299 
SECTIONS IN THE COUNTRY OF THE DON COSSACKS. 
by the physical features of this region, that such desiccation must have resulted 
from at least two great movements of upheaval ; by the first of which the mile- 
stones which occupy the hilly coasts of the Black Sea, Sea of Azof and Caspian 
and large tracts between that sea and the Aral, must have been consolidated and 
left dry ; so as to form the shores of an inland sea of posterior date, which though 
separated from the Aral, still spread over the great steppe north of Astrakhan and 
covering the low steppe of the Caucasus and the isthmus of Perecop, connected the 
sea of Azof and the Black Sea with the present Caspian. We have, indeed, en- 
deavoured to mark this succession upon the Map', first, by a rich yellow colour 
No. 10., to indicate the earliest period of this Aralo-Caspian brackish sea when 
it covered its greatest area ; secondly, by a diminished tint of the same colour (10), 
showing a more recent period of desiccation, when the Caspian and Black Seas 
were still united, but when the Caspian and Aral were separated by the high inter- 
vening plateau of the Ust-Urt. 
Aralo-Caspian or Steppe Limestone.- It is to this formation, for the most 
part we presume of Pliocene age, that we refer the strata, which occur at Novo 
Tcherkask, and under the name of Steppe Limestones occupy a large portion of the 
hills before referred to, at heights of 200 or 300 feet above the sea (see woodcut, 
p. 296). Novo Tcherkask, the new and spacious capital of the DonCossacks, is to a 
great extent built of a rock of this age, which is there excavated to a depth of twelve 
or fifteen feet, showing sands both above and beneath it. Tins rock is of a ginger- 
bread colour, and is made up of a mass of broken shells, so as still more to resem- 
ble the English crag than the inferior marine beds of Taganrog. It may a so e 
compared in lithological aspect with the large cavernous shelly secondary oo ite o^ 
Barnock, near Peterborough in England, like which it may prove a durable an 
good wearing stone though full of cavities . 
The shells which characterize the rock at Novo Tcherkask are-the ■*« 
Cariium mlcatmum and C. incertum (Desk), described by one of us from Odessa 
,• a „„ „ vr„„ scale which we have prepared, it is to 
' In defining the range of the steppe imes one o fe w locallt ; €S are included at or near which 
be again observed that along the edges o t le j ° un S e subjacent rocks ; for example, in the low 
cliffs of Taganrog, v ere know, occur at numerous other localities, and all 
to the real borders of the vast area in Russia, 
or Odessa, is easily cut in the quarries. 
but hardens in the atmosphere. 
