TERTIAJIY AND RECENT DEPOSITS. 239 



The greatest development of the laterite occurs at the east end of 



,,,,,, , the valley, where the iron beds o£ the g-neiss over- 

 Most developed east- •' » 



ward. hung the margin of the supposed lake, or rose up 



as islands from its surface ; but much laterite shows also in the central 

 part, near the Anegwadi (Hungehdee) ford over the Ghatprabha. It 

 there occurs on both sides of the river. 



This hypothetical lake serves to explain the rounded water-worn 



-_r , , ., appearance of the quartzite talus along" the south- 



Water-worn quartzite rr ^ & 



*a^"S' ern base of the lower Kaladgi quartzites eastward 



of Bagalkot and a similar talus noticed at Sirur (eight miles to the south- 

 east) on the south side of the supposed lake basin. The banks of ferru- 

 ginous mud which subsequently assumed the laterite character were 

 deposited upon this marginal fringe of coarse quartzite shingle. 



The extent of the old lake would appear to have been considerable. 



Supposed extent of ^^^ ^^ ^^^^^ ^^^^^^ ^® ^^^T Precisely fixed 

 ^^^®* owing to the presence of subaerial lateritic rocks, 



as well as of immense spreads of regur over great part of the Kaladgi 

 limestone basin. In its eastern part the boundary was probably the 

 edge of the basin formed by the upraised lower quartzites forming the 

 synclinal valley east of the Malprabha ; the continuation of the northern 

 side of that synclinal formed the northern boundary of the central part 

 as far as Anegwadi, where the quartzites trend to the east again, and 

 here the lake probably had a great arm extending eastward as far as 

 the eastern base of the Sita Dongar range of hills. 



The southern boundary was formed by the Sirur hills for a dis- 

 tance of five miles westward of Sirur itself, and then trended northward 

 along the line of the hills forming the north side of the Shimageri 

 synclinal valley. 



It is doubtful whether the lake intruded within the area of the 

 synclinal valley ; the probability is that it did not. Westward of Kaladgi 

 the boundary of the lake basin is very doubtfully definable, though it 



( 229 ) 



