THE SECOWDAllY OHOU*. 169 



grey copper : it is probably the metalloid diallage that has 

 given the Cerro de Guanabacoa the reputation of riches in 

 gold and silver, which it has enjoyed for ages. In some 

 places, petroleum flows* from rents in the serpentine. 

 Springs of water are frequent ; they contain a little sul- 

 phuretted hydrogen, and deposit oxide of iron. The Baths 

 of Bareto are agreeable, but of nearly the same tempe- 

 rature as the atmosphere. The geologic constitution of 

 this group of serpentine rocks, from its insulated position, 

 its veins, its connection with syenite, and the fact of its 

 rising up across shell-formations, merits particular attention. 

 Feldspar with a basis of souda (compact feldspar), forms, 

 with aiallage, the euphotide and serpentine ; with pyroxene, 

 dolerite and basalt ; and with garnet, eclogyte. These five 

 rocks, dispersed over the whole globe, charged with oxi- 

 dulated and titanious iron, are probably of similar origin. 

 It is easy to distinguish two formations in the euphotide ; 

 one is destitute ot amphibole, even when it alternates with 

 amphibolic rocks (Joria in Piedmont, Regla in the island of 

 Cuba), rich in pure serpentine, in metalloid diallage, and 

 sometimes in jasper (Tuscany, Saxony) ; the other, strongly 

 charged with amphibole, often passing to dioritef, has no 

 jasper in layers, and sometimes contains rich veins of copper, 

 (Silesia, Mussinet in Piedmont, the Pyrenees, Parapara in 

 Venezuela, Copper Mountains of North America). It is 

 the latter formation of euphotide which, by its mixture 

 with diorite, is itself linked with hyperthenite, in which 

 real beds of serpentine are sometimes developed in Scotland 



* Does there exist in the Bay of the Havannah, any other source of 

 petroleum than that of Guanabacoa, or must it be admitted that the 

 " betun liquido," which in 1508 was employed by Sebastian de Ocampo 

 for the caulking of ships, is dried up ? That spring, however, fixed the 

 attention of Ocampo on the port of the Havannah, where he gave it the 

 name of Puerto de Carenas. It is said that abundant springs of petroleum 

 are also found in the eastern part of the island (Manantialis de betun y 

 chapapote) between Holguin and Mayari, and on the coast of Santiago de 

 Cuba. 



t On a serpentine that flows like a penombre, veins of greenstone 

 (diorite), near Lake Clunie, in Perthshire. See MacCulloch, in Edinb. 

 Journ. of Science, 1824, July, pp. 3 16. On a vein of serpentine, and 

 the alterations it produces on the banks of Carity, near West-Balloch in 

 Forfanhire, tee Charles Lyeil, 1. c., vol. iii., p. 43. 



