210 
THE GEOLOGIST. 
peated alternations of cupriferous strata ; and tliat it contains a 
flora and a fauna of cliaracters intermediate between those of the 
Carboniferous and Triassic periods. The shells are, to a great 
extentj those of our Magnesian Limestone or Zechstein; and, 
like the conglomerate of that deposit near Bristol, the Permian 
rocks are distinguished by the presence of Thecodont Saurians. 
The interest attached to these vast deposits, which have been 
spread out to the western flanks of the Ural Mountains, is in- 
creased by the inferences which have been drawn, that springs 
and currents holding much copper in solution must have flowed 
from the edges of that highly mineralized 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 Carboniferous 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 j 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 analogous to forms that occur in 
rocks occupying the same geological po&ition 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 have been com- 
pared 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 althougli 
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 difl'erence of opi- 
nion on this head between Mr. Phillips and myself (to which I 
alluded last year) ; for I learn from him, that in England the 
