580 Notes on Geology and Mineralogy of Affghanistan. 



formable position, and that the secondaries appear from 

 inspection of the rocks in the Bolan Pass, to comprise the 

 usual series from the mountain limestone up to the cretace- 

 ous system which is represented by the nummulite lime- 

 stone, specimens of which I likewise received from the hills 

 in the neighbourhood of Kilat, and others from the Gun- 

 dava Pass to the southward of Dadur and Bagh. 



The valley of Quettah is bounded by lofty mountains of 

 fossilliferous limestone, being in fact a continuation of those 

 at Dusht-i-be-dowlut. Towards Koochlak, however, as we 

 proceed in the direction of Pisheen, indications of tertiary 

 strata are again apparent, consisting of deep beds of differ- 

 ently coloured clays, red and grey many times repeated. In 

 the vicinity of the mountains these beds rise into hills of some 

 height, and exhibit alternate strata of reddish clay or marl 

 and semi-indurated sandstones. In the marl beds are found 

 masses of the same foliated gypsum^ which occurs in the 

 outlying hills beyond Dadur, which seem in fact to be iden- 

 tical with the beds of Pisheen. These strata of red clays 

 and sandstones extend over a great portion of the Pisheen 

 valley, and are cut into ravines and mounds of great depth 

 by the winter rains and the drainage of the country. The 

 surface is usually undulating, but in some parts conical masses 

 stand up above the rest, having all the appearance of having 

 been ringed by the long continued action of moving waters, 

 and an unpractised observer could easily be persuaded to 

 believe that the valley had once been a lake, the successive 

 levels of whose subsiding waters were thus to be traced on 

 the mounds in question. Plausible as such an hypothesis 

 might at first sight appear to be, it is nevertheless quite 

 erroneous, for the phenomenon is caused simply by the action 

 of the elements upon strata of unequal hardness ; the semi- 

 indurated sandstones being able to resist the influence of 

 atmospheric agents longer than the softer marly clays with 

 which they alternate ; the consequence is, that the edges of 



