456 
SECTION FROM VERCH-URALSK TO STERLITAMAK. 
strong bands of limestone, for the most part saccharoidal and of white colours, 
appear, and these also have a decided eastern dip (10° north of east) at angles of 
45°, as if they passed beneath the whole mass of the chloritic and quartzose rocks. 
Towards the mountain this limestone is white, crystalline and slaty : at the Zavod, 
somewhat removed from it, the rock is bluish-grey ; and a little to the west, or still 
further from the axis, a similar limestone is found fairly encased between schists 
which are highly micaceous, though less crystalline than in the mountains on the 
east. These beds, having the dominant strike of this portion of the chain, or from 
south and by west to north and by east, pass into thick masses of slaty grey lime- 
stone, which, far removed from any intrusive rock, exhibit a sufficient quantity ot 
organic remains to leave little doubt as to their being of true Silurian age. Among 
the corals were Favosites Gothlandica and Stromatopora concentrica, whilst the chief 
mollusks were two small Terebratulae, one of which we cannot well distinguish from 
the T. plicatella of Gothland, and the other approaches near to a form which occurs 
with the Pentameri at Bogoslofslt and on the Is (see pp. 394, 396). 
Judging from their inclination, it would seem that all these limestones, the whole 
of which have an easterly dip, must pass under the metamorphic crystalline rocks 
of Gara-tash. We have, however, repeatedly shown in the preceding pages, that in 
similar highly dislocated and altered masses of other parts of the chain, it is futile 
to endeavour to read off the order of the strata by superposition ; for to the west 
of Zlataust and elsewhere, as well as in this tract, the masses are often unques- 
tionably inverted, the younger beds dipping under the more ancient. Seeing, how- 
ever that in the parallel of Verch-Uralsk, and wherever the igneous rocks are less 
rife, the carboniferous limestone on the eastern flank of the chain prevails, and that 
as soon as we recede westwards from the great centre of disturbance and metamor- 
phism we meet with Silurian remains, we think that, by fair analogy, the included 
masses may be considered to have been originally grauwacke schists, grits, &c., 
which, like those on the banks of the Serebrianka and other localities, are inter- 
polated between the Silurian rocks properly so called, and the carboniferous lime- 
stones. In advancing to the west across the Nura, Yanick, and other rivers, 
which descending from the slopes of the Yamantau, Bakty and the prolongations 
of the lofty Iremel 1 fall into the Bielaya, we passed over several low elevations 
1 The want of time prevented our deviating from the route to ascend the Iremel, or even its southern 
spurs Bakty and Yamantau. We felt, however, the less reluctance to continue our route, because these 
mountains had been described by Colonel Helmersen, and M. Khanikoff had recently explained to us, that 
