582 TRANS. OF THE ACAD. OF SCIENCE. 
Observations upon the Cretacrous Strata of Texas, by 
B. F. Suumarp, M.D., State Geologist, 
much controversy, some authors assigning them to the Juras- 
sic and Triassic Periods, while others, and by far the largest list 
of authorities, have referred them to their true age—the Cre- 
taceous. Although much has been written concerning the 
of our Cretaceous System, and 
many of the fossils have been described by Roemer, Conrad, 
and that only a single species, the @ryphwa Pitchert, has 
4 3 ie from the Mani to the summit of 
from the Lower into the Upper Cretaceous. __ 
The order of succession and thickness of the different mem- 
bers of the Cretaceous system, so far as observed in ed 4 
are expressed by the following section, which is an ore 
in the main correct, although it is not improbal e . 
further researches may render some slight modifications 2 
cessary : 
