516 Revieivs — Royal Geological Society of Cormvall. 



corner of our island an epitome, as it were, of all the most important 

 phenomena of mineral veins, so that, with a few exceptions, those 

 exhibited in metalliferous deposits in other parts of the world are 

 but repetitions and illustrations on a grander scale of those already 

 observed in this country. 



The first chapter in the volume before us treats of the deposits 

 of the provinces of Kumaon and Guhrwal in North-western India, 

 the rocks being first described, with their geological structure and 

 relative position ; then follows an account of the mode of distribu- 

 tion of the enclosed metallic ores, succeeded by descriptions of the 

 methods of working the mines and dressing the ores. The same 

 order is observed in the succeeding chapters. 



In the second chapter we have an account of the deposits of the 

 rich mining district of Chaiiarcillo, in Chili, whence for many years 

 past very large quantities of silver have been jarocured. Notwith- 

 standing that the yield of silver has been so enormous, and is still 

 very considerable, it appears that great waste is the rule there, and 

 that the very large masses of inferior ores usually accompanying and 

 surrounding the rich hunches, are seldom brought to grass to be 

 dressed, but are thrown aside in the deserted portions of the mine. 

 And this, too, although the place is but fifty miles inland, and has 

 good roads, and for part of the way railway communication to the 

 coast. In these days of improved and economical methods for dress- 

 ing poor ores this is somewhat surprising ; but it may be partly ac- 

 counted for by the want of water, as we read in one place that " a 

 large mining population, attracted by the discovery, quickly stripped 

 the surface of its wood ; so that neither tree, shrub, field, garden, 

 nor even an occasional wild flower, now relieves the brown and 

 dreary monotony, the uniform and frightful barrenness, of this rich 

 but horrible desert. Although the bed of every valley and glen is 

 overlaid by a thick bed of shingle, pebbles, and gravel, deeply scored 

 with ruts and other indications that the country was formerly well 

 watered, there is neither a single spring in the district, nor is one 

 streamlet now visible from the bleak summit of Chanarcillo, except 

 — perhaps twice or thrice in the year — when an occasional shower 

 may for a few hours supply each ravine with a scantily trickling 

 rill ; these are, however, quickly absorbed by the thirsty soil. 



"No water has ever been drawn to the surface of any mine in the 

 district; a little moisture, however, — derived, perhaps, from ascend- 

 ing vapour, — exudes from some of the rocks and veins, but it is im- 

 mediately absorbed by other portions of the neighbouring strata." 



Of the richness of some portions of the Limestone beds which 

 appear to be the silver-bearing rocks here, and particularly of one 

 bed known in several mines under different names, the author says : 

 " Throughout this bed, esjDecially where calcareous spar and earthy 

 iron-ore abound, for some distance on either side of the Candelaria, 

 Colorado, and Descuhridora lodes, the rock is sprinkled, its laminee are 

 interlaid, and its joints are invested or filled with granules, filagrees, 

 leaves, plates, and veins of native silver, mixed with the sulphuret, 

 the chloride, and — less frequently — the chloro -bromide of silver. 



