Charles Scliucliert — Historical Geology, 1818-1918. 73 



York system with those of Europe. At this time he had 

 had a wide field experience in France, Germany, and 

 Russia, was president of the Geological Society of 

 France, and "virtually the representative of European 

 geology" (2, 153, 1846). Hall says, "No other person 

 could have presented so clear and perfect a coup d'oeil." 

 De Verneuil's results were translated by Hall and with 

 his own comments were published in the Journal in 1848 

 and 1849 under the title "On the Parallelism of the 

 Paleozoic Deposits of North America with those of 

 Europe." De Verneuil was especially struck with the 

 complete development of American Paleozoic deposits 

 and said it was the best anywhere. On the other hand, 

 he did not agree with the detailed arrangement of the 

 formations in the various divisions of the New York 

 system, and Hall admitted altogether too readily that the 

 terms were proposed "as a matter of concession, and it is 

 to be regretted that such an artificial classification was 

 adopted." De Verneuil's correlations are as follows: 



The Lower Silurian system begins with the Potsdam, 

 the analogue of the Obolus sandstone of Russia and 

 Sweden. The Black River and Trenton hold the position 

 of the Orthoceras limestones of Sweden and Russia, 

 while the Utica and Lorraine are represented by the 

 Graptolite beds of the same countries. Both correlations 

 are in partial error. He unites the Chazy, Birdseye, and 

 Black River in one series, and in another the Trenton, 

 Utica, and Lorraine. Of species common to Europe and 

 America he makes out seventeen. 



In the Upper Silurian system, the Oneida and 

 Shawangunk are taken out of the Champlain division, 

 and, with the Medina, are referred to the Silurian, along 

 with all of the Ontario division plus the Lower Helder- 

 berg. The Clinton is regarded as highest Caradoc or as 

 holding a stage between that and the Wenlock. The 

 Niagara group is held to be the exact equivalent of the 

 Wenlock, "while the five inferior groups of the Helder- 

 berg division represent the rocks of Ludlow." "We now 

 know that these Helderberg formations are Lower Devo- 

 nian in age. De Verneuil unites in one series the 

 Waterlime, Pentamerus, Delthyris, Encrinal, and L T pper 

 Pentamerus. Of identical species there are forty com- 

 mon to Europe and America. 



The Devonian system De Verneuil begins, "after 



