SECTION FROM VERCH-URALSK TO STERL1TAMAK. 
459 
absence of fossils, to assign to these limestones of Avziansk 1 an exact place in our 
classification. Seeing, however, that they are succeeded on the west by schists, 
red earth and quartzose sandstone which rise out from beneath them, we cannot 
consider them very low in the series, and they most probably pertain either to the 
Lower Devonian or Upper Silurian formations (see Coloured Section, PL IV.). 
For some distance to the west of Avziansk, the road leads over highly undulating 
hills, all of them being composed of quartzose grauwacke, schists and psammite, 
which as they dip easterly, under the trough just described, fold over to the west at 
Bretag, and Priutch Uisse, into the valley of the Nugush. When contrasted with 
the rich valley of the Bielaya, these mountains have a woodland and sterile aspect, 
and their highest summit, the Yurma-tau, is, according to M. J. Khanikoff, 3116 
English feet above the sea. This, in fact, is the most westerly of the four dominant 
ridges of these western embranchments of the Central Ural, being succeeded on the 
west, first by the Kalu, 2755 feet, afterwards by the Ala-tau, about 2000 feet high, 
and lastly by the Akri-tau, a somewhat lower ridge, which forms the western flank 
of the whole chain 2 . On the whole, indeed, these ridges, constituting anticlinal 
domes, may be described as hard quartzose sandstones, having troughs of impure 
limestone between them, which latter rock in the depression watered by the Nu- 
gush, is of grey and blue colours, with numerous white veins, and not unlike the 
Devonian limestone of the North Ural. At the Bashkir station of Kulgliina, which 
is on the western slope of Kalu, we observed very regularly stratified and wholly 
unaltered limestone, both red and grey, with shale, &c. dipping first slightly to the 
west, and afterwards rising to occupy a trough in a valley of some breadth : but 
here also we were unable to obtain fossils. On its western flank this basin is suc- 
ceeded by calcareous flags, passing downwards into quartzose sandstone ol yellow 
1 We were most hospitably entertained at this Zavod of Petrof-Avziansk, between which and the 
western edge of the mountain of Akri-tau, the country is very wild and entirely inhabited by Bashkirs. 
a We were benighted in passing along the slopes of the Kalu, and cannot therefore speak of its struc- 
ture, though we believe it to be composed of quartzose grauwacke. The small horses of the Bashkirs are 
unequal to heavy labour, and eight of them (sometimes nine), with four riders, were deemed essential to 
conduct our tarantass along this “ Commerzi-tract ! ” Our “ attelage ” measured forty-five feet from the 
leading horse to the carriage with such long cords do these wild people fasten on one little pair or 
horses before the other ' The relays of horses, boys and men, were usually stationed in the glade at some 
ferry or natural boundary upon our route. We recur with delight to this very picturesque region, which 
it would give us the greatest pleasure to revisit and work out in detail. Our survey of it was neces- 
sarily hurried; for we were then pressing on, in order to reach the carboniferous steppes of the Donetz 
before the close of the summer. 
