.8^. PHYSICAL GEOLOGY IN COLORADO. 209 



river and the Coconini Plateau above, a succession of life-zones is 

 comprised equivalent to the range from the cactus-plains of Mexico to 

 the pine-forests of northern Canada, the effects elsewhere due to 

 difference of latitude being here given by difference of altitude. In 

 the winter, when the snow lies deep on the plateau, humming-birds 

 flit about among the shrubs in the depths below. 



The precipitous form generally associated with the idea of a 

 cafion and finely exemplified here in the many tributary gorges, gives 

 place in the Grand Cafion itself to a more complex structure. There 

 is a wide outer cafion floored by a broad platform, and through this 

 is cut the deep inner cafion at the bottom of which the river runs. 

 The walls of the main trunk are broken by many minor chasms, 

 enormous if considered by themselves, giving rise to deep recesses 

 and long projecting ridges. These branch-cafions again have their 

 tributaries, and when two of the latter have cut back so far as to meet, 

 the salient point is left standing as a great castellated "butte." 



Of the spectacle as a whole, no description, however vivid, could 

 give any adequate suggestion. A part of the deep impression it 

 produces is due, as Button has well remarked, to the startling sudden- 

 ness with which it bursts upon the traveller. He may have been 

 traversing for days a gently rolling plain, monotonous almost to 

 weariness, and apparently illimitable : he ascends one more gentle 

 undulation, and, as if raised by a magician's wand, a new world is 

 before him. The endless detail of cliff and talus, butte and alcove, 

 is at first bewildering. The imagination is perplexed for comparisons, 

 but perhaps the dominant impression is that of Titanic architecture. 

 Monuments, pinnacles, buttresses, castles, temples, appear in 

 wonderful diversity, and crowd the distant perspective away to its 

 vanishing point. But soon order begins to appear in the confusion. 

 Guided by the characteristic colour of each formation, buff or crimson, 

 lilac or chocolate, the eye can follow the level bedding into deep 

 amphitheatres and round projecting headlands for fifty or sixty miles. 

 In the broad platform which seemed to be the bottom of the cafion is 

 seen the steep inner gorge, only in places disclosing the river in its 

 channel of dark gneiss. For a juster view we must take our stand on 

 one of the abrupt promontories, such as Spanish Point where 

 Coronado, the earliest explorer of the country, obtained his first 

 view. Here we look westward along the cafion, and the true structure 

 of the whole is clearly revealed. 



Far below, at the bottom of the dark inner gorge, rushes the 

 Colorado River, which throughout the two hundred miles of the 

 caiion is a close succession of headlong rapids. As seen from the 

 plateau, its waters, brown from their burden of mud, rise in huge 

 standing waves, a fearsome sight to one who thinks of navigating 

 them. In 1869, Major Powell, now Director of the U.S. Geological 

 Survey, started on a voyage of exploration from Green River 

 Station with a small party in life-boats. Passing down the long 



p 



