SMITHSONIAN EXPLORATIONS, I93O 25 



We noted many scores of hoofs and other parts of deer killed in the 

 great slaughter of the previous fall. 



The morning following our arrival, our pack train was organized 

 and we made our way through the juniper forests up into the pines 

 of the higher levels to the peculiar gap that breaks through most of 

 the thickness of the massive Kaibab limestone and Coconino sand- 

 stone which form the unscalable cliffs just under the rim of the Can- 

 yon. From this point into the Nankoweap Basin, we traversed a trail 

 built in 1881 by Major John W. Powell, then Director of the United 

 States Geological Survey, and used the following winter by Dr. Charles 

 D. Walcott, who succeeded Major Powell and who later became 

 Secretary of the Smithsonian Institution. Today there stands on the 

 South River a finely executed monument commemorating Major 

 Powell's successful navigation of the Colorado River throughout the 

 Grand Canyon. 



It is assumed by the general public, and even by most students, that 

 the geological history of the major national parks is well known. 

 Thousands of people from all over the world who visit these parks 

 each year seek an explanation of the things seen — rocks, fossils, ero- 

 sional features, or plants and animals. Notwithstanding this wide- 

 spread interest, little has been accomplished toward mastering the 

 geologic history of the Grand Canyon since the studies that resulted 

 from Major Powell's and Doctor Walcott's explorations 50 years ago. 



As the Nankoweap trail has not been repaired since it was first 

 constructed, except casually by a prospector or two, travel was quite 

 precarious and at places even dangerous, especially for the pack ani- 

 mals. Fortunately no accidents happened, although several of the 

 animals had very narrow escapes from falling over the cliffs, which 

 at places drop away from the trail-side 3,000 feet. Nankoweap Creek 

 is the most easterly in the Grand Canyon National Park and hence 

 lies below Point Imperial. Its valley is variously referred to as a 

 valley or a basin, the latter designation being unusual for a tributary 

 to the Colorado in the canyon country. Nankoweap valley like its 

 near neighbors is basinlike in its openness, which simply reflects the 

 local structure. With the uplift of the Kaibab plateau, some faulting— 

 slipping of the strata along lines of weakness — took place. These 

 basins lie inside the row of buttes margining the river for many miles, 

 beginning at the up-river edge of the Kaibab Plateau and extending 

 below the mouth of the Little Colorado. The Colorado River cut its 

 channel beyond the fault, and erosion, operating in the usual manner 

 along the fault, produced a high ridge in the intervening space, which 

 was cut into rectangular buttes by the side washes. Nankoweap Creek, 



