356 C. E. KEYES OROGRAPHIC ORIGIN OF LAKE BONNEVILLE 



Sm It Lake, which runiishcs iiiori' tJiaii oiic-Jialf of (lie iolal supply to that 

 body of water, necessarily demaiuled a niucli greater volume of water to 

 teed the ohler and vaster Jake. Bear Eiver, however, does not disphiy 

 any marked signs of e\ er ha^•ing been a much more pretentious stream 

 tlian at present. TJiere are reasons for beiie\ing that it may have been 

 actually smaUer formerly thaji now. The rest of the Wasatch draiuage 

 1? notoriously inconsequential. Willi only the present drahiage systems 

 considered, it might he seriously (juestioncd wliethcr glaciation was ever 

 very elfective o\er the region or Avhether glaciers e\er materially aug- 

 mented the old lake Avaters. 



I'ECULIAh'lTIES OF ^0-t'ALLED RED ROCK OUTLET 



The present ele\'ation of Red Eock Pass, the lo^vest point in the rim of 

 the Bonneville basin, at tlie liead of Caelie Valley, is, according to Gil- 

 bert, about 370 feet below the highest shoreline le\'el and about 30 feet 

 above the Provo level. The north and south valley of which it is the 

 high point is notably broad, the plain l\ing between the piedmonts of the 

 Port Neuf Range on the east and the Bannock Mountains on the west 

 being 10 to 12 miles wide. The two small brooks which have their rise 

 in the pass and which run in opposite directions have cut only iuirro\\', 

 shallow channels in this plain. The bottom of the valley is covered by 

 ailu\ial materials of no great depth. These wash materials are mairdy 

 coarse gravels which were evideiitly being transported southward wlien 

 they came to final rest. Nowhere are there signs of the existence of an 

 old gorge, such as would have been formed by a large river emptying a 

 great lake. If such a canyon ever existed it is now completely obliter.- 

 ated. Farther north, near Pocatello, Idaho, the only trace of an old gorge 

 is that filled with basaltic lava that plainly flowed southward toward 

 Great Salt Lake. In fact, all the usual characteristics of a large outlet 

 are singularly Avanting. 



The j^eculiar physiognomy of the Red Rock Pass district admits of an 

 interpretation very different from that which a generation ago was so 

 plausibly advanced. 



(JOmi'lCUOVS ABlSEyCE OF MOI^T CLIMATE FEATURES 



One of the noteworthy characteristics of the Bonneville basin is that 

 the only details of relief expression which commonly distinguish moist- 

 climate lands are discernible on the east side of the great depression 

 where the shore Avas the mountain base. The small streams coming down 

 from the range seem to be doing about the same Avork noAV that they did 

 ages ago. Along the entire Avestcrn side of the basiu no trace of stream- 



