HANDBOOK FOR THE DEPARTMENT OF GEOLOGY. 567 



(See specimens 39014, 70137, and 70556, from California, England, New 

 York State.) Those resulting from the hydration of other maguesian 

 silicate minerals are to be found grouped with the unaltered rocks of 

 the same nature. (See also exhibit illustrating the origin of serpentine.) 



It is, perhaps, as yet too early to state definitely that all peridotites 

 are eruptive. In many instances their eruptive nature is beyond dis- 

 pute. Others are found in connection with the crystalline schists, so sit* 

 uated as to suggest that they may themselves be metamorphic* Owing 

 to their basic nature and low fusing points the peridotites have not, as a 

 rule, been productive of pronounced contact metamorphism. They have 

 of late excited considerable interest from their supposed connection with 

 the origin of the diamond. (See under head of picrite porphyrites, 

 p. 585.) 



The peridotites are rocks of wide distribution, but covering compara- 

 tively limited areas. The following are the principal varieties and 

 localities represented : 



Dunite: Near Webster, North Carolina,- 39131 and 29004; Corundum Hill, Macon 

 County, North Carolina, 36845; Wake County, North Carolina (serpeutiue), 

 39030; Red Hill, Plumas County, California, 38361 ; Cumberland, Rhode Island 

 (Cumberlandite), 39034; Dun Mountain, New Zealand, 703-16. 



Saxonite: San Francisco, California, 39014 ; Riddle, Oregon, 70600; Lizard district, 

 Cornwall, England (serpentine), 39011 ; Cadgwith district, Cornwall, England 

 (serpentine), 70137; near Troinsoe, Norway, 35758. 



Picrite: llchester, Maryland, 69551 ; Little Deer Isle, Maine, 39044; Clickerton, 

 Cornwall, England, 39010 ; Biedenkoff, Hesse Nassau, Prussia, 36578, (Palajopik- 

 rite) 36579 ; Tringenstein, Nassua, 36580. 



Hornblende Picrite : Stony Point, New York, 38339. Madison County, Montana. 



Wherlite (Eulysite): Near Red Bluff, Madison County, Montana, 70675 ; Volpersclorf, 

 Silesia, 34766; Schriesheim, Baden, 36581; Terra di Zanschetta, Bologna, Italy, 

 36584 and 36585 ; Monte Ferrato, near Prato, Florence, Italy, 73057. 



Lherzolite: Lherz, France, 38240; Areige, France, 6731; Argueuos, Haute Garonne, 

 France, 36582; Fauraft, Markirch, in the Vosages Mountains, 36585. 



The following are so much altered that they can be designated simply 

 serpentines : 



Deer Isle, Maine, 39047; Lynufield, Massachusetts, 70140 ; Hoosac, Berkshire County, 

 Massachusetts, 27205 ; Russell, Massachusetts, 38403 ; Blandford, Massachusetts, 

 38405; Bare Hills, near Baltimore, Maryland, 37435; Saliwick Lake, Alaska, 

 37027; Kupperberg, in the Fiebtelgebirge, Bavaria, 36583; Greipendorf, Saxony, 

 36673; Waldheiui, Saxony, 36675; Ranenthal, Yosg.es Mountains, 36587 ; Gruni- 

 berg, Silesia, 34765; Japan, 27136, 



9. The pyroxenites, 



Pyroxenite, a term applied by Dr. Huntf to certain rocks consist- 

 ing essentially of minerals of the pyroxene group, and which occurred 

 both as intrusive and as beds or nests intercalated with stratified 

 rocks. The curator here follows the nomenclature and classification 

 adopted by Dr. G„ H. Williams,! 



*See Kalkowsky's Elemente der Lithologie, p. 242. 



t Geology of Canada, 1863, p. 667. 



t American Geologist, vol. i, July, 1890, pp. 35-49. 



