238 
ferruginous sands and grit with plants. 
After making this section we could not entertain a doubt, that the whole of the 
strata of shale, sand, marl and marlstone which we had seen near Koroshovo, 
belonged, like those of the Sparrow Hills, to one and the same Jurassic formation. 
A collection of the fossils from Koroshovo was sent by Mr. Frears, at our request, 
to Professor Phillips, who identified a few of the forms. Aware, however, that 
M. Alcide D’Crbigny was exclusively engaged in a general examination of all the 
Jurassic remains of France, and believing that the continental Jurassic deposits 
would be found to present a gi’eater number of analogies to the Russian fossils 
than the series of the same age in the British Isles ; and knowing further that the 
latter were still far from being thoroughly described', we submitted all our Jurassic 
shells from Russia to that author, requesting him to place them in parallel with 
those of France. The divisions of the French series being, M. D’Orbigny has 
convinced himself, the exact counterparts of England, as described by the English 
authors, Smith, Conybeare, and others, he has assured us, that the group of 
animal remains from the central and northern tracts of Russia, including all these 
strata at Moscow, belong to the lower part of the central division of the Oolitic 
system, which he terms the “ Terrain Oxfordien.” We shall offer a few remarks 
upon this comparison at the close of the chapter. 
It yet remains for us to describe the overlying siliceous grits ( d ) of the general 
section of the country around Moscow which are represented in the woodcut at 
p. 235. With no other guide than their lithological character and overlying posi- 
tion, we were at first disposed to place these beds (though with much hesitation) 
on a parallel with the greensand. A subsequent exploration of Southern Russia, in 
which we became acquainted with siliceous sandstones (not exactly similar it is true) 
in deposits above the chalk, induced us to suppose that the Moscow grits might, 
after all, prove to be of tertiary age. Geologists who have not worked amid the 
obscurity of Russian stratification must not feel surprised at this oscillation in our 
minds. They will recollect that proofs have been already adduced of the apparent 
conformity of succession being in truth no criterion of contiguous beds forming 
1 We happen to know, from Professor Phillips himself as well as from Sir Henry De la Beche, that a 
very considerable number of unpublished oolitic species have been discovered by the British Ordnance 
surveyors. From our knowledge, indeed, of the numerous additions made to this fauna in one district 
only by Mr. Buckman of Cheltenham, we are quite ready to admit, that additional monographs must be 
brought out before this important system is thoroughly illustrated in the British Isles. In the mean 
time we refer our readers to a promised new edition of Murchison s Geology of Cheltenham, with addi- 
tions by Mr. Buckman and Mr. H. E. Strickland. 
