GEOLOGY OF SIND. 6 



At the foot of the hills the compact alveolina-limestone comes ia 

 upon the beds of the plain ; it is slightly disturbed, and the junction is 

 much concealed by immense accumulations of boulders and gravel, the 

 beds of which are arranged in terraces at the places where water- 

 courses emerge from the hills. 



The outer range of the Eri Hills runs approximately north and 



south, and, where I visited itj it is double : a lower 

 Eri Hills. 



ridge bordering the plain, and a loftier ridge, about 



1,000 feet iij height, running parallel, about two to three miles further west j 



through both these ridges a gorge is cut by the Mohun River at Mohun- 



kot or E.ani-ki-kot, or Runneekote, a peculiar old fortress of the Ameers 



of Sind^. 



At the entrance to the gorge the limestones, where they emerge 



from beneath the alluvial boulder deposits, have 

 Gorge at Runneekote. 



a low dip to the east. They are sharply twisted 



up at one spot, but continue steadily beyond and rise into a hill about 



460 feet high.f From beneath them, at the west base of this hill which 



is part of the outer ridge already mentioned as bordering the plain, the 



gypsiferous clays and sandstones crop out, much varied in colour as usual, 



but with a very high dip of 60° to the eastward. Yet there is no clearly 



marked unconformity. These beds continue at the same dip for above 



a quarter of a mile, when they roll over at an anticlinal, and continuing 



up the stream to the westward lie at much lower angles, frequently 



nearly horizontal, but generally dipping at 10*^ or 15° to the west or 



north-west. At the axis of the anticlinal the lowest bed seen is txaja^ 



which only appears in the stream for a few yards. It is slightly amyg- 



* The place is said to be the only spot along the range where sweet water is procurable, 

 and this doubtless led to its being fortified, especially as the gorge is well defended by nature. 



f By aneroid measiu'ement. 



