QUARTERLY JOURNAL 



THE GEOLOGICAL SOCIETY OF LONDON. 



PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY. 



June 11, 1873. 



The following communications were read : — 



1. On the Nature and Probable Origin of the Superficial Depo- 

 sits in the Valleys and Deserts of Central Persia. By W. T. 

 Blanford, Esq., Assoc. Royal School of Mines, F.G.S., C.M.Z.S., 

 Deputy-Sup. Geological Survey of India. 



Large Area covered by Superficial Deposits. — Deposits of large and 

 small pebbles, gravel, clay, and sand, of geologically recent origin, 

 and very often of thickness sufficient to conceal all older formations, 

 cover an enormous area in Persia*; probably more than one half of 

 the surface of the country is occupied by them, whilst both their 

 nature and their extent are rendered conspicuous by the general 

 want of vegetation. This abundance of what, for want of a better 

 term, I call superficial deposits, appears at first sight more remark- 

 able, because of the general absence of rivers in Persia, and the small 

 rainfall. So far as I can judge from description, the greater part of 

 Central Asia much resembles Persia in its physical characters ; and 

 throughout Turkestan, Afghanistan, and Tibet there is the same 



* Some of these great gravel deposits are noticed by Loftus, Quart. Journ. 

 Geol. Soc. vol. xi. p. 252 ; but bis researches were chiefly confined to a part of 

 the country in which such formations are probably less extensive than in the 

 regions traversed by myself. 



VOL. XXIX. — PART I. 2 L 



