590 WILLIAM J. MILLER 



developed at some length in its application to the Adirondack 

 region. 



Evidence against intense folding of the Grenville. — In spite of the 

 assumption of severe lateral compression, no large-scale example 

 of intense folding of the Grenville has ever been positively demon- 

 strated in the Adirondacks, and this in the face of the fact that main 

 hundreds of square miles have been mapped in detail. Describing 

 the Grenville structures of the Elizabethtown-Port Henry quad- 

 rangles. Kemp says: "The dips are prevailingly moderate and the 

 ancient sediments appear to have been folded or tilted to only a 

 moderate degree." 1 Regarding the Long Lake quadrangle, Gushing 

 says: "Nearly east and west strikes prevail, and the prevalent 

 dip is southward. This either indicates comparatively little fold- 

 ing, or else isoclinal folding, or else that the foliation does not 

 coincide with the bedding and so does not bring out the folding. 

 It is not possible to demonstrate which of these alternatives is the 

 true one. though the second is very unlikely, ami all the direct 

 evidence obtainable is against the third."- He also states that in 

 the largest Grenville belt "the dips are so tlat that they can seldom 

 be made out with certainty." 



The writer- 5 has described a structure section in the Broadalbin 

 quadrangle four miles long across the strike of Grenville strata 

 with dips oi 20 30 to the southeast. The exposed thickness of 

 Grenville is about 10,000 feet with no repetition of beds due to 

 possible isoclinal folding and no held evidence for profound faulting. 

 Another Grenville section recently described by the writer 4 in the 

 North Greek quadrangle is five miles long with a pretty uniform 

 dip of from 40° to 50 , thus showing a thickness of some 1S.000- 

 20,000 feet oi strata. There is no evidence of repetition of strata 

 by either folding or faulting. The Grenville is extensively devel- 

 oped throughout this quadrangle, and all the available evidence 

 points to only moderate deformation of the strata either by tilting 

 or slight folding. 



1 J. F. Kemp. New York State Mus. Bit!!., No. 138, 1010. p. 85. 

 - H. P. Cashing, ibid., No. 115, 1907, p. 485. 

 - ; W. J. Miller, ibid., No. 153. 101 1, p. 13. 

 * Ibid., No. 170. 1014. p. 15. 



