210 VREDENBURG: SKETCH OF BALOCHISTAn DESERT. 



differences of level, though they may occur in close proximity, as has 

 been mentioned in the chapter on hydrography. 



Yet, amidst all this confusion, there are some curiously regular 

 features : such are the long lines of terraces 



Gravel terraces. 



formed by the conglomerates stretching over 

 wide areas. It frequently happens that the traveller following the 

 narrow camel track beaten out of the stone-strewn "dasht" along 

 what seems an interminable plain, suddenly finds himself on the edge 

 of an escarpment and sees another plain below him some thirty or 

 forty feet lower. This lower ground may again slope gently down 

 to another step like escarpment, and there may be thus three or 

 four of these superposed terraces. If the country had been more 

 thoroughly examined it would have been found probably that these 

 lines of terraces form concentric belts surrounding at a distance some 

 of the larger lake basins. They admit of only one explanation, that 

 they represent ancient shore lines of great lakes, which now have 

 either dried up entirely or are reduced to insignificant shallow 

 marshes or salt swamps. 1 The successive lines of escarpment 

 would represent temporary periods of rest during the gradual drying 

 up of these great masses of water. The level of the waters being 

 constant during a certain period constituted temporarily what the 

 Americans call a " base-level " of erosion ; the surface of the lake 

 was the lowest level to which running water could carry down pebbles 

 and boulders, and thus for the time being the shore of the lake 

 was the limit of the accumulation of conglomerates. 



I visited one of these lake basins, the Lora-Hamun, now absolute- 

 Evidence of a change in ty dessicated, an endless " pat " or plain of sun- 

 the physical conditions. cracked mud of a pale ye llow colour with great 



patches here and there of saline efflorescence, and absolutely destitute 



1 Most of the terraces which I have observed belong to the north, north-east, and north- 

 west margin of the great depression whose lowest portion is occupied by the Hamun-i- 

 Mashkhel and other dried-up ponds. That similar terraces are found on the southern margin 

 of the depression is shown by one of the sketches in General McGregor's " Wanderings in 

 Balochistan," p. 129. (These gravel terraces are also mentioned, pp. 138, 154, etc.) The 

 terraces surrounding the depression once occupied by the former lake of Seistan are mentioned 

 in H. W. Bellew's " Record of the March of the Mission to Seistan. " 



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