1038 The Serpentine of Staten Island, New York. [i 
sides those here mentioned seen on the island, are smal 
coarse-grained granite, having the characters of a vei 
endogenous mass, and Others of an actinolite rock, both 
among the sands on the north-east shore of the island. 
Mather, who described this locality forty years sin 
upon the serpentine as an eruptive rock like the parallel 
diabase seen to the west of it, but Dr. N. L. Britton, of t 
York School of Mines, who in 1880 published in the 
ings of the New York Academy of Sciences a descripti 
geological map of the island, recognized the serpentine. 
to that which is stratified as a contemporaneous member 
ancient gneissic series of Manhatten island, and appears 
Hoboken, a view which is doubtless correct. a 
The appearance of isolated hills of serpentine rising 
newer rocks is common in other regions, and is by the 
attributed to the fact that this insoluble magnesian silicate re 
to a great degree the action of subaérial decay, which 
gneisses and other feldspathic rocks into a clay that is 
moved, leaving the beds and other lenticular masses 0 
bedded serpentine in relief, In many parts of Italy, where 
or belts of serpentine protrude in the midst of Tertiary 
they have been described by the earlier observers as 
masses. The question of their geognostical relatio! 
often complicated by the fact that subsequent moven 
earth’s crust have involved alike the underlying serp 
the newer strata, and have given rise to faults and inve 
which the younger rocks, overturned, are made to ' 
and even beneath the older. This condition of thingst 
illustrated by reference to localities of serpentine lately 
by him in Liguria and in Tuscany, where the true 
relations of these rocks had been first indicated by Ga 
structure above described was farther explained by 
the similar inversions of strata along the western 
Atlantic belt from the Highlands of the Hudson 
along the Appalachian valley. | 
The writer stated that although serpentine, under | 
influences, decays much Jess rapidly than the harder 
does not entirely escape this process. He showed t 
on Staten island is covered in parts with a decayed. 
ing portions of limonite separated by a process of $ 
