GENERAL SECTION ACROSS THE URAL MOUNTAINS. 
431 
quartz rock and other crystalline materials derived from the adjacent hills upon 
the east and north-east. The summit, however, (a plateau from whence the Iremel 
and higher mountains of the chain are well seen,) is composed of limestone and 
sandstone in nearly horizontal masses, impressions of Catamites and other plants 
being visible in the latter. The Carboniferous system occupies, in fact, a fine 
breadth of country in this parallel, extending to about thirty versts west of the 
flourishing Zavod of Simsk, where it is finally overlapped by the gypseous red 
l'ocks of the Permian system which surround the city of Ufa. Void ol all traces of 
detritus derived from the chain, and apparently beyond the region of dislocation, 
Simsk is very remarkable in exhibiting picturesque and broken masses of the 
carboniferous limestone, which surrounding a circular lake, dip in various direc- 
tions. In fact, the strike in one point where we observed it, is from west to east, 
or athwart the direction of the very same formation a little to the east. Such par- 
tial aberrations and eccentric breaks must be looked for in the outermost lolds ol 
a great series of mountain flexures, near their line of frontier with another group of 
deposits. By reference to the Map it will be seen, that Simsk is probably upon 
one of those flanking lines of dislocation parallel to that singular line ol erup- 
tion which traversing the Inser is marked by a long south-south-westerly bend ol 
the Bielaya. It is upon this latter line that the remarkable outliers of carboniferous 
limestone north and south of Sterlitamak, before described, p. 130, have been up- 
heaved to the consideration of which we shall hereafter return. Among the lossils 
at Simsk we may enumerate Productus Martini, P. semireticulatus (Mart.), Spirifer 
lineatus (Mart.), all well-known Derbyshire and British species. 
General Section across the Chain in the parallel of Zlatoust and Minsk. The co 
loured section, PI. III. fig. 1, will best explain the highly diversified character of 
this chain, which, so crystalline in its central parts, tells off in a remarkably clear 
manner on its western flank the original nature of those paleozoic deposits which 
have been sufficiently removed from the great centre of mineralization. On this oc- 
casion, reversing the method employed in explaining the succession from Zlataust 
to Simsk, we will describe the deposits as they succeed each other from the low 
country on the west, across the mountains to the low plateaux of Siberia on the east. 
On the banks of the little river Riga (an affluent of the Ai) sandstones and grits 
occupy the low country, and constitute, as at Artinsk and other places where we 
have before described them, a wide trough in the carboniferous limestone on which 
thev repose (see Map). To the west they are succeeded by true carboniferous 
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