on American Geology, 93 



only brought up on the east against the Upper Silurian and De- 

 vonian, but even to overlap the black shales at the base of the Car- 

 boniferous system. It is remarkable to find that as early as 1822, 

 the idea of a great dislocation of this nature in Eastern New York 

 was maintained by Mr. D. H. Barnes in his description of Canaan 

 Mountain. [Am. Journal of Science, Ql) v. pp. 15-18.] 



To the southeast of this great fault in Canada we have as yet 

 no evidence of Lower Silurian strata higher than those of the 

 Quebec group. At the eastern base of the Green Mts. we find 

 limestones of upper Silurian and Devonian age reposing uncon- 

 formably upon the altered strata of the Quebec group, themselves 

 also having undergone more or less alteration. Immediately suc- 

 ceeding are the chiastolite and mica slates of Lake St. Francis, 

 which as we have long since stated are probably also of Upper 

 Silurian asfe. 



The White Mountains as we suggested in 1849, (Am.Jour.Sci. 

 (2) ix. 19) are probably, in part at least, of Devonian age, and are 

 the representatives of the 7000 feet of Devonian sandstone observed 

 by Sir William Logan in Gasp^. Mr. J. P. Lesley has more re- 

 cently, after an examination of the White Mts. shown that they 

 possess a synclinal structure, and has adduced many reasons for 

 regarding them as of Devonian age. (Amer. Mining Journal, 

 January 1861, p. 99. 



It will be seen from what has been previously said that we look 

 upon the 1st and 2nd divisions described by Mr. Saffbrd in 

 Eastern Tennessee, as corresponding to the hypozoic series of 

 Rogers and to the Green Mountain gneissic formation, which 

 instead of being beneath the Silurian series, is really a portion of 

 the Quebec group more or less metamorphosed, so that we re- 

 cognize nothina: in New Eno-land or south-eastern Canada lower 

 than the Silurian system, nor do we at present see any evidence 

 of older strata, such as Laarentian or Huronian, in any part of the 

 Appalachian chain. The general conclusions which we have 

 previously expressed with regard to thelithological, chemical and 

 mineral relations of the Green Mts. rocks remain unchanged. 

 [Am. Journal of Science (2) ix. 12.] 



The remarkable parallelism between the rocks of Western Scot- 

 land and Canada has already been shown in the existence of the 

 Laurentian, and Cambrian (Huronian) systems, overlaid by quartz- 

 ites containing ScoUthus, to which succeed limestones containing 

 a numerous fauna, identified by Mr. Salter with that of the Chazy 



