218 WAREEN UPHAM, ESQ., ON CAUSES OF THE ICE AGE. 



diaracter and sequence, first, a comparatively long continued 

 uplift, whicli in its cnlniinatioii appears to Have given a high 

 plateau climate with abundant snowfall forming an ice-sheet, 

 whose duration extended until the land sank somewhat lower 

 than now, leading to amelioration of the climate and the 

 departure of the ice, followed by re-elevation to the present 

 level. The coincidence of these great earth movements witli 

 glaciation naturally leads to the conviction that they were the 

 direct and sufficient cause of the ice-sheets and of their 

 disappearance ; and this conclusion is confirmed by the 

 insufficiency and failure of the other theories which have been 

 advanced to account for the Glacial period. 

 37 The epeirogenic movements of the countries which became 

 glaciated were only a portion of wide-spread oscillations of 

 continental areas during the closing part of Tertiary time and 

 the ensuing much shorter Quaternary era. Not only was 

 north-western Europe uplifted thousands of feet, buc probably 

 all the western side of Europe and Africa shared in this move- 

 ment, of which we have the most convincing proof in the 

 .submerged channel of the Congo, about four hundred 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* ftmnd this channel 

 to extend eighty miles into the oceaji to a depth of more than 

 0,000 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 three miles, and its depth 2,000 feet. Thirt}-hve miles off 

 shore the width of the submerged channel or calion is six 

 miles, with a depth of about 3,450 feet, its bottom being 

 nearly .3,000 feet below the sea bed on each side. Fifty miles 

 from the mouth of the river the sounding to the submarine 

 continental slope is nearly 3,000 feet, while the bottom of the 

 old channel lies at 0,000 feet. '1 his very remarkable continua- 

 tion of the Congo valley far beneath the sea level is like those 

 of the Hudson and St. Lawrence rivers, and like the sub- 

 merged valleys on the coast of California ; but the Congo 

 reaches to a greater depth than those of N(-)rth America, and 

 even exceeds the Sogne fjord, the longest and deepest in 

 Norway, which has a maximum sounding of 4,0t^0 feet. 

 Another deep submarine valley, called the " Bottomless Pit," 

 having soundings of 2,700 feet, is described by Buchanan on 

 the African coast 350 nnles north of the equator, and he states 



* Scottish Geographical Magazine, vol. iii, 1887, pp. 217-238. 



