BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 

 Vol. 28, pp. 351-374 June ii, 1917 



OKOGKAPHTC ORKMN OF Af^C^IENT LAKE BONNF/VJLLK^ 



BY UiLARLES R. KJ<]YES 



{Presented before the Society December 29, 1916) 



CONTENTS 



Page 



Introductory 352 



rncongruities of prevailing- liypothesis 353 



General statement 353 



Unusual position of lake's intake and outlet 353 



Preclusion of regional oscillatory changes 354 



Inattention to pre-lacustrine conditions 354 



Comparison with related events of neighboring districts 355 



Inadequacy of existing drainage systems 355 



Peculiarities of so-called Red Rock outlet 356 



Conspicuous absence of moist climate features 356 



Non-coincidence of lake and Glacial epochs 357 



Infelicitous comparison of lake's outlet w^ith Niagara 357 



Pre-lacustrine relief of P>onneville region 358 



Early Quaternary drainage 358 



Ancient Virgen master-stream 358 



Headwaters of old Virgen River 359 



General absence of tributaries 360 



Lower reach of old Virgen waterway 360 



Typical through-flowing stream of desert 361 



Recency of Snake River channel 361 



Orographic movement in Bonneville area 362 



Recent diastrophic changes 362 



Latest uprising of Colorado dome 363 



High channel of Virgen-Muddy River 364 



Diversion of headwaters of old Virgen River 364 



Magnitude of necessary movements 365 



V^olcanic disturbances affecting lake conditions 365 



Choking of main tributaries by lava flows 365 



Formation of Snake River 367 



Contemporaneity of neighboring physical events 368 



Tertiary strata in Bonneville basin 368 



Inner gorge of Grand Canyon 368 



Similarity of old lake terraces ' 368 



Depauperation of molluscan shells 369 



1 Manuscript received by the Secretary of tlie Society January 17, 1D17. 



(351) 



