346 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [June 15, 



2. A hard, even-grained specimen, Avith no entire or large frag- 

 ments of shells visible to the naked eye. 



Grains of Limntean shell showing structure. . 5'7 1 ,o.rv 



Ditto not showing ditto 12"3 J 



Crystallized fine granules of shell, &c 5.t"9 



Quartz sand 13*5 



Very fine sand and decomposed felspar .... 12*1 

 Peroxide of iron chiefly in the substance of 



shell fragments '5 



100-0 



In the above-described marls and limestones are found several 

 curious bodies, but in no great proportion ; and, on the whole, they 

 may be said to be derived from the decay of the freshwater shells 

 found in them, and not from the deposition of chalky mud, which 

 has a totally diiferenc character, though the calcareous matter in the 

 water, from which the shells procured it, may have been derived 

 from the contiguous chalk. It is worthy of remark, that in these 

 marls no Diatomacece are found, though they abound in the clays 

 associated with some of them ; but the examination of tufaceous 

 travertins has furnished the author with evidence which proves that 

 contact for a long period with carbonate of lime decomposes and 

 destroys their siliceous coverings, and therefore they could hardly be 

 expected to occur in such deposits as those under consideration. 



5, On the Geology of part of the Sooliman Range. 

 By Dr. A. Fleming, E.I.C. 



[In a Letter to Sir R. I. Murchison, F.R.S., F.G.S., Pres. R. Geogr. S.] 



Camp Veehowa, Dera Ghazee Khan Frontier, eighty miles N. of latter, 

 close under the Sooliman Range, and about thirty miles direct 

 trom the Tukht-i-Sooliman, March 29th, 1853. 



With the exception of occasional patches of corn crop now in ear 

 (March), the whole central district of the Derajat, between the culti- 

 vated belt, or Kuchee, along the Indus and the foot of the Sooliman 

 Range, is a barren alluvdal plain, thinly dotted with dwarf jungle bushes 

 of wild caper and petoo [Salvadora Pei'sica), and in some places covered 

 with a thick crop of lana (a species of SaJsola ?), by burning large 

 quantities of which the natives obtain a coarse kind of carbonate of 

 soda (Sujee). This latter plant is only found on plains liable to be 

 flooded moderatehj, and in which saline matter is abundant. Its 

 present habitat supplies both the above conditions, for although the 

 river inundation never reaches it, yet, whenever rain falls in the hills, 

 hundreds of mountain torrents escape from the various ravines and 

 passes, and for a time convert the whole country into a sheet of 

 water, which is however drunk up by the thirsty soil long before it 



