On the Eastern Margin of N. Atlantic. 563 



1 in 30 ; while if T went farther and compared the gi-adient of the 

 ■floor of the indentation with the pitch from the promontory upon its 

 eastern side, I should find it 1 in 5 as given b}' Mr. Hudleston. 

 He has studied only the angle of descent of the continental slopes : 

 I have studied the sculpturing of the slopes, with their valleys and 

 gradients. 



This amphitheatre-like indentation, by itself, would not be a strong 

 point, as the data are scanty ; but when the feature is one of constant 

 recurrence, and fuller information concerning such features is often 

 obtainable elsewhere, as Professor Hull has shown to be the case at 

 'numerous points off the coast of France, Spain, and Portugal, 

 •experience makes easy the interpretation of the fragments of 

 drowned valleys which have been recovered. 



Turning now to the Fosse de Cap Breton, at the angle of France 

 and Spain, the data are very much fuller, and Mr. Hudleston's 

 treatment is happier, but still falls far short of the facts, as shown 

 upon the chart, which he has reproduced, and therefrom my 

 ■conclusions reach farther, and fully support the investigations of 

 Professor Hull. 



The Fosse dissects the submarine platform, limited by the 600- 

 foot contour, which has a breadth of about 30 miles. It has a depth 

 •of 1,260 feet near its head. Farther seaward, the next sounding is 

 ISO feet less, as also two other soundings are less, but these are not 

 in the centre of the channel, as illustrated. Only fuller soundings 

 would prove a barrier, but even then an obstruction by river 

 deposits is what might occur. Another chart,* which I have seen, 

 gives more conclusive data than the illustration here analyzed. 

 A little farther outward, the depth has increased to 2,694 feet (on 

 the side of the channel), then to 3,660 feet near the centre, and still 

 farther to 3,750 feet. From this section, Mr. Hudleston passes to 

 " 35 miles " farther seaward, and finds soundings of 1,500 fathoms 

 in an outer platform submerged to about 900 or 1,000 fathoms. He 

 then ascertains the mean slope of the side (1 in 7, which is about 

 750 feet per mile). He cites an example, given by Professor Milne, 

 of the submarine cables being buried by the fall of the vertical walls 

 overhanging them. He concludes as follows : " there are several 

 indications that this depth of 1,500 fathoms represents a hole rather 

 than a channel, for the next sounding seaward shows only 1,250 

 fathoms." But this last sounding is eight or ten miles from the 

 1,000- fathom line adjacent to the coast, leaving plenty of room for 

 the intervening channel to reach an additional depth of 250 fathoms. 

 Indeed, to the north-west of the 1,500-fatliom hole, and landward of 

 it, the lateral depth is 1,370 fathoms. Between this hole and the 

 Fosse de Cap Breton, already established, there is a chain of 

 soundings of 1,170, 1,107 (this is midway between the 1,500-fathom 

 "hole" and the 625-fathom depth of the fosse), and 915 fathoms, 

 between which and the 625-fathom sounding there is one of only 

 500 fathoms. In the application of these soundings, it must be 



1 " Submarine Gullies," etc., by Henry Beuest: Geogr. Journ., October, 1899, 

 p. 405. The soundings on the Admiralty Chart are very numerous. 



