32 



Notes, chiefly Geological, of a Journey 



full of small cavities lined with calcspar, and exhibiting only the im- 

 pressions of the shells, their substance having been absorbed. 



The colour of this compact kind of limestone is whitish, verging to 

 yellow, and its geological position appears to be that of a bed in the 

 wacke, into which last the trap has decomposed ; so that the calcarious 

 rock is imbedded in, and alternates with, the decomposed basalt. De- 

 scending a little lower down, the wacke is again seen, with jasper, of a 

 very compact structure, in the form of thick veins, or thin ramifica- 

 tions, or in beds (No. 25), in which, however, no fossil shells are con- 

 tained, as we know to be the case in other localities in India, where the 

 basalt overlays shell-limestone, and a similar kind of sandstone to that 

 mentioned in these pages. The wacke being removed by atmospheric 

 influences, these pieces of jasper are scattered over the ground. 



The outlines of the hills to the eastward, appeared to indicate their 

 being of the same formation as the one we had examined; and Colonel 

 Cullen, who had, some years before, examined the whole of these hills, 

 confirmed my surmise ; with the addition, that the other hills being 

 loftier than the one we stood upon, and presenting deeper nullahs, ver- 

 tical escarpments and precipices, better opportunities were afforded of 

 seeing the position of the rocks. 



This place is about ten miles from the right bank of the Godavery, 

 in a line with Rajahmundry. Along the road to the last mentioned 

 place, at the foot of this group of hills, immense blocks of conglo- 

 merate red sandstone are seen, apparently underlaying the limestone. 

 Many rounded pebbles, resulting from the disintegration of this con- 

 glomerate, bestrewed the road, and lay in many of the nullahs (No. 26). 



Having travelled a couple of miles towards the Godavery, I saw, in 

 the middle of the road and in a nullah near, the outgoings of a thick 

 bed of limestone, which in texture, compactness and composition, dif- 

 fered from that we examined in the hill. It was crystalline, contained 

 no shells, was of a grey colour, with the aspect of dolomite (No. 27). 

 This bed is evidently flanked by the wacke and basalt, which are seen, 

 the one in concentric laminse in the beds of brooks, the other im- 

 planted in the vicinity.* 



To conclude my short account of this interesting locality, judging 

 by what a cursory examination can warrant our saying, regarding the 

 geological position of these rocks, it seems — 1st. That the lowest visi- 

 ble rock is the conglomerate red sandstone, so common throughout this 

 districtf— 2cl. That shell-limestone is a subordinate rock to it— 3d. 



* Is this crystalline limestone, without shells, of the same ago as the compact kind con- 

 taining them ? And, if we suppose that the igneous rock converted it into dolomite, why- 

 did it not produce the same change in the other 1 



+ Putting aside the consideration that basalt appears to be the lowest rock, not only in 

 this locality, but perhaps in all the crust of our Planet. 



