GULF SERIES. 
MIDDLE CRETACEOUS. 
298 
R. T. Hill—Cross Timbers in Northern Texas. 
Geologic Section of the Cretaceous Strata of the State of Texas, as seen along the Line of the Texas 
thick 
ness, as it occurs thr oughout the State. 
SERIES. 
Lowrr CRETACEOUS. 
COMANCHE 
UPPER CRETACEOUS. 
POSITION. HisTORY AND SYNONYMY. 
‘STR ATIGR APHY. 
BASAL TERTIARIES. 
Ripley Group of Shumard, 
1861. (8) (2) 
Loughridge, 1884. (4) 
Included by Roemer in Krei- 
debildungen am Fusse des 
Hochlandes. (5) 
NAVARRO BEDS. 
Exogyra ponderosa Marl, 
“Austin ” Limestone of Shu- 
by him in series. 
DALLAS LIMESTONE, 
Fusse des Hochlandes. 
Part of ‘‘ Lower Cretaceous”, 
Zone of Ostrea bellaplicata.| of Shumard, 1860, 
mard,1860. Wrongly placed! 
Part of Reemer’s Kreide. am) 
Marls, clays, and limestones. of va- 
rying hardness, and in beds of lim- 
ited extent. Mostly concealed by 
the prairie soil, 
Soft magnesian limestone, earthy 
fracture, fine texture, highly for- 
aminiferous, Biue wpon fresh) 
exposure, but decomposing and 
bleaching shortly after. Agrees,in 
main, with the same formation as 
described in other Gulf States. 
confor mable with above by position 
and faunal continuity. No line of 
demarkation yet made between 
the above gr oups. 
,* Avenaceous Group” and 
EAGLE FORD SHALES. mard’s 
ceous,”’ 1860. 
Kreide. am Fusse des Hoch- 
landes. Roemer. 
“Fish Bed” of Dr. Shu-| 
“Lower Creta- 
Argillaceous shales, var ying ~ from 
blue at top to yellow in middle, 
and to blue again at base, but with 
marked faunal zones. 
‘TIMBER CREEK GROUP. 
Coarse-grained, friable, ferruginous) 
sands, alternating with thin seams 
of yellow clays. Lignitic. 
1 
PLANE OF UNCON 
poune: 
on 
osus, 
a Toxaster elegans, | op 
ae 
a % Gryphea Pitcheri “Washita Limestone.” (1) 
E (with O. corinata) ‘Jurassic and Neocomian! 
5 Ammonites yes_| of Marcou. 
pee DCEMnUS uaeenes 
5 Exogyra fornicu- 
lata. 
Upward extension of next 
two. 
se to t 
zons of 
**Caprina Limestone.’’ (1) 
Comanche Pk. fau. |““Fredricksburg ”” of Reemer. 
= Gryphea Pitcheri ‘‘ Comanche Péak Group.” 
(vith O. Math.) 
§ 2 Requienia Texana. |“ Caprotina Limestone.” (1) 
s 
This series is one of unbroken sedimentation and fa 
—|DINOSAUR SAND. 
e 
CARBONIFEROUS. 
£ = Exogyra arietina, * Tndurated Blue Marl ” (1) | 
Thin alternations of limestone, sand- 
stones, and shales. 
[Alternating bands of tim ‘yellow 
limestones and calcareous mmarls, 
growing thicker downward. The 
8 blue marl” is the same material. 
|Loose bedded or cemented Gryphzxas. 
‘Harder, chalky ‘limestone, 
' Ferruginous, calcareous marls, lim- 
ited. § 0 So Le ee 
Upward continuation of Comanche 
Peak features from groups below. 
‘Hardest limestone of series. Flints. 
\Geamnbinie chalky at top; thin hard 
bands at base, and great bed of 
Gryphea Pitcheri. 
Firmer bands of limestone. 
iferous. 
Pure, uncemented pack sands. 
~ Fossil- 
{1) Trans. St. Louis Acad. of Science, Aug., 
60. 
(2) Trans. § 
(5) Kreidebildungen von Texas, 752. : 
t. Louis Acad. of Science, Aug., 761. 
the western, the latter constantly undergoing the process of 
oblique truneation by erosion. 
As a result of this action it 
becomes thinner and thinner toward the west, until it is finally 
* For convenient reference and brevity, I have 
formulated into a section the 
synonymy, lithology, hitherto published paleontology, and occurrence along the 
Te 
xas Pacific Railway of these strata. 
With a variation of thickness according 
to Tocziy; this section is applicable to the Austin or New Braunfels region. 
