GIANT SLOTHS AND ARMADILLOS 289 
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 succes- 
sion, 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 
_SSS = —————— 
Fia. 109.—Skeleton of Scelidotheriwm. (After Capellini.) 
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 they were engulfed. 
This idea is strengthened by information supplied to Mr. Darwin 
when in these parts (recorded in his Journal). An eye-witness 
told him that during the gran seco, or great. drought, the cattle in 
herds of thousands rushed into the Parana, and, being exhausted 
U 
