138 G. H. Williams — Serpentine {Peridotite) occurring 



1842. The geological position of the serpentine, as defined by 

 Vanuxem, has been so well summarized by Dr. T. Sterry Hunt 

 in his recently published volume of essa} r s,* that no further 

 account of it need here be given, but Vanuxem's descriptions 

 of the rocks themselves are so true that I cannot forbear quot- 

 ing some of them. In a supplement to his Third Annual Report 

 of 1839 he says : "The green and trap-like rocl^s observed near 

 the top of the hill to the east of Syracuse have been examined 

 so far as time would admit. They are all serpentines, more or 

 less impure, and of various shades of bottle-green, black, gray, 



etc Some have a peculiar appearance, like bronze, owing 



to small gold-like particles, with a lamellar structure, resem- 

 bling bronzite or metalloidal diallage ; also other particles, 

 highly translucent, like precious serpentine, with frequently 

 small nuclei, resembling devitrifications or porcellanites, colored 

 white, yellow, blood-red, variegated, etc." In his final report 

 (p. 109) he mentions the occurrence of both black and white 

 mica and " accretions resembling granite." In one case horn- 

 blende replaced the mica producing an apparent " syenite." 

 He also speaks of " calcareous accretions enveloped in the ser- 

 pentine." 



In 1858 Dr. T. Sterry Hunt published an analysis of a speci- 

 men of the Syracuse serpentine which he had obtained from 

 Professor James Hall, of Albany.f This contained 34*77 per 

 cent carbonate of lime, 273 per cent carbonate of magnesia and 

 62*5 per cent serpentine. This latter was found to have the 

 following composition : 



Si0 2 40-67 



Al a O,.__ . 5-13 



FeO 8-12 



MgO 32-61 



HO 12-77 



99-30 



No traces of nickel or chrome were detected. 



The Syracuse serpentine was also mentioned by the Hon. 

 Geo. Geddes in his Report on the Agricultural Industry of 

 Onondaga County,:}: and Prof. James D. Dana, in his Manual 

 of Geology. § It has recently acquired an additional interest 

 on account of the argument for the origin of serpentine by 

 chemical precipitation based upon it by Dr. Hunt.| Yanuxem 



* Mineral Physiology and Physiography, 1886, pp. 443-447. 



f This Journal, II, xxvi, p. 237, Sept. 1858. 



\ Transactions of the N. T. State Agricultural Society for 1859. 



§ Third Edition, 1880, p. 233. 



|| "The Geological History of Serpentines." Transactions of the Royal Society 

 of Canada, vol. i, p. 174, 1883, and Mineral Physiology and Physiography, 1886, 

 p. 443. 



