On the Red Marl Formation of Mysore. o5 



dydroog, are all situated on this tract, and from the summit 

 of Nundydroog all the surrounding country for 30 miles at 

 least appears to be the same. Venkettgherry, Baitmun- 

 galum, and Colar are also, if I remember correctly, situated 

 upon it. This tract is separated from the lower plains 

 which surround it by a sudden rocky break, or abrupt 

 difference in the levels, in which granite is the prevailing 

 rock, mixed with crystalline schists, porphyries, and traps. 

 This break occurs at Naiknairy ; at a few miles east of 

 Oossoor ; at a few miles south of Bangalore, on the road to 

 Seringapatam ; at a few miles west of Bangalore. 



The general surface of this formation is an arid, gently 

 undulating level, in sweeps of a mile or two in width, and 

 about 100 feet high at the most, and it is peculiar also in 

 appearance, from being generally almost bare of trees and 

 wild shrubs, although a few topes of mangoes and some 

 banian trees may sometimes be seen in the hollows, or near 

 tanks. The composition is sometimes a sort of red sandy 

 clay like a half-burned brick, but more generally it is 

 of a friable structure, exactly like some of the softer 

 kinds of the new red sandstone of England ; and as I con- 

 sider it best in describing rocks, that the names applied 

 should give the most correct idea of their structure and 

 composition, without any reference to geological position, 

 I therefore propose to call this formation, " Red marl," a 

 term which I think is not likely to mislead any one, or to 

 cause any person to suppose that the formation has any 

 thing to do with the new red sandstone of England in 

 geological position or associations. 



Although in general the structure is friable between the 

 fingers, yet it is sufficiently firm and solid to resist the action 

 of rain and running water, unless when collected into nul- 

 lahs, and in consequence the channels of these are in ge- 

 neral deep mural ravines, often 20 feet in depth. In some 

 parts I have seen a structure arranged in thin layers, con- 



