588 E. HI >TI>'GTO> ^OLAE HYPOTHESIS OF CLIMATIC CHANGES 



appears to have prevailed in the northern hemisphere. The probable ex- 

 tent of the lands of that time and their transversal arrangement as con- 

 trasted with the longitudinal arrangement of the present is illustrated in 

 figure 23, which is here reproduced from Professor Schuchert's chapter 

 in 'The Climatic Factor/' The subtropical storm belt, according to the 

 cyclonic hypothesis, presumably extended essentially along the line of 

 oceans between latitude 20° and 40°, so that the winds which blew in 

 toward the cyclonic centers were apparently well supplied with moisture, 

 which would help to accoimt for glaciation in low latitudes. Farther 

 north the great belt of deserts would be very poorly supplied with water 

 because of the lack of oceans. In this region we find one of the most 

 , striking characteristics of Permian times, namely, a vast accumulation 

 of red beds, saline formations, and other evidences of aridity. This "rote 

 nordland,'' as Walther has called it, is full of unfossiliferous, arid de- 

 posits, and its condition has hitherto been another of the puzzling fea- 

 tures of the geological middle ages. Similar conditions have prevailed 

 at earlier times, such as the Devonian, and the explanation which applies 

 to the Permian is equally applicable to other i^eriods. 



Finally, in the far north our assumed great increase in the activity' of 

 sun-spots would cause another belt of pronounced storminess, just a- 

 during the Pleistocene. For two reasons, however, the effect of this in 

 producing glaciation would be slight. In the first place. l>emg perhaps 

 pushed farther north than during Pleistocene times, its area would de- 

 crease, for the distance around the earth in latitude 70°. for example, is 

 much less than in latitude 55°. In the second place, even though the 

 storms were numerous, there would be little precipitation. The wind- 

 drawn in from the south would come almost entirely from enormous 

 deserts, where they could not ix)ssibly obtain moisture. Those drawn in 

 from the north would come from regions of intense cold, where the ocean - 

 would be covered with ice, and the air could neither obtain nor hold 

 much water. Thus, even though storminess were as gi'eat as in the 

 Pleistocene ice age, there would be only scanty precipitation. Today in 

 the northern parts of Canada and Siberia we have regions of intense cold 

 which nevertheless show no trace of glaciation, although their mean tem- 

 perature is perhaps as low as that of Greenland. In Pleistocene times 

 glaciation did not extend to them, although the ice-sheets moved toward 

 them from regions with more abundant precipitation. According to the 

 cyclonic hypothesis, the conditions which prevail in these relatively small 

 areas at present were magnified enormously during the Permian era. and 

 thus the STeat "Eed Xorthland" came into existence. 



