54 Notes, chiefly Geological, of a Journey [Jan. 



derived from the decomposition of the amygdaloidal trap, which, with 

 granite, forms the hills to the north of Rajahmundry. In the indurated 

 conglomerate silt composed of large pebbles, are some pieces of porce- 

 lain earth (No. 31), which the natives employ in the manufacture of a 

 fine kind of pottery, very much esteemed all over India. The de- 

 composition of the felspar into porcelain earth, must have taken place 

 after deposition of the fragment, while still hard and compact, so as 

 to be able to withstand in its descent the consequences of attrition J 

 supposing the contrary to be the case, we cannot possibly explain 

 how so friable a body as the porcelain earth, could have been driven 

 to such a distance in water, without crumbling into clay and dissolving. 



Kankar is very abundant about Rajahmundry, and it is burnt as 

 lime. 



Samulcottah, Feb. 3. — About half past live this morning our road 

 lay between two high hills ; the composition of which I could not dis- 

 cover, on account of the darkness. 



At daybreak we approached the village of Puddagarum: before 

 reaching it, I went to examine some hillocks near the road. The 

 summit of the first I came up to, was formed of sandstone of a deep 

 red or purple colour, the grains of quartz being cemented by a ferru- 

 ginous clay (No. 32). The surface of the blocks at the top is extremely 

 scabrous and beset with sharp points. 



In this hill, the sandstone overlays lithomarge, tinged of different 

 colours (No. 33); but in others the lithomarge is overlaid by a lateri- 

 tic rock. Close to this first hillock, there are two others of greater 

 dimensions, in which the abovementioned geological position of the 

 rocks is seen in a more defined and distinct manner. 



A hill to the eastward of the first, has a kind of talus (not formed 

 of any detritus, but by the strata of the sandstone elevated a few feet 

 towards the hill), which extends one or two hundred yards round its 

 foot. This rock being evidently stratified, slabs of any dimensions 

 and forms may be easily detached, for architectural purposes, for 

 which it seems to be extensively employed, judging by the numerous 

 quarries worked in the talus and in the plain round it, where the sand- 

 stone is the surface-rock. 



The small ridge forming the summit of this second hiil is, as it were, 

 capped with modified haematitic iron ore, which last rock, in this 

 locality, is evidently stratified (No. 34). In more than one place of 

 this hill, a bed of lithomarge intervenes between sandstone and the 

 iron ore ; this is the case at the western extremity of the ridge, where 

 a deep well is excavated to procure the lithomarge, with which the 

 natives mark their foreheads. 



