132 



Description of the Valley of Sondur, 



[July 



stones that have been heated under certain circumstances are apt to 

 become. 



Plains flanking the Sondur jyiV/*.— In the phiins lianking the Sou- 

 dur ridges the prevailing rock is gneiss, alternating with mica and 

 hornblende schists, intersected by green stone and basaltic dykes, the 

 general direction of whose main coulees is east and west, varying 

 more or less to the south of west and north of east. Granite occurs 

 in detached clusters. The basalt and this rock appear to be the low- 

 est in the Sondur series, bursting up through the gneiss and its asso- 

 ciated schists. The chloritic schist, crested by the jaspery rock, 

 appears to be the uppermost; the laminae of both these rocks are 

 conformable with those of the gneiss. The circumstance of the schists, 

 resembling argillaceous, lying in the upper-part of the mica schist sys- 

 tem, has been noticed in Europe by Boue, Necker, Phillips and others. 



The soil covering the plains near the hills varies from a dark coffee 

 coloured clayey earth, to a light sandy soil. The former is highly im- 

 pregnated with oxide of iron, and in some situations with carbonate of 

 lime, and arises from the disintegration of the subjacent rock and allu- 

 vium washed by the rains from the hill sides. For a section of the soil 

 and substrata vide plate No. 3. 



Deposits of natron occur sparingly on the banks of some of the ri- 

 vulets, and abundantly of carbonate of lime. This and the oxide of 

 iron, which abounds every where, form the cementing ingredients of the 

 conglomerates now seen in process of formation on the banks and bed.-? 

 of streams. 



I 



