84 The American Geologist. August, i904. 
The termination of the cycle of abundant fluvial deposition 
and ensuing erosion upon our great western Cretaceous area, 
and its renewed epeirogenic uplift to undergo the erosion of 
the broad and flat Red river valley along its eastern margin 
in Minnesota, North Dakota, and Manitoba, were probably 
also contemporaneous with the great epeirogenic movement 
which in California, according to Mr. J. S. Diller, ended a 
long cycle of baseleveling that had extended through the whole 
of Cretaceous and Tertiary time, and raised a part of that 
baseleveled district at the beginning of the Quaternary era to 
form the lofty Sierra Nevada.''' Again, a similar record of 
long-continued baseleveling, followed by uplift and a new 
cycle of rapid valley erosion, is found by Powell and Dutton 
in the plateaus and Grand Canyon of the Colorado river, f 
Like the great changes of drainage which have formed the 
Ohio river, so I think the Missouri river also to have been 
made compositely, and to have taken its present course, since 
the Quaternary era began, with its general epeirogenic eleva- 
tion of the greater part of North America to an altitude 3,000 
tO' 5,000 feet higher than now, which led to snow and ice ac- 
cumulation and the prolonged glaciation of the northern half 
of this continent, excepting Alaska. This opinion was first 
reached by Gen. G. K. Warren. t and has been more amply 
considered and stated by Prof. J. E. Todd.§ The continental 
ice-sheet turned aside the rivers of the northern part of the 
Plains, deflecting the Tertiary predecessor of the INIissouri to 
the west and south from its preglacial course, which may 
have occupied a part of the valley of the James or Dakota 
river, nearly parallel with the Missouri of today, or which per- 
haps farther north passed eastward to the most southern bend 
of the Souris river, or to the Sheyenne and Red rivers. Pro- 
* U. S. Geol. Survey, Eigbth Annual Report, pp. 428-432. Compare also 
articles by Prof. Josrph LeConte, i4nj. Jour. Sc/., third series, vol. six. pp. 
176-190, March, 1880; vol. xxxii, pp. 107-181, Sept., 1886; vol. xxxviii. pp. 
257-263, Oct., 1889. 
t Exploration of the Colorado River of the West, 1875 Geologfv of the 
eastern portion of the Uinta Mountains, 1876. U. S. Geol. Surrey, Xlono- 
graph II, Tertiary History of the Grand Canyon District, 1882. Anier Jour. 
Sci., third series, vol. xxxii, pp. 170, 171, Sept., 1886. 
t Annual Report of the Chief of Engineers, U. S. Army, for 1868, pp. 307- 
314. 
§ Proc. A. A. A. S., vol xxxiii, 1884, pp. 381-393; U. S. Geol Surv., Bulletin 
No. 144. 1896, p. 57. Compare also a paper bj' Prof. E. W. Claypolk. "The 
Storj' of the Mississippi-Missouri," Am. Geologist, vol. iii, pp. 361-377. June, 
1889; and a paper by Prof. G. C. Bro.\i)HKAD, "The Missouri River," a'mer. 
Geologist, vol. iv, pp. 148-155, Sept., 1889. 
