Natural Windows 
269 
we went^ running a third and a fourth with no trouble. The 
walls were now about two thousand feet high and we felt quite 
at home. Through some of the upper narrow promontories 
of sandstone there were large holes^ or arches^ some of them 
probably a hundred or more feet in diameter. They were 
similar to the Hole in the Wall, shown in the cut on page 41, 
only on a much larger scale. The next day, before stopping for 
dinner, we ran nine rapids with no accident. The river was. 
Dellenbaugh Butte, Green River near the San Rafael. 
Photograph by E. O. Beaman, U. S. Colo. Riv. Exp. 
wider than in the upper canyons, and while the low state of 
the water made harder work and pounded the boats more, I 
believe that on the whole it was an advantage. The current 
was less fierce and consequently the boats were always more 
controllable. Yet when the water falls below a certain point 
the danger of striking rocks is so much increased that a rapid 
which, at a little higher stage would be easy to run must be 
avoided entirely by a portage or a let-down. The waves at 
low water are also smaller and hence less likely to upset a boat. 
