116 



kind, in schists of two inches thick, occurring in talcose 

 and micaceous rocks. The sulphurs are massive and of good 

 quality from Campano, Cumana, and Coro. Asphaltum and 

 its varieties are reported to be found on the coasts in great 

 deposits and in springs : the specimens in the collection are 

 of excellent quality. 



The twelve rock specimens of quartz crystals include 

 some of equal purity and size to those obtained from Brazil. 

 The marbles are of inferior quality and quite devoid of 

 colour and beauty; but in the International Exhibition of 

 1862 some excellent green and red marbles were shown. 



The predominating rocks of the mountain ranges in 

 Venezuela are jmlseozoic, metamorphosed talcose and chlo- 

 ritic slates, with great layers of gneiss; and within this 

 range along the line of faults and in veins, are found an 

 endless variety of minerals, of which the collection contains 

 asbestos, serpentine, talc, hornblende chlorite, kaolin, felspar, 

 and selenite. 



Amongst the comparatively recent rocks are stalactites, 

 salt, marl, alum, gypsum, and many calcareous deposits from 

 the sea shores and fresh water lakes. 



The special collection made by Mr. Spence during a visit 

 to the Island of Orchilla is interesting to the geologist. It 

 contains sufficient specimens to decide the main geological 

 character of the island to be entirely metamorphic gneiss, 

 overlaid with modern calcareous tufas. 



The collection includes a number of crude guanos, phos- 

 phates of lime, alumina and urao, a sesquicarbonate of soda 

 — all of commercial value and sources of prosperity if effi- 

 ciently worked. 



