PALEOZOIC ROCKS OF THE CANTON QUADRANGLE 55 



i8p4. Map work was resumed in 1894 with the appearance of 

 Hall's ''Preliminary Geologic Map of New York" a large wall 

 map compiled by W. J. McGee o£ the U. S. Geological Survey, 

 followed by Dr F. J. H. Merrill's " Economic and Geologic Map " 

 of the State, which was reissued in Bulletins 15 (1895) and 85 

 (1905). The latter marks no advance in the knowledge of our 

 area, while the former recognizes the inadequacy of previous work by 

 leaving most of our region blank! Attention thus being directed to 

 our needs, results soon followed. 



iSp^. Mention may be m.ade here of the fourth edition of Dana's 

 " Manual of Geology " for its improved classifications and its con- 

 cise summary of previous knowledge, which render it a starting 

 point for future work (1895), and of an important paper by Dr 

 R, W. Ells on " The Potsdam and Calciferous formations of Que- 

 bec and Eastern Ontario " (Can. Roy. Soc. Proc. and Trans., 12, 

 sect. 4, p. 21-30, 1895), in which he argues for the union and even 

 (citing Emmons, p. 347) partial contemporaneity of these two 

 groups (a view later urged by Grabau), and assigns the Potsdam 

 to the base of the Ordovician (" Cambro-Silurian "). Ells's 

 remarks apply, of course, to the fossiliferous " white Potsdam." 

 In the same year, Winchell again declared his belief in the Keween- 

 awan age of the true (red) Potsdam at Hannawa (American 

 Geologist, 16: 205-13) and in 1897 Merrill discussed the road 

 metals of the State (bulletin 17) with maps still based on the old 

 surveys. More important was Merrill's " Guide to the Study of the 

 Geological Collections of the New York State Museum " published 

 in 1898 as Bulletin 19 of the museum; particularly pages 141-47, 

 187-88, 216 and 219. The handsome map in this bulletin adds little 

 to the early work on our area. 



i8(;>8. In 1898 appeared Mr Edgar G. Blankman's " Geography 

 of St Lawrence County," with a section on its geology (pages 29 

 to 31) and a small colored map based on that of 1842. A new 

 era began, however, with the advent of Prof. H. P. Gushing of 

 Western Reserve University, whose " Report on the Boundary 

 hetiveen the Potsdam and Precamhrian Rocks North of the Adi- 

 rondacks" constituting pages 5 to 27 of the i6th Report of the 

 State Geologist (1898) recorded the first detailed formation trac- 

 ing in this region since the days of Emmons. Professor Gushing 

 worked into the Canton quadrangle from the east, but did not cross 

 it, being interrupted by the close of his field season. He recog- 

 nized, however, the great difficulties presented by the drift-laden 



