MAGNETITE IRON DEPOSITS OF SOUTHEASTERN NEW YORK 39 
For the West Point quadrangle, according to Berkey,* the 
divisions are as follows: | 
West Point Quadrangle Northern New Jersey 
Cambro-Ordovician Hudson River formation | Martinsburg shale 
(Sedimentary) Wappinger limestone Kittatinny limestone 
- Poughquag quartzite Hardyston quartzite 
Great Unconformity 
(Igneous) Basic dikes 
(Igneous) Pegmatites Byram gneiss 
Storm King granite (a mixed product) 
Pegmatites 
Reservoir granite 
Laurentian (?) (a syntectic) Losee gneiss 
(Igneous) Canada Hill graniteand as- (a mixed product) 
sociated injection gneiss 
Pegmatite and magnetite 
Occasional basic injections} Pochuck gneiss 
(Igneous) Peekskill diorite gneiss (a mixed product) 
(an injection type) 
Post-Grenville Precambrian 
Later Grenville Manhattan schist Franklin limestone 
(Sedimentary) Inwood limestone 
Lowerre quartzite 
Grenville metamorphics Metamorphic remnants 
o 
5 Mica schists Chiefly variable schists 
§| Older Grenville Meta quartzites and interbedded lime- 
<5| (Sedimentary) Meta limestones (Sprout| stones 
Brook limestone) 
Para-gneisses (Fordham 
gneiss) 
For the purpose of comparison, equivalent formations in northern 
New Jersey are likewise included. 
The crystalline rocks of the Highlands west of the Hudson river 
in Orange county have not yet been studied with the same care and 
attention as those in New Jersey and those in New York in the area 
covered by the West Point quadrangle. While most of the field 
work in connection with the preparation of this report has been 
necessarily limited to the magnetite bodies and their immediate 
environments, the writer has, with one exception, encountered no 
field units which did not readily lend themselves to the classification 
94 Berkey, C. P., & Rice, Marion. Geology of the West Point Quadrangle. 
N. Y. State Mus. Bul. 225-26. I921. 
