232 Reviews — Wynne's Poorna Valley. 



II. — ^Thb Valley of the Pooena Eiver, West Berae. By A. 

 B. Wynne, F.G.S., &c. 



[Records of the Geological Survey of India, No. 1, 1869.] 



THE Poorna (or Poona ?) Valley, in Central India, lies between 

 longtitudes 76° and 78° east, and is traversed by tbe 21st 

 I>arallel of N". latitude. It is about 124 miles in length, from its upper 

 or eastern end to wbere it passes into the larger valley of the river 

 Taptee. In width it varies from thirty to forty miles, on an average. 

 It is bounded on the south by the Adjunta ghats, an abrupt scarp of 

 the Deccan plateau, into the usual steppe character of which these 

 ranges pass imperceptibly ; while on the north are the bold and 

 varied escarpments of the Gawilghur range. These latter mountains 

 are intersected by steep glens and wide valleys, sometimes presenting 

 nearly vertical precipices of great height, in places probably from 

 1,000 to 1,200 feet. 



The hills and portion of the valley south of the Poorna river con- 

 sist of Trap, similar to that of the Deccan. The stratification is very 

 perceptible, and nearly always horizontal. The Gawilghur range is 

 mainly composed of hard basaltic beds, amygdaloid, and soft traps. 

 A great fault, with a down-throw to the south, crosses the country 

 in an east and west direction, close to the foot of this range, and 

 brings the Trap against the underlying Mahadeva or Bagh (Tanda) 

 sandstones. These sandstones are soft or coarse, white, and even- 

 grained, and would, in Mr. Wynne's opinion, furnish good building 

 stone. 



Impressions of plants have been observed in some of the flaggy 

 beds, and numerous small univalves have been met with in shales 

 and limestones belonging to these Mahadeva beds. 



Mr. Wynne describes at some length the alluvium of this valley, 

 which appears as a great plain. The ground in places is undulating, 

 while the Trappean rocks are here and there exposed at the surface. 

 In every part of the alluvium calcareous conglomerate is of common 

 occurrence. It occasionally contains fragments of bones and teeth of 

 ruminants. Small freshwater shells are not uncommon in the 

 deposit. They appear to belong to existing species of Melania, 

 Paludina, Biihynia, Lymncea, Planorhts, and TInio (?). 



Much of the Poorna alluvium produces efflorescences of salts, 

 chiefly of soda ; and in many places the wells sunk in it are brackish 

 or salt. Wells are specially sunk for obtaining common salt, and 

 some of them are from 120 to 130 feet in depth. They are sunk 

 through yellow clay, then reddish clay, and, below this, into a coarse 

 sand or fine gravel, from which the water issues with great force. 



The alluvium is of considerable depth. In places it may exceed 

 150 feet. 



Whether the whole of this alluvium was deposited in a lake, or 

 by the river, travelling from side to side of the valley, under other 

 conditions that at present obtain, Mr. Wynne considers it diflScult to 

 say. A former estuarine condition of the area, or a large lake, is 

 indicated by the salt-bearing beds ; but the even, though interrupted, 



