384 



THE AZOIC SYSTEM AND ITS SUBDIVISIONS. 



In stating the results obtained by the Canada Geological Survey, as 

 detailed in the Report of Progress for 1847-48, Dr. T. Sterry Hunt re- 

 marked that to the " Chemung and Portage group of New York, with 

 the old red sandstones, .... may perhaps be referred in part the 

 rocks of the White Mountains." (Am. Jour. Sci., 1850, (2) IX. p. 19; 

 Proo. Am. Assoc. Adv. Sci., 1849, II. pp. 333, 334.) 



In 18G3 he wrote: 



" It is moreover probable that the rocks of New Hampshire, iucludmg the 

 White Mountains, are altered strata of Devonian age." (Geol. of Canada, 1863, 



p. 598.) 



In 18G7 the White Mountains were again referred to the Devonian 

 by Dr. Hunt. (Esquisse Geologique du Canada, p. 23; Bull. Soc. G6ol. 

 France, 18G7, (2) XXIV. p. 687. 



Prof. J. P. Lesley, in 1860, stated that lie had a 



" growing conviction that the range of the White Mountains would prove to be 



syndinal instead of anticlinal, and therefore of probably Devonian age 



Ascending Mount Osceola .... the bridle path mounts over successive out- 

 crop ledges of perfectly horizontal plates of granite, as evidently and regularly 

 bedded as any of the sandstone masses of the Alleghanies, the bed planes not 

 being at all disguised by the cleavage planes. Between these plates of granite 

 lie plates of unchanged dark blue sandstone ; a rock which at the cascades 

 . . . . has been nnstaken for greenstone trap." (Proc. Acad. Nat. Sci. Phil., 

 1860, XII. pp. 363, 364. Mining Magazine, 1861, (2) II. pp. 99-101.) 



The probable truth in this is, that Prof. Lesley mistook some old 

 basaltic dikes for sandstone, and the concentric lamination of the gran- 

 ite for stratification. 



Dr. Hunt, in 1878, stated that Logan suggested that the rocks of 

 the White Mountains were "probably altered Devonian strata" (Azoic 

 Rocks, pp. 86, 87, 182) ; while, in 1801, he said : 



" The White Mountains as we suggested in 1849 (this Journal, [2], IX, 19), 

 are probably, in part at least, of Devonian age, and are the representatives of 

 7000 feet of Devonian sandstone observed by Sir William Logan in Gaspc. 

 Mr. J. P. Lesley has more recently, after an examination of the White Moun- 

 tains, shown that they possess a synclinal structure, and has adduced many 

 reasons for regarding them a.y of Devonian age." (Am. Jour. Sci., 1861, (2) 



XXXI. p. 403.) 



In 1870 it would appear that, under the name Terranovan, they 

 were regarded by him in part at least as Potsdam. (Am. Jour, Sen, 

 1870, (2) L. pp. 83-90.) 



