Sketch of the Geology of Northern Russia. 21 
On the precipitous banks of the Oca, ten miles above its junction 
with the Volga, stands the town of Nishney Novogorod, the grand 
centre of the internal commerce of Russia. The chasms in the 
banks of the Oca, show nothing but horizontal strata of red and white 
marl; but above the town, its beautiful valley exhibits smiling land- 
scapes, adorned with tufts of oak and ash, with occasional glimpses 
of the winding river, ‘studded with sails,” and bordered with bril- 
liant verdure, and rich vegetation. Villages adorn the lofty and 
broken banks of the Volga, below the town, as it pursues its way 
south east, through fine orchards, and pastures, and noble woodlands. 
The abrupt chasms which intersect the banks, discover beds of pale 
red sandstone, alternating with marl. ‘The color sometimes varies 
from pale red to dusky green, containing globular concretions. At 
‘the bottom of the cliff, and near the river, is a thick bed of compact 
tuff, the cavities of which are filled with stalactites of sulphate of lime, 
sometimes resembling those found among solid alabaster. Fresh 
water shells are found in this tuff, but are of rare occurrence. 
“Among the greatest curiosities of the salt district,” says Mr. 
Strangways, “are the cavern and rocks of Barnacouva. They are 
situated near the western extremity of a ridge of hills, on the north 
bank of the Piana, which makes a circuitous course around these 
hills, and then running east falls into the Volga. A round hill, cov- 
ered with oaks to the summit, is at this place hollowed on one side 
into a natural amphitheatre, accessible only by a rugged path, which 
follows a little stream issuing from a narrow opening between the 
hills. On pursuing this stream into the recess from which it flows, 
lofty perpendicular rocks appear above the wood, on the right hand, 
and on turning a sudden corner, the dell widens a little, and is bar- 
red across its upper end with a precipitous cliff of snowy whiteness. 
A small lake lies in the hollow, fringed with oaks. The white cliff 
rises abruptly behind it, and’ a woody eminence above terminates the 
scene. The beauty and repose of this sequestered spot are not the 
only features which distinguish it. On reaching the cliff, it is found 
to be of the purest alabaster ; and on passing the tangled brushwood 
that conceals it, is seen the mouth of a cavern, of which it is no ex- 
aggeration to say that it resembles the driven snow. At several feet 
distance from the cave, a remarkable sensation of chill is experienced, 
and it seems as if this appearance of snow, had also its coldness. 
The interior of the cave contracts ‘suddenly, and is intensely cold. 
On the right hand the tops of the larger masses rise above the trees, 
