THE GULF STREAM AND THE PANAMA CANAL. 667 



Strange as it may appear, the records of geology assure us that 

 such changes in the climate of Northwestern Europe have actually hap- 

 pened within a comparatively recent period certainly within the hu- 

 man epoch. Thus it has been well ascertained that at a time when 

 rude tribes of men, unacquainted with the use of metals, were hunting 

 reindeer in Southern France, a vast area in Northern Europe was 

 buried under a great sheet of ice a veritable mer de glace like those 

 ice-sheets which cover up such extensive areas in the Arctic and Ant- 

 arctic regions. Had any one at that time approached the shores of 

 Northwestern Europe, he would have encountered, some fifty miles out- 

 side of the present western shores of Ireland and the Hebrides, a vast 

 vertical wall of ice, like that which confronted Sir J. Clark Ross, Com- 

 modore Wilkes, and the Challenger expedition, and barred all approach 

 to the Antarctic pole. Could our voyager have surmounted the Scoto- 

 Hibernian ice-wall, he would have discovered that he stood on the verge 

 of an interminable plain of snow and ice, extending eastward as far as 

 the eye could reach. Here and there upon the far horizon he would 

 have observed a few inconsiderable rocky hills, representing the upper 

 portions of our highest mountains for the ice which then buried our 

 low grounds was not less than three thousand feet thick. Had he ad- 

 vanced inland until he reached those rocky heights he would have found 

 the icy plain sweeping away in all directions, and bounded only by 

 the horizon ; and had he continued his journey toward the east, across 

 what is now the German Ocean, he would have encountered nothing 

 to break the monotonous level until he approached a low line of snow- 

 covered hills and mounds, marking the site of the ice-drowned Scandi- 

 navian Peninsula. After attaining these hills, had our imaginary wan- 

 derer now shaped his course toward the south, he must next have trav- 

 ersed a distance of more than five hundred miles before he reached the 

 termination of the ice-sheet in Saxony. During this extraordinary 

 condition of things the Arctic- Alpine plants and animals (which are 

 now characteristic of lofty elevations in Central and Northwestern Eu- 

 rope, and of the low grounds of the higher latitudes) occupied the 

 low-lying plains and valleys of middle Europe, a flora like that of 

 Lapland growing in South Germany, Switzerland, etc., and pines and 

 spruce-firs flourishing in Northeastern France, while reindeer, glutton, 

 Arctic fox, lemming, marmot, and others were the prevailing animals 

 of those regions. When we think of the conditions which now obtain 

 in Europe, can we conceive of any stronger contrast than that which 

 is suggested by the few facts which are here summarized? Instead 

 of the splendid navies of war-ships, ocean-liners, and other craft which 

 now crowd its waters, the English Channel had formerly its fleets of 

 ice-floes, and the walrus haunted the coasts of Northern France. When 

 such extreme conditions obtained, it can hardly be doubted that the 

 Gulf Stream, as we know it now, had no existence in the North At- 

 lantic. 



