Series in Kansas, Oklahoma and New Mexico. 211 
of the Lower Cretaceous of the. Central Texas region, which 
are of a light-colored marly nature. 
Although the occurrence of the secondary beds of sandstone, 
No. 2, 8, and 4, immediately above the main body of that 
material, is quite persistent both at Black Hills and Blue Cut, 
Prof. Cragin has not noted its occurrence in his sections of 
these localities. Whether he failed to observe them, or merely 
considered them portions of the Cheyenne sandstone to which 
they logically belong, rather than the shale series above, can- 
not be stated. That he considered the Cheyenne sandstone 
and overlying shales a continuous sequence of sedimentation, 
is clearly shown in his discussion of the Vanheim section, 
where he finds a band of Cheyenne-like sandstone ten feet thick, 
intercalated between ninety feet of shale beneath and forty 
above. The shales overlying No. 4 we call the Belvidere 
shales from the town near which they can best be seen.* 
These formations may be grouped into a generalized section 
characteristic of the bordering breaks of the Plains in southern 
Kansas, western Oklahoma, and northeastern New Mexico, 
which we may appropriately call the Plains section. 
This section is as follows: 
IV. Plains Tertiary. 
III. ‘‘ Dakota” Sandstone. 
II. Belvidere Beds. 
b. Blue and black 
.  ghale with fos- 
sils. 
a. Cheyenne Sand- 
stone grading 
upward into b. 
I. ‘Red Beds.” 
In this section there are two conspicuous time unconformi- 
_ ties, indicative of long periods of erosion, one between the Red 
* Since writing this paper Prof. Cragin has proposed the name Kiowa for the 
shale beds. The name would no doubt have priority over the one herein 
used by me, but owing to doubt as to which subdivision Prof. Cragin would 
have included the beds 2, 3 and 4, I prefer to retain for the present the term 
Belvidere shales. Although the relations of the Cheyenne sandstones and Bel- 
videre shales are transitional, the writer draws the line of demarcation between 
the Belvidere shales and the Cheyenne sandstone immediately above this highest 
sandy layer No. 4, in the sections given. 
