BANKS OF THE VOLGA NEAR SYSRAN. 
159 
are of the lower tertiary age, he infers that its origin is due to the decomposition of 
gypsum and the liberation of sulphuric acid ; effects produced under the influence 
of the igneous phenomena to which Sicily has been subject. If this reasoning be 
admissible in regard to the Mediterranean deposits, it may also, doubtless, be 
applied to our Russian strata, in which gypsum, marls, salt, and asphalt are simi- 
larly associated. We think, however, that the explanation of the origin of the 
sulphur of Sergiefsk, which we suggest at the close of this chapter, is, on the 
whole, more satisfactory. Leaving, then, for the present, the consideration of this 
theoretical point, we simply remind our readers, that as geologists we have done our 
practical duty in proving, that the sulphur beds of Russia, the lithological characters 
of which were long ago so well described by Pallas, are included in strata formed at 
the close of the palaeozoic period. 
We did not examine the banks of the Volga throughout the whole of the remark- 
able elbow which that river makes between Stavropol and Sysran. We have already 
stated (p. 86) that its right bank consists for the most part of lofty cliffs of carbo- 
niferous limestone, and from the details of Pallas we apprehend, that the same 
formation extends (though for a very short space only), to the left bank of the 
great stream and to the right bank of the Sok (see Map). Pallas, indeed, 
states, that the limestone, which is described by him as containing bodies like 
seeds of wheat (our Alveolinse), forms a promontory in that situation. We 
much regret not to have traced the junction which is probably there visible 
between the gypsiferous, sulphureous and saline Permian deposits, and the upper 
member of the carboniferous limestone, and we invite our successors to develope 
these relations. 
At all those points, however, at which we touched upon the edges of the Volga, 
viz. at and to the east of Sysran, at Samara, at the mouth of the Ussa, and at 
Ussolie opposite Stavropol, we perceived that the right bank only of the stream 
was composed of cliffs of carboniferous limestone, the left shore being for the most 
part a slightly undulating plain or steppe, which (with the sulphur hills described 
by Pallas, a continuation of those of Sergiefsk) we place in the Permian system. 
At Ussolie a portion even of the right bank of the Volga, consisting of low grounds, 
the property of M. Davidoff, is also, we believe, referable to the Permian rocks, 
since salt springs issue from the spot. We are further disposed to include among 
the Permian strata a calcareous conglomerate or regenerated rock, which covers 
the carboniferous limestone of the picturesque promontory of Ussolie. This 
y 2 
