64 CAVE AND CLIFF DWELLERS. 
antiquated as drifting sand piled up 
around it. This town, therefore, may 
have been contemporaneous with the 
ruined towns of the Casas Grandes val¬ 
ley generally, although the latter look 
much more recent from being built on 
more compact soil. 
As I have already more than hinted, 
all these valleys along the foothills of 
the Sierra Madre Mountains may have 
held a dense population when these 
ancient people sojourned here, and if 
the physical characteristics were the 
same as at the present time it is very 
easy to account for. To the westward 
it is too mountainous for many people 
to find homes and cultivate the soil, 
while to the eastward the country is too 
barren after one passes the line of the 
lakes, or where the mountain rivers sink. 
