180 Reviews — Geological Survey — Geology of India. 



than 3 per cent, of silica. As much as 13 '76 per cent, of titanium 

 oxides has been found in some samples of bauxite, and as little as 

 2"70 per cent, of ferric oxide. It is contended that the samples come 

 within the limits of bauxite marketable as a source of aluminium, and 

 in this respect compare favourably with the material now being 

 mined so largely in the South of France. Respecting the develop- 

 ment of these Indian bauxites for use as a source of aluminium, the 

 Director appears to favour the notion of the manufacture of pure 

 alumina localh' by extraction with alkali, and the export of the pure 

 oxide to aluminium works abroad. He considers that the exploitation 

 of the Indian deposits offers a promising field for private enterprise. 



Coal. — There is a considerable yield of coal from beds of Tertiary 

 age in Assam, and mention is made of two fields in connection with 

 the Bengal- Assam Railway, belonging to the same series as those 

 well-known in the Makum field. These coals are said to possess 

 a high average A'alue as fuel, but contain much sulphur and moisture. 

 On the other hand, some of the mines in the Makum field itself ai'e 

 known to have yielded very satisfactory results. As an instance, 

 however, of the minor position held by Tertiary coal m India, it 

 appears that, whilst in 1905 about eight million tons were raised from 

 the Gondwana coalfields, not quite half a million tons were raised 

 from Tertiary beds, and of these latter more than 50 per cent, is 

 produced in Eastern Bengal and Assam. Mr. Latouche states that 

 no coal was extracted in Burma, "the mines in the Shwebo district 

 having been closed, but prospecting for coal is being carried on in the 

 Chindwin district. The result of the examination of the Tertiary 

 coalfields of the Northern Shan States has been disappointing, as the 

 quality of the coal was found to be very poor." 



Petroleum. — The production of petroleum remains about the same as 

 before in Assam, where the amount is very small, but has largely 

 increased in Burma, which is now beginning to yield important 

 results. In 1905 the output was again the highest recorded, 

 amounting to over 142 million gallons. The question between the 

 old shallow hand-dug ' twinza ' wells and the scientific borings of 

 the several oil companies is naturally a serious one, and Mr. Holland 

 thinks that the native oil industry must soon begin to wane unless 

 the Burmans succeed in finding some means of reaching a greater 

 depth than 400 feet, which at present is their limit. There are several 

 oil-fields, the geological features of some having already been described 

 in the Records. In one case it is shown that the oil-bearing-sands, 

 instead of being continuous over the whole dome, are very limited 

 sandbanks in which the oil is stored. The great variation in thickness, 

 horizontal extent, and levels of each of them points to this, as also 

 does the abundant current-bedding so typical of the strata immediately 

 above. " Perhaps one of the most interesting and puzzling features of 

 this area is the occurrence of the largest quantities of gas, not in the 

 centre, where the anticlinal crest reaches a maximum elevation, but 

 at a considerable distance further south ; in fact, the field appears to 

 terminate southwards as a gasfield." In another oil-field the effect of 

 a Miocene anticline, lately observed, is brought under discussion. 



Gold. — Mysore heads the list in 1905, as heretofore, with a value 



