EXTENSION TO ONEGA AND ARCHANGEL. 
49 
To the south and east of Vitegra the old red strata descend beneath the carboni- 
ferous limestone, the uppermost beds being seen at Vitegraski, and on both banks 
of a little rivulet. The same relations exist to the west of Divitinskaya, the head- 
quarters of the engineers of the great canal, which, passing over the low watershed 
of this region, is among the most wondrous of the works devised by Peter the Great. 
It connects the drainage of the vast government of Vologda with that of St. Peters- 
burgh and the Baltic. 
To the north-east of this spot the country becomes so low, and the high road to 
the Dwina runs so much upon the carboniferous limestone, that rapid travellers 
like ourselves, who made few deflections from the route, could not define the 
southern limits of the underlying red system. From personal inspection, chiefly 
judging from the red colour of the surface, we believe that strata of this age form 
the subsoil at the mouth of the river Onega, where that river empties itself into 
the White Sea. We also detected these beds (though with great difficulty, owing to 
the quantity of northern drift) in the form of shale and incoherent psainmite, on the 
banks of the river Kianda, between Onega and Archangel — a district in which salt- 
sources are not unfrequent and still worked at one locality 1 . Again, we think that 
the fundamental rock beneath the city of Archangel belongs to the Devonian or 
Old Red System, for the colour of the country (where bogs do not prevail) is of 
a reddish tint, and all the river cliffs, which rise to some height between this city 
and Kholmogor, consist of scarcely any other matter than regenerated red mate- 
rials. Lastly, by marking the most northern points on the rivers Onega and 
Dwina, to which the carboniferous limestone extends, we gain a tolerably accurate 
line of demarcation, from which the Old Red strata may be said to range up to 
the edges of the metamorphic rocks of the White Sea . We further beg to say, 
that from information, derived unfortunately too late to profit by it, we are led to 
think, that the junction of the Old Red Sandstone and Carboniferous Limestone, is 
to be seen on the banks of the river Onega, about 160 versts above its mouth, 
where these rocks occupy a distinct escarpment. 
1 M. Launitz, an intelligent gentleman of Courland. who has been some time resident at Onega and 
Archangel, assured us that he had seen ravines between Archangel and Onega, the banks of which con- 
sisted of finely laminated red and green marls. In our expedition along the edges of the White Sea to 
Onega, we were accompanied by our kind friend Mr. Whitehead, the British Consul at Archangel. 
2 M. Bohtlingk showed us hard sandstones from the northern shores of the White Sea, which we con- 
sider to be identical with the rocks of the Lake Onega near Petrozavodsk, 
