TERTIARY AND liECENT DEPOSITS. 231 



In m*any parts of the valley the surface generally is of a rich 

 Appearance of the ^®^P purple-brown, the rock where broken and 

 mud beds. crushed ( as in the wheel tracks of some cross 



country roads ) showing- the deep red streak of the nearly pure hsematite. 

 The massive laterite , is often of extreme toughness, but when broken 

 shows a hsematitic matrix with many angular grains of quartz enclosed^ 

 and presents an appearance as if the old hsematite of the gneiss had. 

 been ground down by surf action to a perfect mud^ which, on drying, 

 consolidated around the grains of sand and hardened into its present 

 consistency. 



The surface of the laterite often shows vermicular cavities, but 

 not so much so as the conglomeratic coast laterite. Much of the late- 

 rite occurs as gravel of various degrees of coarseness; this is sometimes 

 pure, but more frequently contains rolled fragments of quartzite. 

 The proportion of quartzite pebbles in some cases becomes so large as 

 nearly to hide the laterite. 



In the central and western parts of the old lake valley the de- 

 position of the ferruginous mud was less in quantity ( or subsequent 

 denudation has been more active) than at the eastern part. Many well- 

 marked patches of laterite remain in these parts of the valley. 



The outlying laterite patches to the north-east of Yerkal in the 

 corner enclosed between the Ghatprabha, the Krishna and the crescent- 

 shaped hill ridge running from Yerkal to the Krishna, the Sita Dongar, 

 appear also to have been formed in a shallow lake, probably an arm 

 of the principal one. One section in this corner at Jerankunti 

 (Geedran Koontee) shows a thickness of from 30 to 30 feet of vermicular 

 conglomeratic laterite exposed in the village well. 



An independent shallow lake seems to have existed to the south- 

 Old lake west of ^^^^ ^^ Badami and to have given rise to the 

 Sadami. lateritic conglomerate which covers a consider- 



( 231 ) 



