1 94 Bulletin of Laboratories of Denison University [ vol xi. 
gate thickness of all the strata of this region will not exceed 
1000 ft., and even this thickness is not found in any one locality. 
The Gulf Border Region. This region includes portions of 
Albania, Mississippi, Georgia, Louisana, Tennessee, and Ken- 
tucky. The geological features of the region are so similar to 
those of the former, that there is probably no Cretaceous stratum 
found in the one that does not also occur in the other. Al- 
though the rocks so closely resemble those of the Atlantic 
Border Region, they are on the whole of a harder character, 
and the aggregate thickness is greater, being about 2600 ft. 
We select the following section as being a typical one of this 
region : 
Hilgard’s Misssissippi Section. 
r Sands. 300 
Coffee Group. < Blue or reddish clays, to 
(Some beds of lignite. 400 ft. 
r Soft clays. 
Rotten Limestone Group. < Whitish limestones. 1200 ft. 
( Calcareous clays. 
f Sandy limestones 300 
Ripley Group. < alternating with to 
(beds of dark marl. 350 ft. 
The Texas Region. This region includes portions of Mis- 
souri, Arkansas, Louisiana, Indian Territory, and much the 
greater portion of Texas. In this region we have the whole 
Cretaceous Period from the Trinity formation to the Laramie 
formation. It is remarkable for its exposure of the Comanche 
series, which is probably the best representative of a great di- 
vision of the Lower Cretaceous in North America. Its fossil 
fauna, such as Rudistae, Chamidae, and Radiolites austiimisis, 
would seem to indicate that it was similar to both the Lower 
and Upper Cretaceous of Europe; but, from its position so far 
below the Dakota, it is placed in the North American Lower 
Cretaceous. The series consists of limestones, calcareous 
shales, and earthy calcareous material with stony concretions. 
North Mexican Region. The geology of this region is very 
imperfectly known, but it is of great importance. Its bounda- 
ries lie mainly within Mexico, but it also includes portions of 
