92 NEW YORK STATE MUSEUM 



these formations along the eastern side of the Hudson from Garrison 

 southward, but no occurrence is known which would encourage 

 exploitation. 



Most of these occurrences are undoubtedly of the same genera! 

 origin as is usual in the complete metamorphism of sediments, and 

 this particular content probably is derived from original carbonace- 

 ous materials which belonged to the rock. Plakes of graphite occur 

 in the schists and gneisses and limestone members, but it is more 

 apparent in the very schistose rocks than in the others. An occur- 

 rence of this same type at Tuxedo, 20 miles farther west, was investi- 

 gated with considerable care a few years ago by Mr Lorillard of 

 Tuxedo, and there have been other attempts to determine the work- 

 ability of this material ; but thus far none has succeeded, and most 

 investigators have gone no further than the preliminary stage. The 

 prospects in this quadrangle are certainly no better than at many 

 other points and there is no likelihood of them proving valuable for 

 this mineral. 



A very interesting occurrence of the same mineral in entirely dif- 

 ferent form is found near the west margin of the quadrangle west 

 of Dunderberg. This is an occurrence of graphite in a pegmatite 

 vein. The graphite occurs in large plates and is associated with 

 mica and quartz and feldspar. It is not developed on a large 

 enough scale for exploitation, but it represents a not uncommon 

 type of occurrence. The graphite must in this case have an igneous 

 history. Similar occurrences are found on the east side of the river 

 northwest of Garrison. 



General summary of economic resources. On the whole, the 

 economic resources of the quadrangle are not extraordinary in any 

 respect. For a region of such complexity of geological structure 

 and history they are rather strikingly insignificant. There are prac- 

 tically no mines and the prospects of furnishing products of very 

 high grade of any sort are, to say the least, only moderate. The 

 only industries of this sort which may lay claim to rather unusual 

 quality in the market are those connected with the Tompkins Cove 

 limestone, the Peekskill granite, and the Peekskill emery. 



Engineering Undertakings 



The Highlands of the Hudson lie directly across one of the great- 

 est lines of transportation of the United States. Such transporta- 

 tion facilities as the Hudson river itself presents, raises no question 

 at this point because the river is deep and wide enough to accommo- 



