ARALO-CASPIAN FOSSILS AND SHELLS OF PRESENT CASPIAN. 
305 
tertiary formation of this tract. If this fact were established, it would be at vari- 
ance with all our knowledge of the distribution of such animals over enormous 
surfaces of Russia and Siberia, as well as in other parts of the world ; but as M. 
Huot has never seen these remains imbedded in the same strata with marine remains 
of miocene or even pliocene age, but simply collected them at' the loot of the cliff, 
the natural inference would seem to be, that they had fallen from an overlying mass 
of sand, clay or other superficial detritus, occupying a position similar to that in 
which we found them at Taganrog (see p. 296), and were lodged in their present 
position, just as similar remains subsiding from river banks in inland tracts are 
carried into the beds of the present streams. In corroboration of our own opinion 
it also may be stated, that no remains of these Mammalia are cited by any author in 
the solid tertiary formations of Russia, not even in the Aralo-Caspian 01 uppei 
most stratum ; and since M. Huot himself describes them in another place, as really 
occurring in the superficial detritus or earthy covering of these tracts, we shall now 
simply state, that such is in our view their only true habitat. This terrestrial subject, 
which is not strictly connected with that under discussion, will necessarily be con- 
sidered in a subsequent part of this volume. . 
Though unable from our own researches to describe the continuation of t le 
steppe limestone, from the peninsula of Taman along the northern edge of the 
Caucasus, we believe from the descriptions of others, that the rock is continuous 
We think that it ranges along the low country by Stavropol towards the advancec 
Caucasian spur called the Beshtau. However this may be, the recent publication 
of Professor Eichwald distinctly enables us to synchronize with it all the wide- 
spread horizontal shelly limestones of the Daghestan, Derbend and Baku, w ic 
form low hills on the western shores of the Caspian Sea. There again we are pre 
sented with agglomerates of Cardiace. and Mytili, with Paludin. and other fresh- 
water shells. The labours of M. Eichwald have indeed a special value in 
mining the age and origin of these limestones, for in describing the very limitec ex- 
” L fauna of the Caspian Sea, he has ascertained, that a. least seven spec.es ol he 
fossU shells are now living in it. In these rocks the sa,ne ph— on is repeated 
as in those which we have examined on the shores of the Black Sea and Sea o zo , 
vi, that with the exception of some traces of Rissoa, there are » manne — 
The following table of the Caspian shells, recent as well as fossil, will show bette 
than pages of writing, to what degree the tertiary deposits ainnnd that sea coincide 
with lose we have been mentioning on the shores of the Sea of Azof and B1 
Sea, and how they more fully exhibit the true and unmixed Aralo-Caspian type. 
