54 NEW YORK STATE MUSEUM 
northwest of the exposure mentioned. Neither in field relations nor 
lithologically does it resemble the coarse granites associated with the 
ore (see plate 5, figs. 2 and 3), and otherwise distributed in less pure 
form, involved with the Pochuck-Grenville. 
The Storm King granite. The latest of the granite intrusives 
(the Storm King granite), while recognizable and more or less easily 
differentiated by its lithologic character from the rest of the mem- 
bers of the Highlands complex, is not connected with the origin of 
the ores and is therefore of no importance so far as the magnetites 
are concerned. 
From the foregoing it will be seen that the rocks most intimately 
connected with the ore are those included in the Pochuck and its 
various modifications,’** and that they owe their origin and complex 
character to the extensive differentiation of a basic magma and to 
the invasion and impregnation of an ancient series of metamor- 
phosed and folded sediments by that magma and its differentiates, 
supplemented by later granitic intrusions of the Canada Hill and 
the Storm King types. 
( I The Pochuck (igneous) 
Pyroxenites, hornblendites (rare) 
Diorites, with pegmatitic facies 
Syenites with pegmatitic facies 
The magnetites and associated products 
The Pochuck granite 
saa ove 
The 
Pochuck Il The Pochuck—Grenville 
Gneiss Previously folded and metamorphosed Grenville sediments 
so extensively impregnated with the dioritic and syenitic 
facies of the Pochuck that their original character is 
obscure. 
III Modified Pochuck—Grenville 
Pochuck-—Grenville of II pegmatized and granitized both 
by impregnation and Jit-par-lit injection. (Injection 
gnetss). 
— 
1 Pochuck granite 
Intensely granitized Pochuck—Grenville 
The 2 Canaza Hill granite (a magmatic unit) 
Granites 3 Storm King granite (a magmatic unit) 
Later Precambrian basic dikes 
101 The writer believes that the ‘“ Losee gneiss” of the New Jersey High- 
lands may be merely a differentiation product of the Pochuck. Exposures of 
types equivalent in extent and character to the Losee and Byram gneisses of 
the adjacent Highlands area in New Jersey have not been recognized in 
southeastern New York in the territory covered by the writer. 
