GEOLOGY OF INDIA. (11 



green-stone. We hope soon to be enabled to lay before the Society, a de- 

 tailed description of these formations, accompanied by sections of the 

 strata between Madras and Hyderabad. The waters of the Krishna and 

 Oodaveri expand as they approach the sea, dividing into numerous 

 branches, and depositing their alluvial contents during inundations over 

 the low level tract that separates them : these deposits consist, according 

 to Dr. Heyne, of a black earth, resting on indurated marl, and composed 

 partly of the debris of trap rocks, but chiefly of decayed vegetable matter, 

 yielded by the extensive forests through which these rivers flow. Here 

 may be noticed a characteristic diflerence that marks the alluvial deposits 

 of the principal river of the south — the Caveri. This river, flowing in a 

 long course through the Mysore country, over an extensive and generally 

 jbarren surface of granitic rocks, with scarcely any woods or jungle on its 

 banks, seems to bring down little or no vegetable alluvium ; but a rich 

 clay, produced by the felspar, which predominates in the granites of 

 the south, intermixed with decomposed calcareous conglomerate, render- 

 ing the plains of Tanjore the most fertile portion of the south of India. 



Passing on to Vizagapatam and Ganjam, granitic rocks, chiefly syenite 

 and gneiss, predominate, and are occasionally covered by laterite. The 

 granite of Vizagapatam assumes a new and singular appearance, being 

 small-grained, and intermixed with amorphous garnets, in rounded grains, 

 or specks. This peculiar rock passes into the Province of Cuttack. 

 The only information we possess regarding that interesting district, 

 is derived from Mr. Stirling's valuable paper in the last volume of 

 the Asiatic Researches. Rocks of the granitic class form the basis and 

 principal elevations of this district; some of them are remarkable for 

 their resemblance to sand-stone, and abounding in imperfectly formed 

 garnets, disseminated throughout, with veins of steatite. Here some traces 

 of coal have recently been discovered, which is likely to be produc- 

 tive, and gold is found in the sands of the Mahanadi, brought down 



probably 



