CXXIV PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



and gneissose, the granite-boulders being frequently 4 to 5 feet in 

 diameter, imbedded in a matrix sometimes of coarse sandstone, some- 

 times of the finest shale, and at Parongo of dark-green silt ; and the 

 bed itself is very curious, the authors explaining the transport of such 

 boulders by the moving power of ground or floating ice formed and 

 carried down by rivers. In respect to climatal difficulties in such an 

 explanation, the authors point out that the winter temperature of 

 Thibet is between 23° and 41°, although the summer temperature 

 is between 77° and 81° Fahr., this country lying only 10° to 15° 

 north of Cuttack, so that a very small variation in local circum- 

 stances would be sufficient to account for the change in temperature 

 from the epoch of this deposit to the present epoch ; but, even allow- 

 ing the force of this reasoning, I am myself almost inclined to prefer 

 the Mallet theory of the mud-slips upon a coast, by which the boul- 

 ders lodged along a coast- line would be gradually shifted downwards 

 to deep water, and finally imbedded in the mud : in either case it is 

 a very remarkable example of similar causes producing similar eff'ects 

 at all periods of the earth's history. The fossils are the remains of 

 plants, and the strange deficiency of other organic remains through so 

 large a space is justly contrasted with the exuberance of organic life 

 of the existing epoch. The authors put this series in comparison wdth 

 the deposits of the Nagpur district, described by Messrs. Ilislop 

 and Hunter in the Journal of the Geological Society ; the general 

 parallelism of the several divisions being strongly marked, both by the 

 mineral character of the beds as well as the organic remains. Mr. 

 Hislop has, however, ascribed the carbonaceous beds of Central 

 India to the Oolites, and the authors advance their reasons for diff'er- 

 ing from his statement, principally founded upon the supposed posi- 

 tion of the ]\Iangali shales of Hislop, which appears to be between 

 the upper and lower members of the series. These shales produced 

 the Labyrinthodontoid Batrachian described by Owen ; and, as this 

 group of animals is now found to be characteristic of the Permian as 

 well as of the Triassic deposits, the authors consider it probable that 

 the Talcheer, Damoodah, and other Bengal carbonaceous fields are 

 not more recent than the Permian epoch, whatever may be the ap- 

 parent testimony of the vegetable evidence. 



These deposits being manifestly valueless as coal-bearing strata, Mr. 

 Oldham investigates the circumstances of the iron-ores of Talcheer, and 

 of the manufacture of them into iron. The ores are oxides, either the 

 magnetic or red and brown ha3matites. The fuel used is always char- 

 coal, and the iron produced is of an excellent quality. Mr. Oldham de- 

 scribes the manufacture in detail ; and, having ascertained that about 

 200 tons of charcoal may be produced from a square mile, and that 

 with sundry improvements in the manufacture, 2*5 tons of charcoal 

 will produce 1 ton of wrought iron, he concludes that a circle of forest 

 four miles in diameter would be sufficient to produce 1000 tons of 

 wrought iron, and about 300 square miles would produce fuel for 

 24,000 tons. All these calculations are worked out with the greatest 

 care and ability, and consequently afford a reasonable basis for establish- 

 ing the iron-manufacture with a good chance of permanency, pro- 

 vided proper care be taken in the management of the forests. 



