CHAPTER VI. 
Description of the Fossils collected by Captain John Pope. 
EXOGYRA TEXANA? 
No. 80. From the banks of Red river, near Preston.—This specimen is labelled Ostrea carinata, 
from the ‘‘Neocomian,’’ but consists of a confused mass of fragments of fossil shells, in which the 
specific characters are completely lost. Traces of plication are visible on one of the edges of 
the specimen, but they are not sufficiently well defined to permit of a determination of the 
species. They are not so sharp and angular as in O, carinata, but are more rounded, and more 
nearly resemble the plications of Exogyra Texana. If it were possible to identify O. carinata 
in this specimen, it would indicate a Cretaceous age for the deposit, for this species is charac- 
teristic of the Lower greensand, Upper greensand, and Chalk marl—the three divisions of the 
Cretaceous. Its occurrence, therefore, cannot be regarded as an evidence of the Neocomian age 
of the deposit from which it was taken. 
No. 84. From Big springs of the Colorado.—This lot consists of three specimens of Exogyra 
Texana, Roemer,! a fossil species common in the Cretaceous formation of Texas. It has been 
obtained by Dr. G. G. Shumard, at the Cross Timbers, Texas,? and: by Dr. Roemer, in the 
Cretaceous deposits near Fredericksburg and New Braunfels. 
No. 85. This specimen appears to be a valve of Exogyra Texana, but it is much worn, and no 
label was appended showing the locality. 
GRYPH AA. 
No. 83. From the Big springs of the Colorado.—This lot of shells consists of four specimens 
of Gryphea Pitcheri, Mort. They are rather small, but are well characterized, and indicate a 
Cretaceous age for the formation. One of the specimens contains, among fragments of shells 
adhering to its interior, a portion of a shell resembling a Pecten, but its specific character cannot 
be recognised. 
No. 81. This specimen is labelled ‘‘Outcrop of horizontal strata, 20 miles east of the Sand 
hills, on the Llano Estacado.’’ It is also said to form the highest stratified rock. Like No. 80, 
it consists of a confused mass of fragments of shells, but their characters are more distinct, and 
Gryphea can be easily recognised. It is, however, not possible to determine the species, but it 
is probably G. Pitcheri. 
Nos. 86, 87, 88, 89, and 90. From the Big springs of the Colorado.—These specimens are 
granular limestone, friable and porous, and of a light-drab or buff color. They are said to 
be taken from the base and top, and the intermediate portions of the bluff at the springs. 
One specimen, from near the base, is more compact than the others, and contains a large amount 
of crystallized carbonate of lime in little seams. Specimen 89, from near the top of the bluff, con- 
tains a small Gryphea, which resembles G. vomer, but it is not well enough preserved to be 
identified. This is the only fossil that can be detected, but the formation may be regarded as 
Cretaceous. 
1 F, Roemer, Texas, 396; also, Roemer's Kreid. Tex., 69, Taf. x, fig. 1, a-e. 
? Marcy's Report—Appendix E, 205. 
