UPPER GONDWANAS. 31 



overhangs the well-known temple of Tripati, 1 some 23 miles north-east of 

 Ellore and 28 west-by-south of Rajahmundry; and the name of the 

 group is so taken. 



In no section is there a fair idea given of the thickness of the series, 



Thickness tlie SCaip ° nl ^ B ^ ow i n g some 40 or 50 feet at 



the most of the lowest strata. From the scarp 

 there is a long slope down to the south-east, on which little can he learnt 

 of the upper beds ; but wells are sunk at two or three points, to a 

 depth sometimes of nearly 70 feet, and these do not appear ever to have 

 touched the lowest or scarp beds, so that at a rough calculation the 

 whole thickness cannot be taken at more than 150 feet, if indeed it can 

 be so much, and from personal observation I can only write off 120 feet 

 of this. 



The lie of the beds is from 5° to 10° south-east; perhaps they may, on 



the whole, dip slightly more to the eastward of this 

 Lie. 



and may be flatter than the Ragavapiiram beds. 



The lower portion, or the scarp beds, are often scarcely to be distin- 

 Lithology and succes- guished from the bottom Gollapili beds • indeed, it 

 S10n ' may also be said that they are frequently just 



as undistinguishable from the much newer Rajahmundry sandstones. 

 They are essentially a set of dark-brown and reddish sandstones, gravel 

 beds, and conglomerates, with bands of highly indurated or vitreous 

 siliceo-argillaceous beds of the same kind and concretionary clay-iron- 

 stones. They are rather softer and more varied in colour towards the 

 bottom, becoming harder and more ferruginous higher up; and it is 

 these harder beds which make up a good deal of the Nullacherla and 

 Yernagudem country leading down to the delta lands. Much of the 

 hardness of the upland rocks is, however, due in great part to weather- 

 ing, these heavy ferruginous sandstones and conglomerates having a 

 wonderful tendency to assume a lateritoid character on exposed surfaces. 



1 This is Chinna, or the ' smaller ' Tripati, and only inferior as a place of pilgrimage 

 to the more famous and larger Tripati, in North Arcot, the most sacred temples of which are 

 above a far grander scarp of quartzites of the upper transition series. — See Memoirs Geol. 

 Surv. of India, Vol. VIII, pp. 18, 177, 179. 



( 225 ) 



