4 NEW YORK STATE MUSBUM 
tion embodied in the text. Acknowledgment is also tendered to 
the gentlemen whose names appear in the list of authorities for 
local information. | | 
RELATIONS OF MINERAL DEPOSITS TO ROCKS 
By far the greater part of the crystallized minerals of New 
York State occur in igneous and metamorphic rocks, or grouping 
these two divisions in a rather broader term, in crystalline rocks. 
The areas covered by these embrace two important sections of 
the State; the northern section including the Adirondack region 
and extending over St Lawrence, Jefferson and Lewis counties on 
the west and the southeastern section including New York, West- 
chester, Putnam and portions of Orange, Rockland, Richmond 
and Dutchess counties. The area of Silurian limestones, ex- 
tending from west to east across the State just south of Lake 
Ontario and trending-to the south along the west shore of the 
Hudson, affords many localites for secondary minerals notably 
calcite, dolomite, celestite, barite, quartz ete. 
Igneous rocks 
Granites and pegmatites. The component and accessory min- 
erals of granite are commonly found in independent well formed 
individuals in cavities or vugs where the open space admits of 
free development of crystals formed by the separation of the min- 
eral constituents from the fused rock magma in the process of its 
solidification. Pegmatite occurring in dikes and veins is char- 
acterized by the same genetic series of minerals found in granite ~ 
but commonly in rather larger individuals corresponding to the 
coarser structure of the rock. 
COMMON MINERALS FORMING AND OCCURRING IN GRANITE AND 
PEGMATITE 
pyrite microcline epidote 
mareasite oligoclase allanite 
quartz spodumene tourmalin 
corundum amphibole muscovite 
chrysobery] beryl! biotite 
rutile garnet titanite 
orthoclase zircon xenotime 
albite _ topaz apatite 
MB Ge 
