Series in Kansas, Oklahoma and New Mexico. 233 
G. dilatata zone, Ammonites leonensis Conrad and O. quad- 
riplicata Shumard, characteristic middle and upper Washita 
species of the Central Texas region, which do not occur at 
Belvidere. In general association the species of the Tucum- 
cari locality have greater resemblance to that of the uppermost 
beds of the Washita division of the Central Texas section, 
while the common forms of the Belvidere beds, such as Schlen- 
bachia peruvianus and Gryphea Remeri, are more common 
to the Preston or basal beds of the Washita. More minute 
studies of the range of species in the Tucumeari beds is neces- 
sary before any positive conclusions on these subjects can be 
stated. : 
The seventy-five feet of alleged Dakota sandstone overlying 
the fossiliferous beds of Tucumcari will be more fully dis- 
cussed in a future paper. 
The outlying beds of the Washita division are also found 
far southward in the Trans Pecos region of Texas at Kent,* 
E] Paso and as far west as Arivichi in Sonora, where its fauna 
was reported by Gabb. We cannot here continue the presen- 
tation of the minute data concerning them, but they, together 
with the data we have given concerning the beds in Kansas, 
Oklahoma and New Mexico, all demonstrate the generalization 
we have before presented,t that the beds of the Washita divi- 
sion far overlapped interiorward those of the Trinity division. 
This study has enabled us to classify and understand the sig- 
nificance of the outlying areas of the Cretaceous in Oklahoma, 
New Mexico, and Trans Pecos, Texas, and their paleontologic 
relations as shown in the appended table. 
The geology of these outlying areas of the Cretaceous pre- 
served in the scarps of the Plains adds greatly to our knowl- 
edge of the distribution, variation, paleontology, and history 
of the beds of the Comanche series and of the progressive 
oscillatory conquest of the Great Plains region by the sea in 
Cretaceous time. The Belvidere beds have revealed the fol- 
lowing additions to our knowledge of Cretaceous paleontology : 
First, a lower stratigraphic occurrence of the dicotyledonous 
Dakota flora than known, whereby we may now say that 
dicotyledons make their first appearance before the beginning of 
the Washita sub-epoch, instead of in the Dakota as hitherto 
believed. Second, a similar downward range in the geologic 
scale of the Icthyan vertebrates of hitherto supposed Upper 
Cretaceous range. Third, intermingling of these plants and 
fishes with molluscan species and other vertebrates of the 
Washita division such as has not hitherto been found in the 
Comanche series. 
* See sections by H. T. Dumble, Bull. Geol. Soc. America, vol. vi, pp. 376-388, 
and American Geologist, vol. xii, p. 309. 
+ Bull. Geol. Soc. of America, vol. v, p. 332-338. 
