50 Ailing — Problems of Adirondack Precambrian. 



folded into an anticline which pitches northward. The 

 present surface truncates the fold so that the rocks out- 

 crop in the form of a U. These illustrations show that 

 the Grenville has been folded in the eastern and south- 

 eastern Adirondacks. The work of Martin 3 in the 

 Canton sheet and Newland's description of the Edwards 

 zinc-pyrite district, 4 show that the old sediments have 

 been folded in the western area as well. 



That the Grenville was folded and highly foliated before 

 the intrusion of the Algoman rocks has been pointed out 



Fig. 2. 



f\ppr ox imatc Sca\e 



Algoman Sy enrte - &ramte 

 LaureYvtian Metajgabbro 

 SiUiimanVte Schist 



|; 1 Quavt^ite 



Crystalline Lirnestone 

 G-raphVt'o Schist 

 Garnet-Sillivriarute Gneiss 

 Unclassified G-renviUe 



Fig. 2. Geologic reconnaissance north and south sections of the Flake 

 Graphite Co.'s property, Saratoga Quadrangle. Based upon traverse by G. 

 H. Chadwick and H. L. Ailing, 1917. Note the overthrust faulting and the 

 isoclinal folding. 



by Kemp. He says: 5 "Recent field observations ... in 

 the vicinity of Keene Valley have shown in massive anor- 

 thosite many inclusions of strongly foliated [Grenville 

 para-] gneiss. The foliation of the fragments runs in all 

 directions, even in an area of a few yards. The inference 

 will be drawn that the Grenville [para-] gneisses were 

 already strongly metamorphosed when the anorthosite 

 entered, and that they are very much older than the 

 intrusives. ' ' The significance of this observation does 



8 Martin, J. C: N. Y. State Mus., Bull. 185, pp. 93-108, 1916. 



4 Newland, D. H. : N. Y. State Defense Council, Bull. 2, fig. 3, p. 43, 1917. 



6 Kemp, James F. : Bull. Geol. Soc. Amer., vol. 25, p. 47, 1914. 



