300 
STRATA OF THIS AGE AT ODESSA AND IN THE CRIALEA. 
and Kamiusch Burun at the eastern extremity of Crimaea,— another species of 
Cardmm of this steppe-limestone— undistinguishable from the C. pseudo -car dium 
( Desh.), which we found living in the Lake Akerman near the Dniester, and a very 
small Myhlus (Dreissena), which with a Paludina constitute whole bands of stone, 
the shells being in general triturated and cemented into a porous mass. 
From the character, then, of its imbedded shells, it is evident that this limestone 
was deposited m brackish waters, and from its occurrence at numerous places, where 
it forms the shores of the lower steppes, it must have occupied a vast area. Within 
the limited scope of our own researches, we observed it ranging eastward as far as 
Lepatinsk on the Don, about 100 versts from Novo Tcherkask, where it caps a 
cliff about 120 feet high, and where, having a thickness of thirty-six feet, it reposes 
upon incoherent sands with yellow courses of about forty feet,' beneath which are 
beds of siliceous sands and sandstones, undistinguishable from those we have before 
mentioned as covering the white chalk in other parts of Russia. Such sandstones, 
generally yellowish- white, and crumbling into fine glassy sand, occupy the pro- 
montories on the right bank of the lower part of the Volga, and from Sarepta ex- 
tend along the right bank of the Sarpa where we examined them. Associated with 
some marls and occasional limestone, they constitute, in fact, the western and 
northern shore of the vast lower steppe of the Kalmucks, and in that sense we shall 
hereafter allude to them. We have before us a manuscript description of these 
sandstones written by Mr. Strangways many years ago, in which their eroded surface 
and concretionary structure are well described. Whether near Sarepta on the 
Volga, or on the southern edge of the granitic steppe of the Dnieper extending west- 
wards to Poland, they seem to constitute the oldest portion of these tertiary rocks, 
and to be succeeded by the steppe limestone. In some instances, near Sarepta' 
as Mr. Strangways well observed, they present striking appearances of false strati- 
fication or cleavage oblique to the chief horizontal beds. From our own acquaint- 
ance with them we are unable to assign the relative age of all these sandstones 
occurring as they do at remote distances from each other. In the absence of or- 
ganic remains, we cannot presume to decide, whether they ought to be classed with 
the Miocene or Pliocene deposits, or whether they occur in both of these subdi- 
visions. Some of them have, indeed, been already alluded to as being of the Eocene 
or older Tertiary age. In truth we have already stated, that in many districts the 
development of both the cretaceous and tertiary rocks is so arenaceous that we 
are incapable of drawing clear lines of separation between them. 
