O PROCEEDINGS OF THE BOSTON MEETING 



to 4,000 feet higher than now. Southwestern Europe was then elevated, at least 

 in part, to the very great altitude of nearly 9,000 feet above its present level, as is 

 proved by the " Fosse de Cap Breton," the most remarkable and most fully sur- 

 veyed submerged valley known. It reaches about 120 miles westward from the 

 village of Cap Bi-eton, near the mouth of the river Adour, of which it was a con- 

 tinuation. Many other valleys of similar character, but not traced to so profound 

 depth, are also known on the western French, Spanish, and Portuguese coasts, and 

 they have been recently well studied by Professor Edward Hull, who confidently 

 ascribes their formation to a period of great epeirogenic uplift, attended in its cul- 

 mination by the Ice age of northern Europe.* 



Not only was a great part of Europe uplifted thousands of feet, but probably all 

 the western side of Europe and Africa shared in this movement, of which we have 

 the most convincing proof in the submerged channel of the Congo, about 400 miles 

 south of the equator. From soundings for the selection of a route for a submarine 

 cable to connect commercial stations on the African coast, Mr J. Y. Buchanan 

 found this channel to extend 80 miles into the ocean, to a depth of more than 

 6,000 feet. The last twenty miles of the Congo have a depth from 900 to 1,450 feet. 

 At the mouth of the river its width is 3 miles and its depth 2,000 feet. Thirty-five 

 miles off'shore the width of the submerged channel or canyon is 6 miles, with a 

 depth of about 3,450 feet, its bottom being nearly 3,000 feet below the sea bed on 

 each side. Another deep submarine valley, called the " Bottomless Pit," having 

 soundings of 2,700 feet, is described by Buchanan on the African coast 350 miles 

 north of the equator.! 



COMPETKNCE OF THE PkEGLACIAL EPHIROGENIC UpLIFT TO CAUSE THE ACCUMULATION 



OF THE ICE-SHEETS 



The coincidence of these great earth movements with glaciation naturally leads 

 to the conviction that they were the direct and sufficient cause of the snowy 

 climate forming the ice-sheets ; and this conclusion is confirmed by the insuffi- 

 ciency and failure of the other theories which have been advanced to account for 

 the Glacial period. In our Cordilleran belt, glaciers still remain on the higher 

 ranges and peaks as far south as the general southern boundary of the old conti- 

 nental ice-sheet; and in Tuckerman's ravine on mount Washington the deeply 

 drifted snow of winter usually lasts till August, spanning in a broad arch the 

 brooklet of its melting. In Scotland, on the northern slopes and in the ravines of 

 Ben Nevis and Ben Macdhui, many tracts of snow likewise linger until late in sum- 

 mer; and in Norway, as in Alaska, perpetual snow and icefields cover many 

 square miles. No very great climatic change, probably not more lowering of the 

 mean temperature than 10 or 15 degrees, such as must be produced by an epeir. 

 ogenic elevation of 3,000 to 5,000 feet, would be sufficient to cause the storms 

 of these north temperate regions to bring snowfall instead of rainfall upon the 

 mountains throughout the year. Hence glaciation would gradually reach outward, 

 with extension of the areas receiving snowfall at all seasons of the year, until ice- 

 sheets enveloped vast plains of the uplifted continents, as in the upper part of the 



*The evidences of the preglaeial uplift of Europe are the subject of a paper by the present 

 writer in the Am. Geologist, vol. xxii, pp. 101-108, August, 189S. 

 f/Scottish Geographic IMaguzine, vol.. iii, 1887, pp. 217-238 



