EXTINCT MONSTERS. 



latest geological period, known as the Pleistocene. During part 

 of that time North America, as well as Northern Europe and 

 Asia, were invaded by a great ice-sheet, and an arctic climate 

 prevailed. It is therefore very probable that while the mammoth 

 and the mastodon were roaming over North America, giant sloths 

 and armadillos were monarchs of the southern continent. What 

 cause, or causes, led to the extermination of the giant sloths and 

 armadillos is still a matter of speculation. One writer suggests 

 an explanation that seems to deserve consideration. The 

 southern parts of this great continent are even now subject to 

 long-continued droughts, sometimes lasting for three years in 



Fig. 50. — Skeleton o{ Scelidotherium. {After Capellini.) 



succession, and bringing great destruction to cattle. In fact, 

 the discoveries related above were rendered possible by several 

 successive dry seasons. It is argued that the upright position 

 of most of the skeletons found in situ seems to suggest that 

 the creatures must have been mired in adhesive mud sufficiently 

 firm to uphold the ponderous bones after the flesh had decayed. 

 A long drought would bring the creatures from the drained 

 and parched country to the rivers, reduced by want of rain to 

 slender streams running between extensive mud-banks ; and it 

 is possible that, in their anxious efforts to reach the water, 

 they may have only sunk deeper and deeper in the mud until 



