Page:Quarterly Journal of the Geological Society of London, vol. 33.djvu/213

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AND CIRQUES IN NORWAY AND GREENLAND.
175

AND CIRQUES IN NORWAY AND GREENLAND. 175

fjords, a depth of 200 metres is found at some distance from the shore ; and in the German Ocean soundings of more than 100 metres are very rare. A few examples from the largest fjords of Xorway will suffice to prove this. The depth of the Sogne Fjord in the inner part increases to 1244 metres ; at its mouth, where it joins the sea, this has decreased to 158 metres. The depth of the sea 100 kilo- metres from land is 124 metres. The greatest depth of the Har- danger Fjord is 800 metres, while the depth of the sea 100 kilo- metres from land is 150 metres. The greatest depth of the Xord Fjord is 565 metres, while at the ahove distance from land the sea is also 150 metres deep. In the tributary fjords of the Stor Fjord the depth amounts to 721 metres, while the sea 50 kilometres from the mouth is only 100 metres deep. Some fjords along the coast of Romsdalen are continued for several miles out to sea as strongly marked deeps, much shallower, however, than in the inner parts ; and in front of these large quantities of stones and sand extend, the edge of which is well known to fishermen by the name Storeggen (the large edge). With a view of examining the sea-bottom along the Norwegian coast, I made a survey opposite to the mouths of the fjords, and dredged up stones. At the mouths of those which I ex- amined I found a great quantity of stones of different kinds mixed with clay, such as varieties of granites, gneiss, quartzose-slates, clay- slates, mica-schists — rocks, on the whole, well known as constituting the sides of the fjords of Western Norway. Some flints, however, in- dicated the occurrence of the Cretaceous formation, which has not been observed in the fjords. A great number of pieces of different kinds of rock, of various sizes and with rounded edges, occurring at the mouths of fjords once filled with glaciers, and in the places where their depths are decreasing, seems to prove a glacial forma- tion of moraines under the sea. This view is confirmed by analo- gous facts. The row of moraines mentioned above, on the west side of the Christiania Fjord, runs at last out to sea, and continues as shoals, which in some places emerge as islands, as in the case of Jomfruland Island. As rows of moraines occur on the land with lakes behind them, so in the sea, from the fjord of Langesund towards the town of Arendal, rows of shoals lie in front of the rock- basins of the fjord. If, for example, Norway were to rise 400 metres, the shoals along the west coast and on the bottom of the German Ocean would probably appear as moraines and plains of glacial formation, widely extended in front of the lake-basins of the fjords.

Phenomena similar to the above are repeated in other countries. The fjords of Scotland are shallower at their mouths than within, and if the land rose would become lakes*. The soundings along the coast of Greenland are little known ; but it is evident, from the few observations which exist, that the same peculiar configuration of the sea-bed would here also be brought to light if the land rose. The depth of the Jakobshavn ice-fjord, according to the Green- landers, is about 390 metres ; that of the Torsukatak 346 metres.

  • Cf. Geikie, ' The Great Ice Age,' p. 519.