316 
LOWER STEPPE BETWEEN THE URAL AND THE VOLGA. 
of various strata, occupy the left bank of the Ural and its tributaries, and that 
these are succeeded on the east by a band of Jurassic rocks extending across the 
river Emba, and pointing towards the Sea of Aral. 
Steppe of Astrakhan. — The whole of the low steppe between the Ural and the 
Volga, and which ranges from the watershed of the Obschey Sirt upon the north 
to the Delta of Astrakhan on the south, is (with the exception of the islets of Bogdo, 
Arsagar, &c.) apparently nothing but a desiccated sea-bottom. It is, in fact, en- 
tirely composed of sand, with occasional heaps of fine gravel, is rarely argillaceous 
and loamy, and is almost everywhere strewed over with shells or the debris of 
species, some of which are now living in the adjacent Caspian Sea, such as Mytilus 
polymorphic, Adacna edentula (Eichw.), and Didacna trigonoides ( Cardium , Pall.): 
others have not been found living, such as Mytilus rostriformis, Adacna protr acta, 
and Monodacna catillus. The mean elevation of this steppe above the level of the 
Caspian does not exceed fifty feet, and as that sea is 83‘6 feet below the level of the 
ocean, as will be hereafter explained, it follows, that if the water of the Black Sea 
should, by any subsequent change of level of the intermediate land, find access to 
this region, nearly the whole steppe in question would be again submerged. Ihe 
shelly sands, however, ascend insensibly to the north, or towards the Obschey Sirt. 
They also rise where they approach the isolated hills of Bogdo, whilst at Tcliornoyar 
on the right bank of the Volga above Astrakhan, and near the western shores of 
the desiccated area, beds with Caspian shells are seen to occupy a thickness ol 
about sixty feet above the stream, and in the following ascending order : — a. Lowest 
beds, sands in various courses, 35 feet. 5. Bed with Caspian shells, c. Brownish 
sandy clay or silt, which, on drying, scales off into irregular laminse. d. Yellowish 
argillaceous sand. 
Though one of us 1 traversed this steppe from north-east to south-west, i . e. 
from Uralsk, to the banks of the Sarpa below Sarepta, and therefore in its greatest 
diameter, we have nothing else to state concerning its monotonous internal 
structure. Of its northern and western shore, which was followed by the re- 
mainder of our party, we have yet a few words to say. On the north it is com- 
' In traversing this steppe, which could not have been accomplished without the kind and active 
assistance of General Perovski, Count Keyserling visited the Khan of the Inner Kirghis in the heart of 
the steppe, who is tributary to Russia. Oases affording very tolerable sustenance for cattle occur at inter- 
vals, and the best fresh water is found by digging holes in the sand. Tins fact serves to substantiate 
the belief, that the steppe is saliferous in those spots only where springs rise from subjacent rocks con- 
taining salt. 
