hering in flight. The group courtship displays of these birds 

 are among the most spectacular in the animal kingdom. 

 During breeding season, the colorful air sacs at the sides of 

 the necks are (as shown above and below) inflated with air 

 to a remarkable size. Its trial introduction into other areas 

 has not been successful. 



indicates ihjt the climate there was at no time wet. Indeed was 

 fairly arid at least till the comparatively brief pluvial periods of 

 the Pleistocene. To have cut the canyon, therefore, either the 

 whole area must have been at a vastly greater elevation to give 

 the river sufficient power, or it must have taken much longer to 

 form. Neither the melting of the montane glaciers nor the pluvial 

 periods of the Pleistocene could have provided enough water to 

 do the job without getting ponded, and if they were thus con- 

 tained temporarily, they would have cut a straight rather than a 

 meandering channel through the mountains when they burst out. 

 The drainage pattern left on the plateau certainly seems to 

 indicate ponding and sudden drainage, for it exactly resembles 

 that left on the floor of any pond that has suddenly been emptied 

 by the bursting of a dam. Yet none of these suggestions really 

 explains this vast natural phenomenon, and especially how it 

 managed to form into a serpentine gutter and still cut through 

 the hardest of rocks for scores of miles to a considerable depth at 

 its base level. 



It gives one an almost eerie sensation to ponder such almost 

 planetary concepts as one stands on the rim of this great canyon 

 at sundown and strains one's eyes through the pink and mauve 

 miasma that here so confuses the last slanting rays of the sun. 

 There is a great and vast calm and stillness that usually fills the 

 canyon to its brim. Above may be blue sky, wheeling swallows 

 and eagles, and all around on the plateau are stately pine forests, 

 alive with raucous pifion jays, industrious sapsuckers, and busy 

 chipmunks, but in that chasm there seems to be nothing but 

 diffuse color and a great going down. Here indeed is something 

 of the olden times, stately, ponderous, somewhat exaggerated 

 and perhaps even a bit gaudy, but utterly magnificent. 



ANOTHER HOLE IN THE GROUND 



To the south of the canyon rise the multiple peaks of San 

 Francisco Mountain (12,800 feet), and from this the famous 

 MogoUon Rim runs east to the lava-covered uplands of New 



