8 GEOLOGICAL MEMOIRS. 
tinuation of those which form the coast. The peninsula is, besides, 
contoured by a flat shore of sand of small extent, succeeded by mud, 
which becomes very calcareous at great depths. 
In the North Sea, as well as in the glacial ocean, submarine rocks 
border the fiords and the archipelagos of Norway and Lapland. 
Very extensive zones of clay extend along one part of Norway, and 
must doubtless be attributed to the cropping out of paleozoic schists. 
Besides, as is usual, the ocean adjoining the peninsula of Scandi- 
navia essentially exhibits a bed of sand; mud reappears again, es- 
pecially in the neighbourhood of argillaceous rocks, and in that case 
may probably be derived from their destruction. 
The White Sea also exhibits an inland sea, connected by a wide 
strait with the glacial ocean. The most striking feature of its oro- 
graphy is a depth very much greater in its north-eastern portion 
and in the Gulf of Kandalaks than in its centre and the part nearest 
the ocean. The long Gulfs of the Dwina and of Kandalaks are placed 
the one upon the line of the other, and correspond with an impor- 
tant submarine depression, which is very strongly marked and 
parallel with the Dwina, as also with the principal rivers of these 
regions. 
Soundings have shown the presence of rocks near the shores of the 
White Sea, particularly at its opening in the Gulf of Mezen, and 
also in the Gulf of Onega: these rocks even indicate a connexion of 
the peninsula of Lapland with the continent. 
Sand covers vast surfaces at the entrance of the glacial ocean, but 
in the White Sea it only borders the shores, and silt or mud almost 
entirely covers over the bed. The extent of silt is doubtless due to 
the circumstance that the White Sea, by reason of its orography, 
plays the part of a settling-basin to the troubled waters that it re- 
ceives in great abundance, especially at the time of melting of the 
snows; it is also attributable to the fact that the ice which covers: 
it during one portion of the year also contributes to facilitate the 
deposition of the silt. Shell-bearing beds are very limited in the 
White Sea, probably on account of the fresh and muddy waters which 
pour into it; they, however, occur abundantly on the sands at the 
entrance to the glacial ocean. Hence it is to be seen that the mol- 
lusca multiply and also attain great development in very northern 
latitudes, and as far as within the Polar circle. 
A study of the inland seas of the Old World reveals general and 
very striking characters both in their orography and lithology. First, 
their depth northwards is slight, and increases towards the south ; 
besides, the principal rivers empty themselves more especially on 
their northern sides. These features occur markedly in the Caspian 
Sea, the Persian Gulf, the Sea of Azof, the Black Sea, the Baltic, the 
Adriatic, and finally in the Mediterranean. 
The Baltic, the Caspian, and the Adriatic present striking ana- 
logies; for all three are less salt than the ocean: they receive a mul- 
titude of rivers and of streams, which transport a quantity of débris 
and tend to fill their basins; they are especially remarkable by the 
great extent of their sandy deposits. 
