38 The Middle Devoxiax Deposits of Maryland 



vania, constitute tho equivalents of the Devonian system as developed in 

 Ei;rope " and contain a number of fossils characteristic of European De- 

 vonian strata/ The same year Yanuxem stated that the last three 

 groups of the " Erie Division," viz., the Portage, Ithaca and Chemung 

 " appear to correspond with the Devonian system of Mr. Phillips." " 

 The following year Prof. Hall gave the base as somewhat lower when he 

 stated that the Devonian system appears " to correspond to the Chemung 

 and Portage groups, and also to include a portion of the Hamilton." ' 

 In 1847 Professor Hall stated that " With the Schoharie grit, commences 

 a series of strata containing fossils as distinct from those of the pre- 

 ceding formations, as these are from the lower division. We here, for 

 the first time, recognize several species that are regarded as Devonian 

 forms ; and if zoological characters are to be paramount, we are compelled 

 to unite all the succeeding strata as of Devonian age." * Finally, in 1859, 

 he raised the question whether even the Oriskany sandstone might not be 

 considered as of Devonian age. For he wrote as follows concerning " the 

 line of demarcation for the Silurian and Devonian S3'stems. Shall the 

 advent of the Oriskany sandstone, with its Spirifer of dichotomizing 

 costse, be the division ? Or shall we look for some more marked and more 

 readily defined and recognized feature for the distinction between what are 

 regarded as iwo great geological systems ? " ' 



So far as the writer is aware de Yerneuil, in 18-i7, was the first geologist 

 to definitely correlate the younger formations of the ISTew York System 

 with subdivisions of the Devonian system of Europe. He made the base 

 of the Oriskany sandstone the dividing line between the Devonian and 

 Silurian systems ; " correlated the Hamilton, Tully, Genesee, Portage and 

 Chemung with the formations of the Eifel and Devonshire, and the 



'Jour. Acad. Nat. Sci., Philadelphia, Vol. VIII, p. 232. 



= Geology New York, Pt. Ill, p. 171. 



••' imd., Pt. IV, p. 20. 



■* Pateontology of New York, Vol. I, p. xvii. 



''Ihia., Vol. Ill, Pt. I. p. 42. 



'Bulletin Societe Geologique de France, 2d ser., Vol. IV, p. 677; also Am. 

 Jour. Science, 2d ser.. Vol. V, 1848. p. .367. On the parallelism of the PaliKOzoic 

 deposits of North America with those of Europe, translated by James Hall. 



