724 
Permian Syslem, (Zechstein of Germany—Magnesian limestone 
of England.)—Some introductory remarks explain why the authors 
have ventured to use a new name in reference to a group of 
rocks which, as a whole, they consider to be on the parallel of the 
Zechstein of Germany and magnesian limestone of England*. They 
do so, not merely because a portion of the deposits in question has 
long been known by the name “ grits of Perm,” but because, being 
enormously developed in the governments of Perm and Orenburg, 
they there assume a great variety of lithological features, and con- 
tain the bones of thecodont Saurians and certain fishes, also a more 
copious fauna and flora than have ever been observed in their equi- 
valents in Western Europe. 
The Permian rocks of Russia which occupy so vast a region to 
the east of the river Volga, 7.e., in the governments of Kasan, Viatka, 
Perm and Orenburg, are composed of white limestone with gypsum, 
red and green grits with shales and copper ores, magnesian lime- 
stones, marl-stones, small conglomerates, red and green sandstones, 
&c. By examining numerous natural sections between the neigh- 
bourhood of Sviask, Kasan, and Samara, upen the west, and the 
carboniferous limestone on the edge of the Ural mountains on the 
east, the authors have come to the conclusion, that however the 
lithological sequence may vary in different tracts, the whole of the 
vast region alluded to, is occupied by deposits which belong to one 
class or zoological system of deposits. ‘Thus, though the limestones 
are sometimes white, sometimes yellow and pure magnesian, and 
oftentimes pass into marl and marlstone, all of which can be observed 
to inosculate with strata of red sandstone, conglomerate, &c., the 
same fauna pervades the whole group. The Mollusca and Polypi- 
fers are clearly of a type intermediate between those of the carboni- 
ferous limestone and those of the Trias or new red sandstone group 
of Continental geologists. Among the most characteristic of these 
Le may be enumerated Productus horrescens, n.s., P. Cancrini, 
, Spiryfer lamellosus (L’Ev.), Terebratula elongata (Schloth.), 7. 
Rae (L’Ev.) (7. Roysi, L’ Ev. = Atrypa pectinifera, Sow. Min. 
Conch. No. 107), Natica variata (Phil.), Modzola Pallasi, n.s., 
Gervillia lunulata (Phil.), Ostre@a matercula, n.s., Corbula Rbiianey 
n.s., Avicula Kasaniensis, n.s., 4. antiqua (Schloth.), 4. cheratophaga 
(Schloth.), Lzngula parallela (Phil.), Limulus oculatus (Kutorga), 
Cytherina ; with Retepura flustracea, Gorgonia, Millepora, &c. &c. 
* « T have recently been informed by M. A. Erman, that an erroneous 
view has been communicated in my anniversary discourse, respecting the 
first use of the word ‘ Zechstein ’ in reference to the deposits of Perm, that 
term having been used, as he assures me, by German miners, who visited 
Russia long ago, though no proofs have been since offered to sustain its ap- 
plication in @ geological sense. I also take this opportunity to state, that 
through a misapprehension of his views, derived from a perusal of the Bul- 
letin de la Société Géologique de France, I have been led into a mistake in 
supposing that M. Erman believed a large portion of the Russian rocks, 
now shown to be carboniferous, to belong to the Jurassic epoch. I willingly 
adopt this correction of my views in reference to the distinguished eager 
explorer of Siberia and Kamschatka.”—R. I. M., Sept. 1842. 
