Puerco nnd Torrejon fonnations. It is diffi- sandstone. The mammals and reptiles that 

cult to-clay to interpi·et the history of Puerco ,lived in Tqrrejon time, though similar to those 

and 'l'onejon ·time. The sediments of the of the Puerco, are sufficiently different to sugPuerco fonnntion did not cover a large area, gest the lapse of enough time to permit an 

so· fnr as now known, but those of the Tor- evolutionary change to take plnce. There may 

rejOJi spread out nluch farther ... In the region have been,. thm~efore, a gap between Puerco 

in which both occur they are so n1uch alike deposition and. Torre jon deposition,. but it cnn . 

·that they cnn not be sha;·ply separated. The not yet be rigidly proved. 

Puerco beds, consisting chiefly of dark muds In the north the deposition of materials 

nnd constituting the lower part of the series seems· to have continued without interruption 

of deposits, seem· not to have had a wide from Torrejon time through the interval repreextent-in fact, it would be pure conjecture to sented by the "Tiffnny" zone to true Wasatch· 

say that they n~uch exceeded their present tin1e. '"rhere was no Qhange in the sort of 

]nwwn area in the southwestern part of the sediments that accumulated: they were river-· 

San J'uan Basin. They were deposited on an formed muds and sands of much the same genirregular stu·face of Ojo Alamo sandstone, era1 type throughout. Some of. the animals of 

though the unconforn1ity is not a striking or . Torrejon time lived on into "Tiffany" time, 

conspicuous break. Possibly ~he Puerco beds when the :first Wasatch animals appeared. 

were laid down contmnporaneously with. the The fauna of the Torrejon beds therefore 

later beds of the Aninlas' formation, for they· grades through that of the" Tiffany" zone into 

both contain the same species of plants.. In that of the unquestioned Wasatch. In the 

south no equivalent .of the ((Tiffany". zone has 

the Puerco epoch man1mals became for the been found. There seems to have been an 

first time abundant in the region, and there interval of erosion in this part of the area, and 

were also nun1erous river turtles and croco- the Torrejon beds in San Juan County are 

cliles. The dinosaurs had disappeared com- followed sharply by the basal pebble-bearing 

pletely, and they appeared no more later. sandstone of the Wasatch, and this in turn by 

The Torrejon deposits n1ust have covered prac- alternating shale and sandstone. Near the 

tically the whole basin, for they 1nay be traced Jemez Mountains there. was some uplift, foldaround its south and west sides and reach the ing, ·and erosion after Torrejon. time, and the 

north side. Not the same sort of stuff was Wasatch formation was deposited upon the 

laid clown everywhere, however. In the south upturned and eroded edges. of the Torrejon:. 

chiefly muds were deposite9., some of them and older 't>eds .. Apparently sediments were 

sandy but with sand as only a minor par~. being laid down continuously on the north side 

Toward the north more pure sand was brought of the basin while deformation and erosion 

in and locally lenses of small pebbles in sand. were going on at the so'uth side. .How widely 

This difference is accentuated to-day· by the the Wasatch beds were originally· distributed 

fact that the clayey muds and sandy ~lids in this region is not clearly known, but they. 

forn1ed soft rocks, while the purer sands may have covered a very wide area and sin~e 

fonlled hard, resistant sandstones. The Tor- been greatly reduced by erosion. · 
54 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN .JUAN BASIN. 

BIBLIOGRAPHY. 

The list of publications given below includes 

those. referred to in this paper and a few others. 

. Many publications, especially the earlier papers 

dealing with the mammalian faunas, are omitted: References to these papers may be 

found in the bibliography included in the paper 

by J. H. Gardner on '' The Puerco and Torrejon formations of· the Nacimiento group," 

1910. . ' 

1875 Cope, E. D., The Eocene plateau: Chief Eng. 

Ann. Rept. 1875, pt. 2, 'Appendix G 1, pp. 

\ 981-1017. ' 

1877 Holmes, W. H., Geology of the San Juan district: U. S. Geol. and Geog. Survey Terr. 

Ninth Ann. Rept., for 1875, pp. 241-277. 

1910 

1912 

Brown, Barnum, The Cretaceous Ojo Alamo 

beds of New Mexico, with description of the 

new dinosaur genus Kritosaurus: Am. Mu;. 

Nat. Hist. Bull., vol. 28, pp. 267-274 . 

Lee, W. T., Stratigraphy of the coal fields of 

northern central New Mexico: Geol. Soc. 

America Bull., vol. 23, pp. 571-685. 

1914 Sinclair, W. J., and Granger, ·walter, Paleocene 

deposits of the San Juan Basin, N. Mex.: 

Am. Mus. Nat. Hist. Bull., vol. 33, pp. 297-

316. 

Brown, Barnum, Cretaceous-Eocene correlation in New Mexico, Wyoming, Montana, 

Alberta: Geol. Soc. America Bull., vol. 25, 

pp. 355-380. 

Matthew, W. D., Evidence of the Paleocene 

vertebrate fauna on the Cretaceous-Tertiary 

problem: Geol. Soc. America Bull., vol. 25, 

pp. 381-402. 1892 Cross, Whitman, .. Post-Laramie . deposits of 

C 1 d A J s · 3d 1 44 1915 Lee, W. T., Relations of the Cretaceous forma- o ora o: . m. our. c1., . ser., vo. , pp. 19-42. · tions to the Rocky Mountains in Colorado 

1896 ·Emmons, S. F., Cross, Whitman, and Eldridge, 

G. H., Geology of the Denver Basin in Colorado: U. S. Geol. Survey Mon. 27, p. 217. 

1897 

1899 

1900 

1902 

1906 

Matthew, W. D., A revision of the. Puerco fauna: 

· Am. Mus. Nat. Hist. Bull., vql. 9, pp. ·259-

323. 

Matthew, W. D., A provision::J,l classification of 

the fresh-water Tertiary of the West: Am. 

Mus. Nat. Hist. Bull., vol. 12, pp. 19-77. 

Cross, Whitman, U. _S.' Geol. Survey Geol. Atlas, 

La Plata folio (No. 60). 

Cross, Whitman, idem, Telluride folio (No. 57). 

Smith, J. H., The Eocene of North America west 

of the 100th meridian: Jour. Geology, vol. 6, 

pp. 448-449. . 

Douglass, Earl, The discovery of Torrejon mammals in Montana: Science, new ser., vol. 15, 

pp. 272-273. 

Schrad~r, F. C., The Durango-'Gallup coal field 

of Colorado and New Mexico: U. S. Geol. 

Survey Bull. 285, pp. 241-258. 

1907 Taff, J .. A., The Durango coal district, Colo.: 

· U. S. Geol. Survey Bull. 316, pp. 321-337. 

Shaler, M. K., A reconnaissance survey of the 

western part of the Durango-Gallup coal 

_field of Colorado and New Mexico: U. S. 

Geol. 'Survey Bull. 316, pp. 376-426. 

1909. Gardner, J. H., The coal field between Gallina 

and Raton Spring, N. Mex., in the San Juan 

coal region: U. S. Geol.·Survey Bull. 341, pp· 

335-351. 

1910 

Gardner, J. H., The coal field between Durango, Colo., and Monero, N .. Mex.: U. S. 

Geol. Survey Bull. 341, pp. 352-363. . 

Gardner, J. H., The Puerco and Torrejon formations of the Nacimiento group: Jour. Geology, 

vol. .18, pp. 702-741. 

Gardner, J. H., The coal· field between San 

Mateo and Cuba, N. Mex.: U.S. Geol. Survey 

Bull. 381, pp. 169....:181. 

·1~16 

and New Mexico: tJ. S. Geol. Sur~ey Prof. 

Paper 95, pp. 27-58. 

Gregory, H. E., The Navajo country-a geographic and hydrographic reconnaissance ofparts of Arizona, New Mexico, and Utah: 

U. S. Geol. Surv~y Water-Supply Paper 380. 

-Contributions to ·the geology and paleontology 

of San Juan County, N. Mex.: U. S. Geol. 

Survey Prof. Paper 98, pp. 271-353: 

1. Bauer, C. M., Stratigraphy of a· part 

of the· Chaco River valley. 

2. Gilmore, C. W., Vertebrate faunas of 

the Ojo Alamo, Kirtland, and Fruitland formations. 

3. Stanton, T. vV., Nonmarine Creta-. 

ceous invertebrates :of the San Juan 

Basin. 

4. Knowlton, F. H., Flora of the Fruitland a~d Kirtland formations. 

1917. Granger, Walter, Notes on Paleocene and lower 

1919 

Eocene mamm:;~.l horizons of northern New 

Mexico and southern Colorado: Am. Mus. 

Nat. Hist. Bull., vol. 37, pp. 821-830. 

Matthew, W. D., A Paleo·cene bat: Am. Mus. 

Nat. Hist. Bull., vol. 37, pp. 569-:-571. 

Matthew, W. D., The dentiton of Nothodectes: 

Am. Mus. Nat. Hist. Bull.,· vol. 37, pp. 

831-839, 1917. 

Lee, W. T., and Knowlton, F. H., Geology and 

paleontology of the Raton Mesa and other 

regions in Colorado and New Mexico: U. S. 

Geol. Survey Prof. Paper 101, pp. 162-218. 

Gregory, H. E., Geology of the Navajo countrya reconnaissance of parts of Arizona, New 

Mexico, and Utah: U. S. Geol. Survey Prqf. 

Paper 93. 

Gilmore, C. W., Reptilian faunas of the Torrejon, 

Puerco, and underlying upper Cretaceous 

formations of San Juan County, N. Mex.: 

U. S. Geol. Survey Prof. Paper 119. 
LOCAL SECTIONS. 55 

1919 Co\Iier, A. J., Coal south of Mancos, Montezuma 

·county, Colo.: U. S. Geol. Survey Bull. 691, 

pp. 293-310. 

1920 Bauer, C. M., and Reesicle, J. B., jr., Coal in the 

middle and eastern parts of San Juan County, 

N. Mex.: U. S. Geol. Survey Bull. 716, pp. 

155-237. 

1921. Matthew, \V. D., The Cannonball Lance formation: Science, new ser., vol. 54, pp. 27-29. 

Gilmore, c. v.,r., Sauropod dinosaur remains: 

Science, new ser., vol. 54, p. 274. · 

Matthew, Vi. D., and Granger, ·walter, New 

genera of Paleocene mammals: Am. Mus· 

Nat. l:Iist. Novitn,tes, No. 13. 

Matthew, \V. D., Fossil vertebrates and the 

Cretaceous-Tertiary problem: Am. Jour. Sci., 

5th ser., vol. 2, pp. 209-227. 

1922 Gilmore, C. vV., A new sauropod dinosaur from 

the Ojo Ahuno formation of New :Mexico: 

. Smithsonian Misc. Coll., vol. 72, No. 14, 

pp. 1-9. 

1923 Osborn, H. F., A new genus and species of 

Cemtopsia from New Mexico, Pentacemtops 

stentbergii: Am. Mus. Nat. Hist. Novitates, 

No. 93. 

tOCAL SECTIONS. 

Section exposed along Cat' Oreelc north of Pagosa 

J'unction, Colo. 

Wasatch foi·mation: 

Brown sandstone and gray and reddish 

shale, thickness not determined. 

Feet. 

Animas formation-Co11tinued. 

Sandston9, fine, greenish, tuffaceous __ :.. ___ _ 

Shale, greenish gray to tan, tuffaceous ___ _ 

Sandstone, fine grained, greenish gray, 

tuffaceous; contains plant remains _____ _ 

Shale, greenish gray to tan _____________ _ 

Sandstone, fine grained, greenish gray. to 

brown; contains plant remains ________ _ 

Shale, greenish gray ____________ - ______ _ 

Sandstone, greenish gray, platy, tuffaceous; 

contains plant remains,... ______________ _ 

Shale, greenish gray to tan, tuffaceous, and 

soft salidstone _______________________ _ 

Sand~tone, greeriish gray, tuffaceous _____ _ 

Shale and soft sandstone, tuffaceous, green:.. · ish gray ____________________________ _ 

Conglomerate, pebbles, nearly all of greenish weathered andesite; matrix greenish 

andesitic debris; a few quartz and quartzite· pebbles present; prominent ridgeforming unit; plant remains abundant __ _ 

Shale and indurated sandstone, interbedded; all tuffaceous, greenish gray; 

some layers conglomeratic.; plant reFeet. 

15 

85 

10 

30 

5 

65 

5 

285 

5 

190 

75 

mains abundant_ ___ ~_________________ 260 

Conglomerate, massive, greenish gray; 

pebbles of andesite with niany of quartz, 

quartzite, and other rocks __ --.--------- 25 

Shale and thin sandstone, greenish gray, not 

well exposed ________________ · __ ._ _ _ _ _ _ _ 195 

Total Animas formation _______________ 1, 840 

Unconformity. 

Sandstone, coarse, rusty brown arkosic ___ _ 5 Fruitland formation: 

Shale, variegated, red, gray, green, with 

small dark-colored · phosphatic concre- tions _______________________________ _ 

Sandstone, coarse, arkosic, brown to greenish gray; has coarse feldspar pebbles locally _____________________________ _ 

Shale, variegated, red, gray, and green; 

contains some soft argillaceous sandstone. 

The lower part of this shale contains the 

"Tiffany" fauna ____________________ _ 

Unconformity. 

Animas .formation: 

Sandstone, greenish gray and green, fine 

grai ried, tuffaceous __________________ _ 

Shale, greenish gray to tan, tuffaceous ____ _ 

Sandstone, green to tan, fine grained, tuffaceous __________________________ _ 

Shale, greenish gray to tan, tuffaceous ____ _ 

Sandstone, green to tan, fine grained, 

tuffaceous; contains plant remains _____ _ 

Shale, greenish gray to tan, with some soft 

sandstone; tuffaceous _____________ :.. __ _ 

Sandstone, greenish gmy, fine grain~d, 

tuffn,ceous; contains plant remains _____ _ 

Shale, greenish to tan, with so~ne soft sandstone; contains plant fragments _______ _ 

Sandstone, greenish gray, massive; some 

lenses of fine conglomerate present _____ _ 

Sl-iale, greenish, with some sandstone lenses_ 

Sandstone, bluish gray, dense, medium 

grained; full of vegetable debris________ 6 

65 Shale, gray_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5 

Shale, brown, carbonaceous______________ 9 

Coal bed______________________________ 2 

25 Shale, brown, carbonaceous______________ 10 

Coal bed_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 4 

Shale, brown, carbonaceous______________ 10 

Sandstone, thin bedded, gray, medium 

.305 grained-------~----------~----------- 3 

Shale, brown to black, carbonaceous______ 14 

Sandstone, heavy bed, brown____________ 4 

ShaJe, brown, carbonaceous______________ 2 

Coal bed ___ ~---------~---------------- 3 

30 Shale, brqwn, carbonaceous ______ -------- 70 Pictured Cliffs sandstone: :Massive gray to 

20 

70 

brown marine sandstone __________________ _ 

Lewis shale. 

4 

150 

Section on Pine River-Piedm River divide in sees. 29, 

10 31., 32, T. 35 N., R. 5 W., Colo. 

120 Wasatch formation: . Feet. 

Top ·of formation eroded off. 

10 Sandstone, rusty brown, indurated, and 

gray shale, not well exposed; some ·beds 

200 of conglomerate with pebbles of pink 

feldspar, quartz, and chert. Lower .470 

40 feet of this unit measured; remainder 

20 estimated to crest of divide ____________ 1, 000 

• 
56 UPPE.R CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

'Vasatch formation-Continued. FeJJt. Animas formation-Continued. Feet: 

Arkose, coarse, with pebbles of pink feldspar 

as much ;:ts three-fourths of an inch in 

diameter in a fine greenish matrix; conglomeratic layers separated by thick 

layers of variegated red, green, and gray 

shale. The shale forms the bulk of the· 

unit, but the arkose is resistant and more 

prominent. The lower part of this unit 

contains in this section the "Tiffany" 

fauna ___________________________ ·____ 39.0 

Unconformity, shown by absence of Torrejon 

formation. 

Animas formation: 

Shale, greenish gray to tan, fairly well 

.exposed------------~---------------- 220 

Sandstone, greenish gray ____ ~ ___________ · 5 

'Shale, greenish gray to tan, poorly exposed----------------------------~-- 115 

Sandstone, greenish gray, with andesitic 

debris, medium grained _____________ :__. ·10 

Shale,· green~sh gray to tan; some sandstone included _________ ~------.------- 780 

Sandstone, gr·eenish gray, with andesitic · debris, platy ____________ .:. ____________ . 10 

Shale, greenish gray to tan, fairly well 

exposed------------------~---------- 270 

Sandstone, green, thin, platy ____ .:.. _ _,_·_.____ 2 

Interval poorly exp.osed; probably all greenish shale and fine sandstone___________ 370 

Conglomerate; pebbles all of greenish andesite, as much as 1 inch in diameter______ 5 

·Interval poorly exposed; probably all green-· 

ish shale and fine sa.lldstone_ _ _ _ _ _ _ _ _ _ _ _ 515 

Conglomerate, rather fine; pebbles all andesite in tuffaceous matrix; greenish gray__ 5 

Interval conceaJed_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 23 

Sandstone, coarse, green, tuffaceous_______ 1.0 

Conglomerate, pebbles 2 to 4 inches in diameter and mostly of greenish andesite__ 10 

Interval concealed______________________ 170 

Sandstone, or grit, tuffaceous, greenish gray 10 

. Interval concealed ____ ·~----------------- 100 

Sandstone, containing much fine andesitic 

debris and pebbles of andesite, greenish 

graY---------------------~---------- 40. 

Total Animas formation_____________ 2, 670 

Unconformity, 

Kirtland shale and Fruitland formation, undiff eren tia ted __________ ~-_____________ ~ _ _ _ _ _ _ 7 9 5 

Pictured Cliffs sandstone----------~--------- 125 

·Section of Anim.as and McDermottformations on Animas 

River 4 miles south of Durango, ()olo. 

Torrejon formation. 

Unconformity.· 

Animas formation: Feet. 

Shale, sandstone, and fine ·conglomerate, 

greenish gray to tan;. contains much 

weathered andesitic. d-ebris ____ ~~_______ 850 

Conglomerate, massive; pebbles and cobbles as much as 6 inches i~ diameter, of 

greenish andesite chiefly_ but with a considerable admixture of quartz, quartzite, 

etc.; greenish gray to brown___________ 25 

Shale, yellow, sandy, weathered; coi1tains 

andesitic debris ________ :______________ 30 

Conglomerate, much like second unit above,.· 10 

Shale, yellow, sandy, much weathered; 

probably contains much fine andesitic 

debris_______________________________ 35 

Conglomerate, much like second and 

fourth units above____________________ 25. 

Shale, greenish gray ·to tan,. gritty; contains andesitic debris__________________ 55 

Conglomerate, massive; pebbles and cobbles 

· practically all of greenish andesite, 6 to 8 

inches in diameter, with a few rare pebbles of other rocks; contains fossil logs__ 25 

Tuff, green to buff; much <?f it about as 

coarse as sand but some parts really a 

fine conglomerate and here and there a 

little coarse conglomerate; .material all 

weathered andesite. Some maroon bands 

near the top of the unit and some black 

carbonaceous shale___________________ 40 

Conglomerate, massive; contains boulders 

as much as 3 feet in diameter though 

mostly cobbles 6 to 8 inches in diameter;· 

poorly sorted; practically all of greenish 

andesite with very rare quartzite and 

sandstone ___________________________ ~ 15 

Total Animas formation _______________ 1, 110 

Unconformity. 

McDermott formation: 

Shale, tuffaceous, or laminated tuff; purple 

to maroon, with a few gray streaks; a 

little fine conglomerate ___________ .____ 40 

Tuff, finely. conglomeratic, massive, pui·ple; 

weathers _.into angular fragments_______ 28 

Conglomerate, gray to purple, locally stratified; contains pebbles and cobbles of 

andesite mostly from 1 to 8 inches in diameter but a few as large as 18 inches; 

all subangular; matrix of same material 

as pebbles____________________________ 15 

Shale, tuffaceous, ·purple, laminated, alternating with layers of massive, nonlaminated volcanic debris______________ 45 · 

Sandstone, dense, bluish gray, finely and 

regularly laminated; breaks with conchoidal fracture; practically a porcellanite; weathers almost white ________ :__ 8 

Tuff, purple, containing masses of andesite 

as ri1uch as 4 feet in diameter__________ 100 

Sandstone, yellow, coarse, containing volcanic detritus; near the base a thin shale_ 20 

Total McDerm,ott formation ___________ . 256 
' I 

LOCAL SECTIONS. 57 

Sharp contact, without angulat; discordance; Feet. 

may be an unconformity. 

Kirtland shale and Fruitland formation undifferentiated_______________________________ 1, 200 

Pictured Cliffs sandstone. 

Sect·ion along north side of NE. t NW. t sec. 6, T. 32 N., 

R. 1J. W., La Plata Cmmty, Colo. 

Torrejcin formation: Feet. 

Beds above section mostly concealed, but 

some exposures of light-gray shale are 

visible. 

Shale, drab and yellow-brown _____ '_______ 30 

Shale and soft sandstone, light gray _____ ~. 30 

Shale, drab and yellow-brown____________ 40 

Sar1dstone, ·fine, hard, bluish gray on fresh 

surface and· dark reddish brown on 

weathered stu·face________ ___ _ _ ___ _ _ _ _ _ 3 

Shale, drab and yellow-brown____________ 40 

Concealed interval, forming a valley, probably shale____________________________ 240 

Unconformity · probably present · though not 

observed. 

McDermott formation: 

Conglomerate of siliceous pebbles in a 

matrix of brownish andesitic tuff______ 2 

Interval, largely concealed but apparently 

consisting of yellow-brown tuffaceous 

sha~-----------------~-------------- 84 

Sandstone, gray-white, with lenses of siliceous pebbles; pebbles reach 3 inches in 

diameter ___ . __________________ ~ _ _ _ _ _ _ 25 

Beds below section concealed in valley; prob- ' 

ably Kirtland shale. 

Section of JlticDermott formation at center of NW. i . SW. i sec. 5, T. 32 N., R. 11 W., La Plata County, 

C~o. · 

Beds above section concealed; probably all in 

Torrejon formation. 

McDermott formation: 

Conglomerate of siliceous pebbles in ~brown 

tuffaceous matrix; pebl;>les reach 2 or 3 

inches in diameter_ __________________ _ 

Shale, yellow:, ashY----~----------------

Conglomerate like that above ___________ _ 

Shale, . purple, tan, and drab, with thin 

sandstone layers_---------------------

Sandstone, bluish gray, tuffaceous, in thin 

nodular layers separated by· sandy shale 

of greenish-gray color; upper part of unit 

contains many cobbles of weathered 

andesite; some dinosaur bones,. turtle 

bones, and silicified wood ____________ _ 

Shale, purple, tan, and drab, with some· 

thin· sandstone layers, all containing 

debris from igneous rocks ____ ~_~ _____ _ 

Sandstolw, gray, coarse, with siliceous pebb~s--------------------------------- Shale, gray and p\rrple _________________ _ 

Beds below section concealed to the Farmington 

sandstone member of Kirtland shale. Probably .in part ]{irtland shale. 

Feet.' 

4 

2 

2 

17 

33 

22 

3 

30 

Typical section of M cbermott fonnt.ttion at south side 

of S~V. 't NW. t sec: 19, T. 32 N .. , R. 11 W., La Plctta 

County, Colo. 

Beds l;>elonging to the Torrejon formation mostly 

concealed but with rare exposures of light-gray 

shale, gray-white soft sandstone, and some 

black carbonaceous shale.and thin green sandstone. 

Unconformity. 

McDermott formation: Feet. 

· Conglomerate of pebbles of bright-red 

jasper, reel and white quartzite, chert, and 

rarely andesite; pebbles all chattermarked i:wd as large as 6 inches in cliameter; matrix andesitic tuff_____________ 4 

Shale, yellow-brown, sandy ______ ~_______ 60 

Conglomerate like that above_~__________ 2 

Shale, purple and · yello,v, containing volcanic debris ______________ _. _______ .. ___ 32 

Conglomei·ate, drab to green, composed of.· 

andesite pebbles, cobbles, and boulders 

as much . as 1 foot in diameter and a 

sprinkling of small jasper, quartzite, and 

quartz pebbies; matrix andesitic tuff. 

Unit irtegular along strike. Dinosaur 

·and turtle bones in place______________ 8 

Shale, drab to purple, containing volcanic 

debris ______ ~:--~-----------------~-- 40 

Sandstone, light gray to white, containing 

pebbles of andesite and andesite debris__ 20 

Sandstone, fine, soft, yellow-brown, capped 

·.by ltard, thin platy greenish sandstone; 

loose fragments of dinosaur bone scattered on surface_________________________ 15 

Shale, purple, containing volcanic debris___ 10 

Sandstone, gray-white, coarse ______ · ____ ~ 2 

Shale, variegated, purple and blue-gray, 

containing volcanic debris_____________ 40 

Conc.ealed mostly but apparently occupied 

by sandy yellow-brown shale___________ 85 

Sandstone, gray-white, coarse, t)oorly exposed. Contains lenses of· coarse grit 

and some small quartz and chert pebbles 

and also fossil logs ___ ._________________ 10 

Concealed to Farmington sandstone. member of 

Kirtland shale; interval probably all IGrtland 

shale. 

328 

Section of lower 1JO,?'l of Wasatch formation and 1.tppe1· 

part of Torrejon formation nea1· Cedar Hill, N. Jltfex., 

in sees. 31 and 34, T. 32 N., R. 10 W. 

Wasatch formation: 

Top of formation eroded. Feet. 

Sandstone, gray-white to copper-reel, coarse, 

hard, resistant, and shale, variegated purplish and dove-gray, with some soft, white 

sandstone; . the hard ·sandstone layers 

thicker than the shale. East of the 

point of measurement perhaps 500 feet 

more of similar shale and sandstone beds 

are in sight_------------ -------------- 200 
58 UPPER CRETACEOUS AND TERTIARY FORlVIATIONS IN SAN JUAN BASIN. 

W.asatch formation-Continued. 

Sandstone, gray-white to copper-red, hard, 

resistant_ __________________________ _ 

Shale, variegated, purplish, dove-gray, with 

soft white sandstone __________________ _ 

Sandstone; gray-white to copper-red, resistant _________________ ~---------------

Shale, variegated _____ · _________________ _ 

Sandstone, gray-white to copper-red, resistant ________________________________ ~ 

Shale, variegated ______________________ _ 

Sandstone, gray-white to copper-red, resistant ________________________________ ~ 

Shale, variegated purplish and dove-gray, 

with some soft ·white sandstone ______ ...,_ 

Sandstone,· massive, .persistent, gray-white 

to copper-red, coarse; some parts of the 

rock a grit composed of grains as coarse 

as rice; many chert and quartz· pebbles 

, in the coarse layers; ·a few thin streaks 

with carbonaceous debris ·and stem im- pres~ons ___________________________ _ 

Shale, dove-gray ______________________ _ 

Sandstone, massive, persistent, gray-white 

to copper...,red, coarse, composed locally 

of quartz and jasper but usually of white 

quartz; contains scattered pebbles 1 

inch or less in diameter_·-:.. __________ _ 

Torrejon formation: 

Clay sl{ale, greenish gray, \vith some carbonaceou.s streaks ______________ :.. ____ _ 

Sandstone, soft, gray-white,· coarse _______ _ 

Shale, greenish gray, with carbona~eou~ 

bands near base _____________________ _ 

Sandstone, coarse, gray-white, containing pebbles _____________________________ . 

Shale, greenish gray, with carbonaceous 

bands; contains remains of turtles (Hoplochelys sp., Compsemys sp. Adocus sp., 

trionychid turtle) _____________ · ______ _ 

Sandstone, coarse, gray-white to copperred, resistant _______________________ _ 

Shale, variegated, .wine-red, purple, gray, 

Feet. 

30 

30 

10 

50 

30 

30 

10 

70 

145 

20 

75 

10 

10 

40 

15 

40 

15 

Unconformity, if present at all, very obscure. 

Torrejon formation: 

Sandstone and shale. The sandstone copper-red to gray, lenticular, cross-bedded; 

lighter in color than ·wasatch and softer, 

forming more rounded and broken ledges; 

in hand specimen coarse, friable, chiefly 

of quartz; contains many pebbles of 

chert, gray to black, and quartz 1 inch 

or less in diameter. Sandstones separated by shale, light gray and dark 

gray in lo·wer half of unit but containing red bands 'in upper half like those near Cedar HilL __ .:. _________________ _ 

Shale and sandstone. The shale light · 

gray, dark gray, sanely, and black, carbonaceous; the sandstone -soft, yellowish and white. Unit contains few resistant beds, and outcrops are not numerous_~-----------------------------

Sandstone, brown, fine grained, platy, in 

gray and yellowish sandy shale _______ _ 

U nconform~ty. . 

McDermott formation: 

Conglomerate of siliceous pebbles in a 

brown matrix containing volcanic debris_ 

Shale, yellow-brown, sandy __________ , ___ _ 

Conglomerate composed qf weathered andesite pebbles as much as 8 inches diameter in a matrix of andesitic debris. 

Unit very irregular in composition and 

thickness, greenish gray to drab; con-

, tains scattered dinosaur bones _________ _ 

Shale, variegated purple, white, and green; 

contains volcanic debris ______________ _ 

Sandstone, white to yellow, coarse; contains volcanic debris; well indurated ___ _ 

Sandstone,· soft, white to yellow, coarse, 

with some shale probably. Unit poorly 

exposed and may include some Kirtland 

shale ii1 lower part_ __________________ _ 

Beds below concealed to Farmington sandstone 

· member of Kirtland shale. 

Feet. 

700 

700 

50 

3 

40 

15 

74 

15 

125 

and white, with soft sandstone in thin 

beds _______________________________ _ 

Sandstone, coarse, gray-white to copperSection of McDermott formation on east bank of La 

70 Plata River in SW. ± SW. ± sec. 23, T. 32 N., R. 13 

W., N.Mex. 

red, resistant ______________________ ..: __ 

Shale, variegated, red, purple, gray, and 

white, an'd soft sandstone. Unit con20 Torrejon formation: Gray shale and soft gray 

sand-stone. 

tains two local lenses of indurated brown 

sandstone. Periptych1ts sp. and H oplochelys sp. near base____________________ 200 

Beds below concealed by alluvium, etc. 

Section across Pruett pasture, in sees: 16, 22, and 26, 

T. 32 N., R. 12 W., .San ·Juan County, N. Mex. 

Wasatch sandstone: Sandstone, copper-red 

to gray, resistant; forming vertical unbroken faces and resting apparently without sinuous contact ori the Torrejon beFeet. 

low. Persistent along strike__________ 100 

Unconformity. 

McDermott formation:, 

Conglomerate of siliceous pebbles in a hard 

dark-brown ferruginous matrix ____ :.. ___ _ 

Intervals with beds poorly exposed but apparently of brown, gray, and faintly purplish shale with some thin whitish sandstone. •Dip difficult to determine and 

thickness here given may be excessive __ _ 

Sandstone, greenish gray, pitted; cont~ins 

volcanic debris __________________________ _ 

Sandstone, fine grained, white to yellow, 

with volcanic debris and scattered pebbles of siliceous materials _____________ _ 

Feet. 

·.2 

170 

6. 

15 
LOCAL SECTIONS. 59 

McDermott formation-Continued. 

Sandstone, platy, gray, fine grained ______ _ 

Shale, variegated purple, gray, and green- ish _________________________________ _ 

Shale, yellow _________________________ -_ 

Beds below concealed by ·wash; pi·obably all 

Kirtland shale. 

Feet. 

2 

34 

17 

Section of·McDennott fonnation in SW. iSW. t sec. 8, 

'1'. 31 N., R. 13 W., N.Mex. 

['l'hieknesses approximate.] 

McDermott formation-Continued. Feet. 

Concealed interval, probably soft' yellow 

sandstone ________ ~------------------ 16 

Shale, sandy, black, carbonaceous_ _ _ _ _ _ _ _ 4 

Sandstone, soft, gray, nonresistant; pebbles on surface but none seen in place;. 

contains some carbonaceous lenses and 

becomes yellow toward top; exposed ___ _ 

Concealed interval, extending to. outcrop of 

Farmington sandstone member of Kirtland 

shale. 

12 

Beds Section of McDermott formation in NW. t NE. i sec. above section concealed by wash, etc. 

McDermott formation: Feet. 19, T. 31. N., R. 13 W., N.Mex. 

Shale, purple, with volcanic debris, and 

shale, sandy, brown and drab__________ 40 

Sandstone, gray-white, coarse, with volcanic debris and many pebbles of siliceous 

materials as much as 4 inches in diameter_ 5 

Shale, variegn.tecl, purple, white, etc.; contains volcanic debris__________________ 60 

Sandstone, brown, platy, hard~---------- 2 

Shal9, purple ___________________ _:______ 10 

Shale, sandy, greenish gray, brown, and 

purple______________________________ 40 

Sn.nclstone, soft, gray-white to yellow, 

poorly exposed________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 50 

Beds below concealed by terrace gravels; probably all Kit-tlancl shale. 

Section of McDennot.t formation at center of sec. 18, 

'1'. 31 N., R. 13 W., N .. Mex. 

vVash, wind-blown sand, etc., cover higher beds 

at this point, but along the' strike light-gray 

and white soft sandstone ·and shale are exposed that aro part of the Puerco and Torrejon succession. 

Unconformity. 

McDermott formation: Feet. 

Sandstone, conglomeratic, lim~nitic, brown 

to black,· well indurated; pebbles of 

qun.rtz, jasper, volcanic rocks, and other 

siliceous resistant materials____________ 1 

Shale, drab ______________ ·______________ 2 

Sandstone, white to yellow, soft, finegrained-----------------~----------- 18 

·sn.ndstone, gray-white, dense, resistant, 

containing many pebbles of siliceous 

mn.terials (quartzite, jasper, chert, .and 

volcn.nic rocks)_______________________ 3 

Shale, vn.riegatecl purple, pink, and greenish gray; rather coarse in grain; contains 

volcanic debris_______________________ 16 

Sn.ndstone, coarse, gray-white, argillaceous, 

soft; rather drab on fresh surface ______ _ 

Shale, dove-colored, not sanely, alternating irregularly with greenish-gray sandy shale_. 

Sandstone, gray-white, medium grained __ _ 

Shale, clove-colored, not sandy __________ _ 

Sandstone, gray-white, medium grainecL __ 

Shn.le, dove-colored, not sandy __________ _ 

Shale, · very sandy, greenish. yellow and 

white, poorly exposed _____________ ~ __ _ 

8 

16 

1 

9 

1 

9 

10 

Beds above section concealed by wash,. windblown sand, etc., apparently basal part of 

Puerco and Torrejon succession. 

McDermott formation: Feet. 

Sandstone, hard, brown, filled with pebbles 

of siliceous materials as· large as a man's 

fist_________________________________ ·3 

Shale and soft sandstone, gray and purple, 

tuffaceous--------------~------------ 10 

Sandstone, white to ecru, coarse, tuffaceous. 10 

Shale, variegated purple, gray, and brown, 

tuffaceous--------~---~--------------· 50 

SandF)tone, gray-white to brown, coarse___ 40 

Beds below section concealed under the valley 

extendiug to outcrop of Farmington sandstone 

4nember of Kirtland shale. 

Section of Frnitland fonnation on divide between Barker 

An·oyo and Yo'ungs Arroyo, San Jtwn County, N. 

Mex. 

[Measured by Harvey Bassler .1 

Kirtland shale. 

Fruitland formation: Feet. 

Shale and sandstone____________________ 80 

Sandstone_____________________________ 5 

Shale ______________ ~------------------ 20 

Sandstone---------------~------------- 10 

Shale, car))onaceous in part______________ 80 

Coal, high in ash_______________________ H 

Shale, carbonaceous ____________ ·_________ 2~ 

Coal bed with partings__________________ 1 

Shale, carbonaceot~s _____ ' ____ ~ __ ._ _ _ _ _ _ _ _ _ 2 

Coal bed with partings__________________ 4 

Shale, carbonaceous_____________________ 3 

Coal-------------------~-------------- ~ 

Shale, carbonaceous in part _______ ~------ 75 

Coal bed witl~ partings ___ ..,______________ 14 

Shale and sandstone____________________ 125 

Coal-----------------------~---------- 26 

Pictured Cliffs sandstone. 

426 

Section along north side of NW. t sec. 1, 1'. 30 N., 

R. 14 TI_T., N. 111ex. 

[1Vteasurecl by Harvey Bassler.] 

Ojo Alamo sandstone: Sandstone, massive, 

coarse grained, gray to brown, with streaks 

and lenses of coarse conglomerate of siliceous 

Feet. 

pebbles; top eroded; thickness present_______ 45. 
60 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Unconformity. 

McDermott formation: 

Shale, greenish and gra·y ________________ _ 

Sandstone, coarse, arkosic, soft, with some pebbles in lower part __ -_____________ _, __ 

Sandstone, coarse, soft, with pebbles of 

chert and jasper as much as 3 inches in 

diameter_ ~ _____ ~ ___________________ _ 

Shale, maroon _________________________ _ 

Sandstone, dense, gray, quartzose _______ _ 

Shale and sandstone, green and maroon __ _ 

Sandstone, dense, fine, hard, with apparently some ash in its composition ___ _ 

Shale, green and maroon _____ · __________ _ 

Sandstone, coarse, 'vith clay balls and s~aly 6ands _________________________ _ 

Sandstone, coarse, soft, with pebbles of 

chert and quartz as much as 2 inches 

in diameter _________________________ _ 

Sandstone and shale, maroon ___________ _ 

Sandstone, soft, arkosic; weathers to gray 

and drab color; pink grains common; 

basal 6 feet weathers pisolitic ___ "" _____ _ 

Sandstone, green, micaceous ____________ _ 

Shale, gray, greenish, and maroon, and 

. sandstone ____ ~---~~---------~-------

Sandstone, coarse, gray, arkosic;· weathers 

to a buff color_ ____ =------------------.-

Feet. 

4 

23 

H 

6 

1 

10 

1 

5. 

7. 

3! 

25 

40 1. 

2 

37! 

15 

Section at center of sec. 2, T. 30 N., R. u,.· W., N. Mex. 

Ojo Alamo sandstone: Sandstone, massive 

gray-white to· copper-red, containing lenses 

of siliceous ·resistant pebbles; top eroded, 

thickness of ·part present . .:.~ _____________ ,__~ 50 

lJnconformity. 

McDermott formation: 

Shale·, drab and rusty brown_____________ 30 

· Sandstone, coarse, gray-white, indurated, 

with a thin purple shale layer near 

middle that contains volcanic debris____ 15 

Sandstone, soft, .gray-white, rather coarse 

grained; .contains volcanic debris~______ 30 

Shale, variegated Pl!rple, green, and light 

gray; contains volcanic debris_-..:------- 40 

Sandstone, soft,. gray-white, coarse; contains volcanic debris__________________ 22 

Shale, variegated purple, green, and gray, 

sandy; contains volcanic debris_________ 22 

Sandstone, soft, gray-white, coarse grained; no pebbles seen ________________ :... __ ~__ 10 

Total McDermott formation___________ 169 

Kirtland shale. · 

Section of McDermott formation on north side of Pinyon 

.1l1esa in NE. i SW. i sec. 2, T. 30 N., R. 11,. ·w., 

N .. Mex., 

[Measured by C. E. Dobbin.] 

Ojo Alamo sandstone. 

Unconformity. 

McDermott formation: Feet. 

Shale, gray and green, with one thii1 layer 

of purple_· ______ .:. _______ -: __ ~_________ 46 

McDermott formatiol.1-Continuecl. Fe~t. 

Shale, variegated reel, purple, gray, green, 

and black, capped by a thin persistent 

layer of fine-grained sandstone; contains 

volcan1eclebris __ --------------------- . 6 

Sandstone, gray, with some thin lenses of 

purple shale _________ ·________________ 17 

Shale, purple, contains volcanic debris____ 6 

Shale, yellow, with lenses. of fine-grained 

yellow sandstone, containing -volcanic 

debris _____________________ ·_________ · 23 

Beds beneath concealed by debris. 

Section of :McDermott formation mi north· side of Pinyon 

Mesa in SE. ·t SE. i sec. 3, T. 30 N., R. 1/, W., 

N.Mex. 

Ojo Alamo sandstone. 

Unconformity. 

McDermott formation: 

Shale, gray and yellow ____________ ~ ____ _ 

Shale, gray and purple, with thin sandstone 

attOP------------------------~----- Sanclstone, quartzitic _____ ·_"'" ___________ _ 

Shale, variegated purple, gray, and white, 

micac.eous, with volcanic materiaL ____ _ Shale, gray ______________________ :.. ____ _ 

Shale, purple, micaceous, with volcanic 

materiaL ___ · ______________ -.- ___ -____ _ 

Shale, drab __________ ..:. _______________ ._.,. 

Shale, yellow, sandy, grading dovmward 

into soft yellow sandstone-. ____ :... ____ · __ _ 

Shale, drab, with a 4-inch layer of iildurated 

gray sandstone at top; appears to· contain volcanic materiaL-...,----'------ 1 --

Sandstone, coarse, gritty·, light gray, with 

volcanic materiaL _______ -.- __________ ·_ 

Kirtland shale. 

Feet.-

22 

23 

2 

10 

40 

2 

13 

17 

30 

6 

165 

Section on north side of Pinyon Mesa at center of N E. t sec. 10, T. 30 N., R. 14 W., N. ll'Iex. 

Ojo Alamo sandstone: Sandstone, massive, 

cliff-forming, conglomeratic; light gray to 

copper~red; contains a few thin lenses of shale 

and many pebbles· of siliceous rocks as much 

as 5-inches in.diameter; top eroded, thickness 

Feet. 

of part remaining_________________________ 50 

Erosional unconformity. 

McDermott formation: 

Shale, gray to purple, with volcanic materiaL 10 , 

Sandstone, light gray, containing volcanic 

debris; rather resistant; ·forms ledge:_ 10 

Shale, light gray, grading upward .into soft 

gray sandstone with purple and green 

streaks; contains volcanic materiaL____ 33 

Sandstone, soft, coarse, gray; contains volcanic material_______________________ 10 

Shale, purple and green; contains volcanic 

materiaL_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 8 

Sandstone, light gray, micaceous ___ ._______ 2 

Shale, purple and green, fine grained_-.-__ 14 

Sandstone, green, micaceous _________ _; ___ -· 1 

Shale; light gray,· sandy, with some local 

lenses of soft yellow sandstone________ 30 
LOCAL SECTIONS. 61 

McDermott formation-Continued. 

Sandstone, gray-white, soft, fine grained, 

· irregular; a channel sandstone ___ :. ____ _ 

Shale, light gray, sandy ________________ _ 

Sandstone, coarse, gray to yellow, irregularly indurated; with lenses of small 

pebbles of chert and quartz, rounded to 

subangular, attaining three-fourths inch 

in diameter. Small lenses of carbonaceous shale and silicified logs present __ 

Total McDermott formation __________ _ 

Kirtland shale: 

Light-colored mass of light-gray and 

greenish-gray shale and gray-white soft 

sandstone containing brown hard concretions; forms a valley---------------

Sandstone, gray to brown, indurated, and 

gray shale, forming Farmington sandstone member of Kirtland ____________ _ 

Shale, gray and greenish gray, soft graywhite sandstone; very irregularly beddedFeet. McDermott formation-Continued. Feet. 

Sandstone, soft, gray-white, rather coarse 

5 grained; contains volcanic materiaL___ 28 

18 Shale, purple _____________________ ·______ 1 

Sandstone, soft, gray-white, coarse grained; 

contains volcanic debris_______________ 29 

Shale and sandstone, purple, green, gray, 

brown, varying rapidly in color and composition laterally and vertically; con10 tains volcanic materiaL_______________ 55 

Sandstone, brown, soft, at places carbona151 ceous and well indurated ___ ·-----~----- 10 

220 

500 

400 

Total McDermott formation __________ _ 143 

Kirtland shale. 

Section on west side of Pinyon Mesa in NW. i NW. l sec. 15, T. 30 N., R. 14. W., N. Mex. 

[Measured by Harvey Bassler.] 

Ojo Alamo sandstone: 

Sandstone, massive, coarse grained, gray 

to brown, with streaks and lenses of 

coarse conglomerate of siliceous materials. 

Pebbles as much as 5 inches in diameter_ 

Feet. 

Total Kirtland shale __________________ 1, 120 Shale, sandy, micaceous, gray to green __ _ 

Sandstone, soft, coarse, with pebbles in 

164 

3 

Fruitland formation: 

Shale and sandstone _________________ · ____ _ 

Sandstot1e, brown ______________________ _ 

Shale, gray ____________________________ _ 

Sandstone, brown ______________________ _ 

Shale, gray; carbonaceous in part _______ _ 

Coal bed_...:----------------------------

Shale, carbonaceous~---- ___________ - ___ _ Coal bed ______________________________ _ 

Shale, carbonaceous ____________________ _ Coal bed _____________________________ _ 

Shale, carbonaceous ____________________ _ Coal bed _____________________________ _ 

Shale, gray; carbonaceous in part_ ______ _ Coal bed _____________________________ _ 

Shale and sandstone, in part concealed ___ _ Coal bed _____________________________ _ 

lower part __________________________ _ 

80 Total Ojo Alamo sandstone __________ --

5 Unconformity. 

20 McDermott formation: 

10 Shale, highly colored ___________________ _ 

80 . Sandstone, argillaceous, micaceous _______ _ 2 Shale, gray ___________________________ _ 

2 Sandstone, argillaceous _________________ _ · 1 Shale, purple __________________________ _ 

2 Sandstone, greenish, argillaceous, thickness undetermined. 

23 

190 

7 

2 

5 

1 

25 

4 

3 

6 

75 

14 

125 

3 

Beds below are light-gray shale and soft arkosic sandstone down to the resistant sandstones of the Farmington member of the Kirtland shale. 

Section on south side of Pinyon Mesa in SW. l NW. l sec. 24., T. 30 N., Q,. 14. W., N. Mex. 

[Measured by C. E. Dobbin.] 

Feet. 

426 Ojo Alamo sandstone: Sandstone, massive, 

Total Fruitland formation_----...:------- gray-white to brown, coarse, cross-bedded; 

Pictured Cliffs sandstone_------------------- 225 contains iines and lenses of coarse conglomer- Lewis shale; details not noted _______________ 1,100 ate of siliceous materials _________________ _ 

Mesaverde group. Unconformity. 

Section on north side of Pinyon Mesa at center of sec. 10, 

'1'. 30 N., R. 14. W., N. Mex. 

Ojo Alamo sandstone: Sandstone, massive, 

gray-white to copper-red, cross-bedded, coarse 

grained, with many lenses of pebbles of siliceous resistant materials. Upper 2 feet dark 

brown. No shale present. Apparently all 

of formation present though not covered by higher beds _____________________________ _ 

Unconformity. 

McDermott formation: 

Sandstone, purple to nearly black; con- tains volcanic d~bris _______ ,... _________ _ 

82587-24t--5 

Feet. 

200 

20 

McDermott formation: 

Shale, 'yellow and green, sandy, with thin 

sandstone lenses ____________________ _ 

Sandstone, coarse grained, white, ashy, 

containing many pebbles of siliceous materials of dark color; differs from Ojo Alamo 

in lacking red pebbles _______________ _ 

Shale, yellow, with one thin purple band __ _ Shale, gray and green _____ , _____________ _ 

Shale, variegated gray and purple, with 

5-foot band of bright purple at top _____ _ 

Shale, gray, containing thin lenses of platy 

green sandstone _____________________ _ Shale, purple, sandy ___________________ _ 

Kirtland shale: Light-gray shale and soft graywhite sandstone. 

100+ 

60 

7 

17 

22 

17 

21 

2 
62 UPRER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Section on La Plata River in SW. i SW. i sec. 28, T. 

30 N., R. 13 W., N. Mex. 

Ojo Alamo . sandstone: Sandstone, massive, 

brown to. gray, cliff-forming, with many pebbles of siliceous rocks as much as 6 inches 

in diameter ______________________ · ______ _ 

Unconformity. 

McDermott formation: 

Shale, purple and gray, and soft gray, white, 

and yellow sandstone, varying rapidly 

both vertically and horizontally. One 

sandstone lens contains pebbles of dark 

chert and quartz __________________ ~ __ 

Beds immediately below concealed by allu:. 

vium. 

Feet. 

100+ 

160 

Section along San Jua~ River below Farmington, N.Mex. 

Torrejon formation: Shale,· olive and gray, with 

Feet. 

soft gray-white to yellow sandstone containing siliceous pebbles ______________________ 250+ 

No break observed, though certainly present. 

Ojo Alamo sandstone: 

Sandstone, gray-white to yellow, massive, 

cross-bedded, indurated, medium grained; 

-contains many siliceous pebbles as much 

as 2 inches in diameter________________ 85 

Shale, brownish, not persistent laterallv _ _ _ 6 

Shale, brown, carbonaceous, not persi~tent laterally ___________________ ~_________ 6 

Sandstone, gray-white to yellow, massive, 

indurated, medium grained; contains siliceous pebbles as much as 2 inches in diameter and some limonitic crusts______ 57 

Shale, greenish gray, sandy,. not persist~nt laterally_____________________________ 23 

Sandstone, indurated, gray-white to yellow, . 

massive, cross-bedded; contains lines and 

lenses of pebbles of siliceous materials 

several inches in diameter and some limonitic crusts. A few thin, ::;hort shale 

lenses included_______________________ 92 

Shale, green, sandy, pinching out within a· 

short distance laterally________________ 28 

Sandstone, massive, medium to coarse 

grained, gray-white to brown; contains 

lines and lenses of siliceous pebbles; pebbles as much as 6 inches in diameter. 

Unit forms cliff ___________________ . ____ 100± 

Total Ojo Alamo sandstone ____________ 397::: 

Unconformity, erosional. 

McDermott formation: Gray shale; purple shale 

containing volcanic debris; coarse gr_ay-white 

soft sandstone; variable unit________________ 30 ± 

Kirtland shale. 

Upper shale member: Shale, yellowish, 

sandy, stained ~vith limonite in irregular 

patches, and gray to drab shale, with 

platy dark-brown concretions 1 foot or 

le_ss in diameter, alternating irregularly; 

dmosaur bone from horizon near top of unH _______________________________ _ 80± 

Kirtland shale-Continued. 

Farmington sandstone member: 

Sandstone, brown, massive, fine grained; 

contains lenses of grit with fine black 

chert and clay galls but consists 

mostly of quartz ________________ _ 

Sandstone, friable, buff, stained locally by limonite _____________________ _ 

Shale, drab, sandy, locally carbona- ceous __________________________ _ 

Shale, sandy, salmon-colored ________ _ 

Sandstone, brown, rather coarse, crossbedded; contains crusts of limonite __ 

'Shale, drab, clayey, and light-brown 

sandy shale, alternating irregularly. 

Contains lenses of friable sandstone 

and dark-brown sandstone concre- tions ____________________ _ 

Sandstone, light brown, coarse, hard; 

fresh surface gray with fine white 

s~ec~s_; much cross-bedded; locally pisolitiC ________________________ _ 

Shale, drab, sandy _________________ _ 

Sandstone, light gray, fine grained, 

friable, with a number of platy brown 

concretions; small limonitic crusts 

abundant _______________________ _ 

Shale, gray, sandy _________________ _ 

Sandstone, fine grained, reddish brown 

on weathered surface, light gray on 

fresh surface, micaceous, massive, 

resistant; locally contains clay galls 

and ferruginous concretions;.impresssions of stems of plants and parallelveined leaves abundant __________ _ 

Shale, light brown, sandy, ·with some drab streaks _____________________ _ 

Sandstone, reddish brown, fine grained, 

hard, with platy concretions ofdarkbrown sandstone; clay galls num,erous; lower part lighter and softer_~ __ 

Shale, olive, sandy _________________ _ 

Sandstone, reddish brown, fine grained, 

massive; fresh surface light gray ___ _ 

Shale, gray and buff, sandy, alternating irregularly and inclosing a few 

thin sandstones; gypsum present 

locallY---------------~----------

Sandstone, reddish brown on weathered 

surface; mottled brown and white 

on fresh surface; massive, resistant 

unit ___________________________ _ 

Shale, gray and buff, sandy, alternating 

at about 5-foot 'intervals with thin 

brown sandstones _______________ _ 

Sandstone, yellowish, coarse, friable __ Shale, gray, sandy _________________ _ 

Sandstone, buff, friable, cross-bedded; 

dinosaur bone observed __________ _ 

Total Farmington sandstone mem- ber __________________________ _ 

Feet. 

15 

16 

33 

5 

12 

98 

4 

5 

10 

8 

4 

19 

5 

22 

12 

84 

35 

28 

19 

16 

9 

459 
LOCAL SECTIONS. 

Kirtland shale-Continued. 

Lower slia.le member: 

Shale, clayey; light gray on weathered 

surface, drab on fresh exposure; 

contains a. few thin sandstone layers_ 

Shale, sandy, chocolate-brown, filled 

with carbonized plant fragments; 

much gypsum in small crystals 

present----·---------------------

Sa.ndstone, buff, friable; stained with 

limonite _______________________ _ 

Shale, drab, very sandy; a few dark 

sandstone concretions present _____ _ 

Shale, dark bluish-gray, stained along 

seams with limonite and containing 

gypsom on joint planes; plant fragments abundant _________________ _ 

Shale, light gray ___________________ _ 

Shale, somewhat sandy, black to dark 

brown, filled with cumminuted plant fmgments ______________________ _ 

Shale, sandy, micaceous, light gray on 

"~eathered surface, mottled drab and 

brown on fresh surfaces __________ _ 

Sandstone, shaly, yellowish, soft; contains large crystals of gypsum and 

scattered lignitic material; large concretions of platy dark-brown sandstone __________________________ _ 

Shale, light gray ___________________ _ 

Shale, black, carbonaceous __________ _ Shale, dark gray __________________ _ 

Shale, dark bro·wn, ~arbonaceous ____ _ 

Shale, light gray ·on weathered surface, 

drab on fresh surface ____________ _ 

Shale, yellowish, sandy; perhaps really 

a. soft sandstone; contains much disseminated gypsum and a few thin 

lenses of dark-green indurated shale_ 

Sandstone, buff, soft, with a line of 

clark-brown platy concretions at top_ 

Shale, yellowish, ve;y sandy, grading 

upward into the unit above _________ _ 

Shale, black, carbonaceous, with much 

gypsum ________________________ _ 

Shale, g~ay to yellow, very sandy ____ _ 

Rha.le, chocolate-colored, with carbonized plant remains _______________ _ 

Shale, gray to yellow, sandy ________ _ 

Shale, black, carbonaceous __________ _ 

Shale, gray _______________________ _ 

Shale, brown, carbonaceous, with carbonized vegetable debris _________ _ 

Shale, drab, sanely in part __________ _ 

Shale, black, carbonaceous __________ _ 

Shale, drab, sanely _________________ _ 

I<'eet. Fruitland formation: 

14 

4 

2 

10 

4 

11 

2 

"13 

10 

20 

18 

23 

17 

5 

16 

1 

6 

2 

13 

l. 

2 

Sandstone, gray, fine grained, irregularly bedded _____________________________ _ 

Shale, gray to black; contains fragments of 

carbonized wood and is streaked with 

limonite ____________________________ _ 

Shale, light gray to drab, with limonite 

streaks; sanely in lower portion ________ _ 

Shale, sanely, light gray to buff __________ _ 

Sandstone, brown, friable; contains concretions of light-gray fine-grained sandstone ______________________________ _ 

Shale, drab, sandy _____________________ _ 

Shale, brown, carbonaceous; contains plant fragments __________________________ _ 

Shale, light gray, sandy, with streaks of 

pearl-gray calcareous shale and. drab 

pia ty sandstone concretions ___________ _ 

Shale, dark brown, .carbonaceous; contains 

plant fragment~ and gypsum in small 

flakes ______________________________ _ 

Shale, light gray to drab _______________ _ 

Sandstone, platy, fine grained, light green- ish gray ____________________________ _ 

Shale, light gray, sanely, locally carbonaceous--------------------------------

Shale, clark brown, carbonaceous; contains 

thin lenses of bone ___________________ _ 

Sandstone, light gray, fine grained and car- bonaceous __________________________ _ 

Shale, gray to drab, with carbonaceous 

bands which are burned locally (probably coal bed elsewhere) __________________ _ 

Sandstone, light gray, fine grained; contains 

lenses of carbonaceous shale; sandstone 

· is cross-bedded and stained brown locally_ 

Shale, brown to black, carbonaceous _____ _ Coal bed with partings _________________ _ 

ShaJe, carbonaceous ____________________ _ 

Bone __ ~--------------~---------------- Shale, brown ____________ .~ _____________ _ 

Coal _________________________________ _ 

Shale, sandy, brown ___________________ _ 

Shale, light gray, sandy ________________ _ 

Sandstone, greenish, cross-bedded _______ _ Shale, brown __________________________ _ 

Sandstone, nearly white ________________ _ 

Coal bed with parting __________________ _ 

Total Fruitland formation ____________ _ 

H 

5 Pictured Cliffs sandstone: 

Sandstone, massive, buff on weathered sur2 

35 

1 

35 

faces, light yellow to white on fresh surfaces; contains many 2-inch nodules of 

limonitic sandstone and a few 18-inch 

concretions of clark-brown platy sandstone; If alymenites common __________ _ 

Total lower shale member _________ · 271 

Sandstone, massive, cliff-forming; copperred on weathered surfaces, light gray to 

yellow on fresh surfaces; quartzose, fine 

Total Kirtland shale _____________ _ 810 grained; contains a few large concretions 

with Halymenites _____________ - ______ _ 

63 

Feet. 

7 

8 

11 

12 

15 

1 

2 

14 

7 

10 

20 

15 

6 

18 

30 

25 

3 

15 

2! 

i 

5 

J.. 

3 

5 

2 

3! 

1 

6 

2 

246 

60 

'48 
64 UPPER CRETACEOUS AND T'ERTIAR.Y FORMATIONS IN SAN JUAN BASIN. 

Pictured Cliffs sandstone-Continued. Feet. Mesaverde group-Continued. 

Shale, gray to brown, carbonaceous, sandy, 

in courses about 18-inches thick, separated by 12-inch layers of gray to yelMenefee formation-Continued. 

Shale, soft, light colored, sandy ____ _ 

Shale, sandy, brown, carbonaceous._ 

Feet. 

6 

12 

low sandstone _______________________ _ 42 Shale, containing 18 beds of sandSandstone, yellow-brown on weathered surface, light gray on fresh surface, fine -

grained; a few large concretions of brown 

stone. The sandstone layers range 

in thickness from 3 to 12 feet but 

·average 5 feet __________________ _ 

platy sandstone present _______________ _ 28f Coal ____________________________ _ 619 

1 

15 

25 

7 

8 

30 

Shale·, sandy, gray to brown, interbedded Sandstone.----------------------~ with thin sandstones ______________ ~ __ _ 11 Shale ____________________________ _ 

Sandstone, yellow to brown on weathered 

surface, light g:t:ay on fresh surface, fine 

grained; cont !l.ins large concretions of 

platy dark-br\>wn sandstone; HalymenSandstone _______________________ _ 

Shale ____________ '- _______________ _ 

Sandstone _______________________ _ 

Shale ___________________________ _ 

ites present _______ - __ - ___ --- ___ ------ 22 Sandstone.------------------~----

125 

35 

1 

2! 

10 

1 

26 

12 

1 

Shale, drab ____________________________ - 1! Shale ___________________________ _ 

Sandstone, fairly massive, light gray on 

fresh surface, brown on weathered 

Coal bed with partings ____________ _ 

Shale and sandstone ______________ _ surface_:... ____ .:.. ________ -_____________ _ 5! Coal ____________________________ _ 

Shale and sandstone, rapidly alternating. Shale-------------------~----~---

Shale dn.rk gray, sandy; sandstone shaly, Sandstone _______________________ _ 

Shale ___________________________ _ gray to brown. Fo3sils (locality 9278; 

see p. -) 36 feet above base of unit __ 57! CoaL _____ - - - - - - - - - - - - - - - - - - - - - - - 1 

20 

9 

10 

Sandstone, shaly, gray on fresh surface, 

brown on weathered surface, fine 

Shale ___________________________ _ 

Coal bed with partings ____________ _ 

grained, Sandstone and shale ______________ _ cross-bedded; H alymenites 

present-------------~~-------------- 5 Coal ________ ---_------------------ --- Total Pictured Cliffs sandstone________ 281 

Lewis shale: Gray sandy shale, containing 

some thin layers of arenaceous limestone; 

some large yellow septarian limestone concretions and some brown ferruginous concretions--------------~------------------ 450 

Mesaverde group: 

Cliff House sandstone: 

Sandstone, heavy bed, reddish brown 

to buff ____________ --- ______ -.--·-. 4 

Shale, gray, sandy, with. a f~w thin 

beds of sandstone________________ 96 

Sandstone, massive, heavy bedded, 

reddish brown to buff, with thin 

layers of shale separating the sandstone beds______________________ 330 

Shale and sandstone, gray, interbedded. Sandstone in thin layers 

and more abundant in upper part of 

unit; some layers ripple marked___ 195 

Concealed, probably sandy shale____ 73 

Sandstone, soft, buff_______________ 8 

Shale,· sandy, gray _____ -___________ 11 

Sandstone, massive, pisolitic, dark 

brown on weathered surface, gray 

on fresh surface__________________ 33 

Total Cliff House sandstone_______ 750 

Menefee ·formation: 

Shale, sandy, gray_________________ 6 

Coal_____________________________ 7! 

Shale, sandy, brown, carbonaceous__ 20 

Coal bed with partings ___________ ·__ 10! 

Shale, sandy, brown, carbonaceous__ 28 

Shale and sandstone_______________ 5 

Coal_____________________________ 1 

Shale____________________________ 21 

Total Menefee formation __________ 1, 076 

Point Lookout sandstone: 

Sandstone________________________ 32 

Shale, sandY---------------------- 16 

Sandstone, with some thin sandy 

layers__________________________ 252 

Total Point Lookout sandstone____ 300 

Total Mesaveyde group __________ 2, 126 

Mancos shale: 

Shale, gray, with a few yellow-brown cal- careous concretions ________________ -- 430 

Shale, gray, with many yellow-brown calcareous concretions; forms a marked 

lithologic zone______________________ 25 

Shale, gray___________________________ 105 

Sandstone, concretionary, brown, calcareous ________________ , __ -----·------- 1 

Sb,ale, gray, sandy_____________________ 38 

Sandstone, concretionary, brown, calcareous______________________________ 1 

Shale, gray, sandy_- _________ - ___ ------ 48 

Sandstone, concretionary, brown, calca- reous ______________________________ . 

Shale, gray ______ -- ________ ----- _-----

Sandstone, soft, gray, laminated, argillaceous; contains many "worm track" surfaces ___________________________ _ 

Shale, gray __________________ -- ______ -

Sandstone, concretionary, brown, calca- reous _____________________________ _ 

1 

85 

35 

20 

1 
LOCAL SECTIONS. 65 

Mancos shale-Continued. 

Shale, gray __________________________ _ 

Sandstone, concretionary, brown, calca- reous _____________________________ _ 

Shale, gray; upper part somewhat sandy __ Sandstone, brown _____________________ _ 

Shale, gray __________________________ -

Sandstone, rusty brown,· coarse, sugary 

in grain; contains many scattered pebbles of chert and quartz as much as 

half an inch in diameter; locally bedded 

but mostly massive (Tocito sandstone 

lentil)----------------------------~- Shale, light gray to buff, with some hard· 

layers, probably sandy; exposed _____ -

Shale, gray to black, as interpreted by 

drillers of wells on Hogback dome in sec. 

19, T. 29 N., R. 16 W. , Interval contains some thin sandstones not noted by drillers ________________________ -_---

Feet. 

110 

1 

130 

1 

85 

35 

65 

672 

Total Mancos shale ________________ 1, 889 

Dakota sandstone_________________________ 200± 

Section in sec. 5, T. 9 N., R. 4 W. Navajo meridian, 

near Beautiful Mountain, San Juan County, N. Mex. 

Shale, sandy, dark gray; Mancos shale. Feet. 

Sandstone, massive, light gray on fresh surface 

with carbonaceous streaks, red-brown on 

weathered surface; medium-grained; Dakota 

sandstone of Gregory (?); Tocito sandstone 

of oil geologists and this report __________ -- 7 5 ± 

Shale, drab, sandy on the whole but calcareous 

in some layers. Fossils abundant, particularly in resistant limy layers about 125 feet 

beneath top (locality 10368; see p. 11). 

Thickness not determined. 

Sandstone, light gray, coarse, quartzose; contains nu~erous impressions of plant stems 

and fragments. Only top exposed. May 

be Dakota sandstone or pre-Cretaceous. 

Section of Mesaverde group in T. 29 N., R. 16 W., 

N.Mex., where Chaco River cuts the Great Hogback. 

[Measured by C. M. Bauer.] 

Mesaverde group-Continued. 

Cliff House sandstone-Continued. 

Sandstone, massive, thin bedded on 

top, massive and necarly white bclow _________________________ _ 

Total Cliff House sandstone _____ _ 

Menefee formation: 

Shale, blue and gray, interbedded 

with lenses of buff sandstone. 

Shale beds are carbonaceous and 

contain thin streaks of coal _____ _ 

Sandstone, massive, light gray _____ _ 

Shale, gray, contains beds of sandstone 1 foot thick _______________ _ 

Sandstone, light gray, massive ______ _ 

Shale, blue-gray, containing several 

carbonaceous streaks ___________ _ 

Sandstone, massive _______________ _ 

Shale, drab ______________________ _ Coal ____________________________ _ 

Feet. 

25 

622 

560 

20 

30 

12. 

92 

20 

5 

1 

Shale, carbonaceous, black_________ ! 

Shale, blue-gray, containing carbonaceous streaks____________________ 246 

Sandstone, gray___________________ 10 

Shale, gray_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ! 

Coal_____________________________ ! 

Shale, gray_______________________ 7 

Coal_____________________________ 2 

Shale and sandstone, with thin beds 

of coal which are burned out______ 126 

Total Menefee formation _________ 1, 132 

Point Lookout sandstone: 

Sandstone, light buff and cream- colored, massive ________________ .:. 67 

Sandstone, buff to brown, weathering 

red-brown----------------~----- 158 

Shale and sandstone, thin bedded, 

yellowish gray__________________ 20 

Total Point Lookout sandstone____ 245 

Total Mesaverde group __________ 2, 009 

Mancos shale. 

Section of Pictured Cliffs sandstone in Ojo Amarillo 

Lewis shale. 

Mesaverde group: 

Feet. Arroyo, San J'uan County, N. Mex. 

Cliff House sandstone: 

Shale and sandstone ______________ _ 

Sandstone, brown, pitted ___________ · 

Shale, yeilow, sandy ______________ _ 

Sandstone, light gray, pink in places_ · Shale, blue and gray ______________ _ 

Sandstone, yellow, massive in upper 

part, carrying a few thin beds of 

shale; H alymenites major in lower part __________________________ _ 

Shale,. sandy, interbedded with yellowish sandstone layers, each about 

1 foot thick-------------~------- Sandstone, reddish brown, hard ____ _ Shale, blue-gray __________________ _ 

60 

18 

8 

6 

5 

318 

133' 

10 

40 

Fruitland formation: Sandstone, shale, and coal 

beds .. 

Pictured Cliffs sandstone: 

Sandstone, buff to brown, soft, fine grained, 

cross-bedded, locally pisolitic; top is a 

limonitic crusty irregular layer; 1[ alymenites abundant; crusts and nodules of 

limonitic ___________________________ _ 

Sandstone, light brown, irregular; HaZy- men ites _____________________________ _ 

Shale, buff, sandy _____________________ _ 

Sandstone, well indurated; fairly coarse 

grained; weathered surface light coffeebrown and rough, pisolitic; fresh surface 

gray, blotched with limonitic spots; 

H alymenites very abundant ___________ _ 

Feet. 

27 

2 

5 

4 
66 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN JUAN BASIN. 

Pictured Cliffs sandstone-Continued. 

Sandstone, buff to white, locally stained by 

limonite; contains limonite nodules; 

· rather soft and easily eroded; fresh surface light gray; Halymenites abundant __ _ 

Shale, light yellow, limonitic ____________ _ 

Sandstone, buff, soft, fi~e graiJ.ied _ "" _____ _ 

Shale, sandy, light yellow to white, with 

many layers and streaks of limonitic sand; 

cross seams stained by iron ___________ _ 

Shale, bluish gray, sandy, somewhat car- bonaceous __________________________ _ 

Sandstone dark, red-brown, platy, fine 

grained; fresh surface dark gray mottled 

with brown; unit cross-bedded, irregular 

in thickness ________________________ _ 

Feet. 

21 

3 

3 

4 

4 

5 

Menefee formation-Continued. 

Coal _______________________________ _ 

Shale, dark gray _____________________ _ Coal _______________________________ _ 

Shale _______________________________ _ 

Sandstone ___________________________ _ 

Shale, gray, with carbonaceous streaks __ Coal _______________________________ _ 

Shale, carbonaceous __________________ _ Sandstone ___________________________ _ 

Shale, carbonaceous __________________ _ 

Ft. 

18 

12 

15 

21 

1 

3 

3 

4 

Coal _______________________________ _ 1 

Shale; carbonaceous___________________ 35 

Sandstone_____ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 5 

Shale, dark, carbonaceous______________ 87 

Shale and sandstone in alternating thin 

beds------~----------------------- 195 

in. 

5 

10 

5 

2 

Sandstone, buff to brown, fine grained, light 

gray on fresh surface, soft and easily 

eroded; contains small brown ferruginous 

Section of Fruitland formation in Cottonwood Arroyo, 

·San Juan County, N. Mex. 

nodules 1 to 2 inches in diameter ______ _ 

Shale, greenish gray, sandy, alternating with 

thin sandstones _____________________ _ 

Sandstone, gray, fine grained, platy, stained 

brown locally and carrying dark redbrown platy concretions as much as 1 

foot in diameter; H alymenites present ___ _ 

Lewis shale: Shale, gray, greenish gray, and 

drab, sandy. 

22 

[Measured by C. M. Bauer.] 

30 Kirtland shale: Shale, light gray and yellowish, 

sandy, containing ferruginous concretions. 

Fruitland formation: 

Sandstone, brown, platy _______ ~ ________ _ 

2 Shale, sandy, gray _____________________ _ 

Sandstone, brown, cross-bedded and con132 cretionary __________________________ _ 

Sand.stone; contains iron-carbonate con- cretions ____________________________ _ 

Section of part of Mesaverde group 5 miles west of mouth 

of Cottonwood Arroyo, San Juan County, N. Mex. 

Sandstone, irregularly bedded and unequally indurated ________________________ _ 

Shale, gray, sandy, concretionary ________ _ 

Cliff House sandstone: Sandstone, massive, 

light yellow, weathering pink ___________ _ 

Menefee formation: 

Shale, gray, carbonaceoous ___________ _ 

Shale, gray _________________________ _ 

Coal---------------------~---------- Bone ______________________________ _ 

Shale, carbonaceous __________________ _ 

Coal, weathered_~ ___________________ _ 

Shale, carbonaceous _________________ _ 

Sandstone __________________________ _ 

Shale _____________________________ _ 

Coal _______________________________ _ 

Shale, gray _________________________ _ 

Sandstone, hard, platy _______________ _ 

Shale, carbonaceous __________________ _ 

Sandstone, forming cliff ______________ _ 

Shale, carbonaceous __________________ _ Coal _______________________________ _ 

Shale, carbonaceous __________________ _ 

Sandstone, pink _____________________ _ 

Shale, gray, sandy ___________________ _ 

Shale, dark gray, containing several 

3-inch beds of coaL ________________ _ 

Shale, black, carbonaceous ____________ .. Coal _______________________________ _ 

Shale, dark gray _____________________ _ Coal _______________________________ _ 

Shale, carbonaceous ____________ ...: _____ _ 

Ft. 

65 

15 

12 

1 

2 

3 

6 

4 

6 

2 

16 

4 

3 

22 

3 

1 

2 

14 

10 

5 

4 

61 

2 

in. 

7 

4 

3 

8 

8 

6 

6 

·6 

10 

3 

Coal bed with partings _________________ _ 

Shale, carbonaceous ____________________ _ 

Shale, gray ___________________________ _ 

Sandstone, buff to gray, cliff forming _____ _ 

Shale, carbonaceous ____________________ _ 

Shale, gray ___________________________ _ 

Sandstone, gray, easily eroded __________ _ 

Coal bed with partings _________________ _ 

Shale, carbonaceous, brown and gray _____ _ 

Sandstone, gray; contains lime concretions_ 

Shale, sandy __ · ________________________ _ 

Shale, brown, carbonaceous _____________ _ 

Coal bed '\vith partings _________________ _ 

Shale, carbonaceous ____________________ _ 

Sandstone, nearly white, soft, cross-bedded, 

streaked with limonite _______________ _ 

Shale, gray, sandy _____________________ _ 

Coal, impure ______ ..: ___________________ _ 

Ash (from burned coal) _________________ _ 

Shale, gray ___________________________ _ 

Ash (from burned coal) ________________ _ 

Shale, bluish gray, sandy _______________ _ 

Sandstone, nearly white, soft; contains 

streaks of limonite one_-fourth inch thick 

and in places irregular masses of brown 

· cross-bedded sandstone _______________ _ Coal _________________________________ _ 

Shale, blue-gray, sandy _________________ _ 

Sandstone, shaly in places, light colored, platy ______________________________ _ 

Feet. 

13 

31! 

5 

4 

8 

28 

4! 

1 

15 

20 

1 

35 

11! 

4 

12! 

4 

8 

1 

5! 

6 

15 

2 

It 

2 

3 

7! 

1 

16 

25 

t 

15! 

12 
LOCAL SECTIONS. 67 

Fruitlandlformation-Continued. 

Shale, carbonaceous ____________________ _ Feet. 

i 

Section at head of Ojo Alamo Arroyo, ·r. 24 N., R. 11 W., 

N.Mex. Coal _________________________________ _ i [Measured by C. M: Bauer and John B. Reeside, jr~l. Shale, sandy __________________________ _ 

Coal: bed 'vith partings __________ ·- ___ ..,; __ _ 5 Torrejon and Puerco formations: 

4! Crest of divide. 

Shale, sandy, carbonaceous _____________ _ 3 Sandstone, yellow to brown, medium 

Pi·ctured~ Cliffs:sandstone. 

328j 

Section at head of Pina Veta China Arroyo, San Juan 

County, N. 111ex. 

[Mensmod by C. M. Bauer. 31) 

Puerco formation: 

Higher beds eroded off. 

Shale, gray ___________________________ _ 

Shale, wine-red, irregular _______________ _ 

Sandstone, soft, light yellow ____________ _ 

Shale, blue-gray _______________________ _ 

Erosional unconformity. 

Ojo Alamo sandstone: Sandstone, massive, 

cross-bedded, gray,white, yellow, and brown, 

with some splotches of vermilion, fairly resistant and ledge forming, coarse grained; 

contains pebbles of various siliceous, resistant 

materials as much as 6 inches diameter, comprising chert, chalcedony, quartz, quartzite, 

silicified wood, volcanic rocks, sandstone, 

gneiss, and schist; basal part here has no 

pebbles but toward middle of unit they are abundant _______________________________ _ 

Erosional unconformity. 

Kirtland shale [McDermott formation]: Shale, 

greenish gray, gray, and maroon; carbonaceous brown shale; and soft gray and yellow 

sandstone. 

Feet. 

12 

3 

4 

91! 

Section of Pictured Cliffs sandstone in sec. 14, T. 8 N.', 

R. 1 W. Navajo meridian, N. Mex . . 

Fruitland formation: Sandstone, shale, and coal. 

Pictured Cliffs sandstone: 

Sandstone, massive, white to copper-red on 

weathered surface, light gray, with 

yellow blotches, being the prevailing 

color; medium grained; fresh surface 

shows quartz, weathered feldspar, and 

small fragments of carbonized wood; 

locally contains carbonaceous streaks 

and gypsum; varies laterally in induration; I-I alymenites abundant ___________ _ 

Shale, sandy, light gray to yellow; with 

some platy gray sandstone concretions __ 

Sandstone, fairly coarse, with laminated 

concretions, dark gray, micaceous _____ _ 

Lewis shale: Shale, brown, dark gray, and drab, 

sandy; contains large platy sandstone conCI'etions. · 

Feet. 

69 

11 

3 

31 Shown diagrammatically in Bauer, C. M., Stratigraphy of a part 

of the Chaco River valley: U. S. Goo!. Survey Prof. Paper 98, pl. 70, 

section H, 1916. · 

grained, ferruginous, soft; contains 

limonitic crusts ______________________ _ 

Shale, dark drab _____________________ ~_ 

Sandstone, yellow, soft, with limonitic 

crusts-----------------------~------- Shale, dark gray to drab _______________ _ 

Sandstone, yellow, soft, with brown limonitic crusts and some 2-foot concretions 

of dark-brown sandstone _____________ _ 

Shale, dark drab ______________________ _ 

Sandstone, yellow, soft, with concretions 

of aragonite 1 foot or less in diameter __ _ Shale, olive-green, sandy _______________ _ 

Sandstone, yellow and brown, stained 

locally by limonite; soft and easily 

eroded; contains dark-brown sandstone 

concretions _________________________ _ 

Sandstone, dark-brown, ferruginous, coarse, well indurated ______________________ _ 

Break in section which may be traced for a 

number of miles, but which seems nevertheless to lie within the Torrejon formation. 

Shale, light greenish gray _______________ _ 

Shale, light brown, sandy _______________ _ 

Shale, light gray, greenish gray, and dark 

gray, irregularly intermingled _________ _ 

. Sandstone, light gray, soft, alternating with 

greenish-gray sandy shale ____________ _ 

Sandstone, light gray and brown, fairly 

hard ~nd resistant ___________________ _ 

Shale, greenish gray, sandy, alternating 

with thin soft light:..gray sandstones ____ _ 

Sandstone, light gray and brown, resistant, 

massive, micaceous, fine grained _______ _ 

Shale, light gray, greenish gray, and dark 

gray, irregularly intermingled _________ _ 

Sandstone, light gray, soft, fine grained; 

has locally at the base a resistant layer 

of dense quartzitic sandstone __________ _ Shale, dark gray ______________________ _ 

Sandstone, soft, shaly, light gray with 

greenish streaks- - - - - - - - - ------ --- - -- - Shale, gray and brown, mingled irregularly 

Sandstone, soft, greenish gray, shaly _____ _ 

Shale, light and dark gray, mottled; probably horizon of Torrejon fossils collected 

by Sinclair and Granger32 _____________ _ 

Sandstone; brown, ·yellow, and white, 

mostly rather soft but containing local 

lenses of coarse grit with a ferruginous 

cement in which occur rounded chert and 

quartz pebbles as much as 1 inch. in 

diameter. Laterally this sandstone 

thickens and is a prominent member of 

the section, but at the point of measure- ment it is thin ______________________ _ 

Feet. 

40. 

8 

15 

6 

16 

4 

5 

8 

83 

1 

6 

4 

27 

20 

5 

12 

25 

5 

21 

10 

13 

11 

10 

2 
68 UPPER CRETACEOUS AND TER.TIARY FORMATIONS IN SAN JUAN BASIN. 

Torrejon and Puerco formations-Continued. 

Shale, dark graY-----------------------~ 

Sandstone, soft, shaly, micaceous, light 

brown, olive, and light gray, alternating 

in thin bands with wine-red, light-brown, 

and gray shale ______________________ _ 

Sandstone, olive-green, soft, shaly micaceous--------------------~----------

Shale, dark gray, sandy, locally tinged with 

red ________________________________ _ 

Sandstone, light gray, soft_ _____________ _ 

Shale, dark gray with brownish streaks; 

has a faint reddish tinge in upper 2 feet_ 

Sandstone, soft, shaly, light gray to white; 

locally contains 1-foot beds of dense 

quartzitic sandstone which carry impressions of plant stems ______________ _ 

Shale, light gray, sandy ________________ _ 

Shale, light and dark gray, irregularly 

intermingled ________________________ _ 

Sandstone, soft, light gray, grading into a 

dense resistant quartzitic layer_ _______ _ 

Shale, light gray, mottled locally by ferruginous brown ___________________ .,. ___ _ 

Sandstone, soft, whitish, fine grained., ____ _ 

Shale, light gray, sandy ________________ _ 

Sandstone, dense, fine grained, quartzitic, 

light gray to brown, vesicular and locally 

filled with impressions of plant stems __ _ 

Shale, light gray, sandy; streaks of wine-red 

color near base; probably upper zone of 

Puerco fossils collected by Sinclair and Granger 32 __________________________ _ 

Sandstone, black to very dark greenish 

brown, micaceous, fine grained; cement 

manganitic; contains poor imprints of 

plant stems and leaves; thickness variable owi~g to concretionary character; 

probably horizon of plants collected by 

Sinclair and Granger 32 _______________ _ 

Sandstone, soft, light gray to white; yellowish near top. Contains irregular lenses 

of gray shale and concretions of manganitic sandstone ____________ -~ __________ _ 

Shale, dark gray, with some patches of 

white sand _________________________ _ 

Sandstone, soft, white, shaly, with one 6-

inch streak of wine-red shale _________ _ 

Shale, greenish gray and wine-red~ ______ _ 

Shale, light gray, sandy ________________ _ 

Shale, dark gray, carbonaceous __________ _ 

Shale, light gray, sandy, with small barite 

concretions; probably lower zone of 

Puerco fossils collected by Sinclair and 

Granger 32 ____ · ______________________ _ 

Sandstone, gray, dense, quartzitic, with 

impressions of plant s.tems ___________ _ 

Shale, black, carbonaceous, hard ________ _ 

Sandstone, soft, light gray to yellow, banded and blotched in upper part with red 

sandy shale _________________________ _ 

Feet. Erosional unconformity. 

6 Ojo Alamo sandstone: Feet. 

Sandstone, brown to yellow, cross-bedded, 

irregularly indurated; contains silicified 

logs and scattered pebbles_____________ 33! 

31 Shale, sandy, light bluish green___________ 7! 

Shale, blue-gray________________________ 1 

4 Sandstone, white, soft, cross-bedded, contains concretions of brown sandstone 8· 

6 to 10 inches in diameter_______________ 16! 

1 Shale, wine-red, with irregular blotches of 

light-yellow sandy shale_______________ 3! 

7! Sandstone, white, soft, with concretions of 

brown sandstone__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 6 

Shale, blue-gray________________________ 3 

Sandstone, white, soft___________________ 5! 

10! Shale, gray, sandy______________________ 2 

10 Conglomerate of siliceous pebbles several 

inches in diameter; matrix coarse white 

8 sand with rust-colored blotches_ _ _ _ _ _ _ _ 8 

5 

11 

2 

3 

1 

8 

3 

Unconformity. 

McDermott formation: 

Shale, gr~y, purple, and greenish, and soft, 

argillaceous gray-white sandstone; con86! 

tains andesitic debris__________________ 30 

Sandstone, brown to gray, containing grit 

and fine conglomerate with fragments of 

andesite, quartz, quartzite,.etc_________ 10 

Kirtland shale: 

Shale, gray ________________ ------_·______ 20 

Farmington sands~one member; brown indurated sandstone and softer gray sandstone in lenses separated by gray shale__ 87 

Shale, gray, soft gray-white sandstone; 

some carbonaceous shale, etc__________ 975 

Fruitland formation. 

Section on branch of OJ·o Alamo Arroyo northwest of Ojo 

Alamo, in or near sec. 6, T. 24 N., R. 11 W. 

[Measured by C. M. Bauer.33) 

Puerco formation: Feet. 

38 Shale, gray, sandy______________________ 3 

Shale, dark colored_____________________ 2! 

7 Shale, blue-gray________________________ 4 

Shale, wine-red, banded with yellow sandy 

10 layers----------------------------~-- 3 

3! Shale, gray and yellow, banded, sandy, soft_ 4 

H Unconformity. 

5! Ojo Alamo sandstone: 

Sandstone, light gray with yellowish spots 

and irregular brown indurated areas; unequally indurated and easily eroded; con13 tains streaks and pockets of pebbles and 

large silicified logs, the latter enveloped 

1 in a coarse ferruginous grit____________ 31! 

3 Sandstone, coarse, brown, indurated, con- glomera tic _______________________ · _ _ _ _ . 6! 

Sandstone, brown, soft, with scattered 

6! pebbles_____________________________ 5! 

s2 Sinclair, W. J., and Granger, Walter, Paleocene deposits of the San 

Juan Basin, N.Mex.: Am. Mus. Nat. Hist. Bull .• vol. 33, pp. 305-307, 

14. 

33 Shown diagrammatically in Bauer, C. M., Stratigraphy of a part 

of the Chaco River valley: U. S. Geol. Survey Prof. Paper 98, pl. 70, 

section N, 1916. 

1 r 
LOCAL SECTIONS. 69 

Ojo Alamo sandstone-Continued. Feet. 

Shale, sandy, light green, irregular in thickness and containing patches of white 

sandstone___________________________ lOt 

Sandstone, light colored, conglomeratic in 

basal 1 foot and in upper half; pebbles of 

many sorts of siliceous rocks___________ 16l 

Unconformity. 

Kirtland shale: Shale, dark greenish gray and 

black, carbonaceous. 

70t 

Section on J11eyers Creek in 'T. 7 N., R. 11 W., San 

Juan County, N. Mex. 

[Measured by C. M. Bauer.] 

Kirtland shale: Shale, light gray, streaked with 

yellow and gray. 

Fruitland formation: 

Sandstone, soft; gray, at base, capped by 

hard brown coarse-grained sandstone __ _ 

Shale, gray, sandy, streaked with yellow; 

a few lenses of sandstone containing 

ferruginous concretions _______ -· _______ _ 

Shale, black, carbonaceous ______________ _ 

Shale, gray, sandy, banded with yellow, 

locally a soft gray concretionary sand- stone ______________________________ _ 

Shale, light gray, sandy ________________ _ 

Shale, dark brown, carbonaceous ________ _ 

Shale, gray, with ferruginous concretions 

and barite __________________________ _ 

Shale, black, carbonaceous ______________ _ 

Sandstone, yellow, argillaceous __________ _ 

Shale, dark brown, carbonaceous ________ _ 

Sandstone, argillaceous, gray, streaked with 

yellow; contains brown platy concretions 

of c.oarser sandstone and some aragonite concretions _________________________ _ Coal _________________________________ _ 

Sandstone, black, carbonaceous _________ _ 

Bone---------------~-----------------

Shale, sanely, containing lenses of brown 

and gray sandstone, ferruginous concretions with barite, and lenses of carbona- ceous shale _________________________ _ 

Sandstone, soft, gray with brown streaks; 

cross-bedded and platy at top _________ _ 

Shale, brown, carbonaceous, locally sandy __ Coal bed with partings _________________ _ 

Shale, gray and yellow, sandy ___________ _ 

Shale, gray, sandy, and lenses of yellow con- cretionary sandstone _________________ _ 

Sandstone, light gray, fine grained, unequally indurated; contains dark-brown 

sandstone concretions ________________ _ 

Shale, clark brown, carbonaceous ________ _ 

Shale, dark gray; contains ferruginous con- cretions locally ______________________ _ 

Sandstone, light gray, cross-bedded;· contains ferruginous concretions with barite; 

grades laterally into shale _____________ _ 

Coal bed with partings _________________ _ 

Total Fruitland formation ____________ _ 

82587-24t-6 

Feet. 

4 

42 

! 

10 

25 

12! 

l 

t 

1 

32! 

6 

3 

4t 

lOt 

10 

7 

5 

7t 

5 

196 

Pictured Cliffs sandstone: Feet. 

Sandstone, light gray, soft, shaly; contains 

large concretions of brown sandstone and 

carbonaceous streaks; locally has a hard 

dark-brown layer at top_______________ 24 

Sandstone, light brown, hard and platy; 

H alymenites abundant _______________ :._ 4 

Sandstone, yellow to white, medium grained, 

:rather soft as a whole but with indurated 

masses that stick out as ledges in weather-

. ing; many of these ledges are stained 

·brown by iron_______________________ 61 

Sandstone, hard, brown, platy, persistent 

layer________________________________ 2 

Total Pictured Cliffs sandstone_________ 91 

Lewis shale: 

Shale, sandy, yello'wish, grading upward 

into the Pictured Cliffs sandstone______ 24 

Sandst?ne, platy, b~own, fine grained, discon~nuou~-------------------------- 4 

Shale, light gray to greenish gray, sandy; 

contains two zones of yellow sideritic con- cretions_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 46 

Sandstone, brown, platy, fine grained, discontinuous___________________________ 2 

Shale, light gray to greenish gray, sanely __ ._ 27 

Total Lewis shale _____________________ 103 

Mesaverde group: 

Cliff House sandstone: 

Sandstone, copper-red, fine grained, 

not as massive as the underlying 

unit, but not thin bedded; Cardium 

aff. C. speciosum, Inoceramus sp., 

M actra sp., H alymenites and other 

marine fossils profuse ____________ _ 

Sandstone, almost white, coarse; stained 

brown locally by limonite; massive 

unit,. though with lenses of gray 

shale near top; H alymenites abund- ant ____________________________ _ 

Sandstone, light brown to copper-red, 

fine grained, massive; contains lenses 

of platy rusty-colored sandstone; 

H alymenites abundant ___________ _ 

Sandstone in courses 1 to 3 feet thick, 

medium grained, uniform copper-red; 

H alymenites common _____________ .:. 

Sandstone, light brown to copper-red 

on weathered surface, yellow-brown 

to gray on fresh surface, medium 

grained, massive, contains thin lenses 

· of coarse dark-brown ferruginous 

sandstone; H alymenites common __ _ 

51 

6,5 

70 

117 

66 

Total Cliff House sandstone _______ 369 

Menefee formation: 

Shale, brown, carbonaceous, locally 

sanely___________________________ 14 

Coal, impure_______________________ ll 

Shale, br<?wn, carbonaceous, locally sandy___________________________ 40 

Sandstone,· light brown, medium 

grained; limonitic nodules common__ 15 

Shale, brown, carbonaceous, sandy____ 12 + 
70 UPPER CRETACEOUS AND TERTIARY FORMATIONS IN SAN J'UAN· BASIN. 

Section of Ojo Alamo sandstone in sec. 26, T. 23 N., R. 10 Section of Ojo Alamo sandstone on a branch of Escavada 

W., N. Mex. Wash in sec. 3, T. 22 N., R. 9 W., N. Mex. 

[Measured by F. R. Clark.] 

Ojo Alamo sandstone: . 

Sandstone, coarse, dark brown, highly indurated; contains pebbles ___________ _ 

Sandstone, gray, fairly hard ____________ _ 

Sandstone, gray and yellow, friable, coarse_ 

Sandstone, gray, hard enough to form a 

ledge __ ~----------------------------· Shale, bluish gray, local lens ____________ _ 

Sandstone, coarse, gray, friable __________ _ 

Shale and sandstone, gray and yellow, with 

. hard sandstone concretions· ___________ _ 

Sandstone, hard, dark, with clay pellets __ _ 

Sandstone, white, quartzose, with pebbles 

locallY--------------~--------------­ Shale, bluish gray, with some gypsum crystals----------~----------------------

Sandstone, thin bedded, gray, with veinlets 

of barite ___________________________ _ 

Unconformity. 

Kirtland shale: Shale, bluish gray: with~Lbarite 

and gypsum crystals. 

Feet. 

7+ 

7 

28 

7 

8 

10 

5 

1 

14 

6 

7 

100+. 

[Measured by F. R. Clark.] 

Puerco formation: Shale, bluish, clayey. 

Unconformity. 

Ojo Alamo sandstone: 

Sandstone, brown, highly indurated ______ _ 

Sandstone, friable, yellow ______________ _ 

Shale, bluish gray _____________________ _ 

Sandstone, gray, friable; contains coarse siliceous pebbles _____________________ _ 

Sandstone, red-brown, coarse, conglomeratic, hard_--------------------------

Sandstone, coarse, yellowish ____________ _ 

Sandstone, gray, friable These be~s form a 

Shale, gray __________ -~ l 

Shale, gray, sandy___ _ _ soft um t. 

Sandstone, gray, friable . 

Sandstone, coarse, usually friable, gray to 

white ______________________________ _ 

Sandstone, coarse, yellow, indurated, con- glomeratic __________________________ _ 

Unconformity. 

Kirtland shale: Yellowish shale. 

Feet, 

2 

4 

7 

25 

3 

5 

10 

20 

8 

11 

32 

2 

129 
FLORA 0}., THE ANIMAS POR~iATION. 

By F. H. l(NOWLTON. 

INTRODUCTION. 

The Animas forn1ation as now restricted by 

Heeside (see pp. 32-35) comprises certain 

crreenish-gray and tan beds which contain a 

~onsiderable amount of andesitic n1aterial 

and which, on Animas River, Colo., ''lie 

unconformably upon the purple beds assigned 

to ·the McDerinott fonnation and unconformably below the Torrejon formation." It 

is confined, so far as at present known, to ~he 

northern rim of the San Juan Basin, extending 

from a point about 18· miles southwest of 

Durango, Colo., eastward to Pagosa Junction, 

though future study will probably smnewhat 

extend the limits, especially on the east. The 

beds now named McDermott formation by 

Reeside (p. 24) have heretofore formed a par~ 

of the Anin1as forn1ation. 

As the areal distribution and lithologic and 

structural features of the Animas formation 

have been very fully covered by Reeside 

in the first part of this paper (pp. 32-35), it is 

only necessary in the present connection to 

give a very brief historical review to serve as a 

settincr for the discussion of the flora. 

Andesitic beds on Anilnas River below 

Durango, Colo., which· now include the McDerJnott fonnation and the Animas formation as 

restricted were first noted in 1892 by Whitman 

Cross frmi1 .collections and field observations 

n1acle by T. W. Stanton/ though they were 

not then criven a name. In 1896 Cross 2 discussed th~se beds at greater length, calling 

thein the "Aniinas River beds." He regarded 

then1 as "a n1ost direct equivalent of the 

Denver beds, identical in peculiar lithologic 

character, * * * and containing fossils, 

which, so far as known, indicate a similar 

fauna and flora." The position of the Animas 

beds, thought by Cross to be "between typical 

Laramie and Puerco," has not been corrobo1 Cross, Whitman, Post-Laramie deposits of Colorado: Am. Jour. 

Sci., 3d ser., vol. 44, pp. 25-27, 1892. 

2 Emmons, S. F., Cross, Whitman, and Eldridge, G. H., Geology of 

tho Denver Basin in Colorado: U.S. Geol. Survey Mon. 27, pp. 217-219. 

rated by fuller knowledge,. as the supposed 

Laramie is now known to belong to the 

Montana. 

In 1912 and later W. T. Lee 3 Inacle brief 

n1e~tion of the Anin1as formation, giving a 

section of the .beds on Florida River prepared 

for. him by J. H. Gardner in his n1apping of the 

Ignacio quadrangle, Colo. 

The Animas formation ranges in thickness 

from 100 feet in the Red Mesa quadrangle, 

southwest of Durango, to 2,670 feet on the 

divide between Pine and Piedra rivers in sees. 

31 .and 32, T. 35 N., R. 5 W: It is about 

1,100 feet thick at the type section on Animas 

River, 1,800 feet in the section Ineasured by 

Gardner on Florida River, and 1,840 feet near 

Pagosa Junction. As the top shows everywhere an erosion surface, there is no means of 

knowing to what extent the original thickness 

has been reduced. 

As interpreted by Reeside, the Animas 

formation rests unconformably on the McDermott formation, which was originally cmnbined with it but which is really very distinct, 

and· is unconformably overlain by the Torrejon formation. It is not known to ?e in ~ontact at any point with the Puerco formatiOn, 

but on structural and stratigraphic grounds 

Reeside is of the opinion that it lies below the 

Puerco. 

As to the age of the Animas formation the 

present paleqbotanic study amply confirms .t~e 

original assignment by Cross, namely, .tha.t It Is· 

in close affmity with the Denver, and IndiCates 

also that it is closely related to the Raton 

formation of southeastern Colorado and the 

Wilcox group of the Gulf region and like them 

is, in my opinion, undoubtedly Tertiary. Not 

a single species is known to be common to the 

Animas formation and the Cretaceous exclusively-in fact, there are only five species that 

extend into the acknowledged Cretaceous anywhere. 

a Lee, W. '!'., Stratigraphy of the coal fields of northern central New 

Mexico: Geol. Soc. America Bull., vol. 23, pp. 584-587, 1912; U. S. 

Geol. Survey Prof. Paper 101, pp. 185, 186, 1917. 

71 
72· FLORA OF THE ANIMAS FORMATION. 

LOCALITIES. 

F.ossil plants are not abundant in the Animas 

formation, and most of those that have been 

collected, with the exception of those from the 

vicinity of Pagosa Junction, are fragmentary 

and more or less poorly preserved. Several 

small collections that have heretofore been 

included in the Animas flora came from beds 

now excluded from the Animas. Thus, two or 

three collections made in 1898 by Cross and 

Spencer from Animas River below Durango, 

Colo~, came from the purple andesitic beds 

now named the McDermott formation by 

Reeside. These plants are listed and discussed 

on page 27. 

The several lt. ts of Animas plants are as 

follows: 

731.4 Five miles south of Durango, Colo., above the 

conglomerate [MpDermott formation] that overlies the 

coal-bearing series; collected by T. W. Stanton, 1891: 

Magnolia magnifolia Knowlton? 

A single rather fragmentary example. It was 

first recorded under the name Magnolia tenuinervis Lesquereux, but this species was found to be 

in great confusion, as explained in my paper on 

the Raton fl.ora, 5 and this specimen has been 

transferred with some question to Magnolia 

magnifolia Knowlton. 

5455. Ignacio quadrangle, Colo., east side of sec. 

21, T. 35 N., R. 6 W., 1,650 feet above base of [McDermott formation]; collected by J. H. Gardner, 

August, 1909: 

Juglans berryi Knowlton. 

Juglans? innominata Knowlton, n. sp. 

Platanus aceroides · Goppert. 

Sapindus obtusifolius Lesquereux. 

Corn us studeri Heer. 

· Viburnum rotundifolium Lesquereux. 

5456. Ignacio quadrangle, Colo.; southeast corner of 

sec. 15, T. 35 N., R. 6 W., about 200 feet above base of 

McDermott formation; collected by J. H. Gardner, 

~ugust, 1909: 

Ficus planicostata Lesquereux. 

5667. Ignacio quadrangle, Colo.; pebbles ·near top 

of:: Animas formation; collected by J. H. Gardner, 

August, 1909: 

Artocarpus pungens (Lesquereux) Hollick .. 

Nyssa'? racemosa Knowlton. 

The A rtocarpus was first recorded as A. 

lessigiana Lesquereux, but the finding of betterpreserved material at Pagosa Junction leads me 

to the view that it best referred to A. pungens. 

• The numbers thus recorded are the lot numbers of the _paleobotanic collections of the U. S. Geological Survey. 

6 Knowlton, F. H., U. S. Geol. Survey Prof .. Paper 101, pp. 311-313, 

1917. 

6309. Pagosa Junct~, Colo., half a mile downstream from the station; ._collected by W. T. Lee, 1912: 

· Ficus pseudo-populus Lesquereux. 

Juglans sp. cf. J. berryi Knowlton. 

Nelumbo lakesii (Lesquereux) Knowlton. 

Viburnum antiquum (Newberry) Hollick. 

6443. About 1 mile northeast of Pagosa Junction, 

Colo.; collected by W. T. Lee, 1912: 

Sabal? ungeri (Lesquereux) Knowlton. 

Ficus pagosensis Knowlton, n. sp. 

Ficus sp. 

Artocarpus sp.? 

Platanus aceroides Goppert. 

Platanus raynoldsii Newberry. 

Malapoenna sessilifl.ora (Lesquereux) Knowlton. 

Viburnum speciosurri Knowlton. 

6444. About 1 mile northeast of Pagosa Junction, 

Colo.; collected by W. T. Lee, 1912: 

Sabal? ungeri (Lesquereux) Knowlton. 

Ficus neo-planicostata Knowlton. 

Platanus, probably P. raynoldsii Newberry. 

Oreodaphne pagosensis Knowlton, n. sp. 

Magnolia angustifolia Newberry. 

Rhamnus cleburni Lesquereux. 

7452. Ignacio quadrangle, Colo., 1 mile northwest 

of Bayfield, in SW. i sec. 3, T. 34 N., R. 7 W.; upper 

part o.f Animas formation; collected by J. B. Reeside, 

jr., 1920: · 

Platanus sp. cf. P. raynoldsii Newberry. 

Platanus aceroides Goppert. 

7453. Ignacio quadrangle, Colo., 7 miles northeast 

of Bayfield, in. NE. i sec. 18, T. 35 N., R .. 7 W.; 

collected by J. B. Reeside, jr., October, 1920: · 

·' Anemia sp. 

7460. Ignacio quadrangle, Colo., 5 miles east of 

Durango, in NW. i SE. i sec. 30, T. 35 N., R. 8 W.; 

collected by J. B. Reeside, jr., 1920: 

Platanus? sp. 

7463. Ignacio quadrangle, Colo., 5 miles east of 

Durango, in SW. i sec. 30, T. 35 N·., R. 8 W., 700 feet 

above base of Animas· formation; collected by J. B. 

Reeside, jr., 1920: 

Platanu~ raynoldsii Newberry. 

Rhamnus goldianus Lesquereux. 

Cissus? sp. 

7464. Ignacio quadrangle, Colo., 5 miles south of 

Durango, in SE. i NW. i sec. 13, T. 34 N., R. 10 W., 

400 to 500 feet above base of upper Animas beds 

[Animas restricted]; collected by J. B. Reeside: jr .. 

September, 1920: 

Ficus? sp. 

7479. Pagosa quadrangle, Colo., on first hill west 

of road past Talian mine, 5 miles north of Pagosa 

Junction; collected by Singewald and Reeside, May, 

1921: 

Juglans berryi Knowlton. 

Cyperacites sp. 

7480. Pagosa quadrangle, Colo., top of hill west of 

Talian mine, 5 miles north of Pagosa Junction, about 

600 feet above base o.f Animas formation; coller.ted by 

Singewald and Reeside, May, 1921: 

Sabal? ungeri (Lesquereux) Knowlton. 
FORMS INCLUDED. 73 

7481. Pagosa quadrangle, Colo., hill above Talian 

mine, 5 miles north of Pagosa Junction, loose on slope 

but probably from about 600 feet above base of 

Animas formation; collected by Singewald and Reeside, June, 1921: 

Ane~ia grandifolia Knowlton, n. sp. 

Sabal? ungeri (Lesquereux) Knowlton. 

l'i'icus pseudo-populus Lesquereux. 

Ficus planicostata Lesquereux. 

Ficus monodon (Lesquereux) Berry? 

Magnolia hilgardiana Lesquereux. 

Oreodaphne sp? 

7482. Pagosa- quadrangle, Colo., hill above Talian 

mine, 5 miles north of Pagosa Junction, about 600 

. feet above base of Animas formation; collected by 

Singewald and Reeside, June, 1921: 

Platanus aceroides Goppert. 

Aralia reesidei Knowlton, n. sp. 

7483. Pagosa quadrangle, Colo., 1,000 feet south of 

Talian mine, 5 miles north of Pagosa Junction, about 

300 feet above base of Animas formation; collected 

by Singewald and Reeside, June, 1921: 

Ficus subtruncata Lesquereux. 

Cinnamomum salicoides Knowlton, n. sp. 

Zizyphus lanceolatus Knowlton, n. sp. 

Aralia lobata Knowlton, n. sp. 

Aralia? sp. 

Apocynophyllum wilcoxensis Berry. 

Phyllites eocenica Knowlton, n. sp. 

Phyllites herbacea Knowlton, n. sp. 

7484. Pagosa quadrangle, Colo., on road half a mile 

south of Talian mine, 4~ miles north of Pagosa Junction, about ·1,000 feet above base of Animas formation; collected by Singewald and Reeside, June, 1921: 

Dryopteris cladophleboides Knowlton. 

7485. Same locality as 7484, but about 1,100 feet 

above base of Animas formation: 

Juglans berryi Knowlton. 

Castanea intermedia Lesquereux. 

Platanus aceroides Goppert. 

Platanus aceroides latifolia Knowlton. 

Ficus pseudo-populus Lesquereux. 

Ficus neo-planicostata Knowlton. 

Magnolia angustifolia Newberry. 

Magnolia hi:lgardiana Lesquereux. 

Rhamnus cleburni Lesquereux. 

Phyllites eocenica Knowlton, n. sp. 

7486. Pagosa quadrangle, Colo~, five-eighths of a 

mile south of Talian mine, 4~ miles north o'f Pagosa 

Junction, about 1,200 feet above base of Animas fQrmation; collected by Singewald and Reeside, June, 

1921: 

Crataegus? giganteus Knowlton, n. sp. 

7492. Ignacio quadrangle, Colo., 7 miles northeast 

of Bayfield, in SE. i NE. i sec. 15, T. 35 N., R. 6 W., 

about 500 feet above base of Animas formation; collected by Singe~ald and Reeside, June, 1921: 

7493. Pagosa quadrangle, Colo., 8 miles northeast 

of Bayfield, 2,450 feet above base of Animas forma- · 

tion, practically at top; collected by Singewald and 

Reeside, June, 1921: · 

7496. Pagosa quadrangle,· Colo., half a mile west of 

Pagosa Junction (same locality as Lee's lot 6309) i 

collected by J. B. Reeside, jr., June, 1921: 

Allantodiopsis erosa (Lesquereux) Knowlton and 

Maxon. 

Salix reesidei Knm'\<lton, n. sp. 

Juglans schimperi Lesquereux. 

Juglans berryi Knowlton. 

Fagus crossii Knowlton, n. sp. 

Dryophyllum berryana Knowlton,~· sp. 

Ficus occidentalis Lesquereu:x. 

Ficus denveriana Cockerell. 

Ficus sp. 

Ficus sp. 

Artocarpus pungens (Lesquereux) Hollick . 

Laurus primigenia Unger .. 

Nectandra lancifolia Berry. 

Magnolia angustifolia Newberry. 

Magnolia hilgardiana Lesquereux. 

Cassia puryearensis Berry. 

Rhus coloradensis Knowlton, n. sp. 

Zizyphus fibrillosus Lesquereux. 

Zizyphus daphnogeno~des Knowlton, n. sp. 

Carpites sulcatus Knowlton, n. sp. 

Phyllites pagosensis Knowlton, n. sp. 

Phyllites innominata Knowlton, n. sp. 

Phyllites sp. . 

7497·. Pagosa quadrangle, Colo., on Cat Creek about 

1 mile north of Pagosa Junction (same locality as 

Lee's lots 6443 and 6444), upper part of Animas formation; collected by Singewald and Reeside, June, 

1921: 

Ficus pseudo-populus Lesquereux. 

7498. Pagosa quadrangle, Colo., on Cat Creek about 

1 mile north of Pagosa Junction, upper part of Animas 

formation; collected by Singewald and Reeside, June, 

1921: 

Platanus aceroides Goppert. 

Platanus aceroides latifolius Knowlton. 

FORMS INCLUDED IN THE FLORA. 

As a preliminary to the discussion of the 

Animas flora a complete list of the forms 

recognized is given below: 

Allantodiopsis erosa (Lesquereux) Knowlton 

and Maxon. 

Dryopteris cladophleboides Knowlton. 

Anemia grandifolia Knowlton, n. sp. 

Sabal? ungeri (Lesquereux) Knowlton. 

Salix reesidei Knowlton, n. sp. 

Juglans schimperi Lesquereux. 

Juglans berryi Knowlton. 

Juglans innominata Knowlton, n. sp. 

Fagus crossii Knowlton, n. sp. 

Castanea intermedia Lesquereux. 

Dryophyllum berryana Knowlton, n. sp. 

Ficus planicostata Lesquereux. 

Ficus neoplanicostata Knowlton. 

Ficus occidentalis (Lesquereux) Lesquereux 

Ficus denveriana Cockerell. 

Ficus subtruncata Lesquereux. 

Ficus monodon (Lesquereux) Berry? 
74 FLORA OF THE ANIMAS FORMATION. 

Ficus pseudo-populus Lesquereux. 

Ficus pagosensis Knowlton, n. sp. 

Ficus sp. 

Ficus sp. 

Artocarpus pungens (Lesquereux) Hollick. 

Platanus raynoldsii Newberry. 

Platanus aceroides Geppert. 

Platanus aceroides latifolia Knowlton. 

Laurus primigenia Unger. 

N ectandra lancifolia (Lesq uereux) Berry. 

Malapoenna sessiliflora (Lesquereux) Knowlton. 

·oreodaphne pagosensis Knowlton, n. sp. 

Cinnamomum salicoides Knowlton n. sp. 

Nelumbo lakesiana (Lesquereux) Knowlton. 

Magnolia angustifolia Newberry. 

Magnolia hilgardiana Lesquereux. 

Magnolia magnifolia Knowlton? 

Crataegus? gigantea Knowlton, ri. sp. 

Cassia puryearensis Berry. 

Rhus coloradensis Knowlton, n. sp. 

Sapindus obtusifolius Lesquereux. 

Rhamnus cleburpi Lesquereux. 

Rhamnus goldianus Lesquereux. 

Zizyphus fibrillosus Lesquereux. 

Zizyphus daphnogenoides Knowlton, n. sp. 

Zizyphus lanceolatus Knowlton, n. sp .. 

Aralia lobata Knowlton, n. sp. 

Aralia reesidei, Knowlton, n~ sp. 

Aralia? sp. 

Cornus studeri? Heer. 

Nyssa? racemosa Knowlton. 

Apocynophyllum wilcoxensis Berry. 

Viburnum rotundifolium Lesquereux. 

Viburnum antiquum (Newberry) Hollick. 

Viburnum speciosum Knowlton. 

Carpites sulcatus Knowlton, n. sp. 

Phyllites eocenica Knowlton, n. sp. 

Phyllites pagosensis Knowlton, n. sp. 

Phyllites herbacea Knowlton, n. sp. 

Phyllites innominata Knowlton, n. sp. 

Phyllites sp. 

From the above list it appears that the 

Animas flora comprises 59 forms, of which 

19 are regarded as new to science and 4 are 

not nan1ed specifically, leaving 36 previously 

known species having a distribution outside 

its limits. The distribution of these 36 species 

is shown by the following lists: 

Species common to the Animas and Denver formations 

Allantodiopsis erosa. 

Juglans schimperi. 

Castanea intermedia. 

Ficus occidentalis. · 

Ficus denveriana. 

Ficus subtruncata. 

Artocarpus pungens. 

Platanus aceroides. 

Platanus raynoldsii,. 

Laurus pfimigenia. 

N elumbo lakesiana. 

Magnolia magnifolia. 

Rhamnus cleburni. 

Rhamnus goldianus. 

Zizyphus fibrillosus. 

Zizyphus daphnogenoides. 

Cornus studeri. 

Nyssa? racemosa. 

Species common to the Animas and Raton formations. 

Allantodiopsis erosa. 

Dryopteris cladophleboides. 

Sabal? ungeri. 

Juglans schimperi. 

J uglans berryi. 

Castanea intermedia. 

Ficus neoplanicostata. 

Ficus occidentalis. 

Ficus denveriana. 

Ficus pseudo-populus. 

Platanus raynoldsii. 

Platanus aceroides. 

Platanus aceroides latifolia. 

N ectandra lancifolia. 

N elumbo.lakesiana. 

Magnolia angustifolia. 

Magnolia hilgardiana. 

Magnolia magnifolia. 

Rhamnus cleburni. 

Zizyphus :fibrillosus. 

Cornus studeri. 

Nyssa? racemosa. · 

Apocynophyllum wilcoxensis. 

Viburnum speciosum. 

Speci-es common to the Animas formation and Wilcox 

gro1tp. 

Juglans schimperi. 

Juglans berryi. 

Ficus planicostata. 

Ficus neoplanicostata. 

Ficus occidentalis. 

Ficus denveriana. · 

Ficus monodon. 

Ficus pseudo-populus. 

Artocarpus pungens. o 

Laurus primigenia. · 

N ectandra lancifolia. 

Magnolia an_gustifolia. 

Magnolia hilgardiana. 

Cassia puryearensis. 

Rhamnus cleburni. 

Cornus studeri. 

Apocynophyllum wilcoxensis. 

Species common to the Animas and Fort Union 

formations. · 

Allantodiopsis erosa. 

Castanea intermedia. 

Platanus raynoldsii. 

Platanus aceroides. 

Laurus primigenia. 

Viburnum antiquum. 
HELATION BETWEEN FLORAS OF ANIMAS AND PUERCO FORMATIONS. 75 

A few of the Animas plants have been reported from higher Tertiary horizons. Thus, 

two species (Juglans schimperi and Sapindus 

obtusifolius) have been recorded from the 

Green River formation; three (Allantodiopsis 

erosa, Juglans schimperi, and Ficus planicostata) from the upper part of the Clarno formation; and one (Laurus primigenia Unger) 

from the I-Ianna for-mation. 

RELATION BETWEEN THE FLORAS OF THE 

ANIMAS AND PUERCO FORMATIONS. 

The flora of the Puerco formation is scanty 

and on the whole poorly preserved. The first 

collection was a small one made by Sinclair 

and Granger and was reported oil by ·me in 

their paper.6 The following forms were noted: 

Ficus occidentalis Lesquereux. 

Artocarpus sp. 

Paliurus zizyphoides? Lesquereux. · 

Platanus sp. cf. P. haydenii Newberry. 

Populus sp. cf. P. cuneata Newberry. 

Viburnum lakesii? Lesqllereux. 

Viburnum sp.? 

At a point 1 mile northeast of Ojo Alamo, 

N. Mex., which is at or very near the locality 

from which Sinclair and Granger collected 

their material, J. B. Reeside, jr., procured in 

1921 a small but interesting collection, 1n 

which these forms have been recognized: 

J?icus sp., large leaf. 

Platanus raynoldsii Newberry. 

Platanus marginata (Lesquereux) Heer? 

Viburnum melaenum Knowlton and Cockerell. 

'Viburnum rotundifolium Lesquereux. 

Viburnum sp. 

Magnolia hilgardiana Lesquereux? 

Rhamnus cleburni Lesquereux. 

Fragments. 

I have not had the opportunity of reviewing 

the collection made by Sinclair and Granger, 

but in the light of the recent material, as well 

as knowledge of the Ariimas flora, it is possible 

to n1ake certain emendations in the first list. 

Thus the Artocarpus sp. is in all reasonable 

probability Artocarpus pungens. The sycanlore con1pared with Platanus haydenii is now 

found to be Platanu~ raynoldsii. The leaf 

identified as Viburnum lakesii? is probably only 

a s1nall leaf of Viburnum rotundifolium. 

Neither Fic'I.LS occidentalis nor Populus cf. P. 

cuneata Newberry appears to be. present in the 

Reeside collection. Combining the two lists 

o Sinclair, W. J., and Granger, Walter, Paleocene deposits of the San 

Juan Basin, N. 1\'Iex.: Am. Mus. Nnt. Hist. Bull., vol. 33, p. 306, 1914. · 

we have the following speqies identified with 

a fair degree of certainty: 

Ficus occidentalis. 

Ficus sp. 

Artocarpus· pungens? 

Platanus raynoldsii. 

Platanus marginata? 

Populus cf. P. cuneata. 

Magnolia hilgardiana? 

Viburnum melaenum. 

Viburnum 1rotundifolium. 

Viburnum sp. 

Paliurus zizyphoides? 

Rhamnus cleburni. 

The leaves identified as Platanus marginata? 

differ in a number of respects fron1 the type 

material of that species, which came from 

"post-Laramie beds." at Black Buttes, Wyo., 

and should probably be described as new. 

They agree in shape of base and in nervation, 

but differ in having a pointed instead of 

nearly truncate apex and in having the marginal teeth small and sharp instead of obtuse 

or deltoid. The range in size is also much 

greater than in the type material. 

All the positively identified species in the 

Puerco flora and two of those provisionally 

identified (Artocarpus pungens and jJfagnolia 

hilgardiana) occur also in the Animas flora, 

and non~ of them indicate Cretaceous age. It 

therefore seems legitimate to conclude that, on 0 

the basis of the plants, the Puerco formation 

is of Tertiary age and in the approximate position of the Denver, Raton, and Wilcox beds. 

RELATION BETWEEN THE FLORAS OF THE ANIMAS FORMATIO~ AND THE CRETACEOUS. 

Five of the Animas species have been reported more or less definitely from horizons of 

Cretaceous age. These are · 

Allantodiopsis erosa. 

Sabal? ungeri. 

Ficus planicostata. 

Ficus. denveriana. 

Gornus studeri. 

The distribution of these· species is as follows: 

A single specimen of Allantodiopsis erosa was 

found in beds supposed to be in the Vern1ejo 

formati<?n, at Rockvale, Colo., but the specimen 

was loose on the surface and may or may not 

have come from this horizon. Saoal~ ungeri 

is probably the most abundant and widely 

distributed form in the Raton of Colorado and 

New Mexico, and a single specimen was found 

in the highest known beds of the V ermej o 
76 FLORA OF THE ANIMAS FORMATION. 

formation in Ponil Canyon, N. Mex. Ficus 

planicostata has a recorded range from Mesaverde to upper Eocene and ·hence is of little 

value as a horizon marker .. Its type locality 

is the "post-Laramie beds" af Black Buttes, 

Wyo., wher~ it is abundant. Ficus denveriana 

was found first in the Denver beds at Golden, 

Colo., and later at many points in the Raton 

and Wilcox beds and at a single locality in the 

Lance formation of South Dakota, and was 

identified with question in the Laramie near 

Colorado Springs, Colo. Oornus studeri is essentially a Tertiary species, occurring in the 

Denver, Raton, and Wilcox beds and questionably in the Mesaverde at Point of Rocks, 

Wyo; 

From the above discussion· it appears that 

the relation between the flora of the Animas 

formation and any Cretaceous flora is practically negligible. The real relationshi.P of the 

Animas flora is undoubtedly with those of. beds 

at higher horizons. 

RELATION BETWEEN THE FLORAS OF THE 

ANIMAS FORMATION AND THE BASAL PART 

OF THE WASATCH FORMATION ("TIFFANY 

BEDS" OF GRANGER) IN THIS REGION. 

The flora of the so-called "Tiffany beds" of 

Granger is even more scanty than that of the 

Puerco formation. Two collections are known, 

one of which came from the bas~ of the beds 

furnishing the " Tiffany" fauna. The forms 

recognized are as follows: 

Ficus planicostata Lesquereux. 

Ficus cf. F. denveriana Cockerell. 

Ficus cf.. F. schimperi Le~quereux. 

Ficus sp. 

Aralia? sp. 

Celas trinites cf. C. artocarpidioides Lesquereux 

Platanus? sp. 

This material is so poorly identified that 

very little can be said as· to the age indicated 

by it. If all the suggested identifications were 

authenticated there would be no hesitation in 

. regarding it as approximating in age the Denver 

and Raton formations, and there is nothing in 

the collections that in any way militates against 

this conclusion. 

RELATION BETWEEN THE FLORAS OF THE 

ANIMAS AND McDERMOTT FORMATIONS. 

The McDermott formation unconformably 

underlies the Animas formation. It is composed largely of andesitic material, usually 

purplish, and has-until recently differentiated 

by Reeside-been considered a part of the 

Animas formation. It has yielded plants at 

a number of localities in southwestern Colorado 

and northwestern New Mexico. Thus, at a 

point 1 mile east and a quarter of a mile 

north from Pina V e'ta China, N. Mex., Bauer 

collected the following species (lot 6965) : 

Pistia corrugata Lesquereux. 

Ficus leei? Knowlton. 

Ficus? sp., large broken leaf. 

Unrecognized plant suggesting Selaginella. 

A second lot (No. 6966) obtained 1 mile east 

and three-quarters of. a mile north from Pina 

Veta China· shows the following species:' 

Onoclea ·neomexicana Knowlton. 

Asplenium neomexicanum Knowlton. 

Palm (genus?). 

Ficus leei Knowlton. 

Myrica? neomexicana Knowlton. 

Leguminosites? neomexicana Knowlton. 

J>terospermi tes sp. 

On Florida River, east of Durango, Colo., 

J. H. Gardner collected Ficus planicostata 

Lesquereux in beds over 200 feet above the 

base of the McDermott. 

On the west side of Animas River, below 

Durango, Colo., Cross and Spencer collected 

the following species: 

Fern, new, genus? 

Sabalites sp.? 

Cyperacites sp. 

Ficus denveriana? Cockerell. 

Ficus eucalyptifolia Knowlton. 

Quercus praeangustiloba Knowlton. 

Grewiopsis sp. 

Cissus coloradensis? Knowlton and Cockerell. 

Rhamnus cf. R. cleburni Lesquereux. 

Near the same locality Cross and Spencer. 

procured the follow.ing forms: 

Sequoia acuminata? Lesquereux. 

Cyperacites sp. 

Canna? magnifolia Knowlton . 

Laurus socialis Lesquereux. 

Cinnamomum linifolium? Knowlton. 

A small collection (lot 7457) was procured 

by Reeside 4 miles south of Durango, which 

yielded the following: 

Salpichlaena sp., apparently new. 

Ficus sp .. 

Laurus sp. 

Fragments of dicotyledons. 
SUMMARY AND CONCLUSIONS. 77 

Bringing together the different forms in the 

abo:e lists gives the following species as representing the flora of the McDermott formation: 

Onoclea neoniexicana. 

Asplenium neomexicanum. 

Salpichlaena sp. 

·Fern, genus? 

Sequoia acuminata? Lesquereux. 

Cyperacites sp. 

Canna? magnifolia Knowlton. 

Sabalites sp.? 

Palm, genus? 

Pistia corrugata. 

Myrica? neomexicana. 

Quercus praeangustiloba. 

Ficus eucalyptif<;>lia. 

Ficus denveriana? 

Ficus leei. 

Ficus planicostata. 

Ficus sp.? 

J.Jaurus socialis Lesquereux. 

Laurus sp. 

Cinnamomum linifolium? 

Grewiopsis sp. ' 

Cisstts coloradensis? 

Leguminosites? neomexicana. 

Rhamnus cf. R. cleburni. 

Pterospermites sp. 

The bearing of this flora on the question of 

age is difficult of satisfactory or conclusive 

evaluation. At first sight it would seem that 

the two collections from Pina Veta China . ' 

N. Mex., are umn~stakably Cretaceous, being 

recorded 7 as from the Kirtland formation ' but it is now disclosed that this is the type 

locality for four of the six named species, and 

the. beds in which they occur are now placed 

by Reeside in the McDermott formation 

instead of the Kirtland. This leaves only 

two previously known species (Pistia corrugata 

and Ficus leei) that occur in unquestioned 

Cretaceous rocks. 

The several lots of plants 'from the vicinity 

of Durango, Colo., are also difficult of allocation. Three of the species enumerated (Canna? magnifolia, Ficus eucalyptifolia, and Quercus 

praeangustiloba) are known ·only from the 

Cretaceous. Another ~pecies (Ficus planicostata) is known to range from Mesaverde to 

upper Eocene and is therefore of little value in 

fixing age. The remaining forms (Ficus denveriana ?, Oinnamomum linifolium?, Rhamnus 

c:f. R. cleburni, Laurus socialis, and Oissus 

7 Knowlton, F. H., Flora of the Fruitland and Kirtland formations: 

, U. S. Gcol. Survey Prof. Paper 98, pp. 327-353, 1916. 

coloradensis), although identified with question, seem to indicate Tertiary age. Two 

explanations are possible to account for this 

. apparent confusion. The material, especially 

that indicating Tertiary affinity, may not have 

been. cor~ectly identified; or the beds may be 

so high In the Cretaceous section that the 

plants foreshadowed a Tertiary faCies, ·but 

this is, of course, unsubstantiated conjecture. 

As the matter now rests the plants undoubtedly 

favor placing the McDermott formation in the 

Cretaceous, but they are not conclusive. 

SUMMARY AND CONCLUSIONS. 

1. .The known flora of the Animas formation 

comprises 59 forms, of which 19 are new, 4 are 

not named specifically, and 36 are previously 

known species. 

2. Of the 36 previously known species 18 

are found in the Denver formation, 25 in' the 

~aton formation, 17 in the Wilco~ group, 6 

In the Fort Union formation, 3 in the Green 

River formation, 2 in the. upper part of. the 

Clarno formation, and 1 or· 2 scattered in ·other 

Eocene formations. 

, 3. The flora of the Puerco formation includes 

12 forms. As all of these that have been po~i-· 

tively identified and two of them that have been 

provisionally identified occur in the Animas 

formation, the conclusion is reached that the 

Puerco formation is of approximately the 

same age as the Animas. 

4. The flora of the McDermott formation 

includes 25 forms, 10 of which are not nam.ed 

specifically. Of the 15 named species 5 are 

known. only from the McDermott. The ermaining species, although favoring Cretaceous 

age, are inconclusive. 

5. Of the 36 Animas species having an outside distribution only five, and several of these 

of doubtful authenticity, are found in beds of 

·Cretaceous age. The Cretaceous affinity is 

therefore regarded as unimportant and practically negligible. · 

6. On combining the Animas species found 

in the Denver, Raton, and Wilcox, it appears 

that 33 species, or over 90 per cent of those 

having an outside distribution are held in 

common, and the conclusion is reached that 

the Animas formation . is of the same agenamely, Eocene Tertiary. 
78 FLORA OF THE ANIMAS FORMATION. 

SYSTEMATIC DESCRIPTIONS. 

Phylum PTERIDOPHYTA. 

rather coarse grained, with the result that little 

nervation beyond the midvein is retained. In 

size, angle of pinnules, and sharp points to the Class FILICES. 

Family POLYPODIACEAE. . pinnules it is apparently identical with the species named. 

Allantodiopsis erosa (Lesquereux) Knowlton and Maxon. 

Pia te VI, Figure 1. 

Allantodiopsis erosa (Lesquereux) Knowlton and 

Maxon, U.S. Geol. Survey Bull. 696, p. 61, 1919. 

Pteris erosa Lesquereux, U. S. Geol. and Geog. Survey 

Terr. Ann. Rept. fo~ 1871, Suppl., p. 12, 1872; 

U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary 

flora), p. 53, pl. 4, fig. 8, 1878. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, p. 

244, 1917 [1918]. 

Pteris subsimplex Lesquereux, U. S. Geol. Survey Terr. 

Rept., vol. 7 (Tertiary· flora), p. 52, pl. 4, figs. 

5-7, 1878. 

Osmunda major Lesquereux, U. S. Geol. Survey Terr. 

Rept., vol. 8 (Cretaceous and Tertiary floras), 

p. 121, pl. 18, fig. 5, 1883. 

Pteris undulata Lesquereux, Mus. Comp. Zool. Bull. 

vol. 16, p. 43, 1888. 

The type locality for Pteris erosa Lesquereux 

is Fisher's Peak, Colo., in the Raton formation. 

It was found to be most abundant in the 

Denver formation at Golden, Colo., and from 

specimens obtained at that locality it was at, 

di'fferent times described under the names 

Pteris subsimplex, Pteris undulata, and Osmunda major. Study of a large series of specimens has shown, however, that they are all 

slightly variant forms of the same species, 

which -takes the name Pteris erosa, the earliest 

name applied. A fine fruiting specimen was 

found in beds of the Arapahoe formation near 

the Douglas ·coal mine, a few miles west of 

Sedalia, Colo. It was· on the basis of t~e close 

relation of this specimen to the living Allantodia that the new genus was erected. This 

genus is described in full in my report on the 

flora of the Denver formation now awaiting 

publication. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction; collected by J. B. Reeside, jr., June, 1921 

(lot 7496). 

Dryopteris cladophleboides Knowlton. 

Plate VI, Figure 2. 

Dryopteris? cladophleboides Knowlton, U. S. Geol. Survey Prof. Paper 101, p. 284, pl. 54, fig. 1, 1917 

[1918]. . 

·The collection from Pagosa Junction includes 

oa single fragment that appears to belong to this 

species. The matrix on which it is preserved is 

Occurrence: Animas formation, Pagosa quadrangle, Colo., on road half a mile south of 

Talian mine, 4! miles north of Pagosa Junction; collected by Q. D. Singewald and J. B. 

Reeside,· jr., June, 1921 (lot 7484). 

Family SCHIZEACEAE. 

Anemia grandifolia Knowlton, n. sp. 

Plate V.-

The specimen figured is the only one, with 

the exception of a single fragmentary pinnule, 

that was found in the collections. This ·is a 

nearly perfect frond 29 centimeters long and 

about 16 centimeters wide between the tips of 

the lowest pair of, pinnae. It is narrowly 

deltoid in general outline. The rachis is moderately strong and deeply channeled. The · 

pinnae are alternate, at an angle of about 50°, 

lower ones remote and short stalked, becoming 

closer and decurrent in the middle and confluent in the apical portion. The pinnae are 

linear-lanceolate, with a slender acumin·ate 

apex, and· are deeply cut into numerous lancealate or narrowly deltoid lobes, the margins of 

which are entire or with an occasional small 

sharp tooth; midrib of the lobes (pinnules) 

arising from the secondary rachis at an angle 

of about 80°, reduced by forking several tiines 

before reaching the margin. 

The genus Anemia enjoys a wide geographic 

range in the late Mesozoic and early Cenozoic, 

but it appears always to be rather rare and 

moreover is usually fragmentary. A perfectly 

preserved frond is distinctly exceptional, and 

the present specimen is one of the few that approach this standard. 

Among fossil species there are several that are 

very similar to the one under discussion. Thus 

Anemia eocenica Berry; 8 from beds of Wilcox age 

in the Lagrange formation at Puryear, Tenn., is 

of the same general type but differs in having the 

lobes of the pinnules with six or eight marginal 

teeth, commonly in pairs, each being "distinctly 

serrate, with the points produced arid directed 

upward." The pinnules are said to be ats Berry, E. W., U.S. Geol. Survey Prof. Paper 91, p. 164, pl. 9, fig. 7; 

pl. 10, fig. 2; pl. 11, figs. 1, 2, 1916. 
SYSTEMATIC DESCRIPTIONS. 79 

tached to the n1ain rachis by their entire bases, 

though Berry thinks that low.er down on the 

frond they n1ay have had a narrowed base 

and have free pinnules. In this particular it 

agrees perfectly with Anemia grandifolia: 

A fragment of Anemia 0 not named specifically, from the Fruitland formation of San 

Juan County, N. Mex., is also of this type, but 

it is rnuch larger and has the lobes of the pinnules distinctly toothed. 

Anemia occidentalis I\::nowlton/ 0 from the 

Raton forn1ation, differs in having the pinnules 

strongly toothed rather than lobed. Some of 

the n1ore strongly lobed forms of Anemia 

subcretacea (Saporta) Gardner and Ettingshausen,11 frorn the Middle Bagshot beds 

(Lutetian) of Bournemouth, England, are 

strikingly like Anemia grandifolia but ·differ 

in having the lobes usually toothed and the 

rn:idrib of the lobes less distinctly forked. 

Occurrence: Anin1as forn1ation, Pagosa quadrangle, Colo., hill above I'alian mine, 5 n1iles 

north of Pagosa Junction, collected by Q. D. 

Singewald and J. B. Reeside, ]r., June, 1921 

(lot 7481). 

Phylum SPERMATOPHYT~. 

Class ANGIOSPERMAE. 

Subclass MONOCOTYLEDONES. 

Order ARECALES. 

Family ARECACEAE. 

Sabal? ungeri (Lesquereux) Knowlton. 

S(£bal? 1mgeri (Lesquereux) Knowlton, U. S. Geol. Survey Prof. Paper 101, p. 288, pl. 58, 1918. 

Geonomites ungeri Lesquereux, U. S. Geol. Survey Terr. 

Rept., vol. 7 (Tertiary flora), p. 118, pl. 11, fig. 

2, 1878. 

This species is one of the most abundant 

forms in the Raton formation of the Raton 

Mesa region of Colorado and New Mexico and 

is also found at several localities in the Animas 

beds. 

Occurrence: Anirnas forn1ation, Pagosa quad-. 

rangle, Colo., about 1rnile north of PagosaJunc9 Knowlton, F. iL, U. S. Geol. Survey Prof. Paper 98, p. 333, pl. 84, 

fig. 4, 1916. 

10 Knowlton, F. II., U.S. Cleo!. Survey Prof. Paper 101, p. 285, pl. 54, 

fig. 2, 1917 [1918]. 

II British Eocene Uorfl, Filiccs, vol. 1, p. 45, pis. 8, 9, 1880. 

tion, collected by W. T. Lee, 1912 (lots 6443, 

6444) ; hili above Talian<-.,mine and top of 

hill west of Talian mine, 5 miles . north of 

Pagosa Junction, collected by Q. D. Singewald 

and J. B. Reeside, jr., June, 1920 (lots 7480, 

7481). 

Subclass DICOTYLEDONES. 

Series CHORIPETALAE~ 

Order SALICALES. 

Family· SALICACEAE. 

Salix reesidei Knowlton, n. sp. 

Plate VI, Figure 3. 

Leaf small, linear-\anceolate, petioled, long 

acuminate at apex and narrowly we.dge-shaped 

at base; margin entire; nervation very strong 

for the size of the leaf and deeply impressed, 

consisting of a thick, straight midrib and some 

.ten or twelve pairs of strong secondaries, which 

arise at an angle of about 45°, all camptodrome, 

each arching ins1de the n1argin and joining the 

the one next above; finer nervation not discernible. 

This little leaf is the only one observed in 

the collections. It is 4 centimeters long, including the petiole, and 6 millimeters wide. in 

the middle. 

This species is of the type of a number of 

living species, l?uch as Salix fiuviatilis Nuttall, 

Salix sessilifolia Nuttall, of the central part of 

the continent and the Pacific coast region, but 

both these have a few faint teeth above the 

middle. It is also similar to Salix angustifolia 

Fries and Salix incanea Schrank, of central and 

northern Europe, but differs in details of nervation. It is apparently different from any fossil 

species from this country thus far described. 

It is of the same size as some of the smaller 

leaves of Salix plicata Knowlton/ 2 ·from the 

Raton forn1ation, but this differs in the secondary nervation. . 

Occurrence: Animas fonnation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., June, 1921 (lot 7496). 

12 Knowlton, F .. 1.:1., U.S. Cleo!. Smvcy Prof. Paper 101, pl. 37, fig. 8, 

1917 [1918]. 
80 :FLORA OF THE ANIMAS FORMATION. 

Order JUGLANDALES. 

Family CJ'UGLANDACEAE. 

Juglans schimperi Lesquereux. 

Plate VII, Figure 1. 

Juglans schimperi Lesquereux, U. S. Geol. and Geog. 

~urvey Terr. Ann. Rept. for 1871, Suppl., p. 8, 

1872; U. S. Geol. Survey Terr. Rept., vol. 7 

(Tertiary flora), p. 287, pl. 56, figs. 5-10, 1878. 

Hollick, Louisiana Geol. Survey, Special Rept. 5, 

p. 280, pl. 32, fig: 5; pl. 33, figs. 1, 2; pl. 35, 

fig. 3, 1899. 

Berry, U. S. Geol. Survey Prof. Paper 91, p. 182, 

pl. 18, figs. 3-5; pl. 19,.fig. 4, 1916. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, 

p. 296, pl. 64, fig. 1, 1917 [1918]. 

This species was described from specimens 

collected from the Gree~ River formation of 

Wyoming and has since been. detected in the 

Denver, Clarno, Fort Union, and Raton formations, as well as in several of the formations of 

the Wilcox group of the Gulf region. What-. 

ever may be thought of the probability of a 

· species enjoying so wide a geologic and geographic range as is thus indicated, the fact 

remains that it is impossible to draw any satisfactory line between the forms described. 

They are to all intents and purposes the same 

thing, as may be noted on comparing the many 

figures that have been published. 

The leaflet here figured is nearly perfect, 

except that it lacks the base. It was probably· about 11 centimeters long and is 4 centimeters wide. It agrees perfectly in shape, 

size, and essential details of nervation with 

leaflets as figured by Lesquereux, Hollick, and 

Berry. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., June, 1921 (lot 7496). 

Juglans berryi Knowlton. 

Plate VI, Figures 5, 6. 

Juglans berryi Knowlton, in Berry, U. S. Geol. Survey 

Prof. Paper 91, p. 183, 1916; U. S. Geol. Survey Prof. Paper 101, p. 293, pl. 63, fig. 3; pl. 

64, fig. 3; pl. 73, fig. 3, 1917 [1918]. 

The type of this species was described from 

material obtained in the Raton formation of 

southeastern Colorado, and the species was 

also found by Berry in the Wilcox group in 

Louisiana and beds of corresponding age in the 

Lagrange formation of Kentucky. The specimen here figured does not differ from the type 

specimens. Specimens not figured from the 

Ignacio quadrangle, Colo., are also identical. 

Occurrence: Animas formation, Ignacio quadrangle, Colo., east side of sec. 31, T. 35 N., 

R. 6 W., New Mexico principal meridian, collected by J. H. Gardner, August, 1909 (lot 

5455) ; ·Pagosa quadrangle, Colo., 1 mile northeast of Pagosa Junction, collected by W. T. 

Lee, 1912 (lot 6444); same locality as last, but 

half a mile downstream from station (lot 6309); 

west of Talian mine, 5 miles north of Pagosa 

Junction, collected by Q. D. Singewald and 

J. B. Reeside, jr., June, 1921 (lot 7479); 4! 

miles ·north of Pagosa Junction (lot 7485). 

Juglans? innominata Knowlton, n. sp. 

Plate VII, Figure 2. 

Leaflet very firm in texture, broadly ovatelanceolate, apex missing but apparently acute, 

base strongly 'unequal sided, being abruptly 

rounded on the upper side and cu£ away to 

wedge shape on the lower side; petiole short 

(about 8 millimeters long), very stout; midrib 

very thick, straight.; secondaries about 10 pairs, 

subopposite, emerging at an angle of about 45 °, 

slightly curved upward, apparently camptodrome; finer nervation obsolete. 

This species is represented by a number of 

fragmentary specimens and by the nearly 

perfect one figured. This was probably not 

less than 10 or 11 centimeters· in length and · 

about .5 centimeters in width. The margin 

inclines to be slightly undulate but is otherwise entire. 

This leaflet is about the size and general appearance of the larger of the leaflets of J uglans 

leconteana Lesquereux/3 but the latter 'is 

more nearly entire at the· base and has the 

secondaries more obviously camptodrome. 

Occurrence: Animas formation, Ignacio quadrangle, Colo., east side of sec. 31, T. 35 N., 

R. 6 W. New Mexico principal meridian, collected by J. H. Gardner, August, 1909 (lot 

5455). 

u Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary 

flora), pl. 54, figs. 10, 11, 1878. 
SYSTEMATIC DESCRIPTIONS. 81 

Order FA GALES. 

Family FAGACEAE. 

Fagus crossii Knowlton, n. sp. 

Plate XIX, Figure 2. 

Leaf apparently thin, oblong-ovate, acuminate broadest about the middle, whence it ' . . tapers gradually to the rounded base, marg1n 

perfectly entire below, faintly and obscurely 

toothed above; petiole slender; midrib slender, 

straight; secondaries about 15 pairs, mainly 

alternate, at an angle of about 45°, close, 

parallel, not n1uch curved upward, craspedodrmne ending in the margin or in the upper 

portio~ in the faint marginal teeth; nervilles 

very numerous, percurrent, at right angles to 

the secondaries. 

The specimen is nearly perfect, lacking only 

a s1nall portion of one side. It is 9 centimeters 

long and slightly over 4 centimeters broad, 

and the petiole is preserved for a length of 

1 centimeter. 

This species is very similar· in size, shape; 

and general appearance to the living Fagus 

americana Sweet, the common beechnut of 

eastern North America, except that the marginal teeth are far less prominent. · 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., June, 1921 (lot 7496). 

Castanea intermedin Lesquereux. 

Plate VIII, Figure 1. 

Castanea intermedia Lesquereux, U. S. Geol. and 

Geog. Survey Terr. Bull., vol. 1, p. 386, 187?; 

Ann. Rept. for 1874, p. 313, 1876; U.S. Geol, 

Survey Terr. Rept., vol. 7 (Tertiary flora), 

p. 164, pl. 31, fig. 7 .. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, 

p. 297, pl. 68, fig. 2, 1918. 

One of the collections from Pagosa Junction, 

Colo., contains the leaf here figured, which 

seems indistinguishable from Castanea intennedia Lesquereu.x, especiaHy as described 

and figured 14 .from the specimen found in the 

Raton for1nation of southeastern Colorado, although it is slightly longer and proportionately 

a little narrower. Although this leaf lacks 

the upper portion, it could hardly have been 

less than 15 centimeters long and is fully 4.5 

u Knowlton, U. S. Gcol. Survey Prof. Paper 101, p. 297, pl. 68, fig. 2, 

1917 [l\ll8]. 

centimeters wide. In all the characters except 

size-that is in the long wedge-shaped entire 

basal portion, the numerous sharp marginal 

teeth, the very thick, straight midrib, and the 

numerous close parallel secondaries which 

enter the teeth-it agrees with Castanea intermedia. 

Thus far six species of Castanea have been 

differentiated in American rocks. The other 

five are the living Castanea pumila (Linne) 

Miller/ 5 found in the Pleistocene of Kentucky 

and West Virginia; Castanea castaneaefolia 

(Unger) Knowlton/ 6 from the Mascall formation of Oregon; Castanea pulchella Knowlton/ 7 

from the Miocene of Yellowstone National 

Park, which Marty is inclined to refer to 

Dryophyllum; Castanea claibornensis Berry, 18 

from the Barnwell formation of Georgia; and 

Castanea dolicophylla Cockerell, 19 from the 

Florissant lake beds (Miocene) of Colorado. 

Of these five, Castanea pumila and Castanea 

castaneaefolia (formerly known as C. ungeri 

fleer) are readily· distinguished from the 

Animas form, the latter especially by its 

broader shape and low-angled secondaries. . 

The other species, but ·particularly Castanea 

claibornensis and some of the narrower leaves 

of Castanea pulch'ella, are distinguished with 

difficulty from Castanea intermedia-in fact, 

it is doubtful if a mixed collection could be 

separated. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 4! miles north of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., June, 1921 (lot 7485). 

Dryophyllum berryana Knowlton, n. sp. 

Plate VUI, Figure 2. 

Leaf of medium size, coriaceous, long elliptical-oblong, apparently ·abruptly rounded at 

the base, gradually rounded above to an 

acuminate apex; margin obscurely toothed;. 

midrib rather slender, straight; secondaries 

about a dozen pairs, alternate, slender, emerging at an angle of about 60°, slightly curved 

upward, terminating in the marginal teeth; 

15 Knowlton, F. H., Am. Geologist, vol. 18, p. 371, 1896. 

1s Knowlton, F. H., U.S. Gcol. Survey Bull. 152, p. 60, 1898. 

11 Knowlton, F. H., U.S. Geol. Survey Mon. 32, pt. 2, p. 702, pl. 86, 

figs. 6-8; pl. 87, figs. 1-3, 1899. 

1s Berry, E. W., U. S. Geol. Survey, Prof. Paper 84, p. 138, pl. 28, 

figs. 1, 2, 1914. 

19 Cockerell, T. D. A., Am. Mus. Nat. Hist. Bull., vol. 24, p. 87, 1908. 
82 FLORA OF THE ANIMAS FORMATION. 

finer nervation obscure but apparently with 

the nervilles mostly unbroken. 

The specimen figured lacks the basal part 

but is otherwise nearly perfect. It was apparently about 12 centimeters long and is 4 

centimeters wide. It is of the same width for 

more than half the length of the blade. 

This species is undoubtedly most closely 

related to Dryophyllum moorii (Lesquereux) 

Berry, 20 from the Wilcox group of Mississippi 

and Texas and beds of Wilcox age in the 

Lagrange formation of Kentucky-in fact, if 

a considerable series were available for comparison it seems likely that they would prove 

to be identical. As it now stands, however, 

based on a single example, it seems best to 

consider the Anin1as leaf distinct. The Wilcox 

species is relatively broader, is more ellipticallanceolate, and usually has more pronounced 

marginal teeth. 

Dryophyllum berryana· is also very much 

like certain of the smaller, narrower, less distinctly toothed leaves of Dryophyllum levalense Marty, 21 from the" Paleocene" (Montian) 

of Hainaut, Belgium. Marty has shown a 

very great range in size in his species, and the 

larger examples are very unlike the one under 

consideration. This species· is named in honor 

of Prof. Edward Wilber Berry, of Johns 

Hopkins University, who has done so much to 

elucidate the Eocene floras of the Coastal 

Plain. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., June, 1921 (lot 7496). 

Order URTICALES. 

Family MORACEAE. 

Ficus planicostata Lesquereux. 

Plate IX, Figure 2. 

Ficus planicostata Lesquereux, U. S. Geol. and Geog. 

Survey Terr. Ann. Rept. for 1872, p. 393, 1878; 

U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary 

flora), p. 201, pl. 31, figs. 1-8, 10-12, 1878. 

The type locality for this species is Black 

Buttes, Wyo., in beds believed by me to be of 

2o Berry, E. W., U.S. Geol. Survey Prof. Paper 91, p. 190, pl. 22, fig. 1; 

pl. 23, figs. 1-3, 1916. 

21 Marty, Pierre, Mus. hist. nat. Belgique Extrait Mem ., vol. 5, p. 15, 

pl. 5, fig. 4, 1907. 

post-Laramie age. Since ·it was first described it has been identified, though probably 

not always correctly, in beds that range in 

age from middle Montana to upper Eocene. 

It undoubtedly occurs in the Laramie as well 

as in the Denver of the Denver Basin of 

Colorado ·and in the Wilcox of Louisiana. 

The example figured agrees in every particular with the larger of the types as figured by 

Lesquereux. 

Occurrence: Animas formation, Ignacio 

quadrangle, Colo., in the southeast corner of 

sec. 15, T. 35 N., R. 6 W., collected by J. H. 

Gardner, August, 1909 (lot 5456); hill .above 

Talian mine, 5 miles north of Pagosa Junction, 

collected by Q. D. Singewald and J. B. Reeside, 

jr., 1921 (lot 7481). 

Ficus neoplanicostata Knowlton. 

Plate IX, Figure 4. 

Ficus neoplanicostaia Knowlton, U. S. Geol. Survey 

Prof. Paper 101, p. 303, pl. 73, fig. 4; pl. 74, 

figs. 2, 3; pl. 76, fig. 4, 1917 [1918]. 

Occurrence: Animas formation, Pagosa quadrangle, Co~o., half a mile west of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., June, 1_921 (lot 7485); same locality, collected by W. T. Lee, 1912 (lot 6444). 

Ficus occidentalis (Lesquereux) Lesquereux. 

Plate VIII, Figure 5. 

Ficus occidentalis (Lesquereux) Lesquereux, U. S. Geol. 

Survey Terr. Rept., vol. 7 (Tertiary flora), p. 

200, pl. 32, fig. 4, 1878. 

Berry, U. S. Geol. Survey Prof. Paper 91, pp. 121, 

197, pl. 28, fig. 3, 1916. 

Knowlton,· U. S. Geol. Survey Prof. Paper 101, p. 

331, pl. 73, fig. 1, 1917 [1918]. . 

The type locality of this species is in the 

Denver formation, but it has since been noted 

in the Raton, Wilcox, and Midway formations. The specimen here figured lacks all of 

the upper portion, and the lateral main ribs 

are not quite so much curved upward as those 

of the type, but otherwise they do not differ 

essentially. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by J. B. Reeside, jr. (lot 7496). 
SYSTEMATIC DESCRIPTIONS. 83 

Ficus denveriana Cockerell. 

Plate IX, Figure 1. 

Ji'ic~ts denvm·iana Cockerell, Torreya, vol. 10, p. 224, 

1910. 

Berry, U. S. Geol. Survey Prof. Paper 91, pp. 11, 

198, 1916. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, p. 

302, pl. 75, figs. 1, 2, 1917 (1918]. 

Fic~ts spectabilis Lesquereux, U. S. Geol. and Geog. 

Survey Terr. Ann. Rept. for 1872, p. 379, 1873; 

U. S. Geol. Survey Terr., Rept. vol. 7 (Tertiary 

flora), p. 199, pl. 33, figs, 4-6, 1878. (Homonym, 

Kunth and Bouche, 1847.] 

The type locality for this species is in the 

Denver fonnation at Golden, Colo., where it 

is 11bundant. It was subsequently found in 

the Raton forn111tion of the Raton Mesa 

region of southeastern Colorado and northeastern New Mexico, and by Berry in the 

Wilcox group of Arkansas and Louisiana and 

in beds of Wilcox age in the Lagrange forma-

. tion of Kentucky, as well as in beds thought 

to be of Midway age in Bexar County, Tex. 

It has also been reported from the Lance 

formation near Edgen1ont, S. Dale 

Occurrence: Animasfonnation, Pagosa qu~drangle, Colo., half a mile west of Pagosa Junction, collected by J. B. Reeside, jr., June, 1921 

(lot 7496). 

Ficus subtruncata Lesquereux. 

Plate VIII, Figure~· 

Ji'iws s~tblruncata Lesquereux, U. S. Geol. Survey Terr. 

Rept., vol. ·7 (Tertiary flora), p. 205, pl. 30, 

figs. 7-9, 1878. 

Ji'icus au1·iculata Lesquereux, U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, p. 379, 1873; U.S. 

Geol. Survey Ten·, Rept., vol. 7 (Tertiary flora, 

p. 206, pl. 30, figs. 4-6, 1878. (Homonym, 

Loureiro, 1834.] 

The little leaf figured is undoubtedly identitical with the leaves from the Denver formation at Golden, Colo., figured by Lesquereux, 

especially those figured under the name Ficus 

auriculata. It is distinctly auriculate at 'the 

base and has the fine nerves given off to supply 

the lower lobes of the leaf as originally described. 

The complete history of this species is given 

in my "Flora of the Denver formation," not 

yet published. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 4! miles north of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., ~une, 1921 (lot 7483). 

Ficus monodon (Lesquereux) Berry? 

Plate X, Figure 1. 

Ficus nwnodon (Lesquereux) Berry, U. S. Geol. Survey 

Prof. Paper 91, p. 201, pl. 32, fig. 2; pl. 33, fig. 2, 

1916. 

Populus monodon Lesquereux, Atn. Philos Soc. Trans., 

vol. 13, p. 413, pl. 15, figs. 1, 2, 1869. 

The collection from the Animas beds contains 

the single example here figured, which appears 

to be identical with Ficus monodon from the 

Wilcox group of Mississippi, as figured and described by Berry. It is only a fragment from 

the apical portion of the leaf, and although it 

seems to agree well with the figures given by 

Berry the reference is questioned until further 

data can be obtained. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 5 miles north of Pagosa Junction, 

collected by Q. D. Singewald and J. B. Reeside, 

jr., June, 1921 (lot 7481) . 

Ficus pseudo-populus L'esquereux. 

Plate VII, Figure 4;· Plate IX, Figure 3. 

Fiws pseudo-populus Lesquereux, U.S. Geol. and Geog. 

Survey Terr. Bull., vol. 1, p. 387, 1875 (1876]; 

Ann. Rept. for 1874, p. 313, 1876; U. S. Geol. 

Survey Terr. Rept., vol. 7 (Tertiary flora), p. 

204, pl. 34, figs. 1a, 2, 1878. 

Berry, U. S. Geol. Survey Prof. Paper 91, p. 230, 

pl. 37, figs. 3-5, 1916; pl. 113, fig. 3, 1916. 

Knowlton, U. S. Geol. Survey Prof, Paper 101, 

p. 304, pl. 72, figs. 2-4; pl. 73, fig. 2; pl. 112, 

fig. 3, 1917 [1918]. 

The type locality for this species is in the 

Evanston formation at Evanston, Wyo. It 

was subsequently found to be very abundant 

in the Raton formation ·of Colorado and New 

l\1exico and was also found at several localities 

in the Wilcox group of Louisiana and in corresponding beds in the Lagrange formation of 

Tennessee. Its presence in the Animas formation is attested by several specimens, two 

of the best of which are here figured. They 

are nearly perfect except for the apex. The 

larger one was probably 10 or 12 centimeters 

long and is about 6.5 centimeters wide, and 

the stout petiole is preserved for a length of 

over 2 centimeters. 

Ficus pseudo-populus is essentially palmately 

three-ribbed from the top of the petiole, but 

occasionally the basal pair of · secondaries on 

the lateral ribs is enlarged, thus producing 

a pseudo five-ribbed appearance. The specimen figured, however, is distinctly three-
84 FLORA OF THE ANIMAS FORMATION. 

ribbed, with the lateral ribs diverging at an 

angle of about 20° and passing high up to join 

the lowest secondaries on the midrib.. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile downstream from 

Pagosa Junction; collected by W. T. Lee, 

1912 (lot 6309); 5 miles and 4! miles north 

of Pagosa Junction,. collected by Q. D. Singewald and .J. B. Reeside, jr., June,· 1921 (lots 

7481, 7485); same as last but higher beds 

(lot 7497). 

Ficus pagosensis Knowlton, n. sp. 

Plate XI.· 

Leaves very large, 22 to 25 centimeters long, 

15 to 18 centimeters broad, firm in texture, 

ovate-elliptical, broadest just below the middle, 

whence they are narrowed gradually to the 

near~ truncate base; apex not preserved 

but apparently rather obtuse; petiole exceedingly thick; midrib moderately strong 

for so large a leaf; secondaries about five pairs, 

the lower pairs very strong, arising at the 

very base of the blade, thus producing a threeribbed effect, moderately curved upward, 

reaching well above the middle of the leaf, 

each with from eight to ten strong campto-

.dro'me tertiary branches on the outside, which 

join in broad loops inside the margin, and 

sometimes several on the inner side; upper 

secondaries opposite or nearly so, slightly 

curved upward near the margin; nervilles 

numerous, . very strong, approximately at 

rigl;tt angles to the secondaries. 

· This fine species is represented by one nearly 

perfect leaf-the one figured-and by the very 

well preserved basal portion of another even 

larger example. Together they are sufficient 

to give a fair conception of its characters. 

Ficus pagosensis is of the type. of Ficus 

speciosissima Ward,Z2 a well-known Montana 

species, but differs markedly in being ovateelliptical instead of nearly circular, and more 

particularly in the nearly truncate instead of 

the deeply cordate-auriculate base, often with 

overlapping lobes. Ficus leei Knowlton,23 another Montana species, also belongs to this 

group, but it is much smaller, is nearly orbicular, and usually has the cordate-auriculate 

. 22 Ward, L. F., U. S. Geol. Survey Sixth Ann. Rept., p. 552, pl. 45, 

fig. 1, 1886; Bull. 37, p. 39, pl. 21, fig. 3, 1887. 

23 Knowlton, F. H., U.S. Geol. Survey Prof: Paper 101, p. 261, pl. 39, 

figs. 1-6; pl. 40, figs. 1, 2, 1917 [1918]. 

base as in F. speciosissima. There should be 

no difficulty in recognizing the new species if 

the basal portion is present. 

Occurrence: Animas formation,·! mile northeast of Pagosa Junction, Colo., collected by W. 

T. Lee, 1912 (lot 6443). 

Ficus sp .. 

Plat.e VII, Figure 3. 

The specimen here figured is very obscurely 

preserved i:I;l all except outline. It seemingly 

lacks at least the upper third. It appears to 

have been long elliptical, with a regularly 

rounded, almost truncate base. The margin is 

entire. The midrib is only moderately strong 

for the size of the blade. The secondaries are 

very obscure but appear to be alternate, at an 

angle of 45° or 50°, and not much arched 

upward. Little trace of finer nervation is discernible. The leaf was probably at least 10 

centimeters long and is 6 centimeters wide. 

This leaf resembles a number of described 

species of Ficus, but it is so fragmentary and 

obscure that it can not be identified with certainty. Thus, it is similar in size and shape to 

Ficus uncata Lesquereux, 24 from the Raton 

formation, but the secondary nervation does 

not seem to be so regular. It is also like Ficus 

duplicata Knowlton, 25 which also comes from 

the Raton formation, but this is much larger 

and has the secondaries at a less acute angle. 

Occurrenee: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by J. B. Reeside, jr., June, 1921 

'(lot 7496). 

.Ficus sp. 

Plate VI, Figure 7. 

The specimen that is the basis of the figure 

here given is so much broken that ordinarily 

it would not be taken into account, but it is 

the only one noted in the collection and shows 

a number of features not before observed. It 

was apparently approximately circular in outline, or possibly it was a little broader than 

long. It is very deeply heart-shaped at the 

base, with the basal lobes rounded and full. 

The margin, so far as can be made ,out, is perfectly entire. It is strongly 5-r~bbed from the 

24 Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary 

flora), pl. 35, figs. 1, 2, 1878. 

25 Knowlton, F. H., U. S. Geol. Survey Prof. Paper 101, p. 302, pl. 74, 

fig. 1, 1917 [1918]. 
SYSTEMATIC DESCRIPTIONS. 85 

top of the petiole; the midrib is slightly stronger is no exception, for out of some hundreds of. 

than the others and has several alternate specimens only two have been found-the one 

secondaries in the upper part of the blade. The here figured, with its counterpart, and a fragnext pair of ribs· arise at an angle of 60° ot 70° ment of the upper part of a similar leaf. 

and are considerably curved upward and beat This specimen from the Animas beds was 

a number of secondaries on the outside. The clearly a very large leaf, for it is 22 centimeters 

lowest pair of ribs are nearly at a right angle long and lacks both base and apex. The very 

with the midrib and are curved upward for a thick midrib seems to indicate that there was 

great distance, each with 8 or 10 secondary probably at least one more lobe, and if so, the 

branches on the lower and outer side, which leaf would have been 30 centimeters long. 

supply the rounded basal lobes, several of them The apex of the lowest lobe is not preserved, 

with tertiary branches. The nervilles are but presumably it was sharp pointed. The 

numerous and strong. Reliable measurements upper lobe is small, sharp pointed, and curved 

can not be given for this leaf, though it could upward. The apex of this lobe also is not 

hardly have been less than 12 centimeters long preserved but was apparently pointed. The 

and fully 10 centimeters broad. nervation is characteristically that of ArtoThis leaf is of the type of Ficus speciosissima carpus,. consisting of a strong, straight n1idrib 

Ward, 26 from the ~1esaverde formation; Ficus and three or four strong secondaries, which 

Zeei Knowlton, 27 from the Vermejo formation; terminate in the apices of the lateral lobes, 

and Ficus cockerelli Knowlton, 28 from the Lara- each, but especially the lower ones, with several 

mie and later formations, so far as regards size remote, camptodrome secondaries. There is 

and shape, but it differs essentially in being also a strong primary running to the sinus. 

strongly 5-ribbed instead of 3-ribbed. This leaf is identical in shape and nervation 

Occurrence: Animas formation, Pagosa with one of the types of Artocarpus pungens,29 

quadrangle, Colo., half a mile west of Pagosa but it is much larger. Berry in his report on 

Junction, collected by J. B. Reeside, jr., June, the Wilcox flora figures several leaves ~nder 

1921 (lot 7496). · the name A. pungens, but they are not so 

Artocarpus pungens (Lesquereux) Hollick. 

Plate XII. 

Artocarpus pungens (Lesquereux) Hollick, Arkansas 

Geol. Survey Special Rept. 5, p. 281, pl. 38, figs. 

1, 2, 1899. 

Berry, U. S. Geol. Survey Prof. Paper 91, p. 195, 

pl. 25, fig. 1; pl. 27, fig. 1; pl. 29, fig. 1, 1916. 

Aralia pungens Lesquereux, U .. S. Geol. Survey Terr. 

Rept., vol. 8 (Cretaceous and Tertiary floras), 

p. 123, pl. 19, figs. 3, 4, 1883. 

The leaves of Artocm·pus are difficult to 

identify satisfactorily. They are mostly very. 

large leaves that were either fragmentary when 

entmnbed or broken during excavation, and, 

n1oreover, they are rare in collections, it being 

unusual to find more than three or four in. a 

similar to the present specimen as the types 

above mentioned. 

In 1909. J. H; Gardner collected a single 

fragment of an Artocarptts in the Ignacio 

quadrangle, Colo. This fragment was first 

thought to ·belong to Artocarpus Zessigiana 

Lesquereux and later to Artocarpus similis 

Knowlton, but in the light of the larger example 

here referred to Artoca'l'pus pungens it seems 

probable that this fragment also should be 

referr~d to this species. As a matter of fact, 

it is so small a fragment that an attempt to 

place it definitely is perhaps unwise, although 

it seems to agree well with this species, so far 

as can be nlade out. 

Occurrence: Animas formation, Ignacio 

quadrangle, Colo., top of Animas beds, collected 

large series .of specimens. The present case by J. H. Gardner, August, 1909 (lot 5667); 

2

6 Ward, L. F., U.S. Geol. Survey Sixth Ann. Rept., p. 552, pl. 45, fig. 

1, 1886. 

27 Knowlton, F. H., U.S. Geol. Survey Prof. Paper 101, p. 201, pl. 39, 

figs. 1-6; pl. 40, figs. 1, 2, 1917 [1918]. 

ss Knowlton, F. H., U.S; Geol. Survey Prof. Paper 130, p. 132, pl. 12, 

fig. 2; pl. 23, figs. 1, 2, 1922. · 

Pagosa quadrangle, Colo., half a mile west of 

Pagosa Junction, collected by J. B. Reeside, 

jr., June, 1921 (lot 7496). 

2Q Lesquereux, Leo. U.S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous 

and Tertiary floras), pl. 19, fig. 3, 1883. 
86 FLORA OF THE ANIMAS FORMATION. 

Order PLATANALES. 

Family PLATANACEAE. 

Platanus. raynoldsii Newberry. 

Platanus raynoldsii Newberry, New York Lyceum 

Nat. Hist. Annals, vol. 9, p. 69, 1868; U. S. 

Geol. Survey Mon. 35, p. 109, pl. 35, 1898. 

Knowlton, U. S. Geol. Survey, Prof. Paper 101, 

p. 324, pl. 95, fig. 1, 1917 [1918]. 

Platanus raynoldsii was described originally 

from material collected in the Fort Union 

formation of Montana and has since been 

found to be one of the most abundant and 

widely distributed forms in the Lance and 

Fort Union formations and was also found in 

the Raton formation of the Raton Mesa region 

of Colorado and New Mexico. 

One of the collections from the Animas formation about 5 miles east of Durango, _Colo., 

contains some large leaves of Platanus, which, 

although fragmentary, ehow the decurrent 

base· characteristic of this species. No specimens have been figured, as they would not add 

particularly to knowledge of the species. 

Occurrence: Animas formation, Ignacio quadrangle, Colo., 5 miles east of Durango, in the 

SW. i SE. i sec .. 30, T. 35 N., R. 8 W., 700 

feet above base of Animas beds, collected by 

J. B. Reeside, jr., 1920 (lot 7463); Pagosa 

quadrangle, Colo., 1 mile north of Pagosa 

Junction, collected by W. T. Lee, 1912 (lot 

6443), about 1 mile northeast of Pagosa Junction, collected by w: T. Lee, 1912 (lot 6444); 

1 mile northeast of Bayfield, Colo., collected by 

J. B. Reeside, jr., 1920 (lot 7452). 

Platanus aceroides Goppert. 

Platanus aceroides Goppert, Deutsch. geol. Gesell. 

Zeitschr., vol. 5, p. 492, 1852. 

Lesquereux, U. S. Geol. Survey Terr. Rept.,vol. 

7 (Tertiary flora), p. 184, pl. 25, figs. 4, 5, 1878. 

One of the collections of Animas leaves contains a number of fragn1entary leaves that 

appear to belong to this species. They are, 

for instance, of the same size and nervation as 

certain leaves figured by Lesquereux under 

this name, but they are practically without 

margin, and it is therefore impossible to be 

certain of their identity. So far. as it is possible to compare them, however,. they seem to 

agree with the usual forms of this species. 

Occurrence: Animas formation, Ignacio quadrangle, Colo., east side of sec. 31, T. 35 N., 

R. 6 W. New Mexico principal meridian, collected by J. H. Gardner, August, 1909 (lot 

5455); Pagosa quadrangle, Colo., 1 mile northeast of Pagosa Junction, collected by W. T. 

Lee, 1912 . (lot 6443); 1 mile northeast of Bayfield, Colo., collected by J. B. Reeside, jr., 

1920 (lot 7452); 5 miles north of Pagosa Junction, Colo., collected by Q. D. Singewald and 

J. B. Reeside, jr., 1921 (lot 7482); same as last 

but higher in the section (lot 7485); Oat Creek, 

1 mile north of Pagosa Junction, Colo., collected by Q. D. Singewald and J. B. Reeside, 

jr., 1921 (lot 7498). 

Platanus aceroides latifolia Ki10wlton. 

Plate XIII, Figure 3; Plate XIV, Figure 4. 

Platanus aceroides latifolia Knowlton, U. S. Geol. 

Survey Prof. Paper 101, p. 321, pl. 92; pl. 93 

fig. 3; pl. 94, 1917 [1918]. ' 

Berry, U. S. Geol. Survey Prof. Paper 91, p.13, 

1916. 

These collections include a considerable number of sycamore leaves, but most of them are 

fragmentary. Two of the best-preserved ones 

have been selected to be figured. The smaller 

one is about 13 centimeters long and 11 centimeters wide, and the larger one is about 16 

centimeters wide, but the length can not be 

ascertained. 

These leaves· appear to agree most closely 

with Platanus aceroides latifolia Knowlton, and 

they are so referred. The htrger of the two 

leaves figured also resembles Platanus haydenii Newberry; they differ in the marginal 

teeth. 

Platanus aceroideslatifolia was described frorr1 

specimens· found in the Raton formation of 

the Raton Mesa region of Colorado and New 

Mexico, where it is abundant. It was also 

found by Berry in beds supposed to be of 

Midway age at Earle, Bexar County, Tex. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile south of Talian mine 

4~ miles north of Pagosa Junction, collected by 

Q. D. Singewald and J. B. Reeside, jr., 1921 

(lot 7 485); Oat Creek, 1 mile north of Pagosa 

Junction (lot 7498). 

Order THYMELEALES. 

Family LA URACEAE. 

Laurus primigenia Unger. 

Laurus primigenia Unger .. Lesquereux, U. S. Geol. 

Survey Terr., Rept., vol. 7 (Tertiary flora), 

p. 214, pt. 36, figs. 5, 6, 8, 1878. 

The leaves identified under this name by 

Lesquereux and figured in his " Tertiary flora" 

came from the Evanston formation at Evans-
SYSTEMATIC DESCRIPTIONS. 87 

ton, Wyo. Since then leaves apparently identical with these have been· recorded from the 

1-:Ianna formation at Carbon, Wyo.; the.Denver 

formation at Golden, Colo.; basic brecias of 

Fort Union age in the Yellowstone National 

Park; and the Wilcox group of Louisiana. 

A riumber of leaves have been found in the 

Animt"Ls formation that appear to be referable 

to this speci~s, except that they are a little 

s1naller. One of them has the petiole preserved apparently ·entire; it. i.s over 1 centi-

. meter in length. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 1 n1ile north of Pagosa Junction, 

collected by J. B. Reeside, jr., 1921 (lot 7496). 

N ectandra lancifolia (Lesquereux) Berry. 

. Plate XIII, Figure 1. 

N ectandra lancifolia (Lesquereux) Berry, U. S. Geol. 

Survey Prof. Paper 91, p. 308, pl. 85, fig. 2, 

1916. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, 

p. 318, pl. 90, figs. 1, 2, 1917 [1918]. 

Persea lancifolia Lesquereux, Am. Philos. Soc. Trans., 

vol. 13, p. 419, pl. 19, :Figs. 3, 4, 1869. 

Described originally from specimens collected 

fi·mn the Wilcox group, in which it is found at a 

number of localities in Mississippi, Louisiana., 

and Texas, and in corresponding beds in the 

Lagrange forn1ation of Tennessee. It also 

occurs at several places in the Raton formation of northeastern New Mexico and southeastern Colorado. The specimen here figured 

is indistinguishable from the one shown in Plate 

XC, Figure 1, of my Raton Mesa paper 

(Professional Paper 101). 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 1 mile north. of Pagosa Junction, 

colle'cted by J. B. Reeside, jr., 1921 (lot 7496). 

Malapoenna sessiliflora (Lesquereux) Knowlton. 

Plate XIV, Figure 3. 

M alapoenna sessilijlora (Lesquereux) Knowlton, U. S. 

Geol. Survey Bull. 152, p. 142, 1898. 

La1tr1tS sessiliflora Lesquereux, U. S. Geol. and Geog. 

Survey Terr. Ann. Rept. for 1873, p. 407, 1874. 

'Petranthera sessilijlora (Lesquereux) Lesquereux, U. S. 

Geol. Survey Terr. Rept., vol. 7 (Tertiary 

l1'lora), p. 217, pl. 35, fig. Sa [fig. 9], 1878. 

Leaves small, subcoriaceous, narrowly. 

obovate-lanceolate, rather obtuse at apex; 

long, narrowly wedge-shaped at base, length 

about 6 centimeters, width 2 centimeters; 

petiole long, slender, nearly 2 centimeters long; 

secondaries five pairs, slender, much curved 

upward, camptodrome; nervilles (in the type). 

numerous, nearly at right angles to the midrib. -

The type specimen of this species as at present restricted came from ·the Evanston formation at Evanston, Wyo., and has been well 

described and fig~red by Lesquereux, except 

that the supposed calyx is shown as attached 

to the petiole, which is of course impossible. 

The leaf from the Animas beds agrees perfectly 

with the type but does not have the nervilles 

preserved. · 

Occurrence: Animas formation, about 1 mile 

northeast of Pagosa Junotion, Colo., collected 

by W. T. Lee, 1912 (lot_6443). 

Oreodaphne pagosensis Knowlton, n. sp. 

Plate XV, Figure 5. 

Leaves evidently of firm texture, ovateelliptical, apparently moderately acuminate at 

the apex, abruptly rounded below. to a narrowly 

wedge-shaped, almost decurrent base; length 

about 16 centimeters, width nearly 6 centimeters; petiole stout; midrib very strong; 

secondaries not particularly strong, about 

seven pairs, somewhat irregular, the lowest at· 

acute angles and with several camptodrome 

tertiary branches on the outer side; other 

secondaries alternate, at less acute angles, not 

much curved upward, curving just at the 

margins; nervilles. obscure, apparently at right 

angles to the secondaries. 

This leaf appears . to be congeneric with a 

number of leaves from the Wilcox group 

described by Berry and to fall within his 

section of "leaves with well-marked lateral 

primaries in the lower half of the leaf." In 

size and shape this species suggests Oreodaphne obtusifolia Berry,30 but it differs in 

having the base more decurrent and the basal 

pair of large secondaries less well marked and 

·not ascending for so great a distance; the nervilles are obscure but apparently differ from 

those in the Wilcox species mentioned. The 

Pagosa Junction leaf is also of the type of 

Oreodaphne salinensis Berry 31 except that the 

latter is much smaller and much less wedgeshaped, at the base. 

Occurrence: Animas formation, about 1 mile 

northeast of Pagosa Junction, Colo., collected 

by W. T. Lee, 1912 (lot 6444). 

so Berry, E. W., U. S. Geol. Survey Prof. Paper 91, p. 301, pl. 83, figs. 

2-5, 1916. 

31Jdem, p. 303, pl. 82, fig. 1, 2. 
88 FLORA OF THE ANIMAS FORMATION. 

Cinnamomum salicoides Knowlton, n. sp. 

· Plate XV, Figure 2. 

Leaves small, coriaceous, narrowly lanceolate, broadest below the middle, long wedgeshaped and slightly decurrent at base, narrowly 

acuminate at apex; midrib relatively very 

strong, lateral ribs arising just above the base, 

dividing the space between midrib and margin 

about equally, ascending for one-half or more 

the length of the leaf and then approaching 

the margin; secondaries few, high upon the 

midrib, at an acute angle; all finer nervation 

. obsolete. 

This form is represented by a considerable 

number of leaves, but all of the:tll are broken 

except the one figured, which lacks only a minute 

portion of the tip. This is 5.5 centimeters long 

Order RAN ALES. 

Family. NYMPHAEACEAE. 

Nelumbo lakesiana (Lesquereux) Knowlton. 

Nelumbo lakesiana (Lesquereux) Knowlton, U. S. Geol. 

Survey Prof. Paper 101, p. 308, 1917 [1918]. 

Nelumbium lakesianum Lesquereux,· U. S. Geql. and 

Geog. Survey Terr. Ann. Rept. for 1873, p. 403, 

1874. 

N elumbium lakesii Lesquereux, U. S. Geol. Survey 

Terr. Rept., vol. 7 (Tertiary flora), p. 252, pl. 

. 46, figs. 1, 2, 18.78. 

. A single fragmentary specimen without 

margin but apparently belonging to this 

species; it has not been figured . 

Occurrence: Animas formation, Pagosa quadrangle, Colo., Pagosa Junction, half a mile 

downstream from the station, collected by 

W. T. Lee, 1912 (lot 6309). 

and about 1 centimeter wide, and has the petiole Family MAGNOLIACEAE. 

5 millimeters long. Other specimens are nearly . Magnolia angustifolia Newberry. 

2 centimeters wide and must have been 7 centi- Plate X, Figure 3; Plate XVI, Figure 5. meters or more in length. Magnolia angustifolia Newberry, U.S. Nat. Mus. Proc., This species somewhat resembles the very ] vol. 5, p. 513, 1882 [1883 . 

narrow forms of Oinnamomum Zinifolium Berry, u. s. Geol. Survey Prof. Paper 91, p. 214, 

Knowlton, 82 of the Raton formation, but differs 1916. 

in being acuminate instead of rounded at the Knowlton, U. S. Geol. Survey Prof. Paper 101, p·. 

apex. It is also similar to Oinnamomum ob- 309, pl. 79, fig. 1; pl. 80; pl. 81, fig. 1, 1917 

f [1918]. . Zongatum Berry,ss from the Lagrange orma- Magnolia attenuata Weber. Lesquereux, U. S. Geol. 

tion of Tennessee, but the latter has. the ribs Survey Terr., vol. 7 (Tertiary flora), p: 250, pl. 

near the margin and the secondaries on the 45, fig. 6, 1878. 

midrib at a low angle. This species was named and described but 

Oinnamomum salicoides is much more closely not figured by Newberry in 1883 from specirelated to certain of the narrower leaves of the mens found i:p. beds now known as the Raton 

European 0. lanceolatum-in fact, with tl~e formation of Fisher's Peak, Colo. In 1878 

scanty material available it is difficult to see Lesquereux figured the lower half of a leaf 

any differences. Stau~, in his "Geschichte from the same locality under the name Magdes Genus Oinnamomum," has brought together nolia attenuata Weber, .a European Miocene 

all the published figures of the genus. On Plate species, but the two are quite distinct. It ·was 

XII of hisnionograph are a number of figures next figured by Hollick,84 who identified it 

of 0. lanceolatum and 0. salicifolium that are as Magnolia lanceolata Lesquereux, from the 

certainly very close to the one under consid- Wilcox of Louisiana. It was found to be very 

eration, but they are found mainly in the abundant in the Raton formation of the Raton 

Oligocene and Miocene, and for the present at Mesa region of Colorado and New Mexico. 

least it seems best to regard them as distinct. The larger specimen here figured agrees 

Occurrence: Animas formation, Pagosa quad- perfectly in size and shape with the Raton 

rangle, Colo., 1,000 feet south of Talian mine,· leaves but differs slightly in the more evenly 

5 miles north of· Pagosa Junction, collected spaced . secondaries. The smaller exampl~ 

by Q. D. Singewald and J. B. Reeside, jr:, 1921 figured is in_distinguishable from one found in 

(lot 7483). the Raton formation. 35 

32 Knowlton, _F. H., U.S. Geol. Survey Prof. Paper 101, p. 319, pl. 88, 

fig. 6, 1917 [1918]. 

33 Berry, E. W., U.S. Geol. Survey Prof. Paper 91, pl. 79, figs. 1, 2, 

1916. 

34Hollick, Arthur, Arkansas Geol. Survey Special Rept. 5, pl. 40, 

1899. 

as Knowlton, F. H., U.S. Geol..Survey Prof. Paper 101, pl. 81, fig. 1, 

1917 [1918]. 
SYSTEMATIC DESCRIPTIONS. 89 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 1 mile northeast of Pagosa Junction, collected by W. T. Lee, 1912 (lot 

6444); 4! n1iles north of Pagosa Junction, 

collected by Q. D. Singewald and J. B. Reeside, 

jr., 1921 (lot 7485); half a mile west of Pagosa 

Junction, collected by J. B. Reeside, jr., 1921 

(lot 7496). 

Magnolia hilgardiana Lesquereux. 

Plate XVI, Figure 4. 

Magnolia hilgardiana Lesquereux, in Owen, Second 

report of a geological reconnaissance of the 

middle and southern counties of Arkansas, 

p. 319, pl. 6, fig. 1, 1860; Am. Philos. Soc. 

Trans., vol. 13, p. 421, pl. 21, fig. 1, 1869. 

Hollick, Arkansas Geol. Survey Third Ann. Rept., 

p. 282, pl. 39, 1899. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, p, 

310, pl. 79, fig. 2; pl. 85, fig. 1, 1917 [1918]. 

Quercus lyelli Heer. Lesquereux, Am. Philos. Soc. 

Trans., vol. 13, p. 415, pl. 17, fig. 3 [not figs. 

1, 2], 1869. 

Terminalia hilgardiana (Lesquereux) Berry, U. S. 

Geol. Survey Prof. Paper 91, p. 325, pl. 92, 

fig. 2, '1916. 

The leaf here figured ·agrees perfectly with 

the leaf from the Raton formation of. southeastern Colorado figured by me under this 

nan1e in 1918. The type locality of Magnolia 

hilgardiana is somewhat in doubt, though in all 

reasonable probability it was in the Wilcox 

of Mississippi, where this species has since 

been found at a number of localities by Berry. 

It was identified by Berry in beds supposed to 

be of Midw~y age at Earle, Bexar County, 

Tex. It was also identified 36 in the Miocene 

of Lassen County, Calif., though this identificati9n may require revision. 

Berry 37 has transferred this species to the 

genus Terminalia, but I prefer to retain it 

under Magnolia. 

Occurrence: Animas formation,'Pagosa quadrangle, Colo., 5 miles north of Pagosa Junction, collected by Q. D. Singewald and. J. B. 

Reeside, jr., 1921 (lot 7481); 4! miles north 

of Pagosa Junction, collected by Q. D. Singewald and J. B. Reeside, jr., 1921 (lot 7485); 

half a mile west of Pagosa Junction, collected by J. B. Reeside, jr.~ 1921 (lot 7496). 

86 Knowlton, F. IT., in Lindgren, Waldemar, U .. S. Gcol. Survey 

Prof. Paper 73, pp. 60, 61, 1911. _ 87 Berry, E. W., U.S. Gcol. Survey Prof. Paper 91, p. 325, 1916. 

Magnolia magnifolia Knowlton? 

Magnolia magnifolia Knowlton, U. S. Geol. Survey 

Prof. Paper 101, p. 311, pl. 85, 1917 [1918]. 

Magnolia tenuinervis Lesquereux, U. S. Geol. Survey 

Terr. Rept., vol. 7 (Tertiary flora), p. 249, pl. 

44, figs. 5, 6; pl. 45, figs. 1-3 [not pl. 45, figs. 

4-6], 1878. . . 

The conclusion that this species is present 

in the Animas beds is based on a single rather 

· fragmentary specimen. The species was first 

recorded under the name Magnolia tenuinervis 

Lesquereux and came from the Denver formation at Golden, Colo. It was found, however, 

that Magnolia tenuinervis was a composite 

species, and the Denver leaves were referred 

to M. magnifolia. The Animas leaf is smaller 

than the usual leaves of M. magnifolia, but it 

is so poorly preserved that its identity is somewhat uncertain. 

Occurrence: Animas formation, 5 miles south 

of Durango, Colo., above the conglomerate 

(McDermott formation) that overlies the coalbearing series, collected by T. W. Stanton, 

1891 (lot 731). 

Order ROSALES. 

Family POMACEAE. 

Crataegus? gigantea Knowlton, n. sp. 

Plate X, Figure 2 . . 

Leaf of fir~ texture, broadly deltoid in general outline, slightly wedge shaped at the broad 

base, pinnately 5-lobed, possibly 7-lobed, the 

lobes separated by deep rounded sinuses; lower 

lobes lanceolate, 3 or 4 centimeters long, 1.2 

to 2. centimeters broad at base, acuminate at 

apex; margin remotely toothed, the teeth sharp; 

petiole short, a little over 1 centimeter long; 

midrib slender, straight; secondaries apparently 

three pairs, subopposite, at an angle of 40° or 

50°, a little clirved upward, ending in the 

lobes, the lower pair with numerous tertfary 

branches at various angles, much curved upward and craspedodrome; finer nervation not 

retained. 

This leaf is rather fragmentary, as it lacks 

all of the apical portion, but the base with its 

petiole complete and one basal lobe is well 

shown. It was probably 10 or 12 centimeters 

long and about 10 centimeters between the 

tips of the lower lobes. 
90 FLORA OF THE ANIMAS FORMATION. 

The proper generic reference for this strongly 

marked leaf is uncertain. It can hardly be 

referred to Acer, Aralia, or Sterculia, to each 

of which it has some p.oints of resemblance, 

but it is like certain deeply incised leaves of 

Orataegus, such as Orataegus apiijolia Michaux 

or Orataegus nigra Kitarbel, but it is twice or 

more the size of the usual leaves of Orataegus. 

The sinuses separating the lobes in the deeply 

incised living species are usually sharp or only 

moderately rounded, whereas in the Animas 

leaf they are deep and .distinctly rounded. It 

is doubtful if this leaf really belongs to Orataegus, but it may remain here until a more 

definite allocation can be made. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., five-eighths of a mile south of 

Ta1ian mine, 4! miles north of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., 1921 (lot 7486). 

Family CAESALPIN ACEAE. 

Cassia puryearensis Berry. 

Plate XIV, Figures 1, 2. 

Cassia puryearensis ·Berry, U. S .. Geol. Survey Prof. 

Paper 91, p. 230, pl. 51, figs. 13, 14, 1916. 

I am not able to see any essential difference 

between the leaflet here figured and the figures 

given by Berry. This leaflet is about 8.3 centimeters long and 2.5 centimeters wide, has a 

strong-midrib and about eight pairs of camptodrome secondaries which emerge at an angle 

of about 50°; the finer nervation is obsolete. 

This agrees perfectly with Berry's description, 

except that it is slightly more wedge-shaped at 

base. 

Occurrence: Anlm.as formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by J. B. Reeside, jr., 1921 (lot 

7496). 

Order SAPINDALES. 

Family AN ACARDIACEAE. 

Rhus coloradensis Knowlton, n. sp. 

Plate X, Figure 4. 

Leaflet small, about 4.5 centimeters long and 

2 centimeters. wide, elliptical oblong, rounded 

truncate at base, obtusely acuminate at apex,. 

slightly unequal-sided; margin obscurely and 

remotely toothed; midrib very strong; ·secondaries about eight pairs, strong, alternate, 

· emerging at a nearly right angle below but 

about 40° above, camptodrome, curving just 

within the border and sending slender branches 

to the teeth; finer nervation obscure. 

This little leaflet appears to be of the type of 

the living Rhus copallina Linne, which ranges 

over the eastern United States and as far west 

as Nebraska, Kansas, and eastern Texas, 

except that in the fossil the teeth are a little 

more pronounced. There are a number of 

fossil species that the present one somewhat 

resembles, such for instance as Rhus jrigida 

Knowlton,38 from the Eocene rocks of Herendeen Bay, Alaska. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by J. B. Reeside, jr., 1921 (lot 

7496). 

Family SAPINDACEAE. 

Sapindus obtusifolius Lesquereux? 

Plate VIII, Figure 4. 

Sapindus obtusifolius Lesquereux, U. S. Geol. and 

Geog. Survey Terr. Ann. Rept. for 1873, p. 419, 

1874; U. S. Geol.. Survey Terr. Rept., vol. 7 

(Tertiary flora), p. 266, pl. 49, figs. 8-11, 1878. 

There ·is a single specimen in one of the 

collections of Animas plants that appears to be 

a medium-sized leaflet of this species, but 

inasmuch as the nervation is not very wel1 

preserved I have questioned the identification. 

It agrees in size and shape and in nervation as 

well as this can be made out. 

Occurrence: Animas formation, Ignacio 

quadrangle, Colo.", east side of sec. 21, T. 35 N., 

R. 6 W. New Mexico principal meridian, collected by · J. H. Gardner, August, 1909 (lot 

5455). 

Order RHAMN ALES. 

Family RHAMNACEAE. 

Rhamnus cleburni Lesquereux. 

Plate XVII, Figure 4. 

Rhamnus cleb1trni Lesquereux, U. S. GeoL and Geog. 

~urvey Terr. Ann. Rept. for 1872, p. 381, 1873; 

U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary flora), p. 280, pl. 53, figs. 1-3, 1878. 

Berry, U. S. Geol. Survey Prof. Paper 91, p. 283, 

1916. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, p. 

382, pl. 113, fig. 3, 1917 [1918]. 

The example figured is nearly perfect, laeking only a small portion of ·the tip. It is 

clearly indistinguishable froln the type specias Knowlton, F. H., U.S. Nat. Mus. Proc., vol. 17, p. 227, pl. 9, fig. 6, 

1894. 
SYSTEMATIC DESCRIPTIONS. 91 

1nens described by Lesquereu.-x, from the 

Denver for1nation at Golden, Colo., where the 

species is abundant. This species was also 

· found at a nun1ber of localities in the Raton 

for1nation of southeastern ColQrado and northern New Mexico and was reported by Berry in 

the Wilcox group of Mississippi and Louisiana. 

It was doubtfully identified ao in the lower part 

of the Clarno formation of Cherry Creek, Oreg. 

Occurrence: Animas forn1ation, Pagosa quadrangle, Colo .. , 4-t miles north of Pagosa Junction, collected by Q. D. Singewald and J. B. 

Reeside, jr., 1921 (lot 7485); 1 mile ·north of · 

Pagosa Junction, collected by W. T. Lee, 

1912 (lot6444). 

Rhamnus goldianus Lesquereux. 

Rhamnv,s golclianus Lesquereux, U. S. Geol. and Geog. 

Survey Terr. Ann. Rept. for 1872, p. 381, 1873; 

U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary flora), p. 281, pl. 53, figs. 4-8, 1878. 

A single leaf that appears to belong to this 

species. 

Occurrence: Anin1as forn1ation, Ignacio 

quadrangle, Colo., 5 miles east of Durango, 

in SW. t sec. 30, 1'. 35 N., R. 8 W., 700 feet 

above base of Anin1as beds, collected by J. B. 

Reeside, jr., 1920 (lot 7463). 

Zizyphus fibrillosus (Lesquereux) Lesquereux. 

Zizyph1ts jibrillos1t.s (Lesquereux) Lesquereux, U. S. 

Geol. Survey Terr. Rept., vol. 7 (Tertiary 

flora), p. 276, pl. 52, figs. 1-5 [not fig. 6, which 

= Zizyph1ts claphnogenoicles Knowlton], 1878; 

Mus. Comp. Zool. Bull., vol. 16, p. 55, 1888. 

Knowlton, U. S. Geol. Survey Prof. Paper 101, p. 

335, pl. 102, fig. 1, 1917 [1918]. 

Ceanoth1ts fibrillows Lesquereux, U. S. Geol. and Geog. 

Survey Terr. Ann. Rept. for 1872, p. 381, 1873. 

This species was described originally from 

n1aterial found in the Denver formation at 

Golden, Colo., and subsequent collecting at this 

locality has shown it to be one of the most 

abundant and characteristic species of the 

forn1ation. It was also found at a number of 

localities in the Raton formation of the 

Raton Mesa region of Colorado and New Mexico. The specimen from the Ani1nas formation is absolutely identical with the leaves from 

Golden. Although it lacks the upper part, 

the cordate base, strongly inarching ribs, and 

very strong nervilles are clearly characters of 

this species. 

sP Knowlton, F. H., U. S. Oeol. Survey Bull. 204, p. 80, 1902. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of ;pagosa Junction, collected by J. B. Reeside, jr., 1921 (lot 

7496). ) 

Zizyphus daphnogenoides Knowlton, n. sp. 

Daphnogene anglica? Heer. Lesquereux, U.S. Geol. and 

Geog. Survey Terr. Ann. Rept. for 1873, p. 401, 

1874; Ann. Rept. for 7876, p. 510, 1878; U. S. 

Geol. Survey Terr. Rept., · vol. 7 (Tertiary 

flora), p. 222, pl. 37, fig. 9, 1878. 

Zizyphus fibrillows (Lesquereux) Lesquereux, U. S. 

Geol. Survey Terr. Rept., vol 7 (Tertiary flora), 

pl. 52, fig. 6 [not figs. 1-5], 1878. 

Leaves of firm texture, ovate-lanceolate, abruptly rou~ded or very obtusely wedge-shaped 

at base, long and narrowly acuminate at apex; 

margin entire, perhaps slightly und':llate; petiole very thick, the principal ribs descending 

into it for son1e distance below· the margin of 

the blade; nervation peculiar, strong, threeribbed, the ribs arising well down on the petiole, 

the middle one slightly strongest, straight, ending in the extreme tip; lateral ribs at a very 

acute angle, arching outward but slightly, then 

inward and running nearly or quite to the tip; 

midrib without secondary branches, lateral ribs 

with five or six secondary branches on the outside, the lowest nearly basal, all at relatively 

acute angles, arching and passing high upward, 

camptodrome; lower secondary with. a few 

short, camptodrome tertiary branches on ·the 

outside; nervilles numerous, strong, parallel, 

unbroken, mainly at right angles to the midrib. 

Types: U.S. Nat. Mus. Nos. 317 (identified 

as Daphnogene anglica), 430 (identified as Zizyphus fibrillosus), 51066 (with manuscript identification as Zizyphus raincourtii var.). 

This species is rep res en ted by some half a 

dozen more or less perfect. examples from the 

Denver formation at Golden,· Colo., which together afford a pretty complete knowledge of 

its size and form. They show considerable 

range jn size, the smallest being the specimen 

described and figured by Lesquereux as Daphriogene anglica? I-Ieer ("Tertiary flora," pl. 37, 

fig. 9), which is 6 centimeters long and only 1.6 

centimeter wide, whereas the largest is fully 

12 centimeters in length and about 6 centi-:-

meters in width. 'rhe petiole is preserved for 

about 1.5 centimeters and is evidently not complete. The outline also differs somewhat, ranging from narrowly ovate-lanceolate to broadly 

ovate-lanceolate. The base is in no specimen 
92 FLORA OF THE ANIMAS FORMATION. 

heart-shaped. The apex is long and narrowly 

acuminate. The primary nervation is strongly 

marked and 'is peculiar in that the three ·ribs 

arise well down on the petiole and far below the 

lower margin of the blade. It is really only 

three-ribbed, but the lowest pair of secondaries 

sometimes arise so low down as to make it 

appear :five-ribbed. 

The solitary leaf identified by Lesquereux as 

Daphnogene anglica? Heer is present in the 

U. S. National Museum collection (No 317) 

and has long been a puzzle. Its iden ti:fica tion 

with this European species rested on extremely 

insecure grounds, as it was never :figured, Lesquereux making the identification on the short 

description alone. It has remained unique in 

American ~trata until the present time, but 

although much smaller and narrower than the 

typical form of Zizyphus appears to be, it is so 

absolu_tely similar in everything except size that 

I have no hesitation in placing them together. 

The question of relationship has to be further -considered. Lesquerei:Lx was evidently 

in doubt as to the propriety of referring it 

to Daphnogene and stated: "It is therefore 

probable that, as Saporta supposes, this leaf 

may represent a Zizyphus or a Oeanothus," 

and such seems to me to be. the case. The 

little narrow original specimen has seemingly 

a relationship to Zizyphus vulgaris Linne, the 

common living form, though the latter differs 

in having serrate margins and in lacking the 

strong branching on the outside of the lateral 

ribs. But in the light of the additional 

material now referred to this form it appears 

beyond question to be most closely related to 

Zizyphus fibrillosus Lesquereux-in fact, the 

line separating them is very uncertain. Unfortunately most of_ the leaves of Z. fibrillosus 

are so fragmentary that it is difficult to determine the shape of the base; it appears, however, that this is always more or less deeply 

heart-shaped, whereas in the form under discussion the base is truncate or obtusely wedgeshaped. The apex is also uncertain in many 

of the examples referred to Z. fibrillosus, but 

in none of them does it appear so long or so 

narrowly acuminate as in the specimens under 

consideration. ·The nerva_tion is certainly very 

much of the same type in both, and it may be 

that subsequent discoveries will show that 

Z. daphnogenoides is not a well founded species, 

though in the light of present under~tanding 

it seems a far call from the narrow leaf figured 

by Lesquereux ("Tertiary flora," pl. 37, fig. 9) 

to the large, extremely broad leaves of typical 

Z. fibrilla sus. 

This form is also to be compared with 

Zizyphus distortus Lesquereux, which· is really 

almost too close to warrant separation, .and 

if the type and only examples of Z. distortus 

were better preserved or reinforced by additional material it is possible that all three 

would be thrown together. 

I have also referred to Zizyphus daphnogenoides one of the six specimens figured by 

Lesquereux as Zizyphus fibrillosus (" Tertiary 

flora," pl. 52, fig. 6). This specimen (No. 430, 

U.S. Nat. Mus.) represents the nearly complete 

apical portion of a long, narrow leaf that was 

probably about 7 centimeters long and not 

much if any over 3 centimeters wide. It must 

have been narrowed or very obtusely wedgeshaped at the base and is certainly quite unlike 

the broad truncate or heart-shaped leaves 

normal for Z. fibrillosus. 

Among the specimens from the Denver 

formation acquired by the United States 

National Museum from the Lacoe collection 

there is one labeled by Lesquereux as an 

undescribed variety of Zizyphus raincourtii 

(Saporta) Saporta. This specimen (No. 51066, 

U.S. Nat. Mus.) is a rather fragmentary basal 

portion of a small leaf that appears indistinguishable from certain of the leaves now placed 

in Z. daphnogenoides. Saporta's species/0 

which is from the Eocene of Sezanne, is of 

about the same size as the leaf under consideration but differs in a number of marked particulars. Thus, it is three-ribbed from the top 

of the petiole, but the lateral ribs do not ascend 

much above the middle of the blade, and the 

middle rib has numerous secondary branches 

in the upper part. The margin of the leaf is 

denticulate instead of entire. The Lacoe specimen is undoubtedly referable to Zizyphus 

daphnogenoides. 

The Lacoe collection also contains another 

specimen that must be referred to Zizyphus 

daphnogenoides~ This specimen (No. 51063, 

U. S. Nat. Mus.) was labeled by Lesquereux: 

as Smilax sp., but it is indistinguishable from 

the ordinary leaves of Z. daphnogenoides, 

•o Saporta, Gaston de, Prodrome d'une fl.ore fossile des travertins 

anciens de Sezanne: Soc. geol. France Mem., 2d ser., vol. 7, p. 414, text 

fig. 22, pl. 14, figs. 8-10, 1868. · 
SYSTEMATIC DESCRIPTIONS. 93 

such, for instance, as that figured by LesquerelL"C in the "Tertiary flora" (pl. 52, fig. 6) 

as Zizyphus fibrillos'l.ts. 

little leaf is 5 centimeters long and 1.4 centimeters wide. 

Occurrence: Animas formation, Pagosa quadrfl,r:{gle, Colo., 1,000 feet south of Talian mine, 

5 miles north of Pagosa Junction, collected by 

Q. D. Singewald and J. B. Reeside, jr., 1921 

(lot 7483). 

Order UMBELLALES. 

Family ARALIACEAE. 

Aralia lobata Knowlton, n. sp. 

The above description and discussion was 

prepared for the paper on the flora of the 

Denver formation, but inasn1uch as the species 

has now been found in the Ani1nas formation, 

the account of which is to be published first, 

it is necessary to present the facts and the 

reasons for the action taken. The figures of 

the Denver specimens will be published in the 

paper mentioned. · . Plate XVII, Figures 1, ~. The Animas leaf 1s a very perfect speCimen, 

hteking only a bit of the extreme tip. It is Leaves small ·or of medium size, coriaceous, 

narrowly ovate-lanceolate, about 6 centimeters three-ribbed from the very base, where the 

long and 2 centimeters wide, ~nd has the com- ·lateral ribs form the margin for some distance; 

plete petiole, 2 centimeters long. As may be five or seven lobed, the central lobe much 

seen on comparison, it is identical in all partie- longer than the others, n_arrow, cut into several 

ulars with the Denver leaf identified by Les- very large lanceolate lobes; upper lobes similar 

quereux as Daphnogene anglica? Heer. There to the middle lobe but smaller; next pair much 

can be no question as to their being the same. reduced, with only one or two of the large 

Occurrence: Denver formation, Golden, Colo. lobes; midrib of the central lobe very strong, 

The leaf figured by Lesquereux as Daphnogene with several pairs of alternate, strong secondO/ngZica, ~ I-Ieer was collected in the seventies by aries; lateral ribs that supply the upper pair 

Capt. Eel. Berthoud. The specimen removed of lobes strong, at an angle of about 65°; basal 

from Zizyphus fibrillosus was collected about lobe supplied with a midrib which arises fron1 

1872 by Leo Lesquereux. The additional ex- the lateral rib some distance from the base 

amples were collected by Arthur Lakes on the and which in turn, in seven-lobed leaves, gives 

south face of South Table Mountain, 100 feet rise to the midrib of the lobe. 

below the lava cap. This is a very remarkable species, reproAnimas formation, P.agosa quadrangle, Colo.; sen ted in the collections by the two examples 

half a mile west of Pagosa Junction, collected figured and ·by a number of fragments. 

by J. B. Reeside, jr., 1921 (lot 7496). Although neither of the figured specimens is 

Zizyphus lanceolatus Knowlton, n. sp. · 

Plate XV, Figure 3. 

Leaf s1nall, coriaceous, slightly ellipticaloblanceolate, broadest above the n1iddle, 

whence it narrows below to the long wedgeshaped base and more abruptly above to the 

acuminnte ttpex; petiole short, stout; midrib 

relatively very strong; lateral veins arising at 

a very acuto angle from the top of the petiole, 

thin, pttssing up i1ear the margin to or very 

near the tip of the blade, each with twq or three 

bra.nches on the outside which unite· and form 

:1 thin "vein" nearly to the tip of the blade; 

1nidrib with severa.l pa.irs of secondary branches 

.in the upper part, these joining the intramarginal rib or vein; the lower part of the blade 

has the area between the midrib and the ribs 

with an irregular mesh of nervilles. This 

82587--24t--7 

perfect, there is enough present to give a 

fairly complete idea of the form. The betterpreserved one, shown in Figure 1, must have 

been about 12 or 13 centimeters long to the tip 

of the central lobe and about 8 centimeters 

wide; it has the petiole 2.5 centimeters long. 

The other specimen (fig. 2) was slightly. longer 

but is so brpken that measurements can hardly 

be made. 

Aralia lobata is strikingly similar in facies to 

Aralia dissecta Lesquereux, 41 from the Miocene 

lake beds at Florissant, Colo., but the latter is 

not only very much larger, with the lobes much 

more segmented, but differs in having all the 

seven ribs arising at the top of the petiole. 

There are also certain species of Aralia, as, for 

instance, A.. wellingtoniana Lesquereux,42 from 

t1 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous 

and Tertiary floras), p. 176, pl. 35, 1883. 

t2 u.s. Geol. Survey Mon. 17, pl. 22, fig. 3, 1892. 
94 F.LORA OF THE ANIMAS FORMATION. 

the Dakota sandstone of Kansas, that are of 

. this general facies, but the Dakota form differs 

essentially in having the lobes merely toot;hed 

and in having the lateral ribs arising well above 

the decurrent base of the blade. · 

Occurrence:. Animas formation, Pagosa quadrangle, Colorado, 1,000 feet south of Talian 

mine, 5 miles north of· Pagosa Junction, collected by Q. D. Singewald and J. B. Reeside, 

jr., 1921 (lot 748.3.) 

Aralia reesidei Knowlton, n. sp. 

Plate XVII, Figure 3. 

Leaf of medium size, coriaceous, palmately 

strongly three-ribbed from a point above the 

decurrent base of the blade; five-lobed, the 

central lobe larg~st, broadly lanceolate; upper 

pair of lobes deltoid, short, a~ute; basal pair 

of lobes small, acute; margins of lobes remotely 

few toothed, the teeth low, sharp; three upper 

lobes with five or six pairs of strong, irregularly spaced secondaries which terminate in 

the marginal teeth; midrib of the basal lobes 

arising from the lateral pair of ribs well above 

the base, with three or four secondaries on the 

lower side only; nervilles numerous, strong, 

mainly percurrent. 

This species is represented by the single 

nearly perfect leaf figured. It is about 12 

centimeters long and about 13 centimeters 

broad between the points of the basal lobes. 

The petiole is evidently very strong, as appears 

in the decurrent portion of the blade, where 

it gives rise to the three ribs. 

This species is undoubtedly of the san1e type 

as Aralia coloradensis Knowlton, 43 from the 

R·aton formation of southeastern Colorado, and 

is closely related to it-in fact, if a serie-.; of 

the two were available for comparison it might 

well be found that they are identical, but 

unfortunately each is at present· kno~.n from 

a single specimen. Aralia coloradensis is a 

1nuch larger leaf, being about 20 centimeters 

long and 16 or 18 centin1eters broad between 

the tips of the lateral lobes. · 

Occurrence: Animasformation, Pagosa quadrangle, Colo., hill above Talian mine, 5 miles 

north of Pagosa Junction, collected by Q. D. 

Singewald and J. B. Reeside,jr., 1921 (lot 7482). 

43 Knowlton,.F. H., U.S. Geol. Survey Prof. Paper 101, p. 341, pl. 107, 

fig. 2, 1917 [1918]. . 

Aralia? sp. 

Plate VI, Figure 4. 

This is probably a sn1all, distorted leaf of 

Aralia lobata and perhaps ought not to be 

mentioned, but it is so peculiar that it may be 

worthy of a brief description. It is long 

wedge shaped at the base, with . at least three 

lobes, a strong irregular central one and two 

lateral sharp-pointed ones, which differ greatly 

in size. It has three ribs that arise at the top 

of the petiole, the lateral ones with a fork or 

supplementary rib considerably above the base. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 1,000 feet south of Talian mine, 

5 miles north of Pagosa Junction, collected 

by ·Q. D. Singewald and J. B. Reeside, jr., 

1921 (lot 7483). 

Family CORNACEAE. 

Cornus studeri? Heer. 

Plate XIII, Figure 2; Plate XV, Figure 1. 

Cornus studeri? Heer, Flora tertiaria Helvetiae, 

vol. 3, p. 27, pl.-.105, figs. 18-21, 1859. 

Lesquereux, U. S. Geol. Survey Terr. Rept., 

vol. 7 (Tertiary flora), p. 244, pl. 42, figs. 4, 5, 

1878. 

The two specimens figured are referred to 

Oornus studeri? on the grotmd of their rather 

close agreement with leaves so identified by 

Lesquereux, from the Denver formation at 

Golden, Colo. They are quite different from 

Heer's figures of leaves from the Aquitanian 

of Switzerland, as indeed are the Denver 

leaves figured by Lesquereux, and· they are 

also different from the leaf fron1 the Wilcox 

group· figured by Berry, 44 . and from that from 

the Raton formation of Colorado figured by 

me. 45 In fact, son1e seemingly very diverse 

forms have been referred to Heer's Oorm.ts 

studeri, though always with question, and it is 

doubtful if all are conspecific or even congeneric. 

Thus Berry suggests that possibly this leaf 

should probably be placed in Ficus, and this 

is the conclusiott reached by Saporta regarding 

the European types of the species. I do not 

think that either the specin1ens under discussion 

or those figured by Lesquereux should be referred to Ficus,_ though the forms somewhat 

44 Berry, E. W., U. S. Geol. Survey Prof. Paper 91, pl. 68, fig. 3, 19Hl. 

45 Knowlton,!F. H., U. S.~Geol. Survey, Prof. Paper 101, pl. 109, fig. 2, 

1917 [1918]. 
SYS'rEMA'l'IC DESClill>TIONS. 95 

resmnble certain leaves placed under Laurus, 

but the strongly inarching upper secondaries 

are chn.racteristic of Om·nus. 

The smaller of the two figured leaves is 

about the same size and nervation as Oornus 

rhamnifolia Lesquereux, 46 described from beds 

near Point of Rocks, Wyo., supposed to be 

nen.r Green River age, but the secondaries are 

a little less curved upward. The larger leaf 

figured is slightly obovate-elliptical, as in some 

len.ves of Laur'I.Ls, but the upper secondaries 

arc those of Oornus. 

Occurrence: Anin1as forn1ation, Ignacio 

quadrangle, Colo., east side of sec. 31, T. 35 

N., H.. 6 W. New ::Mexico principal meridian, 

1,650 feet above bn.se of beds, collected by J. 

If. Gardner, August, 1909 (lot 5455). 

Nyssa? racemosa Knowlton. 

Nyssa? racemosa Knowlton, U. S. Geol. Survey Bull. 

152, p. 153, 1898; Prof. Paper 101, p. 343, 1917 

[1918]. 

Sabalites fructifer Lesquereux [part], U. S. Geol. Survey 

Terr. H.ept., vol. 7 (Tertiary flora), pl. 11, fig. 3a 

[not fig. 3], 1878. 

The type locality of this species is Golden, 

Colo., in the Denver formation, where it was 

found by Lesquereux: in association with Sabalites? fructifer, of which it was supposed to 

be the fruit. It has been found to be not unconunon in the Denver formation and has· been· 

identified in the Raton formation near Raton, 

N. }.1ex., and in "post-Laramie beds" ·at 

Black Buttes, Wyo. 

The specimens from the Animas formation 

are detached fruits that agree perfectly in size 

and shape with the types. They are not, however, so distinctly striate, though faint transverse striae can be made out. These speciInens have not been figured. 

The proper generic reference for these fruits 

is still unsettled. They probably do not belong to Nyssa, and if their a:ffmity can not be 

established they should be designated by a 

new generic name. 

Occurrence: Animas formation, Ignacio 

. quadrangle, Colo., pebbles near top of beds, 

collected by J. II. Gardner, 1909 (lot 5667). 

46 Lcsquorcux, Leo, U. S. Geol. Survey '!'err. Hcpt., vol. 7 (Tertiary 

flora), pl. 42, fig. 6, 1878. 

Order GENTIANALES. 

Family APOCYN ACEAE .. 

Apocynophyllum wilcoxensis Berry. 

Plate XIV, Figure 5. 

A pocynophyllum, wilcoxensis Berry, U. S. Geol. Survey 

Prof. Paper 91, p. 342, pl. 103, figs. 2, 3; pl. 

108, fig. 4, 1916. 

Knowlton, U. S. Geol. .Survey Prof. Paper 101, p. 

345, pl. 103, fig. 3; pl. 105, figs. 1, 2; pl. 106, 

fig. 1, 1917 [1918]. 

This species was described by Berry from 

specimens obtained in the Wilcox group of 

Mississippi and Louisiana and in beds of Wilcox age in the Lagrange formation of Tennessee and was subsequently identified by me in 

the Raton formation of southeastern Colorado. 

The leaf here figured, from the Animas beds, 

agrees perfectly in all except size with the 

sn1aller exan1ples from the Raton formation. 

rrhe Raton leaves are from 16 to 23 centimeters 

long and 2.5 to 3.75 centimeters wide, whereas 

the Animas leaf is only 10 centimeters long and 

1.5 centimeters wide. The description of the 

Raton leaves is given ~s follows: 

Leaves thick and coriaceous in texture, narrowly 

lanceolate in shape, more or less unequal-sided and 

slightly falcate, broadest near the middle, thence tapering upward to the long, slender apex arid downward to 

the narrowly wedge-shaped base; midrib very strong, 

especially below, straight; secondary nervation thin, 

delicate, more or less uneven, consisting of numerous 

rather close parallel secondaries which emerge at an 

angle of about 20° and run nearly straight to the margin, each joining the one next above, thus producing a 

somewh~t irregular intermarginal ''stitch." 

A comparison of the figures shows them to 

agree in every essential particular, including 

the coriaceous substance of the leaf, the narrowly lanceolate, slightly falcate shape, unequal sides, and thin secondary nervation, endi:ng in the intermarginal vein. 

The sn1aller of the leaves of Apocynophyllum 

wilcoxensis from the Raton formation, as well as 

the one from the Animas beds, are very similar 

in size, shape, and nervation to the leaf from 

the Green River formation that Lesquereux 47 

described as Eucalyptus? americanus, but the 

Green River leaf differs in having the second47 Lesquereux, Leo, U. S. Geol. Survey '!'err. Hept., vol. 7 (Tertiary 

flora), p. 296, pl. 59, fig. 11, 1878 
96 FLORA OF THE ANIMAS l!"'ORMATION. 

Viburnum speciosum Knowlton. 

Plate XVI, Figure 3. 

aries at an angle of 40° or 45°. It would seem 

that they must be at least c~ngeneric, but they 

are permitted to stand until further specimens· 

are available. Viburnum speciosum Knowlton, U. S. Geol. Survey 

Prof. Paper 101, p. 347, p. 111, figs. 1-5, 1917 Occurrence: Animas [1~18]. formation, Pagosa quadrangle, Colo., 1,000 feet south of Talian mine, 

5 miles north of Pagosa Junction, collected 

by J. B. Reeside, jr., 1921 (lot 7483). 

Order RUBIALES. 

Family CAPRIFOLIACEAE. 

Viburnum rotundifolium Lesquereux. 

Plate XVI, Figure 1. 

Viburnum rotundifolium Lesquereux, U. S. Geol. and 

Geog. Survey Terr. Ann. Rept. for 1874, p. 305, 

1875; U. S. Geol. Survey Terr. Rept., vol. 7 

(Tertiary flora), p. 225, pl. 38, fig. 10; pl. 61, 

fig. 22, 1878. 

One of the collections from the Animas beds 

contains a number of leaves that do not seem 

to differ essentially from the types of Viburnum 

rotundifolium. They are slightly less truncate 

than the types but are otherwise the same. 

Occurrence: Animas formation, Ignacio 

quadrangle, Colorado, east side of sec. 21, T. 

35 N., R. 6 W. New JY,fexico principal meridian, 

collected by J. H. Gardner, August, 1909 (lot 

5455). 

Viburnum antiquum (Newberry) Hollick. 

Plate XVIII, Figures 1-3. 

Viburnum antiquum (Newberry) Hollick, in Newberry 

U. S. Geol. Survey Mon. 35, p. 128, pl. 33, figs. 

1, 2, 1898. 

Tilia antiqua Newberry, New York Lyceum Nat. 

· Hist. Annals, vol. 9, p. 52, 1868. 

Viburnum tilioides Ward, U. S. Geol. Survey Sixth 

Ann. Rept., p. 556, pl. 61, figs. 1-7; pl. 62, figs. 

1-6, 1886; Bull. 37, p. 107, pl. 50, figs. 1-3; pl. 51, 

figs. 1-8; pl. 52, figs. 1, 2, 1887. 

The collection made by W. T. Lee near 

Pagosa Junction, Colo., contains a number of 

finely preserved leaves that I am not able to 

separate satisfactorily from Viburnum antiquum, the well-known· Fort Union species. The 

only difference I am able to note is that in these 

leaves the secondaries are slightly more erect 

than in the Fort Union types. I have figured 

three specimens to show the range in size and 

how closely they compare with those figured 

by Newberry and Ward. 

Occurrence: Animas formation, Pagosa Junction, Colo., half a mile downstream from the 

station, collected by W. T. Lee, 1912 (lot 

6309). 

Lee's collection from Pagosa Junction, Colo., 

contains a number of well-preserved specimens 

that belong to this species. The one here 

figured is seen to agree perfectly with Figures 2 

and 4 of the types as illustrated in the paper 

cited. 

Occurrence: Animas formation, about 1 mile 

northeast- of Pagosa Junction, Colo., collected 

by W. T. Lee~ 1912 (lot 6443). 

PLANTS OF UNCERTAIN OR UNRECOGNIZED 

SYSTEMATIC POSITION. 

Carpites sulcatus Knowlton, n. sp. 

Plate XIX, Figures 3, 4. 

The collection from Pagosa Junction, Colo., 

includes two specimens of a rather peculiar 

fruit of unknown affinity. They are elliptical, 

about 10 millimeters long and 6 or 7 millimeters broad, with two or three longitudinal 

ridges separated by shallow furrows. One of 

the specimens shows a carbonaceous layer 

about 1 millimeter thick, possibly representing 

a shell or in any event a firm exocarp. No 

point of attachment can be distinguished. 

The ridged surface suggests a fruit of Hicoria, 

but the size and shape seemingly preclude such 

affiliation. It will have to remain under 

Oarpites until further information is forthcoming. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction, collected by J. B. Reeside, jr., 1921 (lot 

7496). 

Phyllites eocenica Knowlton, n. sp. 

Plate XVIII, Figure 4. 

The specimen shown was a large leaf, probably not less than 15 centimeters long and 8.5 

centnneters wide. It is apparently thick and 

firm in texture and ovate-lanceolate, but it is 

so fragmentary that the characters can not all 

be made out. Thus it appears to have been 

rounded and obtusely wedge-shaped at the base 

and probably acuminate at· the apex, though 

both are missing. The margin so far as can 

be made out is perfectly entire. The nervation 

is very strong, consisting of a very thick, 
SYSTEMATIC DESClUPTIONS. 97 

straight midrib and about five pairs of nearly 

as strong secondaries. The basal pair appear 

to arise at the base of the blade and might 

almost be called ribs. They pass upward at an 

angle of about 75°, with a very slight curve, 

nearly two-thirds the length of the blade; they 

have several branches on the outside. The 

other secondaries are also at an angle of about 

75° and arch just inside the margin. The finer 

nervation is not retained. 

This leaf ~·esembles a number of described 

species, but its fragmentary nature prevents n. 

decision on certain characters. Thus, it suggests some leaves of Cornus studeri? Heer, as 

figured by Lesquereux/8 but it has fewer secondaries, and the broken apex prevents determining whether they curve inward, as in Cornus. It is apparently more of the type of Ficu::; 

planicostata goldiana Lesquereux, 49 from the 

Denver, forn1ation at Golden, Colo., but it is 

proportionately narrower and has the secondaries at a slightly more acute angle. The critical character of the origin of the basal pair of 

secondaries can not be ascertained, as the base 

of the leaf is lacking. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 1,000 feet south of Talian mine, 

5 miles north of Pagosa Junction, collected by 

Q. D. Singewald and J. B. Reeside, jr., 1921 

(lot 7483); half a mile south of Talian mine, 4! 

miles north of Pagosa Junction, collected by 

Q.: D. Singewald and J. B. Reeside, jr., 1921 

(lot 7485). 

Phyllites pagosensis Knowlton, n. sp. 

Plate XVI, Figure 2. 

The collection obtained near Pagosa Junction, Colo., contains a single specimen of the 

fo:rm here figured. It is presumably a ·leaflet, 

as the base is almost squarely truncate on one 

side and greatly reduced and wedge-shaped on 

the other side. It was apparently narrowly 

ln.nceolate in general outline, though the apical 

portion and much of one side is absent. The 

1nargin is cut by very large sharp-pointed teeth, 

some .of which are again cut by sn1aller teeth. 

The n1idrib is strong, straight, and provided 

with numerous evenly spaced parallel secondaries, which emerge at an angle of about 30° 

and terminate in the large teeth, with a smaller 

•a Lcsquoroux, Loo, U. S. Gool. Survey Terr. Rept., vol. 7 (Tertiary 

flora), pl. 42, fig. 5, 1878. · 

v Idem, pl. 33, figs. 1-3. 

branch entering the secondary teeth. The finer 

nervation is obscure. No satisfactory measurements can be given beyond the width of one 

side, which is slightly over 1.5 centimeters. 

The whole l~ngth must have been $Orne 8 or 9 

centimeters. 

There is so much unc~rtainty concerning the 

proper generic reference for this fragment that 

it seems best to place it, temporarily at least, 

in the noncom1nittal Phyllites. At first sight 

it strongly suggests Myrica, with its low-angled 

secondaries and strongly toothed margin, but 

the double serration excludes it from. the majority of species of that genus. Heer 50 has describec~ a doubly serrate species fron1 the Swiss 

Miocene under t~1e name Myrica graifii, but it 

is very different from the one under consideration. 

Occurrence: Anin1as formation, Pagosa quadrangle, Colo., half a 1nile west of Pagosa Junction, collected by J. B. Reeside, jr., 1921 (lot 

7496). 

Phyllites herbacea ~nowlton, n. sp. 

Plate XV, Figure 4. 

Leaf small, thin, broadly ovate, slightly unequal sided, truncate at the base, with a wedgeshap~d decurrent portion; apex destroyed but 

apparently rather obtuse; n1argin coarsely and 

irregularly toothed; nervation thin, threeribbed fron1 the very base of the· decurrent 

portion of the blade, the midrib with two or 

three pairs of very thin secondaries in the upper 

part, craspedodrome; lateral ribs at an acute 

angle (about 70°), each with a strong branch 

that arises some distance above the base, the 

one on the narrow side of the leaf entering the 

lowest marginal tooth, that on the .broad side 

with about four. secondary branches on the 

lower side; finer nervation obscure. 

The specin1en figured is the only one of this 

kind noted in the collections. It is nearly perfect except for the apical portion, and was npparently about 6.5 centin1eters long. It i:-5 

slightly over 1.5 centimeters wide on the nat·-

row side of the leaf and 2.5 centimeters wide 

on the broader side. 

I have not been able to place this leaf satisfactorily. Its obviously thin texture and irregularly toothed margin suggest a herbaceous plant, 

such as some species of Aster, but the likeness 

ao Heer, Oswald, Flora tertiaria Helvetiae, vol. 3, pl. 150, figs. 19, ~o. 

1859. 
98 FLORA OF THE ANIMAS FOHMATION. 

is n<?t sufficient to warrant plac~ng it in this or 

any other genus that has been recognized. It 

also suggests perhaps rmnotely some of the 

leaves of the European poplar (Popttb.ts alba), 

but its thin texture, unequal sides, and threeribbed, decurrent base apparentiy exclude it 

from Populus. It seems best to refer it to 

Phyllites and await further light on its affinities. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., 1,000 feet south of Talian mine, 

5 miles north of Pagosa Junction; collected by 

Q. D. Singewald and J. B. Reeside, jr., 1921 

(lot 7483). 

Phyllites innominata Knowlton, n. sp. 

Plate XIX, Figure 5. 

Leaf large, firm, elliptical-ovate, abruptly 

rounded to a truncate base (apex wanting); 

margin perfectly entire; petiole short, moderately strong; nervation pinnate, the midrib 

strong, straight; secondaries probably about 

eight pairs, mainly alternate, at. an angle of 

about 40°, little curved upward, the lowest 

pair arising at the very base of the blade, with 

three or four tertiary branches on the outside; 

nervilles strong, mainly at right angles to the 

secondaries. 

This is a large, :fine leaf that must have been 

approximately 15 centimeters long, but the 

apex is destroyed; it is 8.5 c·entimeters wide. 

The peti~le, which appears to be· completely 

preserved, is 2.5 centimeters long. 

Although this leaf is seemingly' so well 

marked, its affinity is not recognized. It is 

similar to certain leaves that have been referred to Ficus, and on this basis it would perhaps do no great violence to convention to 

make such an assignment, but that genus is 

already overburdened, and in the absence of 

proof it seems best to place the leaf under 

Phyllites until its biologic affinity is recognized. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a 1nile west of Pagosa Junction; collected by J. B. Reeside, jr., 1921 (lot 

7496). 

Phyllites S.ll· 

Plate XIX, Figure 1. 

The fragment here figured is only the basal 

portion-of a very large leaf that n1ust have been 

20 or 25 centin1eters long and 10 centin1eters 

or more wide. It appears to have been lanceolate in general outline, though this is, of course, 

uncertain, and obtusely wedge-shaped at the 

base. It has a very thick petiole and midrib 

and very strong alternate secondaries. 

Ordinarily it would hardly be worth while 

to describe and figure· so fragmentary a specimen, but it is so much larger than the other 

leaves in this collection that it seems to merit 

brief mention. .It may be the basal part of a 

large leaf of Artocarpus, and it is also suggestive 

of certain large-leaved species of Quercus, but 

it is too fragmentary to warrant a decision. 

Occurrence: Animas formation, Pagosa quadrangle, Colo., half a mile west of Pagosa Junction; collected by J. B. -Reeside, jr., 1921 (lot 

7496). 
··-

-- .... ·-- . - --

S25S7-2J·i·--s · 99 
PLATE V. 

Page. 

Anemia gmndifolia Knowlton, n. sp. Pagosa quadrangle, Colo., Talian mine, about 5 miles north of .... ,. Pagosa Junction. U.S. Nat. Mus. No. 36631. Reduced one-tenth _____________________ ~-------- 78 

10() "·· .. 
U. S. GEOLOGICAL SURYEY PROFESSIONAL PAPER 134 PLATE V 

FLORA OF T HE ANI MAS FORMATION. 
U . S. GEOLOGICAl. SURVEY PROFESSIONAL PAPER 134 PLATE VI 

2 

6 

7 

FLOHA OF THE ANIMAS FORMATIO . 
PLATE VI. 

Page, 

FtGUHt~ l. Alla:ntod'iops'is erosa (Lesquereux) ]{nowlton and Maxon. Pagosa quadrangle, Colo., 4~ miles 

north of Pagosa Junction. U.S. Nat. Mus. No. 36632________________________________ 78 

2. Dryo7Jleris cladophleboicles :Knowlton. Pagosa quadrangle, Colo., 4t miles north of Pagosa 

.Junction. U.S. Nat. Mus. No. 36633---------------------------------------------- 78 

3. Sal·ix 1·eeside·i Knowlton, n. sp. Pagosa quadrangle, Colo., half a mile west of Pagosa Junction. 

U.S. Nat. Mus. No. 36634-------------------------------------------------------- 79 

4. Aralia sp. Pagosa quadrangle, Colo., near Talian mine, 5 miles north of Pagosa Junction. 

U.S. Nnt. :Mus. No. 3()635. __________________________________ ..:_____________________ 94: 

5, 6. J'uglans berryi J(nowlton. Pagosa quadrangle, Colo., near Pagosa Junction. U.S. Nat. Mus. 

NOS. 3663(), 36637---------------------------------------------------.. ------------ 80 

7. li''ic'us sp. Pagosa quadrangle, Colo., half a mile west. of Pagosa Junction. U. S. Nat. Mus. 

No. 36638----------------------------------------------------------------------- 84 

101 
PLATE VII. 

Page. 

FIGURE 1. Juglans schimJJeri Lesqucreux. Pagosa quadrangle, Colo., half a miles west of Pagosa Junction. U.S. Nat. Mus. No. 36639__________________________________________________ SO 

2. Jnghms innominata Knowlton, n. sp. Ignacio quadrangle, Colo., sec. 31, T. 35 N., R. 6 ,V. 

New Mexico principal meridian. U.S. Nat. Mus. No. 36640__________________________ SO 

3. Fic1ts sp. Pagosa quadrangle, Colo., half a mile west of Pagosa Junction. U. S. Nat. Mus. 

No. 36641 ______ ~---------------------------------------------------------------- S4 

4. Fic'us pseudo-pop1tl1ts Lesquereux. Pago1sa quadrangle, Colo., 5 miles north of Pagosa Junction. U.S. Nat. Mus. No. 36642__________________________________________________ S3 

102 
U. S. GEOLOGICAL SURVEY PROFESSIO AL PAPER 134 PLATE VII 

2 

4 

3 

FLORA OF THE ANIMAS FORMATION. 
U. S. GEOLOGI CA l, SLRVEY PROFESSIONAL PAPER 134 PLATE VIII 

2 3 

4 

FLORA OF T HE AJ\IYI AS FORMATION. 
PLATE VIII. 

Page. 

Fwun1~ l. Castanea intennecl'ia Leqsuereux. Pagosa quadrangle, Colo., 4! miles north of Pagosa Junction. U.S. Nat. :Mus. No. 36643__________________________________________________ 81 

2. D1'?J07Jhyll1mt ben·y·i Knowlton, n. sp. Pagosa quadrangle, Colo., half a mile west of Pagosa 

J"unction. U.S. Nat. Mt.ts. No. 36644______________________________________________ 81 

3. Ji'·ic·us .mbtr·uncatn Lesquereux. Pagosa quadrangle, Colo., 4! miles north of Pagosa Junction. 

U.S. Nat. Mus. No. 36645 ______________________________ .:. _____ -------------------- 83 

4. Sa.p-indns oblusifol-i·us Lesquereux'? Ignacio quadrangle, Colo., sec. 21, T. 35 N., R. 6 W. 

New ·Mexico principal meridian. U.S. Nat. Mus. No. 36646__________________________ 90 

5. Ji'·icus occ·idental·is (Lesquereux) Lesquereux. Pagosa quadrangle, Colo., half a mile west of 

Pagosa Junction. U.S. Nat. ·Mus. No. 36647_______________________________________ 82 

8258i-24·i·--!) 103 
PLATE IX. 

Page. 

FIGURE 1. Fictts denveriana Cockerell. Pagosa quadrangle, Colo., half. a mile west of_ Pagosa Junction. 

U.S. Nat. Mus. No. 36648----------------------------------------------·---------- 83 

2. Ficus planicostata Lesquereux. Ignacio quadrangle, Colo., sec. 15, T. 35 N., R. 6 \V. New 

Mexico principal meridian. U.S. Nat. Mus. No. 36649______________________________ 82 

3. Fic'us pseudo-popnlus Lesquereux. Pagosa quadrangle, Colo., half a mile west of Pagosa 

Junction. U.S. Nat. Mus. No. 36650______________________________________________ 83 

4. F1:cus neo-planicostata Knowlton. Pagosa quadrangle, Colo., half a mile west of1Pa.gosa Junction. U.S. Nat. Mus. No. 3665L_________________________________________________ 82 

104 
U. S. GEOLOGICAJ, SURVEY PROFESSIONAL PAPER 134 PLATE IX 

FLORA OF T HE ANIMAS FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 134 PLATE X 

FLORA OF THE ANIMAS FORMATION. 
PLATE X. 

Page 

.FIGUHI~ 1. Ji'·iws monoclon, (Lesquereux) Berry'? Pagosa quadrangle, Colo., 5 miles nQrth of Pagosa 

Junction. U.S. Nat. :Mus. No. 36652--------------~--------------:..________________ s:3 

2. G-rataerrus? rrigantea ](nowlte>n, n. sp. Pagosa, quadrangle, Colo., 4} miles north of Pagosa Junction. U.S. Nat. lVIus. No. 36653_ ------------------------------------------------ S9 

3. · jltf'agnol·ict a:n(J'ttsl?fol?:a Newberry. Pagosa quadrangle, Colo:, 4J miles north of Pagosa June-

., tion. U.S. Nat. Mus. No. 36654-------------------------------------------------- SS 

<1. J?.lms colorculens·is Knowlton, n. sp. Pagosa quadrangle, Colo., half a mile west of Pagosa 

Junction. U.S. Nat. Mus. No. 36655 _______ ·---------------··----------------------- 90 

105 

' 
PLATE XI.. 

Page. 

Ficus pagosensis Knowlton, n. sp. Pagosa quadrangle, Colo., 1 mile I'lortheast of Pagosa Junction. 

U.S. Nat. Mus. No. 36656. Reduced one-tenth_______________________________________________ 84 

106 
U. S . GEOLOGICAL SURVEY PROFESSIONAL PAPER 134 PLATE XI 

FLORA OF THE ANIMAS FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSiONAL PAPER 131 PLATE X U 

FLORA OF THE ANIMAS FORMATION. 
PLATE XII. 

Page 

A ?'loca:r1J·us 1mngens (Lesquoreux) Hollick. Pagosa quadrangle, Colo., half a mile west of Pagosa Junction. U.S. Nat. Mus. No. '36657 _______________ ~ ____________________ ...:_______________________ 85 

107 
PLATE XIII. 

Psge. 

FIGUilE 1. N ectandra lancifolia (Lesquereux)- Berry. Pagosa quadrangle, 'Colo., 1 mile north of Pagosa 

Junction. U.S. Nat. Mus. No. 36658 ______________________________________________ . 87 

· 2. Corn·us st1tderi? Heer. Ignacio quadrangle, Colo., sec. 31,. T. 35 N., R. 6 \V. New Mexico 

principal meridian. U.S. Nat. Mus. No. 36659 ______ _: _______ ~--·-------------------- 94 

3. Plata.1nts acemides la.tifolia. Knowlton. Pagosa quadrangle, Colo., 4! miles north of Pagosa 

Junction. U.S. Nat. Mus. No .. 36660 __ ~------------------------------------------- 86 

.108 
U. S. GEOLOGlCAL SURVEY PROFESSIONAL PAPER 134 PLATE XIII 

3 

FLORA OF THE ANIMAS FORMATION. 
U. S. GEOLOGICAL SURVE Y PROFESSIONAL PAPER 134 PLATE XIV 

3 

5 

4 

FLORA OF TH E ANIMAS FORMATION. 
PLATE XIV. 

Page. 

Fwurms 1., 2. Cass·ia 1mryea·rensis Berry. Pagosa quadrangle, Colo., half a mile west of Pagosa Junction. U.S. Nat. :Mus. No. 3666L______________________________________________ 90 

3. 1l1alo.1Joenna sessil-i:jlom (Lesquereux) :Knowlton. Pagosa quadrangle, Colo., 1 mile north 

of Pagosa Junction. U.S. Nat. rvius. No. 36662__________________________________ 87 

4. Plcttmms ace·ro·ides latifolict Know.lton. Pn,gosa quadrangle, Colo., 4t miles north of Pagosa 

Junction. U.S. Nat ... Mus. No. 36663-------------------~----------------------- 86 

5. 1.l1Jocynophyllmn wilcoxensis Berry. Pagosa quadrangle, Colo., .5 miles north of Pagosa 

Junction. U.S. Nat. Mus. No. 36664___________________________________________ 95 

109 
PLATE· XV. 

FIGURE 1. Com·u:; stwleri? Heer.~Ignado quadrangle, Colo., sec. 31, T. 35 N., R. 6 "\V. New Mexico principal meridian. U.S. Nat. Mus. No. 36665 __________________________ · ______________ _ 

2. Cinnamom-um salicoides Knowlton, n. sp. Pagosa quadrangle, Colo., 5 miles north of Pagosa 

Junction. U.S. Nat. Mus. No. 36666_ ---------------------------------------~-----

3. Zizyph'us lanceolal'lts Knowlton, n. sp. Pagosa quadrangle, Colo., 5 miles north of Pagosa 

Junction. U.S. Nat-!.Mus.~No. 36667 _ -----------:--'--,----.--------~-----------------

4. Phyllites herbacea Knowlton, n.!sp. Pagosa quadrangle, Colo., fj miles north of Pagosa Junction. U.S. Nat. Mus. No. 36668 _____________________________________________ :... ___ _ 

5. Oreoc!aphne pagosensis Knowlton, n. sp. Pagosa quadrangle, Colo., 1 mile northeast of Pagosa 

Page. 

94 

88 

93 

97 

Junction. D. S. Nat. Mus. No. 36669______________________________________________ 87 

110 
U. S, GEOLOGICAL SURVEY 

PROFESSIO)IAL PAPER 134 PLA'l'E XV 

1 

FLORA OF THE ANIMAS FORMATION. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 134 PLATE XVI 

2 

3 

4 5 

FLORA OF THE ANIMAS FORMATION. 
PLATE XVI. 

Page. 

Fwuru~ l. 'V·t:bnnt:u:rn 1·otnncl-ifolinm Lesquereux. Ignacio quadrangle, Colo., sec. 31, T. 35 N., R. 6 \Y. 

New lVIexico principal meridian. U.S. Nat .. Mus. No. 36670_________________________ 96 

2. Phyll·ites pa.gosens·is Knowlton, n. sp. Pagosa quadrangle, Colo., half a mile west of Pagosa 

Junction. U.S. Nat. ·Mus. No. 3667L --------------------------------------------- 97 

3. V·ibnnw.m SJJec·ios·um Knowlton. Pagosa quadrangle, Colo., 1 mile northeast of Pagosa 

Junction. U.S. Nat. Mus. No. 36672 _______________________________ .:______________ 96 

4. kta.anolic£ hilacmliana Lesquereux. Pagosa quadrangle, Colo., 1 mile north of Pn.gosa Junction. 

U.S. Nat. Mus. No. 36673-------------------------------------------------------- 89 

5. Magnolia ananstijolia Newberry. Pagosa quadrangle, Colo., 4! miles north of Pagosa Junction. ·U.S. Nat. ·Mus. No. 3()674__________________________________________________ SS 

111 
PLATE XVII. 

Page. 

FIGUHES 1, 2. Aralia lobata Knowlton, n. sp. Pagosa quadrangle, Colo., 5 miles north of Pagosa Junction. U.S. Nat. Mus. Nos. 36675, 36676_________________________________________ 93 

3. Aralia Teesidei Knowlton, n. sp. Pagosa quadrangle, Colo., 5 miles north of Pagosa Junction. U.S. Nat. Mus. No. 36677_______________________________________________ 94 

4. Rlwnws cleburni Lesquereux. Pagosa quadrangle, Colo., 4! milc3 north of Pagosa Junction. U.S. Nat. Mus. No. 36678 ___________________ --------------------------- 90 

112 
U. S. GEOLOGICAL SURVEY PROFESSI01'1 AL PAPER 134 PLATE X\'II 

FLOHA OF THE ANIMAS FOHMATION. 
U. S. GEOLOGICAL SURVEY l'ROFE SIONAL PAPER 134 PLATE XVJJJ 

2 3 

FLORA OF THE ANIMAS FORMATION. 
PLATE XVIII. 

Page. 

FIG UHI~S l-3. V·ilnu·num ant·iqnum (Newberry) Hollick. Pagosa quadrangle, Colo., half a mile west of 

Pagosa .Junction. U.S. Nat. Mus. Nos. 36679,36680, 36681_______________________ 96 

4. Phyll-l:tes eocenica Knowlton, n. sp. Pagosa quadrangle, Colo., 5 miles north of Pagosa Junction. U.S. Nat.lVIus. No. 3GG82_______________________________________________ 96 

113 
PLATE XIX. 

Page. 

FIGURE 1. Phyllites sp. Pagosa quadrangle, Colo., half a mile west of Pagosa Junction. U. S. Nat, 

Mus. No. 36683 __ .. __ · __________________ .. ___ ..: ___ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 98 

2. Fagus crossii Knowlton, n. sp. Pagosa quadrangle, Colo., half a mile west of Pagosa Junetion. U.S. Nat. Mus. No. 36684_------------------------------------------------·· 81 

3, 4. C(~rpites sulcatns Knowlton, n. sp. Pagosa quadrangle, Colo., half a mile west of Pagosa 

Junction.· U.S. Nat. Mus. Nos. 36685, 36686 __________ .. ·-------------------------- 96 

5. Phyllites innominata Knowlton, n. sp. Pagosa quad•angle, Colo., half a mile west of Pagosa 

Junction; U.S. Nat. Mus. No. 36687 _______________ ,______________________________ 98 

114 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPJ, R 134 PLATE XIX 

FLORA OF TilE AN IMAS FORMATION. 
INDEX. 

A. Page. 

Acknowledgments for aiu __ -------------------------------·------- 2 

Allantodiopsis erosa (Lcsquereux) Knowlton and Maxon ___ 78, Pl. VI 

Anacardiaccae. ____ -------------------------------•-------------- 90 

Anemia eocenlca BerrY----------------------------------~-------- 78-79 

grnndifolia Knowlton, n. SP------------"-------------- 78-79, Pl. V 

occldontalls Knowlton _____ ---------------------~------------ 79 

subcretacca (Saporta) Gardner and Ettingshausen___________ 79 Angiospormao .• ________ ~ __________________________________ ------ _ 79-96 

Animas formation (restricted), age and correlation oL------------ 34-35 

deposition oL _ ----------------------------------------------- 52-53 

distribution or__· _____ ----------_------------"---------------- 32-33 fossils from •. ---- ____________________________________ -------__ 34 

geologie studies oL _______ ---- __ ---- ____ ---- _______ ---------- _ 71 

lithologic character oL _ -------------------------------------- 33 

localities at which plant fossils were collected.---------------- 72-73 

plants found also in Clarno formation________________________ 75 

. Denver formation ____ ----------------------------------- 74 

Fort Union formation·----------------------------------- 74 

Green River formation----------------------------------- 75 Hanna formation_________________________________________ 75 

Raton formation _____ ------------------------------------ 74 'Vilcox group _______________________ --------------------- 74 

plants known In ___ ------------------------------------------ 73-74 relation of, to adjacent formations _________________________ 33,48-49 

relation of flora of, to that of McDermott formation __________ 76-77 

to that of Puerco formation-----------~------------------- 75 

to that of the "'l'iffany bods"---------------------------- 76 

to those of Cretaceous ago_------------------------------- 71}-76 

sections of. ______________ ---- __ ------------- ______ -------- ____ 55, 50 

summary and conclusions on·------------------------------·-- 77 

thickness of ____ ----_----- __ ------ _________ --·-- ________ ------- 33 

Animas H.ivcr south or Durango, Colo., section on ________ ·------- 56-57 

Apocynaeoac •. ___ ---------------- _ ------- _____ ------------------- 95-96 

Apocynophyllum wilcoxcnsis Derry_-----------------.-- 95-96, Pl. XIV 

Aralia coloradcnsis Knowlton____________________________________ 94 

dissecta Lesquereux_ ------ __ --- ____________ ------------------ 93 

lobnta Knowlton, n. SP----~- ---------------------- 93-94, Pl. XVII 

pungens Lesquereux ___ -------------------------------------- 85 

roosidei Knowlton, n. SP------------------------------ 94, Pl. XVII 

wellington Ia Lcsqu~reux ___ ---------------------------------- 93-94 

Aralia 1 SP-------------------------------------------------- 94, Pl. VI 

A ral iaceno. __ -____ -_---------------------------------- __ ------- _-- 93-94 

A rocacono.- ----------------------------------------------------- _ 79 Artocarpus pungcns (Lcsqucrcux) llollick __________________ 85, Pl. XII 

B. 

Barker Arroyo-Youngs Arroyo divide, section on_________________ 59 

Beautiful Mountain, N. Mox., section ncar ___ ------------------- 65 

llibllography or tho region ________________________________________ 54-55· 

Brown, Barmuh, fossils determined bY-----------------,--------- 31 

c. 

Caesalplnaceao •• --------------------------- _----- ___ -_ __ _ _ _ _ _ _ _ _ _ 90 

Caprlrollacoae ____ ------------------.----.-- _----.- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 96 

Carpitcs sulcatus Knowlton, n. SP----------------------- 96, Pl. XIX 

Cassia puryearonsis BonY--------------------------------- 90, Pl. XIV 

Castanea castanoaefolia (Unger)){nowlton_______________________ 81 

intcrmedla Lesquereux ________________________________ 81, Pl. VIII 

·Cat Crook north of Pagosa Junction, Colo., section on____________ 55 

C oanothus fibrillosus Lcsquereux _____ --- _________________________ · 91 

Cedar Hill, N. Mex., section near _________________________________ 57-58 

Chorlpotalae .• ---- _ --------- _- -- ___ • ____________________ -------- 79-96 

Cinnamomuru lanceolatum -------------------------------------- 88 

linlfolium Knowlton ________ ------ __ --------------------______ 88 

oblongatum Berry--------- ________ ------- __ ------- ____ --~-___ 88 

sallcifoliuru _________ --- _ --- _____________ ----------------- __ ___ 88 

sallcoidos Knowlton, n. sp _____________ _. ________________ 88, Pl. XV 

CliO' House sandstone,Edeposition oL----------·------------------ 50 

sections oL-----------------------~------------------------ 64, 65,69 

Cornaccae __ ---------------------- __ ---- __________________________ 94-95 

82587--24t----10. 

Pag{'. 

Cornus rhamnifolia Lesquereux__________________________________ 95 

· studeri ? Heer ------------------·-------------- 94-95, Pis. XIII, XV 

Correlation of formations, diagram showing______________________ 48 

Correlation of usages of formation names.--·--------------------- 6-8 

Cottonwood Arroyo, N.Mex., section iD------------------------- 66-67 

section west ofmouth oL.----------------------------------- 66 

Crataegus 1 gigantea Knowlton, n. SP--------------------- 89-90, Pl. X 

D. 

Dakota sandstone, features of._---------------------------------- 9 

Daphnogene anglica? Heer ___ ----------------------------------- 91,92 

Dicotyledones _________________ ------- ____ -- _ -------------- _______ 79-96 

Dryophyllum berryana Knowlton, n. SP---------------- 81-82, Pl. VIII 

levalense Marty _______ ------- __ -------_---___________________ 82 

moorii (Lesquereux) BerrY----------------------------------- 82 

Dryopteris cladophlcboides Knowiton.---------------------- 78, Pl. VI 

E . 

Earlier surveys, use of results oL--------------------------------- 2-3 

Escavada Wash, N.Mex., section on branch oL_________________ 70 

Eucalyptus ? americanus ___________ ------------ _________ --. _ -- _ -- 95 

European time scale, correlation with---------------------------- 49 

F. 

Fagaceae _______ ----_--------------_------------------_------_---- 81-82 

Fagus crossii Knowlton, n. SP----------------------------- 81, Pl. XIX 

Ficus auriculata JJesquereux_ _ _ __ ____ _ _ _ _ __ _ __ _ __ __ __ __ _ __ _ __ __ __ 83 

denveriana CockerelL ____________________ _' ______________ 83, Pl. IX 

duplieata Knowlton ____________ ----------------------~------- 84 

loci Knowlton ____________ --------- ___ -------------- ______ ----· 84 

monodon (Lesquereux) Berry 1--------------------------- 83, Pl. X 

neoplanicostata Knowlton.------------------------------ 82, PI. IX 

occidentalis (Lesquereux) Lesquereux __________________ 82, Pl. VIII 

pagosensis Knowlton, n. SP------------------------------· 84, Pl. XI 

planicostata Lesquereux _________________________________ 82, Pl. IX 

goldiana Lesquereux __________________________ -------- _ _ _ 97 

pseudo-populus Lesquereux ____________________ 83-84, Pis. VII, IX 

:~:~~~~~~~~e;~~~~e-~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~-~~:~ 84,: 

subtruncata Lesq·uereux ______________________ . _________ 83, Pl. VIII 

uncata Lesquereux _____ -------------- __ ---------- __ -------- __ 84 

sp __ -------; _____ ---- _ -- __ ------------ _ ------.----- __ --- 84, PI. VII 

'sp ______ ---------- __ ---------··----------:---•-------- 84-85, Pl. VI 

Field work, record oL--------------------------------------·---- 2-3 Fill cos ________________________ ------------ __ -------~--- __________ 78-79 

Formations, columnar sections of-------------------------------- 2,10 

Fruitland formation, age and correlation of. _____________________ 21,24 

deposition of ___ ---------------------·------------------------ 50 

distribution of _____ ------------------------------------------ 20 

fossils from_ •• _____ ------------------------------------------ 20-21 

lithologic character of. __ ------- __ ---------------------------- 20 

relation to adjacent formations------------------------------- 48-49 

sections oL _____ ------------------------------ 55, 59, 61, 63,66-67,69 

thickneSS oL _______ ------------------------------------------ 20 

G. 

Geonomites ungeri Lesquercux _____ ----------------------------- 79 

Gidley, J. W., cited.·--------------------------------------------- 46 

fossils determined by ________ -------------------------------- 4 7 

Gilmore, C. W., cited----------------------------------------- 24, 38,42 

fossils determined by _____________ ------_-------------_------ 27, 31 

Granger, Walter, cited _____ -------------------------------------- 46 

Great Hogback, N.Mex., section OD----------------------------- 65 

H. 

History of western part of the basin __________________ ------------ 49-53 

J. 

Juglandaceae_. ___ • __ --------------- ___ ----- ___ ------------------ 80 

Juglans berry! Knowlton ____________________________________ 80, Pl. VI 

leconteana Lesquereux. ------------------------------------- _ 80 

schimperi Lesquereux _______ ~--------------------------- 80, Pl. VII 

J~glans? innominata Knowlton, n. SP---------------------- 80, Pl. VII 

115 
1.16 l.NDKX. 

K. Page. 

Kirtland shale, age oL------------------------------------------- 24 

deposition of _____ ---------------------- ____________ --------:- 50-,'\1 

distribution oL ___________ --------------------------------- __ -21 fossils from ______________ .____________________________________ 23 

lithologic character oL __ ------------------------------- ______ 21-22-

rclation of, to adjacent formations _________________________ 2:3,48-4\J 

sections oL _______________ ----------------------------- 61, 62-63, C8 thickness oL _: _________ -____________ -__________________________ 22-23 

Knowlton, F. H., cited __ ------------------------------------- 24, 27, 34, all 

fossils determined by ______ ------------------- 27,31-32,38, 42-4:-!, 17 

L. 

La Plata County, Colo., sections in______________________________ !l7 La Plata River, N.Mex., sections on _________________________ 58-59,62 

Lauraceae _______________ ---------.------------------------------- 86-88 

Lanrus primigenia Unger ___ -------~------------~---- __ ----------· 86-87 

:;;essiliflora Lesquereux _______ ------------ ___ ---------------- _ 87 

Lewis shale, age and correlation oL._----------------------------- 18- . deposition oL _ ---" _________________ "- ________________________ - 50 

distribution of ____ ._,---.-----------.------------. __ ------------ J fl 

fossils fron1. ______ ---,~--------- --------------- ___________ , __ .17 

lithologic ch~ractcr oL -~ --------- ___________ ------------ _____ .16-:17 

sections oL ______ ---------- _______ -------------- ---~-- ____ 61, 64, 69 

thickness of _________ ------- __ -------------___________________ 17 Location of the area ___________ -___________________________________ 1, 2 

l\f. 

1V£cDermott formation, age and correlation or_ ___________________ 27-28 

definition and disti'ibution oL _______________________________ 24-25 

deposition of __ --- ____________________________________________ 51-52 

fossils in ____________ ~ ___________________________________ ~ ____ 26-27 

lithologic character oL ___________ -----------~---·------------- 2.'\ 

relation of, to adjacent formations ______________________ 25-26,48-49 

relation of flora of, to that of Animas formation _____________ " 76-77 

sections oL ________________________________ 56, 57, 58-59, 6(}-61, 62,68 

thickness oL __________________________________ -"- ___ _ _ _ _ _ _ _ __ 25 

Magnolia angustifolia Newberry ____________________ 88-89, Pis. X, XVI 

attenuata Weber _________________ ~ ______________ :____________ 8S 

hilgardiana Lesquereux ______________________________ 89, Pl. XVI 

lanceolata I-'csquereux___ ___ __ _ _ _ __ _ __ __ __ _ _ _ _ __ _ _ _ _ __ _ _ _ _ _ __ _ 8S 

magnifolia Knowlton?------------------------------------·___ 8\J tenuinervis _______________________ • ________________ · __ .:_ _ _ _ __ _ _ 8!J 

Magnolia<;eae ___________________ -- ________ --- __ --- ___ -- ___ -: __ -- __ 88-89 

:Malapocnna sessiliflora (Lcsqucreux) Knowlton ___________ 87, Pl. XIV 

Mancos shale, age and correlation oL~-----------~--------------- 13 

deposition of_------------------------------------------------ 49 distribution oL ______________________________________ .__ _ _ _ _ _ _ _ n 

-fossils. from _____ -~---·------------~-------------------------·--- 1(}-12 

lithologic character oL _ -"------------- ----------------------- 9 sections of. ___________________________ , ______ ~- ______________ .. 64-65 

thickness oL ___________________________ " ___________ : __ _ _ _ _ _ __ 9-1.0 

Matthew, W. D., cited __________________________________ 38, 41, 42, 43,46 

Menefee formation, deposition of. ________________________________ 49-50 

sections oL-------------------------------------------- 64, 65, 66,69 

Mesaverde group, age and correlation oL________________________ 16 

distribution oL _ ------------------- __________ _-_______________ 13 fossils from ____________________________________________ ._______ 15 

lithologic character oL _ --------- ___ ------ _ ------------------- 13-14 thickness of_ __________________________________________ ·_______ 14 

Meyers Creek, N.Mex., section on __ ----------------------------- 69 

Monocotyledones __ ---------------------------------------------- 79 l\1oraceae. ______________________________________ -L _______________ 82-85 

Myrica graffii Beer. _____ ~--------------------------------------- - 97 

N. 

Nacimiento group, formations included in________________________ 35 

Nectandra lancifolia (Lesquereux) Berry------------------ 87, Pl. XIII 

Nelumbium lakesianum Lesquereux __ o-------------------------- 8S 

lakesii Lesquereux __ -------- __________________ --------------- 88 

Nelumbo lakesiana (Lesqucreux) Knowlton __________________ ,___ 88 

Nymphaeaceae __ ------------------- ______________ -------------- _ 88 

Nyssa? racemosa Knowlton_____________________________________ 95 

0. 

Ojo Alamo Arroyo, N. Mex,, section at head oL _________________ 67-68 

·section on branch oL _________ c_: ____________________________ 68-69 

Ojo Alamo sandstone, age and correlation oL____________________ 32 deposition oL ________________________________________________ 52-53 

distribution oL _ --------------------------------------------- 28-29 

Page. 

Ojo Alamo sandstone, fossils from ________________________________ 3(}-32 

lithologic character oL _ ------------------- ___ ---------------- 29 

relation of, to adjacent formations _________________________ 30,48-49 

sections oL ________________________________ 59, 60, 61, 62, (ii, 68-U!J, 70 

--·thickness oL------------------------------------------------- 30 Ojo Amarillo Arroyo, N. 1\:[cx., section on _______________ J ________ 65-66 

Orcodapbne obtusifolio Berry------------------------------------ 87 

pagosensis Knowlton, n. SP--------------~-------------- 87, Pl. XV 

salinensis Derry ______ ---------------------------------------- SZ 

Osmuncla maj9r·Lcsqucrcux ____ -____________________________ ·----- 78 

P. 

Pebbles, siliceous, in the McDermott fonnatiotL-----------~----- 21i 

siliceous, in the Ojo Alamo sandstone--------------------~---- 29-30- Persea·lancifolia Lesquereux ____________________ · ___ ~ _ _ __ _ _ _ _ __ __ _ _ 87 

Phyllites eocenica Knowlton, n. SP----------~-------- 96-97. Pl. XVIII 

hcrbacea Knowlton, n. SP--------------------·---~----97, Pl. XV 

innominata Knowlton, n. SP-------------------------- \JS, Pl. XIX 

pagosensis Knowlton, n. SP--------------------------- 97, Pl. XVI 

SP--------------------~-------------------------------- 98; Pl. XIX 

Pictured Cliffs sandstone, age and correlation oL __ ~------------- 19 

deposition of _____________________ ----~--------- ___ ----------- f>O 

distribution oL __________ -------- _______________ :_____ _____ _ _ 18 

sections oL ______________________________________ 63-64, 65-66, 67, fi\J 

fossils fronL ____________ -------------------------- _____ ------- 19 

lithologic character oL __ ------- --------------------------·-- __ 18-1\J 

thickness of ____________ -~-------- ________________ :___________ 19 

Plna VetJa China Arroyo, N. Mcx., section at head oL_____________ fi7 

Pine .River-Piedra Hiver divide, section OIL---:---------------- 55-56 

Pinyon Mesa, N. l\•Iex., sections on·---------------------~----~-- 60-61 Platanaceae ______________________________________ -____ . ___ • ______ ·__ 8tl 

Platanus aceroides Gop pert. ____ -------~------------------·--_____ 86 

aceroides latifolia Knowlton _______________ _. ____ SO, Pis. XIII, XIV 

haydcnii Newberry __ ---------------------------:--~--------- S!i 

raynoldsii Newberry_-"______________________________________ 8ti 

Point Lookout sandstone, deposition oL-----------------------~- 4\J 

sections of._------------- _____ -------------------------------- 64, 65 

Polypodiaceae ____ ----------------------- ----~-~------------ ------- · 78 Pomaceae ________________________________ . __________ ~- ____________ 89-90 

Populus monodon Lcsquereux.-----------~---------------------- 83 · 

Pruett pasture, San Juan County, N. JV[cx., section in ______ .______ ."iS 

Pteridophyta __________________________________________ ~, ________ 78-79 

Ptcris crosa Lcsqucrcux___________________________________________ 78 

suhsimplex Lesquereux ______________ ; ___________ _.____________ 78 

undulata Lcsqnereux_________________________________________ 78 

Publications dealing with the San Juan Basin __ ·----~----~:---~--- 54-51i 

Puerco formation,- age and correlation oL _________________________ 43-44 

deposition oL __ --~ _____ -------------------------------------- li3 

distribution oL ________________ ------------------------------ 35-:.!6 fossils from. _____________ c ______________ c _____ c _______________ 38-39 

lithology and thickness of. ___________________________________ 36-37 

relation of, to adjacent formations _________________________ 37,48-49 

relation of flora of, to that of Animas formation________________ 75 

sections of._----------------------~--------------------------- 67-68 

Q. 

Quercus lyclli Heer__ ______________________________ ; ____ ~·-------- 89 

R. 

Rhamnaceae _ _ _ _ _ ___ _ _ __ _ _ _ _ _ _ __ _ _ ___ _ __ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ __ __ 90 

Rhamnus cleburni LesquereuX----------------~------- 90-91, Pl. XVII 

goldianus Lcsquereux _ -----------~------------------------ ___ 91 

Rhus coloradensis Knowlton, n. SP---------------------------- 90, Pl. X 

frigida Knowlton _____ ----------------------------------______ 90 

s. 0 

Saba!? ungeri (Lesquereux) Knowlton___________________________ 79 

Sabalites fructifer Lesquereux part ___ ----------- ___________ ------ 95 

Salicaceao _____ . __ ----- ___________ ------ __ -- _ -- _ -- ________________ · 79 

Salix plicata Knowlton___________________________________________ 79 

reesidei Knowlton, n. SP------------------------~~------- 79, Pl. VI 

San Juan Basin, geologic map of western part oL________________ 2 

San Juan River below Farmington, N. Mcx., section on ______ ~--- 62-6/i 

_ Sapinclaceae ______________________ ---------- __________ ------------ 90 

Sapiridus obtusifolius Lcsciuereux?. _____________________ 90, Pl. VIII 

Scbizeaceae. _______________________________ ---------- __ ---------- 78-79 

Section, general, of Cretaceous and Tertiary formations._________ 4-5 Sections, columnar. ______________________________________________ 2,10 

measured. ________________ ---c----- __ ---------- ______ ------- _ 55-70 

Smilax sp. Lcsqucrcux~- _____________ -------------------- ________ 92-!J3 
INDJ<::X. 117 

Page. 

Spemmtophyta. _________________ . ___________ · ____________________ i!Hl!i 

Stanton, T. W., citetl. _ ------ _________________ ------ __ _____ ___ __ _ 24 

Stmtigmphy or the area .•.... ------------------------------------ 3-4!} 

Sumnmry or the paper .. _____ · ___ -------------------------________ 1 

'1'. 

'.l.'erminalin hilgnrdinno. (1:-csquercux) BerrY----------------------- 89 

'l'ctmnt;hem sessiliflom (Lcsqncre.ux) Lcsqucrcux_________________ 87 

"Till"auy beds," uge oL. ----------------------------------------- 47-48 

chamctCI' of .• -.-------·----............ ----------------.... -- 44-45 

deposition oL •• ----------------------- ________ ------------- _ _ 53 

fossil:; from .•• ____ ---------- __________ ------------------ ______ 46-47 

I'Olo.tion or flom or, to that or Animas formation_______________ i6 

'.l'ilh\ antiqua NewberrY----------~------------------------------- 96 

'J'orrejon formation, ago and correlation of. _______________________ 43-44 

deposition oL _. -------------- ___ --------------------------- __ 53 

distribution oL. ________ ------------------------------------- :l!J fossils in ________________________ : ____________________________ 41-43 

lit;hology nn<l thickness oL----------------------------------- :l!l-41 relation or. to adjacent formations _________________________ 41,48-4!} 

sectio1is oL----------------------------------------- 57, 58,62,67-68 

u. 

Uncertain position, plants oL-----------------------------~------ 96-98 

V. Page. 

Viburnum anti(iuum (Newberry) llollick _______________ 96, Pl. XVIII 

rotuudifolium Lcsqucrcux ___________________ c _______ 96, Pl. XVI 

speciosum Knowltouc--------------------------------- 96, Pl. XVI 

tilioidcs Ward .... -------------------------------------------. !}() 

W. 

Wasatch formation, age and correlation of. _______________________ 47-4!; 

deposition of.. ___________ ------------------------------------ f•~{ 

fossils from ___ ------------------------------------------------ 46-47 identification and distribution of. ____________________________ 44-45 

lithology and thickness oL __________________________________ 45-46 

relation of, to adjacent formations _________________________ 46,48-49 

sections oL ____________________________________________ 55-56, 57-58 

White, C. A., fossils determined bY------------------------------ 42 

z. 

Zizyphus daphnogenoides Knowlton, n. SP---------------------- 91-!}3 

tlistortus Lcsqucreux _________________________________ -------- 92 

fibrillosus (Lcsquercux) Lcsqucrcux __ ------------------------ 91,92 

lm10eolatus Knowlton, n. SP--------------------------- 93, Pl. XV 

raincourtii (Snporta) Snporta var _____________________________ 91,92 

0 

' Q