3°4 CAVE AND CLIFF DWELLERS. 
All this portion of the Sierra Madres 
is unsurpassed for magnificent and thrill¬ 
ing views over dizzy mountain trails. 
At many places one could look off into 
infinity from a ledge not over a foot 
and a half in width on which the mules 
must walk. Occasionally a steep wall of 
rock rises many hundreds of feet on one 
side and along this the mule will carefully 
scrape. The descent into Cerro Colorado 
was the most continuous steep I ever 
saw. Almost before we knew it we were 
in the tropics again, and that by an in¬ 
cline where, in a dozen places, the uphill 
rider on one zigzag could, without taking 
his foot out of the stirrup, kick off the 
hat of one below him on the other course 
as he passed. 
Cerro Colorado is reputed to be the 
largest gold mine in the world, and was 
