78 FOOTE : GEOLOGICAL STRUCTURE OF THE EASTERN COAST. 



Similar gritty sandstone was turned out in small quantity from the 

 bottom of the municipal filtering tank at the north end of the great 

 irrigation reservoir known as the Black Tank. 



o 



Separated from the Guntur sections by a band of alluvium varying 

 from 5| to 9^ miles in width are the two Rajmahal inliers, already 

 Cbebrolu and Tan°-el- referred to several times, of Chebrolu and Tan= 

 lamudi mliers. gellamudi. These two inliers form a low but 



well-marked ridge running 14^ miles through the alluvial flat in a 

 very nearly due north-east-to-south-west direction, with only one break 

 through which flows the Guntur nullah, which falls into the " Old 

 Tungabhadra," the most westerly branch of the Kistna in the delta. 

 The ridge has an average width of about 2 miles, roughly speaking. 

 It is the more conspicuous from being generally covered with red 

 sandy soil, which contrasts strongly with the dark black regur which 

 covers the surrounding alluvium flat. 



Here, as elsewhere in this region, no satisfactory section is to be 

 No good sections to be found showing the relation of the various rocks 

 found - composing the inliers, and considerable uncertainty 



exists about their stratigraphical position. 



A friable gritty sandstone, in many respects a good deal like the 



Guntur beds, is exposed in a new well to the south- 

 Tangellamudi inlier. 



west of Kolakalur, at the extreme north end of the 



Tangellamudi inlier. The relation of this to the reddish and purplish, 

 hard, gritty sandstones at Tangellamudi, and the soft and purple mottled 

 sandstones at Kazipett (Khabampeta), is quite problematic, and there are 

 no intermediate sections to throw light on this point, for, in the three- 

 quarter mile distance between Kazipett and Kolakalur and the £5 miles, 

 between the latter place and Tangellamudi quarries there is room for a 

 variety of changes of position. Similarly, in the Chebrolu inlier it is 

 quite doubtful whether the hard sandstones forming the northern half of 

 the inlier lie under or over the soft shaly beds forming the southern half. 

 In this case, however, I was able to form the conclusion that the hard 

 ( 78 ) 



