VREDENBURG : SKETCH OF BAlOchISTAn DESERT. 



Where the rocks are more violently disturbed, with the develop- 

 ment, frequently to a considerable degree and over wide areas of 

 slaty cleavage, the differences which mark the various types of shales 

 in their unaltered condition become greatly obliterated. We come 

 across various kinds of slate in which it is difficult to discover 

 what the characters of the rock could originally have been. They 

 often assume quite an archaean facies, and were it not for the 

 distorted nummulites still recognisable in some of the limestone 

 bands, it would be difficult to realise that such rocks could be tertiary. 

 In the neighbourhood of great igneous intrusions, these rocks 

 become still further transformed by contact metamorphism. 



The limestones occur as bands of various thickness from a foot 

 upwards and also in considerable masses 



Limestones. 



hundreds of feet thick, when they'rise into 

 conspicuous hills. Just as in the case of the other varieties of rocks, 

 the age of these great masses cannot be determined without the 

 help of fossil evidence. The instance above given of Saindak and 

 K6h-i-Malik-Sicih shows that their development is local, and they 

 seem to occur indifferently and with very similar characters at 

 various geological horizons. The tall crags of Malik Gatt are of 

 the age of the u Cardita beaurnonti" beds, while considerable lime- 

 stone hills at K6h-i-Malik-Si£h, at the Lar Koh, at Shekh Hosein, are 

 full of nummulites. Owing to the absence of fossils it is not 

 possible to determine the age of those huge masses of limestone 

 that form the Chapar range, and the Gatt-i-Hamun. 1 Petrologically 

 and structurally, no characteristic differences can be detected in any 

 of these rocks. At Amir-Chah and K6h-i-Humai, some thick 

 limestones showing sections of hippurites on their weathered surface 

 are of an exceptionally compact and crystalline texture compared 

 with the other limestones of this region, 



Section 3. — Igneous intrusions. 

 The topography as well as the geology of the ranges consisting 



1 These limestones have lately been recognised as upper cretaceous. (See the foot-note 

 on page 58.) 



( 2a ) 



