﻿1851.] STRACHEY — GEOLOGY OF THE HIMALAYA. 



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enter again a region of fossiliferous rocks, which extends as far as my 

 examinations have been carried. And it is not a little wonderful to 

 find at this immense elevation a regular succession of most of the more 

 important formations, from the Silurian to the Tertiary Periods. 



The Palaeozoic beds, met with immediately above the slaty rocks I 

 have just mentioned, seem to have a thickness of about 6000 feet, but 

 it is quite possible that organic remains may extend lower than I 

 supposed ; indeed, from the very difficult nature of the country, the 

 precise thickness of the deposits and the limits of the different forma- 

 tions cannot be determined properly without a much more careful 

 examination of the country than I was able to give it. 



The lower portion of these strata are undoubtedly of Silurian age, 

 and I am indebted to Mr. Salter for the following list of the species 

 that he has been able to recognize on a somewhat cursory examination 

 of my specimens. 



Among the Trilobites are — Cheirurus (the Silurian form of the 

 genus), Lichas, Asaphus (only as yet found in Lower Silurian beds), 

 Cybele, Illcenus. 



Of Molluscs are — Strophomena, a strongly ribbed Orthis, Terebra- 

 tula, Leptcena very like L. depressa, Lingula, Orthoceras, Cyrtoceras, 

 and Lituites. 



Of Polyps — Favosites, Ptilodictyon, Chcetetes. 



Also Encrinites and Cystidece ; Tentaculites and other Annelids, 

 and Fucoids. 



I was likewise fortunate enough to have an opportunity of showing 

 these fossils to M. Barrande, who appeared to have little doubt, from 

 their general character, that some of the beds from which they came 

 were certainly of Lower Silurian age. 



The lowest beds of these Palaeozoic strata consist of dark-coloured 

 thick-bedded limestones, in some places filled with Corals. These, 

 however, I have not yet had an opportunity of having examined. They 

 are succeeded by limestones mixed with slates, in which were found 

 the strong-ribbed Orthis, Terebratula, Lingula, a large Univalve, and 

 fragments of Encrinites. Above these come flaggy limestones with 

 grits, that contain the greater part of the Trilobites, Strophomena, 

 Leptcena, Lituites, Ptilodictyon, Cystidece, and Fucoids. The beds 

 then become more argillaceous, and shales and slates mixed with an 

 impure concretionary limestone follow. In these beds are found 

 Cyrtoceras and Orthoceras, and amongst the nodular concretions of 

 limestone a Chcetetes is common. Next in order come dark-red 

 grits, sometimes marly, containing only a few fragments of Encrinital 

 stems. Above these, pale flesh-coloured quartzite, and finally a white 

 quartzite, in neither of which I ever found any fossils, and which form 

 the highest peaks of the ridges composed of the Palaeozoic rocks. 



The whole of these strata are in various degrees affected by cleavage 

 and joints, which penetrate all the beds without regard to their mineral 

 character, although in a somewhat less-marked degree in the lime- 

 stones and quartzites. 



That the general sequence of these strata is pretty regularly main- 

 tained, I have seen over a longitudinal extent of about fifty miles, but 



