260 VREDENBURG I SKETCH OF BALUCHISTAN DESERT. 



rock penetrated by the other. In this connection reference may be 

 made again to the very fresh lava, possibly of Siwalik age, that was 

 mentioned in a previous chapter (page 30). It occurs at a short dis- 

 tance from these very recent looking dykes. The question is an inter- 

 esting one and deserves further study : it is quite possible that they 

 represent a period of volcanic activity older than that of the most 

 recent volcanic outbursts, though quite distinct from the flysch erup- 

 tions of cretaceous and lower eocene times. To the same com- 

 paratively recent age might belong the deposits of ochres formed by 

 solfataric action along fissures such as were mentioned at Saindak 

 (page 79). These bright coloured ochres are again conspicuously 

 developed in some parts of Robat Koh, where they are impregnated 

 with sulphate of copper, sulphate of alumina and sulphate of mag- 

 nesia. Furthermore, some recent deposits of travertine occur upon 

 the eastern slopes of K6h-i-Malik-Siah and west of Lar K6h, indicat- 

 ing the former presence of thermal springs, though their situation in 

 the neighbourhood of the formations just described might be a mere 

 coincidence, 



Great masses of sub-recent gravels occur at various heights above 



the present bed of the broad valleys occupied by 

 Recent gravel terraces. . ' 



the Lar river and the Shamidar or Robat river. 



Like the terraces of silt at Kirtaka, they bear witness to the high 



level which the water formerly reached in the lake that occupied the 



Seistdn depression. Plate XII shows these gravels in the Lar 



river capping highly tilted Siwalik strata. A similar feature may be 



observed in Plate VII. 



From Robat to Ladis. 

 The return journey from Rob£t to Mirjawa was accomplished 

 through the Persian province of Sarhad. The alluvial plain of Mirjawa 

 (see ante ) page 77), north-west of that locality, shares the fate of 

 the t( Dasht-i-Tahlab "; it becomes gradually narrower until the moun- 

 tain ranges which it separates unite into one folded region. Thus the 

 region visited exhibits nothing but numerous parallel ridges without 

 ( 88 ) 



