1847.] SHARPE ON THE PALHOZOIC ROCKS OF N. AMERICA. 155 
species are common to the Chemung and Hamilton groups; such as 
I have been able to identify lead me to class this group in the De- 
vonian system. In fact, but for their separation by the non-fossili- 
ferous beds of the Portage group, the Chemung and Hamilton groups 
would hardly be divided: thus all the beds of the ‘‘ Erie division” 
form a closely connected series well-characterized by common species 
of organic remains. 
The following species are European :— 
Avicula Boydii. Productus plicatilis ? 
Damnoniensis ? fragaria ? 
Athyris concentrica. Terebratula reticularis. 
Strophomena umbraculum ? aspera. 
Spirifer Urii. borealis. 
—— aperturatus. nucula ? 
Qld Red Sandstone. 
The “New York System” of our American colleagues closes with 
the Chemung group, which is surmounted by a formation of sand- 
stone, considered identical with our old red sandstone. The argu- 
ments in favour of this classification are its position above the great 
fossiliferous Erie division, which is identified with our Devonian sy- 
stem, and below a series of beds identified by their organic contents 
with our carboniferous system, and the occurrence in this sandstone 
series of the remains of fishes stated to resemble those of the old 
red sandstone of Great Britain. Upon this latter pomt I can pro- 
nounce no opinion, not having examined the evidence ; but I see no 
reason to doubt the soundness of the American classification of the 
formation. It is however worthy of particular notice, that in New 
York there is clear stratigraphical evidence for placing this red sand- 
stone formation above the whole of the fossiliferous Devonian series. 
Having thus passed in review the separate members of the “‘ New 
York System,” let us now look at its larger features. The whole 
system divides itself naturally mto three great divisions, marked by 
differences both of mineral character and of organic remains. Owing 
to the general conformity of the beds and the gradual change of 
characters throughout, it is difficult to fix on the exact lines where 
these great divisions should be made, and the geologists who have 
described the country are not exactly agreed on them; yet the main 
features are well-marked, and have struck every one nearly in the 
same light. 
Looking at the mineralogical characters of the rocks, we see, Ist, 
a vast accumulation of sandstones, with occasional beds of limestone 
reaching from the earliest fossiliferous beds upwards to the Medina 
sandstone ; the Clinton group of beds which he upon that sandstone 
being intermediate in character between the lower group and the next 
above. 
2ndly. A great calcareous series, varied with some shales and sand- 
stones, commencing with the Niagara shale, and ending, according 
to Mr. Conrad, with the Upper Pentamerus limestone inclusive, or, 
according to Mr. Hall’s views, reaching upwards to the top of the 
corniferous limestone. 
