SECTIONS OF ILCHEGULOVA, THE DIOMA AND ZAYAKAYA. 
151 
pand in another. After passing over a barren steppe of considerable width, inha- 
bited by Bashkirs, the surface of which is covered at intervals with much black 
earth or “ Tchornozem,” we first perceived on the sides of a ravine near the 
Bashkir camp of Ilchegulova, about half way between Sterlitamak and Bielebei, 
bands of impure limestone, in parts resembling English “ cornstone,” alternating 
with grey and red grit and shale. In these beds, most of which are flaglike, we 
found the Modiola Pallasii, the Productus Cancrini, and some corals, impacted in a 
dull red matrix, overlying other limestone flags of grey colour and compact struc- 
ture, beneath which are thin bands of smoke-grey and greenish calcareous sand- 
stone and grit. The beds exposed are in all about thirty feet thick, and they 
occupy the summits of the plateaus watered by the Nadir and other rivulets which 
flow into the Dioma. In our journey to the west we perceived that the calca- 
reous matter thickened rapidly, inclining upon the whole to the west ; for we shall 
presently see, that beds containing the same fossils which here occupy the plateau, 
occur at the bottom of the deepest denudations. 
The reader will not fail to observe, that on this line of section, as on that of 
Orenburg (p. 1415), limestone with fossils of the Zechstein is not met with, except 
at some distance from the edges of the carboniferous rocks. 
On the banks of the Dioma, this limestone series thickens in fine escarpments, 
composed of strong bands of red and grey grits with plants ; and the latter, some- 
times calcareous, alternate with courses of fossiliferous limestone. 
This is well seen at Nikefur, on the banks of the Zayakaya, a tributary of 
the Dioma, in cliffs of about 140 feet in height, which expose the following suc- 
cession : — 
Summit. — Bands of white and brownish compact flaglike limestone, with courses of yellow and greenish gritty 
sandstone, with Productus Cancrini (nob.), P.horrescem (nob.), Terebratula concentrica, small Modiolce 
and plants, &c. 
Calcareous grit, with thin courses of flint. 
Grev maid with thin courses of limestone. 
Sandstone and grits (with schists of conchoidal fracture forming the laminae of deposit), containing many 
stems of plants. 
Limestone, -whitish and grey, in beds of one to two feet. 
Dull red argillaceous beds. 
Base. — Thick beds of purple and grey grit and sandstone. 
In all this tract, the limestone seemed to prevail on the summits, and the grits 
towards the bottom of the valleys. 
Further westwards, at Metaftamak, twenty-two versts from Bielebei and west of 
x 2 
