Serpentines Near Philadelphia. — Jonas- 299 
at Staten Island in New York City and at Castle Point, 
Hoboken, N. J. 
t Mr. Newland has described all these serpentines and 
believes that they are derived from pyroxenytes and peri- 
dotytes. He objects to J. D. Dana's view that the New 
Rochelle serpentine is derived from a limestone contain- 
ing intruded silicates, i Mr. F. J. H. Merrill says that the 
serpentine of New Rochelle, is derived chiefly from amphi- 
bole and bronzite which are almost completely serpentin- 
ised. The rocks from which serpentine was derived were 
amphibolytes and other magnesian silicate rocks intruded 
into Ordovician schists.* Julien describes in detail, amphi- 
bole schists, (pyroxene schists), dioryte schists and gneisses 
throughout Manhattan island. The one area of serpentine 
that is of importance occupies a long belt between West 
Fifty-fourth and Sixty-third streets from Tenth avenue to 
the Hudson river. It represents a further alteration pro- 
duct of the hornblende schists ; both are alterations of basic 
igneous intrusions. 
New Jersey. — A different origin has been proposed for 
the deposits at Montville, N. J.t Mr. G. P. Merrill consid- 
ers the serpentine to be the result of the alteration of a non- 
aluminous pyroxene enclosed in a magnesian limestone. At 
Mendham in the same belt of limestone there is found ser- 
pentine with a similar origin. 
Pennsylvania. — In Pennsylvania serpentine is found in 
Northampton, Bucks, Montgomery, Delaware, Chester and 
Lancaster counties, forming in general, lenticular areas 
with a strike southwest and northeast. :|: There is an area 
north of Easton in Northampton county and small areas 
along the Lehigh river. The Easton area occurs on the 
southeastern slope of Chestnut hill. The hill is composed 
of pre-Cambrian gneisses interstratitied with beds of cal- 
* New York Acad. Trans., vol. i. p. 58. 
t School of Mines Quarterly, Apr. 1901, p. 307, July 1901, p. 399, article 
by D. H Nkwland. 
t Appendix A. The Geology of the Crystalline Rocks of Southeastern 
New York, by F j. Merrill, Keprinte 1 rfom tin' New York State Mu- 
seum Report, 1896. 
* Bull, of Geo. Soc. Am., vol. 12, pp. 421-494. Genesis of the Amphi- 
bole Schists and Serpentines of Manhattan Island, N. V., bj ALBXia A. 
Julien. 
t Proceed. U. S. Nat. Mus., vol. xii. 
* Reprint from Annals N. Y. Acad. Sci., vol. xiii., No. 6 .pp. 419-430. 
Jan. 14. 1901, by F. B Pk< k. 
