120 
FOURTEENTH REPORT. 
the region of the Great Lakes of North America, for their bottoms are 
considerably lower in places, than the present level of the sea, and 
whether formed by glacial ice, or, as according to Spencer’s excellent 
work,* by the subaerial baseleveling of great river systems, these must 
be taken as evidence of former higher altitude of the region relative to 
the level of the sea. 
Darwin, Agassiz and Dana speak for the Pacific coast of Patagonia, 
and Dana likewise for New Zealand and Tasmania. 
In one of the fjords of eastern Greenland a sounding of 3,000 feet 
failed to find the bottom. f 
SUBMERGED VALLEYS OF RIVER EROSION ON CONTINENTAL MARGINS. 
Closely related to the channels cut by moving ice are those cut by 
moving water. It is now well known that not only do the continental 
plateaux extend out under the sea to the depth of 100 fathoms, but 
lliese submerged borders are in places deeply channelled as if by river 
valleys and gorges. The great preponderance of geological opinion is 
that they could have been formed in no other way than by rivers. t 
SuossA dissenting from this prevailing opinion, mentions that there is 
a similar gorge or valley in Lake Constance, where the Pliine flows 
through, but to this we may easily object on the grounds that no good 
reason appears why it may not be properly explained by ponding of the 
waters after the old gorge was cut by the river. He seems to approve 
also the opinion of a French writer to the effect that the submerged de- 
pression which is found at the mouth of the Rhine cannot be attributed 
to river erosion because it is asserted that, were that the case, sedimen- 
tation would ere this have obliterated it. 
When Buchanan ]| found such a submerged gorge something like SO 
miles long at the mouth of the Congo, he interpreted it as the result 
of building up of the sides by deposition instead of erosion by the river 
when the now submerged continental border was above the sea. Suess 
also approves this but it fails wholly to take account of similar and re- 
lated phenomena which are scattered widely over the world. With 
these exceptions, geological opinion seems to be unanimous that the 
drowned gorges and valleys on the submerged continental margins are 
explainable only on the basis of former elevation above the level of the 
sea. 
Figure 3 shows the distribution of certain well-authenticated instances 
of this “river drowning” and the amount of vertical movement which 
they are held to indicate. 
On the Pacific coast of the United States the original work was by 
*Spencer, J. W., “Origin of the Basins of the Great Lakes of America,” Quart. Jour. Geol. Soc. London 
tUpham!°Warren, "Submarine Valleys on Continental Slopes,” Proc. Am. Ass. Adv. Sci., vol. 41, 
1 8 j'see^pVam, Warren, loc. cit. and also "Fjords and Submerged Valleys of Europe.” Am. Geol.vol. 
X X s S ues's S ifcfua rd , “The Face of the Earth,” Eng. Trans, vol. ii. Chap, xiv “The Oceans.” 
[i Buchanan J. Y., “On the Land Slopes Separating Continents and Ocean Basins, especially those 
.on the West Coast of Africa.” Scottish Geol. Mag., vol. iii, May 1887, pp. 217-238. 
