Mr. Blanford on the Superficial Deposits of Central Persia. 461 



June 11, 1873.— Prof. Eamsay, F.R.S., Vice-President, in the Chair. 



The following communications were read : — 



1. "On the Nature and probable Origin of the superficial De- 

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

 Blanford, Esq., F.G.S. 



In this paper the author described the general characters of the 

 superficial deposits of Central Persia, and noticed the physical geo- 

 graphy and rainfall of that country. He described especially the 

 desert plains of the interior of the country, the paucity and scanti- 

 ness of the streams, most of which terminate in salt swamps and 

 lakes, and the occurrence of vast slopes of gravel on the margins of 

 the desert plains, covering up the junction of the latter with the 

 surrounding mountains. The desert plains he regarded as in general 

 the beds of ancient lakes. His general results may be summed up 

 as follows : — Persia has undergone a gradual change from a moister 

 to a drier climate simultaneously with the elevation of portions of 

 its surface, resulting first in the conversion of old river-valleys into 

 enclosed basins containing large lakes, probably brackish or salt. 

 Then, as the rainfall diminished, the lakes gradually dried up, leaving 

 desert plains. The amount of subaerial disintegration among the 

 rocks of the high ground he considered to be in excess of the force 

 available for its removal, the water which now falls only sufficing to 

 wash the loosened materials from the steeper slopes into the valleys; 

 and hence the valleys in the upper parts are gradually being filled 

 up with coarse gravel-like detritus, just as their lower portions have 

 been already hidden beneath lake-deposits. 



2. " On Oaryophyllia Bredai, Milne-Edwards and Haime, from 

 the Red Crag of Woodbridge." By Prof. P. Martin Duncan, M.B., 

 F.R.S., V.P.G.S. 



The author recorded the occurrence in the Red Crag of the "Wood- 

 bridge district of a variety of Caryophyllia Bredai, M.-Edw. & 

 Haime. The species was originally described from the Maestricht 

 Chalk ; and the specimen referred to, which was obtained by Mr. E. 

 Charlesworth, appears to be a remanie fossil, derived from the upper- 

 most beds of the Chalk, some traces of which still remain in the 

 neighbourhood of Norwich. 



3. " On the Cephalopoda-bed and the Oolite Sands of Dorset and 

 part of Somerset." By James Buckman, Esq., F.L.S., F.G.S. 



In this paper the author discussed the true position of certain 

 beds containing abundant remains of Cephalopoda, found in various 

 parts of the Jurassic region of this country, and of the sandy bed 

 underlying the Inferior Oolite at Cleeve Hill and other places 

 (called by Prof. Phillips the "Midford Sands"), which has been 

 regarded by most authors as belonging to the Lias. From an in- 

 vestigation of the Cephalopoda-bed in quarries at Bradford Abbas 

 in Dorsetshire, the author comes to the conclusion that it is quite 

 distinct from the Cephalopoda-bed of Gloucestershire, and that it is 

 the representative of the Rubbly Oolite at the top of Leckhampton 



