© Houston Geological Society, 2007 - Geology of the Gulf Coast and Central Texas, and Guidebook of Excursions, 1962
34Z
FIELD
EXCURSION NO.
TERTIARY FORMATIONS
SPECIAL EMPHASIS
10, N O V E M B E R
11,
196Z
BETWEEN AUSTIN AND HOUSTON WITH
ON T H E M I O C E N E A N D P L I O C E N E
John A. W i l s o n
I
GENERAL
T h e g r o u p will depart f r o m the north entrance of M e m o r i a l S t a d i u m
(Z3rd Street b e t w e e n S a n Jacinto Blvd. and R e d R i v e r Street, Austin, T e x a s ) at
7:00 A. M . , Sunday, N o v e m b e r
iI, 196Z. T h e bus will face east. T h o s e in cars
line up behind the bus facing the s a m e direction. B o x lunch will be furnished.
A detailed road log for the trip w a s not m a d e .
T h e route is outlined on
the m a p (Fig. i). It will follow T e x a s 71 f r o m Austin to L a G r a n g e ; T e x a s 159, T e x a s
Z37 and U. S. zg0 to B r e n h a m ; T e x a s 90 to Navasota; T e x a s 6 to H e m p s t e a d ; T e x a s
159 to Bellville; T e x a s 36 to Sealy; a n d U. S. 90 to Houston.
INTRODUCTORY
GEOLOGY
T h e regional strike in this part of the Gulf Coastal Plain is N E - S W a n d
the regional dip is about l° to the southeast. T h e route along T e x a s 71 f r o m Austin
to g a G r a n g e will cross the U p p e r C r e t a c e o u s and L o w e r Tertiary at a slight angle to
the direction of dip.
In spite of the i m p r e s s i o n you m a y receive f r o m this short trip over well
traveled h i g h w a y s , there are m a n y outcrops on the Coastal Plain. M o s t of t h e m are
along the banks of tributaries to the m a j o r rivers. T h e m a j o r rivers like the Colorado and B r a z o s have alluvial-filled valleys with w e l l - d e v e l o p e d terrace s y s t e m s .
Only
w h e r e a m e a n d e r of the larger s t r e a m s strikes the b e d - r o c k valley wall do you find an
exposure. T h e upland divide areas, in this part of Central T e x a s , are partly c o v e r e d
with b r o a d sheets of gravel, variously t e r m e d "high level gravel" or "Uvalde Gravel",
w h i c h quite effectively m a s k the b e d rock. N o b o n e s have ever b e e n found in t h e m .
M o r e about t h e m later.
i.
Professor,
~epartment
of Geology, T h e University of T e x a s , Austin, T e x a s
343
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FROM GEOLOGICAL HIGHWAY
MAP OF THE DALLAS GEOLOGICAL SOCIETY
MODIFIED
0
I0
20
,-j-,.~,,~,,~_
FIGURE
I.
GENERALIZED
30
40
50
MILES
QH
HOUSTON GROUP PLEISTOCENE
Qw
WILLIS
FORMATION
TG
GOLIAD
FORMATION
-rF
FLEMING
To
OAKVILLE
Tc
CATAHOULA
TJ
JACKSON
TCL
CLAIBORNE
Tw
WILCOX GROUP EOCENE
TM
MIDWAY GROUP PALEOCENE
K6
UPPER
Kc
LOWER CRETACEOUS
GEOLOGIC
PLEISTOCENE
FORMATION
?
MIOCENE
FORMATION
MIOCENE
FORMATION
OLIGOCENE
?
GROUP EOCENE
GROUP EOCENE
CRETACEOUS
MAP
SHOWING
F I E L D TRIP R O U T E
AND
STOPS.
344
T h e r e are two general keys to the surface geology of the Tertiary of
the coastal plain: i) scarps f o r m e d by the inface of the gently, gulfward dipping
cuestas, and Z) the vegetation. T h o s e sands that have a lime or silica c e m e n t and
the
are
mudstones
low and
that
subtle,
have
a lime
others
are
cement
are more
high and prominent.
resistant
and
form
cuestas.
Some
In general the vegetation reflects the bedrock. M e s q u i t e and huisache
g r o w in the c h e r n o z e m s f o r m e d f r o m the w e a t h e r i n g ~clay. Cultivated crops on this
soil are cotton and s o r g h u m .
Sands w e a t h e r to podsols and support the B l a c k j a c k
and Post oaks. W a t e r m e l o n is g r o w n on the podsols of the cleared areas. T h e high
level gravels also support a B l a c k j a c k - P o s t oak flora so, w h e n m a p p i n g , one has to
use the vegetation carefully. Nonetheless, part of this a r e a is a classic one for
s h o w i n g b e d r o c k control of vegetation.
AUSTIN
TO
LAGRANGE
T h e Austin Chalk outcrops a c r o s s the street f r o m M e m o r i a l Stadium. It
is of Late C r e t a c e o u s age and roughly correlates with the N i o b r a r a C h a l k of K a n s a s .
W e will be on the Austin Chalk as w e p r o c e e d along M a n o r R o a d to Airport B o u l e v a r d .
At this intersection w e are on one of the higher terraces of the C o l o r a d o River. W e
quickly drop to the l o w e r terraces and cross the C o l o r a d o River. B e r g s t r o m Air
F o r c e B a s e is on a l o w e r terrace. B e y o n d B e r g s t r o m , w h e r e T e x a s 71 c r o s s e s
O n i o n C r e e k , there is a n e x p o s u r e of the T a y l o r M a r l on the left side of the highway.
T h e m o s a s a u r skull on exhibit at the T e x a s M e m o r i a l M u s e u m
c a m e f r o m this locality.
T h e T a y l o r M a r l is overlain by the N a v a r r o Clay (the s e q u e n c e of f o r m a tions is given on Fig. 2) w h i c h also contains occasional bones of m o s a s a u r s .
Note
the black soil. Y o u are crossing the B l a c k Prairie of Central T e x a s , a physiographic
unit w h i c h includes the limestones, m a r l s a n d clays of the U p p e r C r e t a c e o u s a n d P a leocene that w e a t h e r to a c h e r n o z e m soil. M o s t of the cotton a n d grain feeds are
g r o w n in the area. T h e B a l c o n e s Fault zone b o u n d s the B l a c k Prairie on the w e s t
a n d the W i l c o x e s c a r p m e n t f o r m s the b o u n d a r y on the east. T h e vegetation on the
B l a c k Prairie w h e r e the fields are uncultivated is m e s q u i t e , b r o o m - w e e d a n d huisache.
T h e N a v a r r o Clay is the highest C r e t a c e o u s f o r m a t i o n and is m a r i n e to
the v e r y top. Overlying the N a v a r r o is the M i d w a y g r o u p of the P a l e o c e n e , also m a rine clay. T h e contact b e t w e e n the two is poorly a n d rarely exposed. E v i d e n c e is
a c c u m u l a t i n g that the " u n c o n f o r m i t y '~ b e t w e e n t h e m is of s u b m a r i n e origin. C o n t r a r y
to general opinion, this a r e a w a s p r o b a b l y not uplifted and subjected to subaerial erosion, but w a s subjected to s u b m a r i n e scour (Rainwater, 1960).
At the top of the M i d w a y n e a r - s h o r e sands, oyster reefs a n d other evidence of s h a l l o w - w a t e r conditions appear. T h e s e grade on up into the n o n - m a r i n e
W i l c o x g r o u p of the E o c e n e .
This c h a n g e is m a r k e d by a rather abrupt inface of a
cuesta w h i c h is held up by partly cemer~ted lenses of sand. T h e change in vegetation f r o m the open m e s q u i t e prairie or the cultivated land to the Post o a k - B l a c k j a c k
oak forest is abrupt.
345
NORTH AMERICAN
PROVINCIAL AGES
~o'~
TEXAS COASTAL
PLAIN
TEXAS AND
1
LOUISIANA C O A S T A L
PLAIN (SUBSUR FACE
~Cochr
a r e ane
Tazewell
Sangamon interglacial
Illinoisian glacial
Y a r m o u t h trite r ~Iacial
K a n s a n glacial
ARonian interglacial
N e b r a a k a n glacial
Blancan (Early
N e b r a a k a ~ or posaibly
pre Nebraskan)
Astian
Heln phillian
Plainancion
Willis F o r m a t i o n
(No F¢~ssils)
[,agar to C r e e k
Member
Clar endon~an
P¢}ntian
Bar.tovxan
Samartian
Tor tt,nian
Hemlngior dian
Gold Spring
Fauna
Helvetian
[Nu 1, Bogga Stratton
R:dge Field, T e x a s
I
BurkevilLe
Fauna
Burdigalian
Aquitanlan
Whir neyan
Stanlpian (Rupelian}
Chadronian
'
Sannoiaian
(Lattorfian)
Ludian
Bar tonian
Caddell F o r m a t i o n
Yegua F o r m a t i o n
Uintan
Auv,' ,-~ L,~,i
Cook kitn, F o r m a t i o n
Stone Clt For m a t i ~
SEar ta F o r m a t i o n
Wechea F o r m a t i o n
Queen City F o r m a t i o n
Br i d g e r i a n
Lutetian
Waaatchian
Ypr eui&n S p a r n a c i a n
Ciar kforkian
Thanetian
Titfanian
TorrejonIan
UPPER
* M~mal
Montian
Dragoman
?
Puer ~an
?
?
N a v a r r o Group
CRETACEOUS
h e a r i n g (not including Pleimtocene)
FIGURE 2. CORRELATION TABLE S H O W I N G SEQUENCE OF TERTIARY AND
QUATERNARY STRATIGRAPHIC UNITS
346
The upland
between
the Wilcox
escarpment
and the town of Bastrop
is
covered
by "high level gravel"
so we will not be able to see an exposure
of the Wilcox which
consists
of a succession
of alternating
sands
and clays,
deposited
on the
shoreward
side of but probably
very close to sea level.
At Bastrop
we once again cross
the Colorado
River.
On the west side,
as we drop down
from
the high level gravel-covered
surface,
note the well-developed
river terrace
system.
On the east side of the river we climb
up the inface of the
cuesta
formed
by the Carrizo
Sand.
The combination
of the higher
humidity
near the
river and the deep sandy
soil has made
conditions
right for a relict flora.
The edge
of the main
piney woods
area is approximately
i00 miles
farther
east.
T h e n e a r - s h o r e conditions of the C a r r i z o are s u c c e e d e d by the m a r i n e
Reklaw Formation.
T h e upper m e m b e r ,
the M a r q u e z (pronounced m a r - k a y ) is a
dark gray, glauconitic, highly fossiliferous clay. It is not e x p o s e d along this highway.
R e d and orange colored sands on the left of the h i g h w a y are e x p o s u r e s of
the Q u e e n City F o r m a t i o n .
This is another n e a r - s h o r e formation of the Middle E o cene Claiborne group w h i c h consists of alternating m a r i n e and n o n - m a r i n e formations.
A s w e cross the C o l o r a d o River for the third time at Smithville you will p e r h a p s see
an e x p o s u r e of the W e c h e s F o r m a t i o n on the south bank to the left of the highway.
The
W e c h e s is fossiliferous, glauconitic clay with sharks teeth, fish bone f r a g m e n t s and
otoliths. It overlies the Q u e e n City.
Between
the marine
Weches
Formation
Formation
is the unfossiliferous
near-shore
Sparta
are exposed
in stream
cuts away
from
the highway.
is, for a way,
on a Pleistocene
river terrace.
and the marine
Cook
Mountain
Sand.
It and the Cook
Mountain
Beyond
Smithville
the highway
Just b e y o n d Kirtley, w e leave the terrace and pass outcrops of the nonm a r i n e but n e a r - s h o r e Y e g u a F o r m a t i o n .
It is lignitic with alternating lenses of
silt and clay. T h e U p p e r E o c e n e J a c k s o n group begins a p p r o x i m a t e l y at P l u m but
is poorly e x p o s e d along this highway.
A s w e near L a G r a n g e you can see M o n u m e n t
bluff is the inface of the Oakville cuesta.
STOP
i.
Bluff on the right.
The
Catahoula - Oakville on T e x a s 71, south of L a G r a n g e .
The Catahoula
Formation
in Central
Texas
is a light green,
non-calcareous
clay.
Near
the top of the Catahoula
are channel
lenses
of cross-bedded
calcirudite which
is the Oakville
lithology.
There
is no single line of contact between
the
Catahoula
and the Oakville,
but rather a zone within which
channel
calcirudites
become
more
common
and finally take over.
Uplift along the B a l c o n e s Fault zone rejuvenated the rivers and s t r e a m s
to the northwest.
T h e y gradually, at first, b e g a n to erode the U p p e r C r e t a c e o u s
N a v a r r o and T a y l o r clays and to transport this material t o w a r d the Gulf. T h e calcirudite lenses contain as high as 7 7 % r e w o r k e d calcareous fragments, m o s t of w h i c h
347
are C r e t a c e o u s E x o g y r a shells, I n o c e r a m u s p r i s m s , shark a n d ray teeth, a n d
Foraminifera.
(A micropaleontologist identified s a m p l e s of the Oakville as being
of C r e t a c e o u s age, an e x a m p l e of paleontology without stratigraphy! F o r U p p e r
C r e t a c e o u s to be at the surface here an uplift of a p p r o x i m a t e l y 7000 feet w o u l d be
needed. This w o u l d m a k e an attractive structure to p e t r o l e u m geologists).
T h e Oakville F o r m a t i o n contains three different lithologic types of rock
w h i c h w e r e deposited in three different e n v i r o n m e n t s .
C r o s s - b e d d e d , coarse, lenses h a p e d bodies of p o o r l y - s o r t e d calcirudite are s t r e a m channel sands. G r a i n size
analyses (Ragsdale, 1960) s h o w that they are quite similar to m o d e r n river sands.
T h e clay, within w h i c h the channel sands are i m b e d d e d represents the back-levee or
back-swamp environment.
T h i n - b e d d e d sands represent flood-plain deposits w h e r e
the sand s p r e a d out f r o m the channels.
T h e rivers and s t r e a m s during this time could not have b e e n e n t r e n c h e d
as they are n o w , b e c a u s e the outcropping Oakville a n d F l e m i n g F o r m a t i o n s f o r m a
continuous b a n d parallel to the coast. Yet the shoreline during that time w a s about
as far a w a y as the present shore is f r o m g a G r a n g e , about i00 miles. T h e backs w a m p deposits of one river m e r g e d with the b a c k - s w a m p
deposits of adjacent rivers f o r m i n g one vast deltaic plain, v e r y likely with o p e n s a v a n n a h s here a n d there.
X - r a y analyses (Anderson, 1958; T h o m a s ,
1960) s h o w that the Catahoula
in Central T e x a s is a c a l c i u m - m o n t m o r i l l o n i t e without illite. T h e Oakville a n d F l e m ing clay is s o d i u m - r i c h , m i x e d - l a y e r m o n t m o r i l l o n i t e with illite. T h e U p p e r Cretaceous T a y l o r a n d N a v a r r o clays are of a l m o s t identical c o m p o s i t i o n with the Oakville
a n d F l e m i n g clays.
T h e Oakville f o r m a t i o n is divided into a L o w e r Oakville m e m b e r ,
M o u l t o n Sandstone m e m b e r
w h i c h f o r m s the r i m of M o n u m e n t Bluff.
w a s found.
a n d the
O n e - h a l f mile south of Stop l an A r c h a e o h i p p u s blackbergi u p p e r tooth
M o r e about the fauna later.
LAGRANGE
TO
NAVASOTA
F r o m L a G r a n g e to N a v a s o t a the route is parallel to the strike of the form a t i o n s and, as far as C a r m i n e , the road follows closely the Catahoula-Oakville
contact. In s t r e a m cuts along the road m a y be seen first Catahoula then Oakville
lithology. T h e cuesta is m o r e difficult to see here but it will be pointed out at C a r m i n e .
Just b e y o n d C a r m i n e a road leads off to the right to W o o d and W o o d ' s
(1937) W a t e r R u n locality. It w a s there that a C o e n o p u s cf. ? premitis maxilla w a s
earlier found. It w a s d i s c o v e r e d in w h a t is s u p p o s e d to be Catahoula F o r m a t i o n a n d
all by itself, for it is the only vertebrate f r o m the Catahoula. This dates the Catahoula here as Oligocene. A s e a r c h has been m a d e for other vertebrate fossils but
so far without success.
From Carmine
of the F l e m i n g F o r m a t i o n .
to B r e n h a m to N a v a s o t a the route is on the rolling terrane
Calcirudite lenses in the clay are m o r e resistant and hold
348
up the hills. M i o c e n e calcareous clays are m u c h m o r e fertile than the E o c e n e sands
so cotton and s o r g h u m f a r m s and good pastures are c o m m o n .
T h e d o m i n a n t trees
are the Live oaks. Sm~ll dense forests of Post oak and Blackjack oak indicate outliers of Willis sand. M o r e about this later.
T h e r e are m a n y places along the creek banks and in road cuts b e t w e e n
C a r m i n e and N a v a s o t a w h e r e I have collected a bone here, a tooth there. F o r instance, w h e n an u n d e r p a s s w a s cut for U. S. Z90 to skirt B r e n h a m a Synthetoceras
nasal horn, an A m p h i c y o n l o n g i r a m u s lower jaw, and a handful of m e r y c h i p p i n e teeth
w e r e found. If this area w e r e badlands, it w o u l d be paradise for the vertebrate paleontologist; teeth and bones are plentiful but outcrops are few.
NAVASOTA
STOP
Z.
Lower
AND
VICINITY
Oakville e x p o s e d in cut of F a r m
R o a d Z44 near N a v a s o t a
H e r e you can see a fossiliferous calcirudite lense in the Oakville, the
Catahoula below and the Oakville cuesta. P e r h a p s you will find a tooth or two. G a r vin Gully, about a mile to the east, is practically g r o w n over with grass and, at present, not w o r t h visiting.
T h e G a r v i n Gully fauna, to date, includes the following:
H i p p o d o n texanus (horse)
Lepisosteus (gar)
A n c h i t h e r i u m australis (horse)
Amieurus?
decorus (catfish)
D i c e r a t h e r i u m sp. (rhinoceros)
T r i o n y x (soft-shelled turtle)
D i n o h y a s hollandi (giant pig-like form)
Alligator sp.
C y n o r c a proterva (peccary)
(land turtle)
?oreodont (small grazing artiodactyl)
Paleolagus sp. (rabbit)
Oxydactylus cf. brachyodontus (camel)
Paleocastor cf. simplicidens (beaver)
D a p h a e n o d o n superbus (dog-like carnivore) ?Oxydactylus floridanus (camel)
A m p h i c y o n l o n g i r a m u s (dog-like carnivore) M a c h a e r o m e r y x
sp. (small deer-like
C y n o d e s m u s i a m o n e n s i s (dog-like
form)
carnivore)
B l a s t o m e r y x sp. (small deer-like form)
P a r a h i p p u s blackbergi (horse)
?Floridatragulus sp. (deer-like form)
H i p p o d o n vellicans (horse)
Synthetoceras rileyi (deer-like form)
T h e G a r v i n Gully fauna correlates a p p r o x i m a t e l y with the T h o m a s F a r m
local fauna. H i p p o d o n vellicans is probably conspecific with P a r a h i p p u s leonensis
of the T h o m a s F a r m .
In Texas, about I0 of e v e r y 100 teeth of H. vellicans s h o w a
connected crotchet.
F r o m the F a r m R o a d 244 locality w e will retrace our route to Navasota.
Note that for a w a y w e travel on the top of the Oakville e s c a r p m e n t .
Of~ a very clear
day you can a l m o s t see T e x a s A. & M . College about Z0 miles to the north. T u r n
east on T e x a s 90. A b o u t two miles east of N a v a s o t a s o m e n e w road cuts have yielded
a rhino jaw and m e r y c h i p p i n e , synthetocerine and c a m e l teeth.
349
STOP
3.
Fleming Formation,
of N a v a s o t a .
road cut on T e x a s 90 two m i l e s east
We are now south of the Oakville
escarpment
and, therefore,
stratigraphically
higher
than the Moulton
Sandstone
member
of the Oakville.
Garvin
Gully itself is about a mile and a half north and over the hill.
The clay of the Fleming
formation
is the same
composition
as that of the Oakville,
but the calcirudite
lenses
are more
widely
scattered
through
the clay.
Only two low-crowned
merychippine
teeth have been found at this locality but they are sufficient to identify the Burkerifle fauna.
T h e Burkeville fauna contains s o m e w h a t m o r e a d v a n c e d f o r m s than the
G a r v i n Gully fauna. T h e h o r s e s have connected crotchets, the synthetocerines are
a little larger a n d A p h e l o p s m e r i d i a n u s , a n d M y l a g a u l u s a n d E d a p h o c y o n pointblankensis are introduced to the fauna.
O n c e m o r e w e retrace our route to Navasota. At the junction with T e x a s
6 turn south then east (left) on T e x a s 105. A t the top of the first rise w e find the
Willis S a n d overlying F l e m i n g Clay.
STOP
4.
F l e m i n g - W i l l i s contact on T e x a s I05, one mile east of
Na va s ota.
T h e Willis F o r m a t i o n is p e r h a p s a n eastern facies of the high-level or
U v a l d e gravel. W e c r o s s e d s o m e outliers of the Willis in W a s h i n g t o n C o u n t y but
f r o m G r i m e s C o u n t y e a s t w a r d the Willis is m u c h m o r e prevalent. It is red, m o t tled, deeply leached sand that occupies the upland, inter-river areas. It dips beneath the Pleistocene Lissie a n d B e a u m o n t F o r m a t i o n s a n d overlies the M i o c e n e Pliocene Goliad F o r m a t i o n .
The Willis can be traced
into the Williana
Formation
of Louisiana.
To
my knowledge,
no bones
have been found in either Formation.
From
their stratigraphic
position
the Willis and Williana
are presumed
to be either latest Pliocene
or Early
Pleistocene.
NAVASOTA
TO
STEPHEN
F.
AUSTIN
STATE
PARK
NEAR
SEALY
Retrace
route to Texas
6 and turn south toward
Hempstead.
We are
going up in the section but still in Fleming,
capped
by Willis.
Just before
reaching
Hempstead
turn west (right) on U. S. Zg0 and cross
the Brazos
River.
Exposures
in the road cut on the west
side of the Brazos
River
are the type section
of the Lagarto Formation,
which
equals
the Fleming
Formation.
STOP
5.
T y p e section of L a g a r t o clay on U. S. H i g h w a y
Chapel
Hill and the Brazos
River
Z90 b e t w e e n
The Lagarto
clay Formation
is traceable
into the Fleming
Formation,
and Stenzel,
Turner
and Hesse
(1944) and Wilson (1956) have used the latter name.
At this site Quinn
discovered
vertebrate
remains
which
belong
to the Cold Spring
350
fauna. In the clay on the south side of the road Q u i n n found a m a s t o d o n t skull. T h e
channel sand on the north side of the road has p r o d u c e d horse teeth, synthetocerine
teeth, and part of a rhino skull. M o r e a n d better material has c o m e f r o m Cold
Spring w h i c h is about 80 miles to the northeast.
THE
COLD
Lepisosteus
? T rionyx
Mylagaulus
Amphicyon longiramus
A l e u r o d o n francisi
mastodont
Ticholeptus rileyi
H e s p e r h y s sp.
P r o c a m e l u s sp.
Synthetoce ras francisi
M a c h o e r o m e ryx
SPRING
FAUNA
Dice rathe rium
Teleoceras
H i p p o d o n sp.
M e rychippus sp.
Protohippus sp.
Pliohippus circulis
E o e q u u s wilsoni
Nanhippus
sp.
hipparionid
Calippus francisi
Griphippus sp.
B a c k t r a c k on U. S. Z90 to H e m p s t e a d .
G o south on T e x a s 6 (within
H e m p s t e a d ) to T e x a s 159 and follow it to Bellville. F r o m Bellville continue south
on T e x a s 36 to Sealy. W e are traveling on Willis a l m o s t all the w a y to Sealy. T h e
Willis has n e v e r b e e n m a p p e d in detail and the contact b e t w e e n the F l e m i n g and G o liad has not b e e n determined.
At Sealy turn east on U. S. 90 a n d go about two miles before turning
north to Stephen F. Austin State Park. H e r e w e will m e e t with Field Trip No. 3
w h i c h is under the leadership of H. A. B e r n a r d , R. J. L e B l a n c and C. F. M a j o r .
STOP
6.
M e a n d e r b e n d of B r a z o s River in Stephen F. Austin State
P a r k exposing Goliad below Pleistocene
A small patch of Goliad is exposed. At this site E. L. Lundelius, Jr.
found three horse teeth, two belonging to Pliohippus and one to a Neohipparion.
This places us within the section w h e r e the E a p a r a C r e e k F a u n a is found.
M o s t of the L a p a r a C r e e k fauna w a s collected in southwest T e x a s near
Beeville, but e l e m e n t s of it are being found farther to the northeast. This is a controversial fauna. Q u i n n (1955) studied s o m e of the h o r s e s and W i l s o n (1960} has
studied the carnivores. T h e rest of the fauna is still to be investigated. O n e controversy involves w h e t h e r it is M i o c e n e or Pliocene. H o w e v e r , those w h o have
studied the fauna agree it is close to the line. Q u i n n (1955) r e a s o n e d that since
the h o r s e s s h o w shorter c r o w n s than those of the B u r g e l.f. and that at that time
it w a s informally a g r e e d that the B u r g e l.f. w a s earliest Pliocene, then the Z a p a r a
C r e e k h o r s e s had to be latest M i o c e n e .
M o r e controversial, w a s his extending Pliocene n a m e s of horses into the M i o c e n e .
If his first p r e m i s e is granted, the h o r s e s
are m o r e clearly related to the Pliocene genera than to M e r y c h i p p u s .
351
E v e n m o r e controversial w a s Quinn's (1955) identification of so m a n y
species in a single fauna. I have slowly been working on the horses on a statistical basis and would w e l c o m e assistance f r o m anyone on this problem.
Fig. 3 (modified f r o m Quinn, 1955) s h o w s the regional extent of the biostratigraphic units in the M i o c e n e of the Texas Coastal plain. T h e m o r e important
localities are n u m b e r e d as follows:
M a p No.
1
2
3
4
5
6
7
8
9
i0
1l
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
B.E.G.
No.
County
31160
31087
31057
31183
31200
31219
31191
31243
31190
31242
3087 3
40071
40070
31272
40067
40068
31259
31278
3127 3
31262
30896
31132
31080
31170
30936
30904
31089
30895
Newton
Tyler
Polk
Polk
Polk
San Jacinto
San Jacinto
San Jacinto
San Jacinto
San Jacinto
Walker
Grimes
Grimes
Washington
Washington
Washington
Fayette
Fayette
Zavaca
DeWitt
Bee
Bee
Bee
Bee
Live O a k
Live O a k
Duval
Goliad
40539
40193
40224
Austin
DeWitt
San Jacinto
Return to U. S. 90 and p r o c e e d east to Houston.
Location
N e a r Burkeville
N e a r T o w n Bluff
Near Moscow
N e a r Goodrich
N e a r Goodrich
N e a r Cold Spring
N e a r Cold Spring
N e a r Point Blank
N e a r Point Blank
N e a r Point Blank
Aiken Hill
Near Navasota
Sommers
Pit
N e a r Chapel Hill
Hidalgo Bluff
Near Carmine
Near LaGrange
N e a r Amandsville
N e a r Shiner
N e a r Concrete
N e a r B e rclair
N e a r Birnabl~a
N e a r B e rclair
Near Normanna
Near George West
Near George West
Palangana d o m e
Goliad State P a r k
Saratoga field
S . F . Austin State P a r k
Near Hocheim
N e a r Point Blank
352
Z
0
Iz
Z
03
_z
co
X
~I~
~ o
o
z
m
CD
0
~E
0
a
LL
D
D
0
~E
z
Q-
0
U
o~
co
~E
x
z
z
U
m
I
Q.
0
w
z
w
U
0
~E
©
/"
l
r~
J
rl ~
353
REFERENCES
CITED
Anderson, A. E., 1958, Geology of the Cold Spring A r e a and clay mineralogy
of the F l e m i n g Formation, San Jacinto County, Texas, Univ. Texas,
unpublished M . A. thesis.
Quinn, J. H., 1955, M i o c e n e Equidae of the Texas Gulf Coastal Plain, Univ.
Texas, B u r e a u E c o n o m i c Geol., Pub. 5516.
R a g s d a l e , J. H., 1960, Petrology of M i o c e n e Oakville Formation,
Plain, Univ. Texas, unpublished M . A. thesis.
Rainwater,
Stenzel,
Thomas,
Wilson,
E. H., 1960, Paleocene
of America,
Int. Geol.
97-116.
H.
Texas Coastal
of the Gulf Coastal
Plain of the United States
Congress,
Zlst Session,
Report,
Pt. 5, pp.
B., Turner,
F. E., and Hesse,
C. J., 1944,
marine
Miocene
in southeastern
Texas,
Amer.
Geologists,
Bull., v. Z8, no. 7, pp. 997-i011.
Brackish
Assoc.
and nonPetroleum
G. L., 1960, Petrography of the Catahoula F o r m a t i o n in Texas, Univ.
Texas, unpublished M . A. thesis.
J. A,, 1956, Miocene
formations
Texas
Coastal
Plain, Amer.
v. 40, no. 9, pp. ZZ33-ZZ46.
and vertebrate
Assoc.
Petroleum
biostratigraphic
Geologists,
units,
Bull.,
, 1960, M i o c e n e carnivores, Texas Coastal Plain, Jour. Paleontology,
v. 34, no. 5, pp. 983-1000.
W o o d , H. E., and W o o d , A. E., 1937, Mid-Tertiary vertebrates f r o m the Texas
Coastal Plain: fact and fable, A m e r i c a n Midland Naturalist, v. 18,
no. I, pp. 129-146.