242 PROFESSOR JAMES GEIKIE, LL.D., D.C.L., F.R.S., ETC., ON 



proved that the Isthmus of Panama was sufficiently sub- 

 merged, either at the one time or the other, to permit the 

 escape of the Atlantic Equatorial into the Pacific Basin. But 

 let it be supposed that the Isthmus has become so deeply 

 submerged that the Equatorial Current is wholly deflected, 

 and that no Gulf-stream issues through the Straits of Florida 

 to temper the climate of higher latitudes. What would 

 result from such an unhappy change? Can any one, con- 

 versant with the geographical distribution of the glacial 

 phenomena, imagine that the conditions of the glacial period 

 could be thus reproduced? Norway might indeed become a 

 second South Greenland, and perennial snow and ice might 

 appear in the mountainous tracts of the British Islands. The 

 climate of Hudson's Bay and the surrounding lands might be 

 experienced in the Baltic and its neighbourhood, and what 

 are now the temperate latitudes of Europe, north of the 50th 

 parallel, would possibly approach Siberia in character. But 

 surely these changes are not comparable to the conditions of 

 the glacial period. The absence of a Gulf-stream would not 

 sensibly affect the climate of South-Eastern Europe and Asia, 

 and could not have the smallest influence on that of the 

 Pacific coast-lands of North America. 



Yes, but if we conceive the submergence of the Isthmus of 

 Panama to coincide with great elevation of Northern lands, 

 would not such geographical conditions bring about a glacial 

 epoch comparable to that of Pleistocene times ? It is hard 

 to see how they could. No doubt, the climate of all those 

 regions that would be affected by the withdrawal of the 

 Gulf-stream alone would become still more deteriorated if 

 they stood some 3,000 feet higher than now. A vast area in 

 the north-west of Europe would certainly be uninhabitable ; 

 but it is for the advocates of the " earth-movement hypo- 

 thesis" to explain why those inhospitable regions should 

 necessarily be covered with an ice-sheet. For the production 

 of great snow-fields and continental ice-sheets, considerable 

 precipitation, no less than a low temperature, is requisite. 

 Under the conditions we have been imagining, however, 

 precipitation would probably be much less than it is at 

 present. But to whatever extent North-West Europe might 

 be glaciated, it is obvious that the geographical revolutions 

 referred to could have little influence on the climate of 

 South-Eastern Europe, not to mention Central and Eastern 

 Asia. Nor could they possibly influence the climate of the 

 Pacific coast-lands of North America. And yet, as is well- 



