1840.] 



from the Peninsula of India. 



29 



124. — Mica schist with garnets and carbonate of copper— Gurumany- 

 penta, Nellore mining district. 



125. — Carbonate of copper in layers in hornblende schist— Bungeral 

 Mettah, Nellore mining district. Mr. Prinsep thinks the phenomenon 

 of the ore alternating with the hornblende interesting in a geological 

 point of view, as affording exactly the appearance of gradual deposition 

 from a liquid, at this earliest period of geological formations. But 

 when we see, as in some specimens of this very rock, the ore running 

 through it in fissures and lines nearly perpendicular to those of stratifi- 

 cation, we must look to some other cause than a- mechanical deposition 

 from a liquid to account for its occurrence in such situations, and pause 

 ere we pronounce the ore to be coeval with the primary rock which im- 

 beds it. 



126. — Mica schist, in which the mica is, in part replaced by innu- 

 merable small garnets, imparting a granular structure to the rock. 



127. — Specimens of the copper ore, principally from Gurumanypenta, 

 Bungeral Mettah, Salighirry and Yerrapully — Nellore : they present for 

 the most part the carbonate passing into malachite and mountain blue. 

 Some fragments have a quartjiose matrix; both coloured green, and ap- 

 pearing so, from the imbedded ores — another variety runs in veins 

 through a dark red oxide of iron, which Prinsep considers, to be the 

 same as that of Dr. Thomson's specimen. (These ores have been ana- 

 lyzed in England, by Dr. Thomson, and more lately in India, by Mr. 

 Prinsep, vide Madras Journal, for April 1836, p. 154). The mixture of 

 sulphuret of iron, according to Prinsep, and perhaps of copper, with the 

 oxide, gives the whole a dark arenaceous character. The first ore yield- 

 ed 30.2 per cent of metal, and the last 39.5. 



128. — Copper ore with grey metallic lustre internally, and penetrated 

 with green streaks : probably the combination of the carbonate and sul- 

 phuret, mentioned by Prinsep as the richest ore met with, and yielding 

 69 per cent, of pure copper ; highly malleable ; specific gravity, interme 

 diate between the carbonate and sulphuret. 



129. — Schorl crystallized in prisms with quartz, mica and traces of 

 copper : much finer crystals of this variety of tourmaline may be obtained 

 from the locality whence these were obtained, but I had not the means 

 of detaching them from their bed, which occurs in the mica schist of 

 Bungeral Mettah, Nellore mining district. This variety of schorl differs 

 slightly from that of Europe. It melts into a greenish grey enamel, 

 instead of a black slag — hardness between quartz and topaz. With 

 borax it fuses into a transparent glass tinged green. 



