

wii.uams. 1 HALL, DE VERNEUIL. 69 



This had been roughly attempted by Hall, bat, as we examine the 

 changes proposed by De Verneuil, it is evident that the final grouping 

 was greatly influenced by his suggestions. 



In the first volume of the Paleontology of New York, published in 

 1847, no attempt was made by Hall to form subordinate groups of the 

 several formations included in the lower or " Ghamplain division," the 

 Potsdam sandstone, Calciferous sandrock, Chazy limestone, Birdseye 

 limestone, Black River limestone, Trenton limestone, Utica shales, 

 Hudson River shales). De Verneuil thought there were several subor- 

 dinate groups, viz, (1) Potsdam, (2) Calciferous, (3) Ohazy, Birdseye, 

 and Black River limestone, (4) Trenton limestone, Utica and Hudson 

 River shales. The placing of the Oneida conglomerate and the Me- 

 dina sandstone with the Niagara limestone was supported by de Ver- 

 neuil. It had been proposed by Vanuxem and Mather, but was not 

 followed by Hall; in this review the latter expressed his assent to its 

 propriety. 



The combination (Water-lime, Pentamerus galeatus limestone, Del- 

 thyris shaly limestone, Upper Pentamerus) to form the Lower Helder- 

 berg group, was the suggestion of de Verneuil. 1 This is in accordance 

 with Conrad's identification of this combination with the "Wenlock 

 limestone" in 1841, but does not agree with HalPs previous grouping 

 of the equivalents of the Wenlock limestone. 



The inclusion of the Oriskany with the Corniferous in the Devonian 

 was suggested by de Verneuil. The combination Marcellus, Hamilton, 

 Tully, and Genesee as a lower group, and Portage and Chemung as an 

 upper group of the Erie division of the New York reports was also his. 



De VerneuiPs parallelisms of the strata of Europe and America were 

 as- follows: 



The Potsdam sandstone he regarded as the equivalent of the " sand- 

 stone with obolus " of Russia and the " Carboniferous sandstone " of 

 Scandinavia. The siliceous limestone and Black River aud Trenton 

 limestones were the " bituminous schist and Orthoceratite limestone " of 

 Sweden and Russia. The Utica shales and Hudson River group were 

 the " Graptolite slates " of Sweden and of Bain, France. These to- 

 gether form the equivalent of the inferior stage of the Silurian system, 

 and as we study his classification of the next division, it is apparent 

 that the groupings suggested are not those arising from the particular 

 American sequence of rocks, or alone from the faunas themselves, but 

 from their equivalency to the divisions of the European classifications. 2 



In the western exposures in Indiana and Ohio, herecoguizeda union 

 of the faunas of the Lower and Upper Silurian, but in New York these 

 are separated by the Oneida and Medina arenaceous deposits, and he 

 drew the line so as to include the latter in the Upper Silurian with the 

 Clinton and Niagara. The limestones and shales of the Niagara he re- 

 garded as the equivalent of the limestones and slates of Wenlock and 



1 Am. Jonr. Sci., 2d 8er., vol. 5, p. 180. 2 Ibid., pp. 179, 180. 



