26 THE POPULAR SCIENCE MONTHLY. 



connection between the Glacial period and the flood, and the 

 probable reason why no tradition has descended to us of the 

 former ; first, because man was born during its epoch and was 

 formed by it and accustomed to it, and living in the one temper- 

 ate zone on the equator saw nothing strange in his surroundings, 

 and, secondly, because the only change that man saw was the 

 sudden accumulation of waters descending from the earthquake- 

 riven and colder portions of his then imexplored globe. 



Thus, man's remains have been found with those of the mam- 

 moth a mammal of the warm, subtropical Pliocene period, that 

 lived on into the cold Pleistocene epoch. Probably his origin was 

 previous to that of man ; but man may not have appeared until 

 the end of the Pliocene period and the commencement of the cold, 

 which, in all likelihood, gradually and surely came on, as the 

 interior of the globe shrank farther and farther away from con- 

 tact with the easily chilled outer crust, which it left to fields 

 of ice bordering a narrow temperate zone ; the ice reaching from 

 the north pole as far south possibly as 50 north of the equator, 

 and from the south pole as far north as 40 south of the equator ; 

 thus the present temperate zones became arctic, and the tropical 

 zone became almost unvaryingly temperate. Man probably in 

 his first ages had spread far and wide north and south of the 

 equator, but not so far as at present we find ourselves ; he had 

 been gradually driven back by the advancing cold, yet so slowly 

 that the change did not make itself noticeable to him, and as his 

 civilization advanced to the time when he began to build and to 

 establish great cities he found himself settled near the equator, 

 even further south than ancient Thebes, and probably where the 

 great deserts of Arabia, Nubia, and those of the Sahara stretch 

 their vast plains of sands, and perchance now cover works even 

 older than the stepped pyramid of Ata. However long, therefore, 

 these periods of change may have been, it seems very probable 

 that man first appeared in a fresh, temperate climate, the only 

 proof of which is that he has several times been found with the 

 remains of the mammoth, an animal that outlived the primal 

 warm periods. Probably no preglacial period existed for man. As 

 for the length of time that must have elapsed between the first 

 appearance of vegetation upon the earth until the time that the 

 climax of the Glacial period arrived, when the flood took place, 

 ten thousand years need not be too much. Midst the surround- 

 ings of that Glacial period, however, man's remains have been 

 found, but not in those of the preglacial ages that lead back to the 

 ichthyosaurus, plesiosaurus, and other monsters of the deep, or of 

 the age of gigantic flora, huge pine trees, and enormous ferns. 



If the flood, then, as some have calculated, was only five or six 

 thousand years ago, then the coldest period of the Glacial age can 



