SPITI VALLEY, &c. 



277 



actually picked up some of the shells was on the crest of a pass elevated 

 17,000 feet, where also were seen numerous blocks of the calcareo-silicious 

 matrix. I was not able to pass more than a single day at this interesting 

 spot, but I brought away numerous fragments of the rock. If the obser- 

 vation of shells and mountain strata of organic remains at such an altitude 

 be worthy of attention to the geologist, I am happy in having enjoyed the 

 opportunity of verifying the fact — leaving to more experienced hands the 

 recognition of the species and the age of the fossils, the classification of 

 the strata in which they are imbedded, and the theory of their being raised 

 to their present elevation. 



NOTE. 



It will he seen by the heading of this paper, that it contains only the " first part" of Dr. Gerard's 

 observations on Sp'UU and treats of the geography, elevation, and climate of the valley; the 

 second part, \vhich was to iiave descrihed more particularly the geological features of tlie country, 

 in illustration of the fossils presented by the author to the Society, lias been delayed by Dr. 

 Gerard's journey to the Oviis, and cannot now arrive in time tor insertion in the present volume : 

 the last paragraph has therefore been added from information contained in the author's letters to the 

 Society accompanying the specimens. It may also be convenient to notice here that duplicates of 

 many of the shells described in the Ilev. R. Everest's memorandum, page 107, were sent at that 

 gentleman's request to Mr. Sowr.nnv, author of the " iVlineral Conchology," the substance of whose 

 reply is here subjoined, with alteration of the numbers, that they may coincide with the figures of the 

 plates of Mr. Everest's paper. 



Extract from Mr. J. D. C. Sowerby's letter to Mr. James Priiisep, Sec. Ph. CI. 



" I had before seen some specimens from the same mountains in the possession of Mr. Stokes 

 and Dr. Buckland, among which were several ammonites that are as yet unnamed. The Rev. Mr. 

 Everest's deductions are correct as far as they relate to the formations the fossils belong to, as will 

 be seen by the aceomi)an\ ing list of names, to each of which I have added the formation in which 

 that species occurs in England. In the geniis Terthratitla there are many species that rannot bo 

 depended upon as indicating particular formations, because very similar ones arc found in several 

 beds, and the species arc dilhcult to detcrnnnf, especially if i^ot ([uite perfect. The Pectin 



\ 3 



