distinctly definable from one another, but the section is presented 
in this form for convenience in making reference to the respective 
horizons at which collections of fossils have been made. 
1. Reddish and mottled sandy clays, with occasional layers of 
sandstone. 
2. Variously colored clayey and sandy concretionary strata, with 
a few irregular layers of impure concretionary limestone ; embrac- 
ing near its middle a somewhat persistent stratum of limestone of 
greyish blue color. 
3. Sandstones alternating with clayey and sandy concretionary 
layers and a few fine grained silicious layers. 
4. Reddish and buff colored clayey and sandy shales with occa- 
sional layers of sandstone. 
5. Sandstones and sandy shales ; with beds of reddish sandy 
clay: passing gradually into the. Coal- measures beneath. 
Vertebrate remains, which Prof. Cope confidently refers to the Per- 
mian, occur at numerous localities and at many horizons from the 
base to the top of this section ; but invertebrate remains have hith- 
erto been discovered only in strata which are included in Nos. 2 and 
3 respectively of that section. The lowermost known horizon of in- 
vertebrates is about 400 feet above the base of the series, and the 
uppermost is about as much below the top of the same. That is, 
the invertebrate fossils described and figured in this article come 
from the middle 200 feet in thickness of the Permian series as it has 
just been defined. 
The localities at which these fossils were obtained, only three in 
number, are in Baylor and Archer counties ; and as the country is 
still an unsettled one, they can be designated only in an indefinite 
way. The first of these localities, which is in the northwestern cor- 
ner of Archer county, will be designated as "Camp Creek." The 
second is in Baylor county, near the middle of its eastern boundary 
line, and will be designated as " Godwin Creek." The third is ni 
the northeastern part of Baylor county, near where the old military 
road, constructed by General Van Dorn, crossed the Big Wichita 
river. This locality will be briefly designated as the " Military 
crossing of the Big Wichita." The strata of the two first mention- 
ed localities occur in Xo. 3 of the foregoing descriptive section of 
the Permian, and the last named one, in No. 2. 
