SOUTH-WESTERN PORTION OF KARACHI COLLECTORATE. 165 



rising 120 to 130 feet above the surrounding plain, and is composed of 

 harsh quartzose sandstone, varying considerably in texture and hardness, 

 being very fine in places, coarse, gritty, and quartzose in others, parts 

 being so compact as to be almost a quartzite. There are a few bands 

 containing pebbles. No fossils were detected in this rock. The under- 

 lying formation is Khirthar limestone ; there may be a thin band of 

 the Orbitoides sandstone (Nari) intervening, but it was not observed, 

 the base of the hill being covered with talus. 



South of the old high road, which runs along the southern base of 

 Sindar Hill, and also to the east of the railway, there are some large 

 spreads of the harsh sandstones occurring as outliers or small caps on 

 the higher beds of the Khirthar limestone. 



In the last chapter (page 154) some isolated rises of Gaj rock were 



Isolated hillocks in al- said to occur in tne alluvium south of the 

 luvmm south of Tatta. area represented on the map accompanying this 



memoir, and beyond the Indus. The most important of these rises is 



26 1 miles south-by-east of Tatta, and 11 miles south-south-east of Bibi 



Miriam; it is 1^ miles long from north-east to south-west and half a mile 



broad, and comprises 5 or 6 small hillocks, the loftiest a conical mound 



known as Aban Shah, used as a trigonometrical station, 95 feet above the 



sea. There are also two rocks in the channel of the Indus — one known 



as Gungani, on the right bank of the river, between 5 and 6 miles 



north-west of Aban Shah, the other a mere pile of stones in the middle of 



the river, rather more than 2 miles farther down. All are of hard grit 



or coarse gritty sandstone, much like the rocks just described near Jung- 



shahi, and probably belonging to the same formation. The structure of 



the beds varies as usual, sometimes being fine, sometimes coarse, and even 



conglomeratic. A few fragmentary and ill-defined fossils, chiefly casts, 



were observed at Aban Shah, and amongst these was a lower valve of 



Ostrea multicostata, which had, however, been rolled before being imbedded. 



A small Clypeaster and a large silicified coral were also noticed in the 



rock. 



It is as well to repeat that it is far from certain that these beds are of 



( 165 ) 



