(jeolofjy of JUchnioiid Count ij, 2\. Y. 105 



Brighton ; near the scliool-hoiise at Garretsun's .Station; on 

 Meissner Avenue near Richmond, and near Egbertville. Tiie 

 highest point of the ridge is nearly opposite Garretson's Station, 

 and abont half-way across the liills, where the elevation, as 

 measured by an aneroid barometer, is four hundred cind twenty 

 feet. 



There are a number of interesting minerals associated with the 

 serpentine rocks ; the following species and varieties have been 

 collected at Pavilion Hill, and in New Brighton : — Compact 

 Serpentine, Fibrous Serpentine (" Araianthns," ''Chrysotile"), 

 Marmolite, Silvery Talc, Apple-green Talc, Gnrholite, Dolomite, 

 Calcite, and Chromite. Pink Talc and Deweylite are reported 

 by Prof. I). S. Martin, and Magnesite by Prof. Dana (Mineral- 

 ogy, 1868, p. 774), as found on Staten Island. It is stated by 

 Mather that magnesic hydrate (Brucite) occurs there, but none 

 has been found recentl}^ The fibrous variety of the serpentine 

 has been very generally known as asbestus; this mineral, however, 

 is properly a fibrous amphibole, and does not occur on Staten Is- 

 land. These minerals must be regarded as products of metamor- 

 phism, and were formed during the period when this action was 

 in progress. 



The metamorpliic rocks of Staten Island are apparently a 

 southern continuation of those of Hoboken, N. J., and New 

 York island; the facts from which this conclusion is drawn are as 

 follows : 



First. — The strike of the rocks is nearly the same at both 

 places, and the direction of the Staten Island ridge would, if 

 prolonged, meet the Hoboken exposure of serpentine at Castle 

 Point. 



Second. — The serpentine lies west of the granitic rocks at 

 both places. 



Third. — Although the texture of the serpentine at Hoboken 

 and that of Staten Island is slightly different, yet their chemical 

 composition and associated mineral species are very similar. 



Fourth. — It is highly probable, though not proven, that the 



