oct.' — dec. 1856.] of the Southern Division. 



95 



the oxide of iron. Farther to the north where other smaller ra- 

 vines come into the large one a still lower stratum is laid bare, it 

 consists of a well-defined gneissoid sandstone. It is plainly and 

 evenly stratified with layers of mica, silicious sand and felspar, or 

 lime. The stone is soft and friable and appears to be considerably 

 extensive, underlying much of the western part of this plain, its 

 thickness is unknown. In a bank in the lower part of the ravine 

 were strata of a pure white clay, or chalk alternating with, layers 

 of a dark dun-colored substance of the same apparent composi- 

 tion ; both containing carbonic acid and effervescing freely with 

 acids. This dun-colored clay is very extensive throughout this re- 

 gion and becomes indurated and passes into limestone. Much of 

 the recent limestone in which the shells are imbedded is evidently 

 formed from this clay ; as it exists in different parts of this plain 

 underlying the cotton soil in almost every degree of hardness from 

 that of marl and soft clay to that of compact and solid limestone. 



On the east side of this ravine, this clay and the cotton soil 

 which commences here is overlaid with an earth containing salts 

 of different kinds ; those containing nitrate and muriate of soda 

 are conspicuous. The sulphate of lime in the form of bladed, 

 amorphous, and fibrous gypsum was so prevalent as nearly to cover 

 the ground in some places although some bandy loads had been 

 collected and sent to Madras. In and on the banks of this ravine 

 were found a large number of the shells called belemnites and spe- 

 cimens of globular, cylindrical and over-shaped substances, of va- 

 rious sizes from that of an ounce bullet to that of some six or 

 eight inches in diameter and length. These substances were com- 

 posed invariably of a dark blood-red or brown-jointed oxide of 

 iron and laterite or fine radiating zeolite. Sometimes these round 

 substances were inclosed as nuclei in nodules of pure white chalk ; 

 but more frequently they were covered with a thin smooth cretace- 

 ous substance, which gave them an uniform appearance as far as 

 the texture of this external coat was concerned. 



In our farther examination of this interesting locality, it was 

 found, that this black soil and these globular specimens of fossil 

 Crustacea, (as there is evidence to believe they are), extended to 



