MAGNETITE IRON DEPOSITS OF SOUTHEASTERN NEW YORK 59 
Any structures suggestive of folding, either in the rocks as now 
exposed, or in the magnetite bodies themselves, must have been 
inherited in large part from the Grenville, provided the foregoing 
conception is correct; these structures have already been spoken of. 
Geologists who have studied the problems of the Precambrian rocks 
in the Adirondacks generally agree that these rocks present evidence 
of compression and metamorphism.*°* 
Similarly most of those who have studied the complex geology 
of the Highlands of New York and New Jersey, believe that 
the remnants of the Grenville found in these areas exhibit evi- 
dence of folding.’°’ On the other hand, a few of the geologists 
who have worked in this region are inclined to be noncommital in 
their expressions of opinion with respect to folded structures in the 
Grenville; they assign an igneous origin to the gneisses and explain 
the foliation by movement in the still pasty or semimolten igneous 
mass, but make a distinction between “ structural foliation” and 
“textural foliation.” *°° “ Structural foliation” is explained as the 
“interlayering of different varieties of rock,’ and the “ orientation 
of component mineral grains”; “textural foliation ” is explained as 
the development of a sort of parallel structure during consolidation 
under flowage conditions. Miller *°’ later reversed his opinion as 
104 Kemp, J. F. Annual Rep’t State Geol. 1803-95-97; also N. Y. State 
Mus. Bul. 14-21-1109, 138. Also forthcoming bulletins now in press. 
Newland, D. H. Annual Rep’t State Geol. 1897; also N. Y. State Mus. 
Bul. 119, and Econ. Geol. v. 2, 1907. 
Cushing, H. P. N. Y. State Mus. Bul. 95, 115, 145, 160. 
SmiythewCy EageN. Yeu State! Mus! (Bull 145: 
Ogilvie, I. H. N. Y. State Mus. Bul. 06. 
IMleeem, Jo (Cy ING Ms Stieie Wiles Ibi aes, 
Alling, H. L. N. Y. State Mus. Bul. 199, also Am. Jour. Sci. (4) 48, 1919. 
Buddington, A. F. Rep’t of the Director of the State Mus. 1917. 
MaillermWi i NEO Yn State Misys Bali 170: 
105 Rogers, H. D. Final Rep’t Geol. N. J., 1840. 
Mather, W. W. Geol. First Geol. District, 1843. 
Ann. Rep’t Geol. N. Is 1854-55-56. 
Cook, G. H. Geol. J., 1868. 
Ries, Heinrich. Gr Orange Co., N. Y., Rep’t State Geol. 1895. 
Nason, F. L. Annual Rep’t State Geol. GNESI  nacsomalsommiransa eAwaln 
M. E., 24, 1804. 
Wolff, J. E. Annual Rep’t State Geol. N. J., 1803. 
Berkey, C. P. WN. Y. State Mus. Bul. 107, 146. 
Also abstract, Annals, N. Y. Acad. Sci., 23, 1914, and N. Y. State Mus. 
Bul. 225-226. 
106 Bayley, W. S., in folio ney, We So Ee Se! Ws Ay UOMO WOM. , Bs AVEO 
Iron Mines and Mining in New Jersey; v. VII, 1910. Final Report Series 
of the State Geologist. Bayley is a little more definite here, as he states 
. . Cases where folding has been proven are extremely rare.’ (Go Okey 
Spencer, AMES) ine folio 161, Wer Sa Gy Sei pn: 
107 Miller, W. J. Origin ‘of Foliation in the Precambrian rocks of North- 
ern New York, Jour. Geol. 24, 1916, p. 587-610. 
