^6 NEW YORK STATE MUSEUM 



pressed the view that " the gnarled and twisted rocks of the Archean 

 speak of the presence beneath them of molten magmas rather than 

 of an enormous degree of compressive forces upon them," and W. J. 

 Miller (191 6) has stated it as his belief that none of the published 

 Adirondack maps or available data affords any reasons to believe 

 that the Grenville strata were ever profoundly folded or compressed, 

 qualifying his statement in another place in saying, " that the 

 Adirondack Grenville strata are more or less folded is . . . 

 admitted, . . . but, in the light of recent studies, the writer (Miller) 

 doubts the interpretation of folded, tilted and foliated stru' tures 

 as due to intense lateral compression." 



As in this latter case a distinct area, the Adirondacks of New York, 

 has furnished the evidence, and the question is thus clearly cir- 

 cumscribed and also representative of the whole problem, we shall 

 consider it a little more fully. 



Those pioneers of Adirondack Precambrian geology, Cushing, 

 Kemp, Newland and Smyth, have all directly claimed, and presented 

 strong evidence, that intense orogenic forces have acted upon the 

 Precambrian gneisses of the Adirondacks with the conspicuous result 

 of isoclinal folding. Likewise has Martin (1916) in a publication 

 that is contemporaneous with Miller's asserted a folded character 

 for the gneisses of the Canton quadrangle in the northern Adiron- 

 dacks, and still more lately have Newland (191 7), Ailing (1919) and 

 Buddington (19 19), in view of Miller's conclusions paid special 

 attention in their researches in the Adirondacks to the evidence 

 of folding and all found such of a conclusive character. Ailing (1919, 

 p. 67) concludes " that the Grenville strata have been extensively 

 isoclinally folded " and Buddington (1919, p. 101) infers that his 

 observations, " for the most part confirm Miller's conclusions as 

 to the primary origin of most of the foliation in the igneous gneisses, 

 but on the other hand they conform to the belief that strong orogenic 

 forces of mountain-building intensity have affected the rocks of 

 this district " (in the northwest). 



Chamberlin, in discussing the order of the magnitude of the 

 shrinkage of the earth, in his truly path-finding series of articles 

 on " Diastrophism and the Formative Processes " (1920, p. 5) finds 

 diastrophism displayed in three great fields, namely, (1) " the defor- 

 mations of the distinctly stratified terranes, chiefly those of the 

 Paleozoic and later ages," (2) " the complicated distortions and 

 the metamorphosed phases of the Proterozoic and Archean com- 

 plexes," and (3) " the deeper and more massive deformations of 

 the earth body." 



