AMERICAN GEOLOGY — : DECADE OF 1850-1859. 477 



During- 1857-58 Prof. J. S. Newberry, as geologist, accompanied the 



corps of topographical engineers, under the immediate direction of 



Lieut. J..C. Ives, on an expedition up the Colorado River from its 



mouth to a point called Fortification Rock, north of 



The Ives Expedition . . ... 



up the Colorado the thirtv-sixth parallel. Ihe mam obieet of the expe- 



River, 1857-58. ... * r . .," l 



dition was to ascertain the navigability of the Colo- 

 rado, with especial reference to its availability for the transportation 

 of supplies to the various military posts in New Mexico and Utah. 

 Newberry entered the country from San Francisco and San Diego, 

 and in Chapters I and II of his report makes reference to the generai 

 geology of this part of the region. The party, as above noted, 

 ascended the river as far as the Great Bend, above Black Canyon, and 

 returned thence to the Mojave Valley, south of Pyramid Canyon. 

 Thence the homeward route lay eastward overland to Fort Leaven, 

 worth b} 7 " way of Sitgreaves and Railroad passes in the Black and 

 Cerbat mountains, Bill Williams and the San Francisco mountains, 

 Salt Springs of the Little Colorado, northward to the Moqui Pueblos, 

 and eastward to Fort Defiance, Santa Fe, and Las Vegas (see map). 

 In the latter part of the trip the route lay along that traversed by 

 the surveys for a railroad route to the Pacific under Lieut. Whipple, 

 with which Jules Marcou was connected as geologist. Newberry's 

 report, Part III of the report of Lieutenant Ives, comprised 154 

 octavo pages, with 3 plates of fossil invertebrates and plants. 

 Made necessarily as a hasty reconnaissance, it nevertheless contains 

 interesting generalities. He rightly regarded the canyon of the Colo- 

 rado as a canyon of erosion, but conceived that in earlier times the 

 river filled to the brim a series of isolated basins formed by the vari- 

 ous mountain chains and interlocking spurs of the synclinal trough 

 through which the river runs, and that during the lapse of ages "the 

 accumulated waters, pouring over the lowest points in the opposing 

 barriers, have cut them down from summit to base," thus forming 

 the canyons. The massive granite walls of Pyramid Canyon, with 

 their capping of stratified gravel, he regarded as conclusive proof of 

 the former existence here of an unbroken barrier "stretching across 

 the course of the Colorado and raising its waters to an elevation of at 

 least 250 feet above their present level." The idea of a possible uplift 

 across the river's course, an uplift so slow as to be counteracted by 

 erosion, as afterward taught b} 7 Dutton, was undreamed of, and the 

 mental restorations of past surface contours given are at times start- 

 ling for their magnitude. Thus, in accounting for the presence of the 

 large bowlders in the gravel of Elephant Head south of the entrance 

 to Black Canyon, with its walls of porphyry from 800 to 1,200 feet in 

 height, he wrote: 



When the Colorado began the task of cutting down the gigantic wall at the 

 point where its accumulated waters, in greater volume than now, poured down its 



