Le oe we be tae 
A. C. Peale—Ancient Outlet of Great Salt Lake. 443 
the season of 1877, noticed on page 56 of the current volume 
of this Journal, there is no mention of the observations at Red 
Rock Pass, but the omission appears to have been accidental, &c.” 
The portion of this statement that I have italicised is a gratui- 
tons assumption. The omission was not accidental. I did not 
believe that the outlet was at Red Rock Gap, and in the Pre- 
liminary Report (page 7), I made the following statement: 
“The lower valley of the Portneuf is interesting from the fact 
that it is the probable ancient outlet of the great lake that 
once filled the Salt Lake Basin.”™ 
Mr. Gilbert also hopes that I “will not advocate in” my 
“report the idea that the divide between the Malade and 
Marsh Creek was one of the old outlets of the ancient Salt 
Lake when its waters were at the highest level.” 
Had I been writing a final report on the subject I would 
perhaps have used the word overflow instead of outlet. It 
summit, although” he “bad undertaken last summer to examine 
every divide between the Columbia and Salt Lake Basins, that 
might have afforded passage to the water.” 
In all his investigations he seems never to have noted any 
evidences of a lake having a higher level than his Lake Bonne- 
ville. Such evidences, however, do exist. On both sides of 
the Portneuf where it comes into Marsh Creek Valley an upper 
terrace is seen, and in 1872 Professor F. H. Bradley also 
readily identified an upper terrace in Marsh Creek Valley at 
the lev bo n 
Report 
no warrant for the statement that he made the “ astonishing 
* Preliminary Report of the field work of the United States Geological and 
perce Sea i of the Territories for the season of 1877. Washington, 
1877, p. 7. ; { 
+This Journal, vol. xv, April. 1878, p. 258. Mr. Gilbert appears to take it 
for granted that the point of outlet must necessarily be found at one of the exist- 
ing divides between the Great Basin and the Columbia. 
The railroad profile from the bluffs on Bear River in Cache Valley to Red Rock 
Pass (a distance of fifteen miles) shows a difference of elevation of only eleven 
f the descent of Marsh Creek from Red Rock Pass to a point twenty-six 
ly 1°07 feet per 
draining of Lake Bonneville — easily have 
present the divide for several miles is a swamp. 2 
¢ Sixth Annual of the United States Geological Survey, for 1872. 
Washington, 1873, p. 203. 
