Jfotes on the Geology of Central Webrasha. — Russell. -±3 
the stone pitted from casts. Many diatoms occur, the most com- 
mon being Navicula splicer ospliora, Cymbella lanceolata, C. cistula y 
Epithemia gibba, Encyoneme gracile. In the superimposed 
Loess-like formation will be found Succinea, Pupa, Helix, etc. 
As one approaches the base of the chalk formation a decrease 
in the abundance of fossils is noted. At the same time the rock 
becomes more heavily bedded. The increase of silica and mag- 
nesia is at once apparent. Near the top of the outcrop the rock 
becomes very chalky and shaly. Fragments of the stone are en- 
closed in the superincumbent material like boulders in the glacial 
clay. 
Owing to the favors of the Burlington and Missouri railroad I was 
permitted to visit a similar exposure at Seneca, in Hooker county. 
Indeed, I may say that owing to these favors I have been enabled to 
make a much more satisfactory stud}' of this region than would 
othei'wise have been the case. The outcrop at Seneca presents no 
point of difference from the outcrop at Scotia. Near the top of 
the Seneca Tertiary limestone, I found the well preserved femur, 
tibia and some vertebrae of Equus excelsus. Also a tooth showing 
some resemblances to Procannelus. 
fi t'tJii it, uh 
i ] iM ''ill 
Fig. 2 
These limestone outcrops seem to he Tertiary Unites, criteria by 
which we are enabled to measure the amount of erosion in this 
region. Standing as huge pinnacles, from them we can conceive the 
amount of removed Tertiary material. They are valuable leaves in 
the geology of Nebraska. The buttes conclusively prove thai Bub- 
sequent to the deposition of the beds of which they are the rem- 
nants there was a long period of erosion. Finally upon the worn 
