28 WYNNE: GEOLOGY OF KUTCH. [PABT I.! 



The ' Thur ' or little desertj along the northern edge of the Runn, 

 is described as a succession of sand hills or dunes such as fringe the 

 sea-coast elsewhere, their only peculiarities being little basins of 

 salt water in the hollows between them, and that they are in places 

 covered with a miniature jungle of stunted shrubs. 



To whatever causes the great plains of Sind and the coast plains 

 of Western India are due, that of the Runu may also be ascribed. Its 

 origin must be traced further back than the formation of the deltas of 

 the Indus and other neighbouring rivers, because something in the nature 

 of a plain or open ground was necessary to receive such deposits. This 

 open ground was here more hilly than to tlie north in all probability, for 

 the high islands which rise from the Runn are evidently but the modified 

 summits of an older surface ; and the sil ting-up of the sea-inlet which it 

 formed was only the natural result of its land-locked capacity to retain 

 the materials brought down by rivers. The Bunnee is a bank formed 

 most probably by the discharge of the Kuteh streams ; and the slight 

 elevation en masse which subjected the old shore-deposits to denudation 

 has aided the tendency of the basin to retain transported sediment, which 

 must accumulate yearly under present circumstances until the rivers 

 that convey it find their way across the tract through channels traver- 

 sing an alluvial plain. The surface of the Runn differs much from that 

 beneath the neighbouring sea as shown by the Coast Survey Chart, on 

 which are marked descents of 84 feet within less than a mile, besides 

 various inequalities which do not exist upon the Runn. This may be 

 accounted for by the protection from external currents formerly afibrded 

 by the land of Kutch. 



Had the elevation above mentioned been but sHghtly greater, the 

 present peculiarities of the Runn would have disaj^peared ,• and had it 

 returned to its former level, it would have become again an inlet of the 

 sea. 



( 28 ) 



