1815.] Diluvial and Wave Translation Theories, 229 



others are evidently derived from the denudation the laterite has 

 been subjected to during the elevation of the land. 



Sand beds of Baroche underlying the Regur. Beds of a yellowish 

 brown micaceous sand, I am told by Professor Orlebar, underlie the 

 regur near Baroche, extending inland as far as Ahmednugger, in 

 which no fossils have been found. 



The Black clay of Coromandel. The cities of Madras and Pondi- 

 cherry, and other places on the Coromandel Coast, stand on an alluvi- 

 um which overlies beds of bluish black clay, interstratified with layers 

 of sand and reddish clay. The surface black clay imbeds marine shells 

 of existing species. 



These beds sometimes extend several miles inland. The bluish black 

 clay appears analogous to the regur, which will be described below. 

 This accumulation of clays and sands it is probable extends with little 

 intermission along the coast to the mouth of the Ganges, where they 

 will be interrupted probably by the fluviatile deposits of this mighty 

 river. The delta of the Ganges, as far as we can gather from one 

 boring experiment, consists at Calcutta of a series of dark clays and 

 sands ; they rest at the depth of 350 to 485 feet on a gravel com- 

 posed of rolled pebbles of granitic crystalline rocks, similar to those 

 described by Captain Cautley at the base of the Himalayas. The 

 uppermost strata contained portions of peat, kunker, and fragments of 

 trees, and the lowest beds, beneath a layer of dark carbonaceous 

 clay under which were fragments of coal, fossilized portions of tur- 

 tles, and the caudal vertebra supposed to be that of a Saurian. In 

 the arenaceous beds above this, more than 200 feet from the sur- 

 face, were found the lower half of a humerus, which Mr. Prinsep 

 supposed to be like that of a dog, and a fragment of the carapace 

 of a turtle. From the granite and gneiss gravel it has been inferred 

 by Dr. M'Clelland, that bold mountains of these rocks existed in close 

 proximity to the present site of Calcutta. The superimposed carbo- 

 naceous beds indicate a marshy surface clothed with vegetation, 

 prior to which the currents which brought down the gravel, he thinks 

 were arrested by the contemporaneous subsidence of the mountains 

 and the lowering of the bed of the Ganges. 



The Regur deposit. In a paper read before the Royal Society, 

 several years ago, I have already endeavoured to show that the re- 

 markable loam called Regur, is not a fluviatile deposit, as supposed by 



