PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



Vol. II. 1837. No. 50. 



February 22. — John Backhouse, Esq., of Hans-place, Sloane-street, 

 was elected a Fellow of this Society. 



A paper on the Geology of Cutch, by Captain Grant, of the Bonn- 

 bay Engineers, and communicated by Charles Lyell, Esq., F.G.S., 

 was read. 



This district, so highly interesting on account of the phenomena 

 which accompanied the earthquake that devastated it in 1819, is 

 situated near the eastern branch of the Indus, between 22 and 24 

 degrees of north latitude, and 68 and 72 degrees of east longitude. 

 On the north, it is bounded by the Grand Runn, and the Thur or 

 Little Desert, on the south by the Gulf of Cutch and the Indian Ocean, 

 on the east by the province of Guzerat, and on the west by the eastern 

 branch of the Indus and the territory of Sinde. Its superficial con- 

 tents are about 6500 square miles. The surface is traversed by three 

 ranges of hills, having in general an east and west direction. The 

 hills constituting the northern chain, which borders the Runn, present 

 a perpendicular capping of sandstone, surmounting towards the north 

 a sloping talus, and towards the south an inclined plune, both com- 

 posed of laminated clay and slaty limestone, with occasionally layers 

 of sandstone. The second or central range, is constituted partly of 

 the formation last mentioned, and partly of another consisting of sand- 

 stone and shale. The third or southern, is formed wholly of volcanic 

 rocks, but has nearly the same linear direction as the others. 



To the south of the last range is an extensive flat, composed of a 

 deposit, cpnsidered by Capt. Grant to be tertiary, and of an alluvial 

 band, bordering the sea coast. 



The first of these formations, which constitutes the northern range 

 of hills, abounds with Ammonites, Nautili, Belemnites, Trigonise, and 

 other fossils characteristic of the oolitic system of England. The for- 

 mation of sandstone and shale, which occupies a much greater surface, 

 contains, in various localities, thin beds of coal, sometimes very im- 

 pure, but at others tolerably good ; also layers of iron ore ; and in 

 the shale as well as in the sandstone, casts of reeds and impressions of 

 ferns are stated to occur. With respect to the relative age of these 

 two formations, Capt. Grant was unable to procure any decisive 

 information ; but he thinks that the sandstone and shale system, 

 passes beneath that of laminated clay and limestone. 



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