Maryland Geological Survey 79 



with those of England and France. His purpose in coming to America was 

 "to ascertain if the stratigraphieal distribution of animals is the same 

 there as in Europe." He became enthusiastic over the extensive develop- 

 ment of the Paleozoic formations of this country, particularly of New 

 York, and stated : " No country in Europe offers us so complete and un- 

 interrupted a development of the Silurian and Devonian systems; to 

 observe it, it is necessary to cross the Atlantic.'' 



Hall recalls that de Verneuil " suggests a union of the water-lime, the 

 Pentamerus galeatus limestone, the Delthyris shaly limestone, and upper 

 Fentamerits limestone, as one group. In this not only do we readily 

 acquiesce, but are happy to be sustained in what we have already done in 

 effect, by so able and impartial an observer as M. de Verneuil " (p. 180). 

 This corresponds nearly with the present usage of the serial term Helder- 

 berg, as defined by Clarke and Schuchert,^ and would be identical with 

 their delimitation if the " water-lime," now the Manlius, were excluded. 

 Again, de Verneuil proposed to unite the Caudagalli grit ( = Esopus) 

 with the Schoharie grit, but in this Hall's view has proved to be the cor- 

 rect one. He states that " the Caudagalli grit commences with the termi- 

 nation of the Oriskany sandstone, contains no fossils except the peculiar 

 ' enigmatical ' one giving it the naine, is coextensive in New York with the 

 Oriskany sandstone " (p. 181). 



In this paper it is found that de Verneuil step by step placed the lower 

 boundary of the Devonian lower and lower, from Conrad's limit " below 

 the Portage group " until finally the Oriskany was made the base of the 

 American Devonian (Hall's translation, pp. 366-370). This was a great 

 departure from the delimitation of the Silurian and Devonian systems 

 then recognized. Hall states : " It appears clearly established, judging 

 from the facts advanced and opinions expressed by M. de Verneuil, that 

 the horizon recognized in Europe as the base of the Devonian system, 

 finds its parallel at the base of our upper limestone series of the Helder- 

 berg, or at the bottom of the Schoharie grit. The Oriskany sandstone 

 must remain for the present debatable ground '" (p. 230). In 1849, there- 

 fore, Helderberg was Silurian, Oriskany remained debatable as to which 



"■ Science, vol. x, 1899, pp. 874-878. 



