CARBONIFEROUS LIMESTONE AND MILLSTONE GRIT. 
415 
On the coast of the glacial sea, this carboniferous limestone occupies the two 
capes, on either side of the ridge, called Suvoinov and Svetoi-nos. The river Indiga 
traverses the carboniferous band on the eastern flank of the Tinian at thirty-five 
versts above its mouth, and exposes cliffs 100 feet high, which contain thick beds 
near their summits, and flagstones towards their base. The river Bielaya, an 
affluent of the Indiga, also exhibits on its less lofty banks, courses of limestone 
charged with Fusulinse, fossils, as we have before shown, which characterize the 
upper part of this formation. 
The same calcareous zone is also traversed by the river Tzilma in north latitude 
65^°, and forms the mountain Stchipina. In this parallel, the axis of the ridge is 
composed of Devonian rocks, the carboniferous limestone being seen on its eastern 
side only, and not upon the west. Nor is this limestone continuous, even on the 
eastern side ; for upon the river Ijema or Ishma, the Devonian rocks are at once 
surmounted by Jurassic shales. Towards the southern extremity of the Timan, the 
same carboniferous limestone constitutes the chief mass of the range, and is laid 
open on the banks of the rivers Vol, Tsher and Milva, as well as on those of their 
recipient the Vitchegda ; and we believe that it again appears in the form of an 
outlier or outliers on the river Soiva, a feeder of the great Petchora. 
The carboniferous system of these regions contains another member, which is 
only to be seen at the northernmost extremity of the Timan range. Such are 
certain whitish grits charged with pebbles of white quartz, and therefore resembling 
the millstone grit ; like which they also contain coal plants. Seeing that these 
beds have the same inclination as the carboniferous limestone, we believe then 
geological position to be precisely similar to that of the millstone grit of the 
Tchussovaya (p. 126). This inference cannot, however, be distinctly proved in the 
North Timan, where they form the lateral cover of a remarkable band of igneous 
rock. 
Eruptive Rocks of the Timan .— The chief eruptive zone of the Timan extends 
from the. cape Tchaitzin-mis for seventy versts towards the south-east, is from four 
to five versts broad, and rises to the greatest heights of these latitudes, all of them 
being sharp-backed, like the “ Serras” of Spain. The rock has, on the whole, 
what British geologists would call a trappeean aspect, resembling certain basaltic 
rocks of the Hebrides and the south coast of the Isle of Man, and in it are amyg- 
daloidal masses which contain Heulandite and Stilbite, minerals unknown in the 
rich and varied crystalline depositories of the Ural Mountains. Usually, however, 
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