106 



from the edges of that highly minieralized and metamorphic chain, 

 while the Permian strata were accumulating. But the great value 

 of having worked out a fuller and richer type of a group of strata 

 between the "Cai'boniferous and Triassic epochs than any which 

 exists in Western Europe, will be found in the fossil shells, the plates 

 of which are already far advanced ; for, with some species hitherto 

 known in the Zechstein of Germany and Magnesian Limestone of 

 England, we shall publish others which are identical with or analo- 

 gous to forms that occur in rocks occupying the same geological 

 position in North America, of which I will speak hereafter, and 

 concerning the age of which great doubts had prevailed. - 



In America, indeed, as in Russia, these beds had been compared 

 with every deposit, from the coal to the Keuper inclusive, whilst in 

 our work they will be shown to have no connection with the New 

 Red Sandstone or Triassic group, but to occupy a definite position, 

 truly intermediate between that system and the carboniferous. At 

 the same time it is manifest, that although they overlie and are, as 

 they ought to be, very distinct from the Carboniferous system, yet 

 they contain some species of shells which occur in that division. 

 Thus it will be made evident, that after all there now remains scarcely 

 any real difference of opinion on this head between Mr. Phillips and 

 myself (to which I alluded last year) ; for I learn from him, that in 

 England the analogy between the fossils of the Magnesian and Moun- 

 tain Limestone obtains to a far greater extent than could be supposed 

 from any publislied catalogues. I trust, therefore, that the ensuing 

 year will not be without its fmits iti the production of new works 

 on the shells of the Magnesian Limestone of our own country ; and 

 I am glad to have it in my power to inform you, that Mr. King, the 

 Curator of the Natural History Society of Newcastle-on-Tyne, is 

 preparing some excellent materials for this purpose. 



A better 'acquaintance with the Permian fossils, particularly the 

 prevalent Mollusca, induces me, notwithstanding the arguments 1 

 employed last year, to infer that this deposit, so naturally connected 

 through its characteristic fossils with the Carboniferous strata, must 

 be classed with the Palaeozoic rocks*. The physical structure of 

 Russia is also greatly in favour of this view; for, in large portions of 

 that country, there is an entire absence of the great rupture between 

 the Carboniferous rocks and the Magnesian Limestone, which is so 

 prevalent in the British Isles. The examination of rocks of this age 

 in North America, to which I shall hereafter advert, leads to the 

 same opinion ; viz., that the Permian deposits must be viewed as the 

 fourth or uppermost stage of the Palaeozoic series, notwithstanding 

 the occurrence of Thecodont Saurians. 



Jurassic, Cretaceous a?id Tertiary Strata. — Overlapped as these 

 Permian deposits are, in certain tracts of Russia, by red and white 

 mai-ls and sands, we are not positively prepared to state (in the 

 absence of decisive fossil evidences) whether some of them may not 



* My companions, M. de Verneuil and Count Keyserling, have long en- 

 tertained the same views as Mr. Phillips on this point. 



