10 



aess, which ia known as the " Tully Limestone." This limestone thins out, in proceeding 

 westward, before Lake Erie is reached, and it is not represented in Canada. 



VIII. GENESEE SLATES. Overlying the Tully Limestone, or in its absence the Hamil- 

 ton Group, is a series of black, bituminous, sparsely fossiliferous shales, to which the New 

 York geologists have applied the name of " Genesee Shales " or " Genesee Slates." Professor 

 Hall unites these with the Portage Group, and their occurrence has not been satisfactorily 

 recognized in Canada, unless they should be represented by the fissile shales of Kettle Point, 

 Lake Huron, as has been generally supposed. In this case, the Genesee Shales of Canada 

 are very important and interesting, from the presence in them of well-preserved remains of 

 plants. 



IX. PORTAGE GROUP. This group is composed of a considerable thickness of shales, flags, 

 and shaly sandstones. Few fossils are present, and the group is not known to be represented 

 in Western Ontario. 



X. CHEMUNG GROUP. If the Catskill sandstones and shales be regarded as belonging 

 to the Carboniferous, the summit of the Devonian System in Eastern America is constituted 

 by the so-called " Chemung Group." This consists of a great series of sandstones and shales' 

 containing a considerable number of fossils ; but no equivalent of the group has been recog- 

 nized in Canada West. 



The following table exhibits, in a summary form, and in ascending order, the various 

 members of the Devonian Formation of the State of New York, with their equivalents in 

 Ontario. 



Devonian Strata of the State of New York. Equivalents in Ontario. 



I. Oriskany Sandstone ..Sandstones of North Cayuga and Oneida ? 



II. Cauda-Galli Grit No equivalent. 



III. Schoharie Grit Sandstones of North Cayuga and Oneida? 



[Or no equivalent ? 

 Onondaga Limestone ) 



IV. Corniferous Limestone / Corniferous Limestone. 



( Upper Helderberg Limestones) 



V. Marcellus Shale \ 



VI. Hamilton Shales f Hamilton Group 



VII. Tully Limestone 



VIII. Genesee Shales Fissile Shales of Kettle Point, Lake Huron, 



[with remains of plants. 



IX. Portage Group No equivalents. 



X. Chemung Group No equivalents. 



