28 Notices of Memoirs — Geological Survey of India. 



formation. It is not certain that they are of Paleeozoic age ; they 

 may even be older than this, but according to present knowledge, 

 they are Azoic, for no traces of life have been found in them. These 

 Kadapah and Karnul rocks rest upon the Crystalline rocks or 

 Gneissic series, which occupy a narrow belt of country all round the 

 outermost boundaries of the newer rocks. 



They consist of a great succession of Clay-slates, Quartzites, 

 Limestones, and Shales, with Traps, and constitute two unconform- 

 able series, the older of which is largely developed in the Kadapah 

 (Cuddapah) district, while the younger is developed in the Karnul 

 (Kurnool) district. 



After pointing out the physical structure of the country, Mr. 

 King describes the two formations in detail. 



In the Karnul formation there is a series of Quartzites, Sandstones, 

 Grits, and Pebble-beds, which might be called the Diamond-bearing 

 Group, as until lately there was no knowledge of diamonds having 

 been found in any other set of rocks of either the Karnuls or 

 Kadapahs. The old diamond-workings near GostapuUy, on the left 

 bank of the Kistnah, have however been visited by Dr. Oldham, 

 who considers that they were executed in quartzites of the Kadapah 

 series. A local name has, therefore, been adopted for the diamond- 

 series of the Karnul formation — it is called the Banaganpilly Group. 

 This group forms a capping, 10 to 20 feet in thickness, resting 

 unconformably on a much older set of shales and traps. This 

 capping is pierced by shafts 15 feet or less, from the bottoms of 

 which horizontal galleries are driven to get at the seams of diamond 

 gangue. While the rocks of this group are hard and vitreous where 

 exposed to the atmosphere, down in the shafts, owing largely to 

 the confined moisture, the rooks are quite unaltered, and it is in 

 more or less clayey and shaly seams of pebble-beds that the dia- 

 monds are found. 



The main resources of the Karnul and Kadapah formations are 

 diamonds, copper, lead, iron, and building materials. Their mode 

 of occurrence and economic value are pointed out, and where 

 necessary the report is illustrated with sketches and geological 

 sections. It is essentially a volume of practical geology, the total 

 absence of organic remains depriving the formations of a good deal 

 of the interest they would otherwise have to those not specially 

 interested in the economic geology of the district. Nevertheless 

 the field geologist will find much to interest him in the descriptions 

 of the rocks, and in the explanations of the many complications of 

 structure which they present. 



2. — The Geology of Mount Sirban, in the Upper Punjab. 

 By W. Waagen, Ph.D., and A. B. Wynne, F.G.S., Geological 

 Survey of India. 



THIS mountain, which has an elevation of 6243 feet, with an elon- 

 gated oval iDase, is one of the most lofty of the Hazara Hills, 

 a portion of those which form the outer spurs of the north-western 



