566 



A letter addressed to C. Lyell, Esq. was then read from Dr, Mc 

 Cleland, who has been associated with Mr. Griffith in the scientific 

 de})utation sent under Dr. Wallich into Upper Assam to investigate 

 the natural history of the country v;here the tea-plant is found growing 

 wild. The deputation left Calcutta in the end of August, and reached 

 the Kossia Mountains early in October. In crossing the Delta of the 

 Ganges and Bramaputra (Burrampooter), a high tract of land, two or 

 three hundred feet above the level of the plain, was observed but not ex- 

 amined near Dacca. Between this and the Kossia Mountains, distant 

 sixty miles, the old channel of the latter river extends, so that the 

 above high land is situated between the channels of the two greatrivers. 

 The country is generally composed of silt, but at Mymensing (where 

 the navigation is most obtructed), the Bramaputra crosses abed of yel- 

 low clay containing ferruginous and calcareous (the kunknr of India) 

 concretions. The author thinks this bed of clay extends from the 

 above hi^h land to the foot of the Kossia Mountains, or the extreme 

 point of the portion called the Garrow Hills, where the late Mr. Scott 

 found the fossil remains of animals. The partially inundated plain at 

 the foot of these mountains is interspersed throughout with small 

 rounded hills, which reposing on the above-mentioned yellow clay 

 are themselves composed of various layers of sands, clays, gravels, 

 and boulders, even at the greatest heights. These appear to be the 

 remains of a talus of great extent, which had covered the foot of these 

 mountains and been swept away by the Soorma and other great rivers 

 falling from them. 



The foot of the mountains is composed of a rock in which Num- 

 mulites are imbedded in a compact calcareous basis. iSandstones 

 seemed to rest upon this, but the relative position of the two rocks 

 could not be clearly ascertained from the dense vegetation and the 

 short time available for the examination. 



On ascending to Cherraponji, a sanatory station established at 

 an ascertained height of above 5000 feet, the limestone was soon 

 lost sight of; but great masses of sandstones presented themselves, 

 which had been rent and the fissures filled up with boulders and gra- 

 vel. If the mountain acclivity be supposed to be divided into three 

 stages, the first forms a steep slope covered with deep soil and vege- 

 tation ; the second is precipitous and more or less naked ; and tlie 

 third is composed of sloping ridges terminating in mountain and table 

 lands from 5, to near 6000 feet high. 



At the top of the first stage, or at about fifteen hundred feet above 

 the sea level, the author discovered a well-defined marine beach, con- 

 taining shells and other marine exuviae about two feet deep, and 

 reposing upon sandstone and covered with soil. The shells consist 

 of Pectens, Cardia, Ostrese, Terebratulse, and Melaniae, mineralized 

 by a fine yellow sandy matter, and united together by a brown indu- 

 rated clay. Between the curved slaty layers of animal matter and 

 shells, as well as in nests, loose sand is found. The whole presented 

 the form of shingles caused on a beach subject to tides. In the course 

 of an hour several hundreds were, and with more time many thousands 

 might have been obtained. These shells were compared with a col- 



