nEOLOGY. The topographic divisions of India with their characteristic features are based largely upon difference, in geological structure. The main system of the Himalayas, so far as explored. has been found to be composed of crystalline strata—gneisses. schists, and il..meolis rocks—which show the effects of upheaval and folding during the great crustal movements that elevated the ranges in late Tertiary times. In the southern flanking chains, or snh-flimalayas, the most prominent formation comprises Tertiary sandstones, conglomerates, and clays, in dis thrbed position. These strata (the Siwalik group) are enormously developed. and contain a remarkable assemblage of fossil mammals. The great river plains of India occupy depressions in sedimentary strata, mostly of Eocene age. The Deccan plateau is formed largely of basalt which paired out from great fissures 'during tho Cretaceous period. These basaltic sheets occupy an area estimated at 200,000 square miles, and attain a vertical thickness of several thousand feet. The Vindliya Mountains on the north have a gneissic axis, with Paleozoic sediments on the flanks. East and south of this range there is a large area underlain by sandstones and shales, to which the name Gondwana system has been given. This group extends probably from the Permian to the Jurassic period: its fossil fauna and flora are more nearly allied to the life-forms of South Africa and Australia than to those of the Eurasian continent.
Mrmxn. Considering the extent of area and the large population, the mining industry is strikingly insignificant, though the recent de velopments are beginning to give it sonic im portance. Increased utilization is being made of the coal resources of the country. much to the advantage of the railroad and milling interests.
The annual output of coal increased from 000 tons in 1893 to 6.095.000 tons in 1900. The Province of Bengal produces over three fourths" of the total product, the output having grown from 1,915.000 tons in 1893 to 3.883.000 tons in 1S99. The principal other coal-mining regions are the Nizam's Dominions, Assam. the Central Provinces, and Central India (Hewn). in each of which the output was greater in 1899 than in any preceding year. The increased pro duction has resulted in the decrease of the im ports of coal—which amounted in 1900 to only 83.200 tons—and the increase in the exports of coal. amounting to 541.400 tons in the same year. Coolie labor is prominent in the working of the coal-mines.
The mining of gold is also rapidly becoming important, the yield having steadily increased from 107,273 ounces in 1890 to 513,266 ounces in 1900. The greater part of this is mined from the quartz deposits of Mysore. although some gold is obtained from river gravels in the Hima layas and elsewhere. A parallel growth is being made in the production of petroleum, the output in 1900 having been nearly 38.000.090 gallons, the greater part of which was obtained from Upper Burma. The importation of mineral oil is still 7110r0 than twice as great as the home produc tion. The Cos-eminent has long maintained a monopoly in the production of salt. It is ob tained mainly bv the process of evaporation. and i the industry is carried on along the coast region and at some of the interior lakes. The anneal yield is estimated at about 1.000.000 ton. Salt petre is obtained in the plains. lead and copper are mined in the Himalayas. and tin and rubies in Burma. India was long famous for its dia monds, but the output in the last eentury has shrunk into insignificance.