96 
TRANSACTIONS OF THE TEXAS ACADEMY OF SCIENCE. 
tion to a calcareous sandy clay entirely destitute of fossils of any kind. 
Other limestone beds in the Albany division when traced to the north- 
eastward would gradually pass into sandstone, while still others would 
entirely disappear. 
By this manner of work we were enabled to observe also the gradual 
change in the fauna of the different beds. As the beds would change 
in lithological character, indicating a change in the conditions of the 
waters in which they were deposited, difference in the fauna to corres- 
pond with this change of condition was readily observable. 
At most places in the Albany division there are only Coal Measures 
fossils, but going northeastward these would gradually become extinct 
as the habitat changed, and newer forms would come in and take their 
places. 
I began tracing these different beds at the mouth of Fish creek, on the 
Clear Fork of the Brazos river in Shackelford county, where the line of the 
general section from Albany to the foot of the Staked Plains, as pub- 
lished in a previous report, crosses the line between the Albany division 
and Clear Fork divisions, as then described. 
The hills at this place are capped by a bed of limestone two feet thick, 
with beds of shale and other limestones below. The following fossils 
were collected at this place: Myalina subquadrata, Bellerophon, Allo- 
risma subcuneata, Pinna peracuta, Fenestella sp?, Productus semireti- 
culatus, Aviculopecten sp?, Hemipronitis crassus, Orthoceras sp?, Nati- 
copsis sp?, Phacoceras dumblei, Hyatt, Nautilus sp?, Euomphalus sp?, 
Schisodus wheeleri, Murchisonia sp., Synocladia sp., Meekella striata- 
costata, Pleurophorus sp. 
From this point we traced the beds to the northeast as far as the hills 
on the north side of the Big Wichita river, and noted the gradual 
changes in the lithological character in the several beds. There was no 
trouble in tracing the beds across the supposed northern boundary of 
the Albany division, although they had greatly changed in appearance 
from what they were at the place of beginning. 
North of the Brazos river, in the area heretofore designated as the 
Wichita division in previous reports, the strata of the escarpment be- 
1 came more and more composed of red clay and the limestone beds less 
conspicuous. The limestone gradually loses its limy nature. Only a 
few of the limestones of this escarpment continue as far north as the 
Big Wichita river, and they are very much modified, some of them pass- 
ing into a white or gray indurated day which breaks into hard, rough 
nodular fragments. 
The line of levels run across the Wichita division, and published in the 
Second Annual Report, crossed this escarpment just south of the Big 
