62 WYNNE : GEOLOGY OF THE SALT RANGE IN THE PUNJAB. 



the cutting of the Indus* aud other gorges, and the excavation of preci- 

 pitous valleys over 1,000 feet depth. 



It has been thought that the cliff feature, here so striking, resulted 



■_ . from marine erosion ; of course this may have 



Marine erosion. 



taken place, but so great has been the subaerial 



denudation, that the traces of marine action would now be sought in 



vain. 



.5010 



Pig. 3. — Profile of Sfln Sakesar basin. Natural scale | inch=l mile. 

 Sakesar Mountain, 6 miles to west. 



The salt lake basins of the Son valley present some peculiarity as 



to their excavation; the largest, the Samundar lake, 

 S6n Plateau lakes. i • -, n r^n n -i - ^ 



at an altitude of 2,536 leet and with a catchment 



area of about 60 square miles, covers 6 square miles of surface, and 

 varies in depth and area with the accession of rain water, but is usually 

 shallow. It has no visible outlet, and the difference between the altitude 

 of the lake aud that of the lowest part of the edge of its basin may be 

 less than 100 feet. The greater part of the basin is formed of limestone 

 and is rocky, but in an easterly direction there are large deposits of 

 coarse detrital materials that may conceal some spot where the water 

 could have escaped, before the passage was blocked up by their accumu- 

 lation. No sufficient reason for calling in the aid of ice to assist in 



* If only a coincidence, it may be observed that the depth to which the last results of 

 atmospheric erosion have reached at the vv^ater escape of the Indus from the hills, is nearly 

 equal to the whole fall of that river from Kalabagh to the sea. The average of twenty 

 heights on the Potwar plateau gives 1,426 feet, and the depth of the Indus gorge at 

 Kalabagh, including that of the river itself, is about 650 feet, the fall from thence to the 

 sea (taken from the height on the maps) being equal to 681 feet, or 82 feet less than half the 

 average elevation of the Potwar country. 



( 62 ) 



