36 The Middle Devoxiax Deposits of Maryland 



"grand divisions of the Xew Yorlv system'"' appears No. "V. Catskill 

 Division " composed of tlie Portage, Ithaca, Chemung, and Catskill 

 groups.' It appears probable, however, that the Catskill division was 

 considered as separate from the New York system for it was stated 

 that " It forms by itself a distinct system, and has been described by 

 Mr. Phillips under the name of Devonian system. It is designed to 

 embrace not only the peculiar rocks of Devonshire, but those of Scotland, 

 and of places on the Continent which have hitherto been known and 

 described under the name of Old Red sandstone," ' while on p. 116 he 

 used the expression " The Silurian or New York system " apparently for 

 the Champlain, Ontario, Helderberg, and Erie divisions. Under the 

 classification of the New York rocks where the formations composing 

 the different divisions are briefly tabulated it is stated that the Erie 

 division embraces the Marcellus shale and the Hamilton, Portage, and 

 Chemung groups.' In the detailed account of the Erie division, how- 

 ever, only the Marcellus and Hamilton shales and TuUy limestone are 

 described,* while the Portage and Chemung groups appear imder the 

 Catskill division. 



Preceding these rejwrts Conrad, who became Paleontologist of the 

 Survey after the first year of field work, published an article in 1843 

 in whicli he stated that " The rocks of the Ithaca group, Chemung group, 

 and the Old Bed Sandstone near Blossburg, in Pennsylvania, constitute 

 the equivalents of the Devonian system as developed in Europe, and con- 

 tain a number of the organic remains which characterize the Devonian 

 strata." ° While Professor Hall in his final report carried the base of the 

 Devonian somewhat lower concluding that the Devonian system appears 

 " To correspond to the Chemung and Portage groups, and also to include 

 a portion of the Hamilton." " After the publication of the final reports 

 of the New York Greological Survey the famous French geologist de 



"^Loc. cii., pp. 187-193. 



' hoc. cit., p. 188. 



' Loc. cit., p. 116. 



*Ibid., pp. 180-187. 



•> Jour. Acad. Nat. Sci.. Philadelphia, Vol. VIII, p. 232. 



'Loc. cit., p. 20. 



