INCONGRUITIES OF PREVAILING HYPOTHESIS 355 



waters were already gathered. in ^-reatest exj^anse. From whatever angle 

 the theme is viewed, the pre-lacustrine features have a fundamental func- 

 tion in shaping all later events, for the genesis of the lake is not nearly 

 so simple a process as to include only a mere filling of a chance depression 

 with abundant waters from postulated glacier-fed streams. Perhaps the 

 most important periods of the lake's history are the prenatal ones. 



Omitting to take iiito account tliese prenatal lake conditions necessarily 

 leads to a misunderstanding of some features, a WTong interpretation of 

 many others, and concerning- still others the introduction of unnecessary 

 and irrelevant hypotheses. Inattention in tins respect also develops un- 

 expected incongruities and renders inexjilicable otlierwise easily compre- 

 hended characters. 



C02IPARIS0N WITH RELATED EVENTS OF NEIGHBORING DISTRICTS 



AVith the numerous physical events which are known to have al)ounded 

 in the region, the geological dates of which are now pretty \\'ell fixed, it 

 is quite singular that those directly associated with the Glacial epoch 

 should have been considered to the exclusion of all others. Even the 

 connection of the lake with ice effects is not at all convincing, and later 

 observations indicate that this is only partially ])erfinent. It is even 

 possible that the existence, much less tlie birth, of Lake Bonneville was 

 not only not associated in any w^ay with the inferred consequences of a 

 giacial climate imposed on the region^ but that it really antedated by a 

 very considerable lapse of time the dawn of the Glacial epoch. 



Critical consideration ot the later gorge-cutting of the Grand Canyon 

 of the Colorado Eiver, the canyon work of the Green Eiver in the Uinta 

 Eange, the development of the Snake Eiver drainage, the remarkable 

 terrace work in adjoin ijig areas, the sprcrMl of lava flows, and the minor 

 diastrophic chaiiges in the region is i)()ujul to throAv a new flood of light 

 on Bonneville affairs. The climatic factor may be finally found to be 

 p>ractically negligible. 



INADEQUACY OF EXISTING DRAINAGE SYSTE3IS 



It Avas the manifest incompetency of the present drainage to keep np a 

 great lake that caused the Boimeville historians to cast about for a water 

 supply ample enongh to satisfy all requirements. The simplest method 

 Avas to postulate a larger supply from existing streams. Only by direct 

 appeal to different physical conditions giving a moister climate could this 

 be done. The Glacial epoch A\as thought to be near enongh to fulfill the 

 idesired requirements. The step to glacial environment was short and easy. 



The utter insufficiejicy of Bear Eiver, the principal tributary of Great 



XXVI^BuLL, QEor/. Soc. Am., Vol. U'S, 191G 



