UPPER DIVISION ON THE RIVERS MSTA AND BELAIA. 
45 
Terebratula prisca, Leptcena productoides, Serpula omphalodes, &c., &c., we also 
met with Terebratula Helmersenii (V. Bucli), Spirifer tenticulum (nob.), and the 
Orthoceratites subfusiformis (Munster). 
A little to the east of Korostino, and at Porogi, where the same strata undulate 
to some extent, dark purple, unctuous clays and marls are exposed at the base of 
the cliffs. 
The great thickness to which inferior strata of the system expand to the south 
of Lake Ilmen, has been proved by the sinkings recently made in the hope of pene- 
trating to the sources of the salt-springs at Starai Russa, and in which, it is said, 
no perceptible change of ground was met with through a depth of about 600 feet. 
As the deepest point from which these brine-springs rise has not been attained, 
we are left in doubt whether the real source of the salt is in the lowest beds of the 
Devonian rocks or even in the Silurian system. 
It will be shown in the sequel, that salt-springs and rock-salt are very prevalent 
in the red rocks overlying the Carboniferous system, and thus Russia affords distinct 
proofs within itself, that this mineral occurs in formations of very dissimilar age. 
From the absence of rocky cliffs, the rounded nature of the elevations, and the 
detritus which obscures the surface, the whole of the intermediate strata cannot be 
seen in any one section of the Valdai Hills. Still, by examining the banks of the 
Msta and its tributaries (the only river of any magnitude which runs transverse to 
the Valdai), we find sections of the upper division of the system, which for clear- 
ness are not exceeded, if equalled, in any part of Europe. The best evidences of a 
succession from the red ground into the overlying carboniferous limestone, are 
seen in the sequestered valley of the Belaia (or White River), a tributary of the 
Msta, about twenty-five versts south of Borovitchi '. Immediately to the north 
of the picturesque village of Sherokovitchi, the rivulet Priutchka falls into the 
Belaia, and by following the former to its source you ascend a well-wooded and 
watered, narrow gorge, on the sides of which are natural sections, in great part ver- 
tical, of near 200 feet in height. The greatest number of strata exposed in any 
one spot, may be seen near the place where coal-works have been established, and 
galleries have been driven from the side of the hill into certain bituminous schists, 
half-way up the cliff, which occur in the lower member of the Carboniferous system, 
1 We were conducted to this spot by our young friend and companion Lieut. Koksharof, who had pre, 
viously accompanied Colonel Helmersen in his examination of the tiact. 
H 
