REVIEW OF GEOLOGICAL STRUCTURE. US 2o 
of north-eastern Pennsylvania and Ohio. That the Vespertine connects 
through this gap with the Waverly of Ohio is indicated by the Waverly 
fossils found continuously from McKean county to the Ohio line, but that 
the Umbral and Catskill do not reach Ohio seems demonstrable. 
The local red color of the Bedford shale is certainly insufficient proof 
of relationship with the Catskill, while the paleontological evidence is 
incompatible with the theory of their identity. The Bedford shale con- 
tains in some places great numbers of fossils, among which may be 
mentioned Syringothyris typa, Spiriferina solidirostris, Orthis Michelini, Rhyn- 
chonella Sagerana, Chonetes Logant, etc., all Lower Carboniferous species, 
while not a trace of the Catskill fishes has yet been found in Ohio. 
The truth in regard to the Catskill formation probably is that it was 
formed in an enclosed—perhaps fresh water—basin which had its centre 
in south-eastern New York and eastern Pennsylvania, and that it shoaled 
away to a Chemung shore in western Pennsylvania, beyond which its. 
deposits did not extend. 
The Clev:land Shale is considered by Prof. Lesley to be of Chemung age, 
but this was necessitated by his identification of the Bedford shale with 
the Catskill, and the arguments against one are as cogent against the 
other. As has been already stated, the fossils found at and even under 
the base of the Cleveland shale are identical with those of the Bedford. 
It may be thought that the preceding remarks are inconsistent with 
the view before presented, that the Chemung and Catskill as well as the 
Waverly group should be included in the Carboniferous system, for if all 
are parts of one formation why insist upon their distinctness? It is 
true, however, that the well-marked subdivisions of each formation hold 
invariable positions in regard to each other, and are characterized by 
differences in lithological characters and fossils, although some species 
are usually common to all the members of the group. We may hereafter 
find in Pennsylvania such a blending of Chemung and Waverly fossils 
as shall unite them more closely than heretofore, but such blending 
would in no wise affect the question of the identification of the subdi- 
visions of the Carboniferous system in Pennsylvania with those of Ohio. 
THE LOWER CARBONIFEROUS LIMESTONE, 
In the discussion of the phenomena presented by the Carboniferous 
system in Ohio, published in Vol. I, Geology, of this Report, mention is 
made of the discovery by Prof. Andrews of a thin bed of limestone in 
the southern part of the State, proved by its fossils to be the representa- 
tive of the Chester limestone of Illinois, the upper member of the great 
Carboniferous limestone series. Facts are also stated there which prove 
