978 



SCIENCE 



[N. S. Vol. XXV. No. 651 



same elevation and are clearly remnants of a 

 once continuous slope or inclined plane. 



Antiquity of the Slopes. — In further sup- 

 port of the view of the great geological anti- 

 quity or Tertiary age of the initial slopes, 

 reference may be made to the high auriferous 

 gravels of the Sierra Nevada of California, 

 which probably were coincident in formation. 

 Like the ancient detrital slopes of Arizona, 

 they are cut through in all directions by 

 existing rivers. Their great antiquity is un- 

 doubted, and is generally regarded as late 

 Tertiary. Russell, in his Quaternary History 

 of the Mono Basin" (1889) records his opinion 

 that the excavation of many of the valleys of 

 the Sierra Nevada began long previous to the 

 Quaternary, and are, in fact, relics of a drain- 

 age system which antedates the existence of 

 the Sierra as a prominent mountain range. 



The detrital slopes of the mountains around 

 the ancient lake Bonneville were found by 

 Gilbert to be older than the lake deposits and 

 to extend below the old shore lines and lighter 

 deposits of the lake. He writes : 



The alluvial cones do not find their bases at 

 the level of upper shore lines, but extend down- 

 ward continuously to the bottom of the valleys, 

 while the shore-lines are wrapped about them.' 



So, also, Russell found similar conditions at 

 Lake La Hontan. He uses the term ' alluvial 

 slopes." 



Turner, following Russell, has recognized 

 the early Pleistocene or Sierran age of a por- 

 tion of the materials filling the Great Valley 

 of California and of portions of the alluvial 

 fans of the Great Basin.' 



Bed Earth Deposits. — Upon the surface of 

 the flanking slopes of the southwest, the earth 

 is sandy and gravelly, and there is a general 

 absence of vegetable mold or soil containing 

 humus. 



The presence of a large amount of red 



"Eighth Annual Report, U. S. Geological Sur- 

 vey, p. 350. 



° ' Contributions to History of Lake Bonneville,' 

 Second Annual Report, U. S. Geological Survey, 

 p. 184. 



' Israel Cook Russell, ' Geological History of 

 Lake La Hontan.' 



' ' Origin of the Yosemite Valley,' California 

 Acad., VoL I., No. 9, p. 269, 1900. 



earth in many places is a notable fact, espe- 

 cially as it is more or less argillaceous, strati- 

 form, and interstratified with coarse gravelly 

 layers. It is found in quantity in some of 

 the sections of the general slope, exposed by 

 erosion of surface waters. At the northern 

 end of the Santa Catalinas, red earth con- 

 stitutes a large part of the upper slope at 

 about 4,000 feet altitude. It is there largely 

 in terrace form and is suggestive of the red- 

 clay formation of the ancient Lake Quiberis 

 in the valley of the San Pedro, evidently an 

 ancient estuary, or landlocked valley ; a good 

 evidence of former submergence. 



Conclusion.. — If it is objected to these views 

 of the origin of the broad slopes under water 

 that we do not find strongly marked sea- 

 cliffs and beach-shingle in connection with 

 the slopes, an explanation may be found in a 

 gradual but continuous uplift, so that all ac- 

 cumulations of shingle were leveled off by the 

 retreating water. And in regard to the shore 

 lines, if any were sculptured, the great anti- 

 quity of the formation has permitted their 

 effacement. 



The absence, so far as known, of any marine 

 remains is readily aceoimted for by the earthy 

 and gravelly nature of the detritus, its rapid 

 formation and its constant disturbance by 

 the tides and ocean currents, preventing the 

 local development of marine life. 



William P. Blake 



Univeksitt of Arizona 



QUOTATIONS 



THE PRESIDENCY OF THE MASSACHUSETTS INSTI- 

 TUTE OF TECHNOLOGY 



The difficulties of the Massachusetts Insti- 

 tute of Technology in finding a president are 

 deserving of more than local interest. Presi- 

 dent Eliot remarked in substance to one of the 

 trustees recently, " You offered the place to a 

 Latin professor and he declined, and now I 

 see that you have offered it to a professor of 

 Greek," an observation suggesting that for a 

 school of theoretical and applied science the 

 institute does not. object to going considerably 

 afield in its search for a president. The trus- 

 tees answer, however, that the great college 

 administrator is the great president, and that 



