988 Notes, chiefly Geological, across the Peninsula QNo. 156. 



trap of the overlying formation, are seen lying on and partially imbed- 

 ded in the Regur, with scattered, rugged, scabrous blocks of a com- 

 pact cream and buff-coloured limestone passing into chert. The 

 latter contained a cast of a small fresh water shell resembling a 

 Physa. 



Ascending the gentle slope, beyond the village of Cummumpilly, the 

 overlying trap was first seen in situ in a section afforded by the steep 

 bank of a nullah. The trap is petrographically identical with that of 

 Bejapore. The structure is at once sheeted like that of modern lavas 

 imperfectly columnar, and globular. The globular trap disintegrates 

 by a process of concentric exfoliation. The concentric coats, weather 

 into a brown speckled, friable wacke, which falling off and washed 

 away by the rain leaves the hard spheroidal nuclei of basalt scattered 

 on the surface; frequently in such numbers as to present the appear- 

 ance of having being showered down by some volcano. These spheroids, 

 vary in size from a pigeon's egg to a 16 inch shell. 



Recent conglomerate. — A few miles to the S. of Sedashipett, a low 

 flat topped range of hills is seen ; which, from the calcedonies, jasper 

 and fragments of trap brought down by the nullah, are probably of trap. 

 These transported pebbles have been formed into a solid bed cemented 

 together by lime, and form cliffs from three to ten feet in thickness on 

 the nullah bank. Small rounded fragments of laterite are also included 

 in this recent conglomerate, which is also seen in the beds of other rivu- 

 lets between Moonapilly and Beder. These conglomerates rarely extend 

 more than 20 or 30 yards from the present channels of the streams, 

 and generally not above several feet. The lime contained in the water 

 of the stream, and its tributary springs, has evidently assisted in the 

 consolidation. 



About four or five miles S. W. from Moonapilly, the low range of hills 

 there seen was found to be of trap ; the highest peak capped by a 

 lateritic rock resembling that of Hor Muth S. of Bijopore described 

 pp. 6 and 7 No. 2 Geological notes. This laterite near its junction with 

 the trap passes into a bed of crimson-spotted, lithomargic earth resem- 

 bling that of the Nilgherries, and is slightly impregnated with calcare- 

 ous matter. The trap occupies the lowest situations, and constitutes 

 the basis of the plain to Beder, where it is overlain by an extensive bed 

 of laterite 200 feet thick. 



