588 TRANS. OF THE ACAD. OF SCIENCE, 
This subdivision should eee a grouped with the pre- 
ceding. It corresponds with No. 2 of the Nebraska Section. 
Caprotina Limestonr.—The Cephottat Limestone, which 
alows in descending order, forms the base of the Upper 
Cretaceous, and is composed of li ght gray and yellowish gray 
earthy limestone, with intercalated bands of yellow marl, and 
sometimes flint. It is exposed at the base of the hills near 
Comanche Peak, and is seen underlying the haba yg Lime- 
ant near the Colorado, at the foot of Mt. Bon 
II. Lower Cretaceous. 
For a knowledge of this division of our Cretaceous system, 
I am indebted to Dr. G. G. Shumard, who has had excellent 
opportunities for examining it. He describes it as being 
composed of sandstones, and gypseous and marly clays; the 
latter containing numerous septaria filled with fossils. It is 
separable into two groups; namely, Arenaceous and Marly 
Clay, or Red River 8 
ARENACEOUS GRO p—Thi is member consists of light yel- 
low and blue sanasbo ne; and beds of sandy clay with crystals 4 
selenite and some lignite. Its characters may be understoo 
from the following section taken by Dr. G. G. Shumard, on 
Post-Oak Creek, in Grayson County. 
No _ Soft, fine-grained, yellow sandston e cbecneey Aa 
. Hard, fine.grained, blue sandstone, becoming yellow up- 
oe soe and sometimes passing into gs i 
conglomerate ++++++ ++ dete tors. “ 
3. Yellow gota pretince same as No. Liseese sorree see? : 2 a 
“ 4, Indurated, blue, slaty aes, with a ag - selenite os 
“ 6. Thinly laminated layers, same as 
“ee 
Fossils —The upper part is characterized by Ostr e an 
PUgOSa, ate congesta, Lucina, Plicatula, a sma spec 
gui: 
mains, which Dr. Leidy refers to the following 8 
Prtye ieoiuk mammilaris, Lamna a L. 
Galeocerdo pristodontus, and Carcharod: ly equive 
The strata of this sronp J I regard as peing _ tee Set pie 
lent to divisions B, C the Pyramid M 
of Prof. Marcou, re in “a by him to the Ju 
Tass) 
al 
The stratigraphical position is the same, and the Saale 
