296 ARALO-CASPIAN OR BRACKISH WATER STEPPE LIMESTONE. 
of superposition, exposing strata of different age in the same vertical section, is 
seen at Kichenef in Bessarabia 1 . 
But, to confine our remarks, in the first instance, to tracts which we have visited, 
it may be stated, that even with our limited time, we observed certain natural 
junctions in the tertiary series which distinctly proved, that the purely marine beds 
of which we are treating, lie beneath the peculiar steppe-limestone to which we 
shall next call attention. The sections of the low hills to the north of the Sea 
of Azof establish this succession. The strata exposed at the level of the Sea of Azof 
on its northern shore and at the town of Taganrog, are unquestionably of date an- 
terior to the shelly limestones of the adjacent hills of Rostock and Novo Tcherkask, 
by which they are distinctly overlaid, as expressed in the woodcut of the following 
page. 
46 . 
Taganrog. 
Sea of Azof. 
Hills of steppe limestone. S. 
~\b 
d. Clay drift with Mammoths’ bones. 
c. Sands with fluviatile shells. J 
b. Aralo-Caspian or steppe limestone. 
a. Upper miocene limestone. 
^j- Terrestrial deposits. 
^ Tertiary deposits. 
In this woodcut the miocene limestone of Taganrog is seen to be overlaid by fluviatile shells in sand 
and by detritus containing the bones of Mammoths, &c. The geologist will at once see, that these last- 
mentioned deposits have no connection with the tertiary succession under review ; they will necessarily 
be considered in a separate part of this work. 
The lowest and perfectly horizontal beds (a), as seen along the quays of Ta- 
ganrog, are light buff-coloured limestone, in beds from two to three feet thick. This 
rock, in parts cavernous, and in parts oolitic, is there so stained with ferrugi- 
nous matter as to resemble the hard beds of English crag, whilst in other examples 
it may be lithologically compared to the best white building-stones of the calcaire 
grossier of Paris. Among the fossils, which are very abundant, we observed three 
species of Cardium, one of winch we will describe under the name of C. Fittoni 
1 There seems to be no doubt, that the fossils collected by M. Hommaire from Kichenef and that part 
of Bessarabia, some of ■which we have seen, differ to some extent from those from Poland, Volhynia and 
Podolia, of the true miocene type. Like the shells of Taganrog, they appear to form a passage from 
miocene to pliocene, and to be immediately subjacent to the Aralo-Caspian deposits. The exact limits 
therefore, between the two formations throughout this western region, cannot be precisely laid down upon 
our Map, and in referring to it our readers must understand, that over a considerable area in Bessarabia 
and the adjacent countries, the miocene marine strata are occasionally overlapped by and pass into what 
we consider Aralo-Caspian or its equivalent. 
