106 PALEOZOIC FISHES OF NORTH AMERICA. 
Section B.—FIsHes oF THE CATSKILL GROUP. 
The Catskill formation took its name from the Catskill Mountains, 
which are in large part composed of it. It consists of a series of conglom- 
erates, sandstones, and shales, of which the prevailing color is red, and the 
thickness in southern New York and Pennsylvania is not less than 5,000 to 
6,000 feet. The area occupied by the formation is not large. It reaches 
southward along the Alleghanies into Virginia, but does not pass westward 
beyond the limits of New York and Pennsylvania. In its lithological char- 
acters (all land-wash) and its limited area it resembles the Trias of the 
eastern United States and the Old Red Sandstone of Scotland, and there 
are many reasons for believing that, like these formations, it was deposited 
in a circumscribed body of fresh water. 
Aside from the fishes it contains—which are for the most part generic- 
ally identical with those of the Upper Old Red Sandstone—comparatively 
few fossils have been found in the Catskill; these are land plants (ferns, 
Lepidodendra, and Sigillaria) and fresh water shells (Anodonta). The most 
‘ common ferns belong to the genus Archewopteris (formerly included in Cy- 
clopteris and Paleopteris), which is very characteristic of the Upper Devo- 
nian and Lower Carboniferous rocks. 
From these facts and others which might be cited we may fairly con- 
clude that the Catskill rocks were deposited in a fresh-water lake, which 
lay immediately along the west base of the ancient land now represented 
by the Highlands of New York and New Jersey and their southern con- 
tinuation, the Blue Ridge. Just how far this lake extended north and south 
we do not know, but apparently not more than two hundred miles, while 
its breadth from east to west did not exceed one hundred and fifty. I have 
elsewhere given my reasons for considering the Chemung group, which 
immediately underlies the Catskill, as the base of the Carboniferous system, 
This was not the classification originally adopted by the New York geolo- 
gists, but since their schedule was made up many new facts have come to 
light which have led me to adopt the views now presented. 
The Catskill also was formerly attached to the Devonian system, but 
there is no other reason than conservatism for this usage. We know, of 
