DYNASTY OF MAN 679 



perennial iee and snow. The zone of this arctic flora and fauna 

 now lies mostly north of 60. The subarctic zone of stunted conifers 

 moved northward about 12, and expanded to a width of 400 to 

 600 miles. The cold-temperate belt of deciduous and evergreen 

 trees moved a less distance, but expanded almost equally, while 

 the warm-temperate flora spread over the territory abandoned by 

 the last. 



With each of these vegetal zones went the appropriate fauna. 

 The musk-ox, whose remains have been found skirting the glaciated 

 area in l'enn>vl\ ania, West Virginia, Ohio, Kentucky, Oklahoma, 

 Missouri, and Iowa, 1 has since retired to the extreme arctic regions. 

 The reindeer, which had a similar distribution about the edge of 

 the ice, occupies the barrens of the northern border of the conti- 

 nent, while fur-bearing animals distributed themselves through the 

 three/ northerly zones. 



At the south the floras and faunas of the southeast spread west- 

 ward but little, but the arid and prairie floras and faunas of the 

 southwest spread eastward at the expense of the southeastern group. 

 This does not seem to be equally true in the higher latitudes, where 

 the trees of the eastern group are distributed far to the northwest. 



The arid and semi-arid floras and faunas of the southwest seem 

 to have pushed the more boreal and arboreous forms to the north- 

 ward, or forced them to ascend the mountains; but the movement 

 was less sweeping and more complicated than that of the east, 

 because of topographic interference and the effect of the lingering 

 mountain glaciation. 



Human dispersal. As yet there is little geologic evidence 

 relative to the place of man's origin, or to the earliest stages of his 

 development. Various considerations connected with his physical 

 nature and his distribution seem to point to the warm zone of the 

 eastern hemisphere, perhaps southern Asia or northern Africa, as 

 the place of his appearance. There are some grounds for the in- 

 ference that the earliest developments of those qualities that gavei 

 him dominance were associated with the open tracts of the sub-1 

 tropical zone, rather than with the forests of the equatorial belt. 

 Subsequent history, as well as the nature of the case, teaches us that 



1 Hay's Catalogue of Fossil Vertebrates in North America, Bull. 179, U. S. 

 Geol. Surv., 1902. 



