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SCIENCE 



[3^. S. Vol. XL. No. 1027 



could be cited, and it is not evident tow 

 sharply diflFerential movements like the raising 

 of the east African plateaus and the sinking 

 of the Red Sea and Mediterranean basins can 

 in any respect be responses to such a general 

 change of figure. 



The causes of the existence of Permian 

 glaciation in low latitudes constitute one of 

 the unsolved problems of geology, and the phe- 

 nomena have been utilized by the various 

 creators of hypotheses, but each hypothesis 

 raises difficulties as great as those it is invoked 

 to explain. Although the pole as located in 

 the Permian by Kreichgauer would bring 

 South Africa into the Antarctic circle, the 

 Permian glaciation of Brazil and Australia 

 would still be within the torrid zone. The 

 Permo-Carboniferous axis as located by 

 Jacobitti, while giving antipodal polar lati- 

 tudes to northern South America and to 

 Australia, would throw glacial South Africa 

 into the torrid zone. The pendulation hypoth- 

 esis of Eeibisch, while permitting polar lati- 

 tudes to invade Africa, would never give high 

 latitudes to either India or South America. 



The advocates of polar wandering have come 

 near to agreement upon one supposition, — that 

 in the Pleistocene the pole was in Greenland, 

 or to the east of it, giving higher latitudes at 

 that time to the glaciated regions of north- 

 eastern North America and northwestern 

 Europe. This would imply a polar movement 

 of as much as 15° since the latter part of the 

 Pleistocene. Eeibisch in his first papers cites 

 the fact that during the glacial period the 

 volcanoes of equatorial Africa were glaciated 

 to elevations 800 to 1,000 meters below the 

 present limits. He regards this as a proof of 

 his pendulation theory on the meridian E. 10°, 

 Africa then having a more northerly latitude. 

 According to this, however, there should just 

 as definitely have been no climatic change in 

 the equatorial Andes, since these are adjacent 

 to the oscillation pole. The fact that in Peru 

 glaciation descended to altitudes below the 

 present limits comparable to the descent on the 

 equatorial mountains of Africa is, however, 

 a most embarrassing fact not cited by Eeibisch. 

 For those who would move the Pleistocene pole 



into Greenland, these facts of glacial advance 

 in Peru beyond the present limits are even 

 more disconcerting, since their position of the 

 pole would bring Peru directly under the 

 equator during the Pleistocene. Simroth, 

 who goes far beyond Eeibisch in his detailed 

 discussion, does note and explain away these 

 diificulties. He states (p. 533) that Eeibisch 

 had in a third, still unpublished work reached 

 the important conclusion that a more northerly 

 position of the Alps of only 3° or 3|° was 

 necessary. The resulting elevation above sea 

 level would be sufficient to originate the gla- 

 ciation. In regard to the glaciation of the 

 tropical mountains which according to others 

 indicate a general lowering of terrestrial tem- 

 peratures during the Pleistocene, Simroth 

 says (p. 531) : 



Here it becomes our duty to go at least a little 

 into argumentation. Kilimandjaro presents no 

 difficulty. It lies so near the oscillation circle that 

 pendulation could have easily carried it into other 

 and cooler latitudes. During out Diluvium it must 

 have lain well under the equator or somewhat north 

 of it, but certainly not near either the north or 

 south pole. One must, therefore, refer it back to 

 the Tertiary in order that it should be permitted to 

 wander to the south pole. There comes then the 

 first thought in regard to those moraines; we do 

 not know their age. 



The problem as to how these moraines could 

 have been preserved from erosion since the 

 middle Tertiary is not entered upon by the 

 author. Space forbids further quotation, but 

 Simroth suggests as another alternative ex- 

 planation that the glaciers may only appear to 

 be far above their terminal moraines because 

 visited in the dry season, during which a rapid 

 melting takes place. As the moraines in ques- 

 tion are stated elsewhere to be at elevations 

 800 to 1,000 meters below the present fronts 

 of the glaciers, this would be a rapid seasonal 

 melting indeed. His elimination of the diffi- 

 culties connected with glaciation in the Andes 

 is of a similar character. 



In view of these quotations from Simroth 

 it should be said that the great part of his 

 work consists of a presentation of biological 

 evidence. In this he is at home and his maps 

 and text bring out many significant facts re- 



