42 REVIEWS. 
important conclusion, and we shall hereafter see its application by nier 
ranges, and also to the Rocky Mountain range taken in the aggregate. 
om evidence of a similar nature the Laramie Mountains, the Big 
Horn and Wind River Mountains are shown to have been elevated at 
some time during the Tertiary perio 
pe IR this connection I ‘hare thought it best w remark gos systematically in regard to the . 
e Missouri River and its tributa- 
ties tun one of the largest as well as most important Peat basins n America. It 
countr y. 
drains area of nearly or q 1,000, , Taking its rise in the loftiest portion 
of the Rocky Mountains, near latitude 44°, lo: de , it hward in three principal 
branches, Madison, Gallatin, and Jefferson forks, to weis junction, and then proc ward 
— it eme qe som Ae p gare Por the dpt a ien ce of nearly 200 miles; it then bends 
ula t f White th River, a distance of 
Ear iv 
as. 500 mi es; it then gradually bends southward and yestward to. its junction with i Mis- 
il 
ates distance of 1,500 to 2 miles. f th ssouri 
rise in the central portions of the Rocky Mountain range, flowing through rene basalt, 
and the older -seammsaaabargs? are € it emerges from the gate of the mountains, when the 
triassie and j The falls of the Missouri, extending a distance » o 
miles, eut their way through a great joda of compaet triassie rocks. Below the falls the 
eed oper dpen! ay thr iso the soft yieldin g élays "anf sands ot "me Oretaceous beas peg 
T 1 ti ling ly to the mouth of Milk River, where the lignite 
tiary formations commence. These are also composed of sands, marls and clays, as the 
seine iso of the valley will c A. iit er flows through these tertiary rocks to the Monik 
of en River below Fort Union, a distance of nearly 250 miles, where the Cretaceous rocks 
com the surface a pin. hese BB er gie at nd nearly to Council Bluffs, a distance of 
santa Thay ed inastraight line as nearly as possible. Just 
above Council Bluffs the coal me e limestones commence, and the valley of the Missouri 
hae ipt ecomes more dicis pie it is of moderate width even below the mouth of 
me Kans 
MAA xe 
y far the 1 tb h he Missouri, and for 400 miles from 
to b 1 I a i itself hon Fort Union to Fort Pierre. It 
luri tl i 1 y summer for 300 400 miles above 
its junction with the Misso uri. the main divide of the Rock 
Mountains, near latitude 44 1- 2° a an pi longitude 110°, in a lake, as some suppose, called Yellow- 
stone lake, whieh is ceo 60 miles long and 10 to 20 wide. Its channel is formed in rocks simi- 
lar to that of the Missouri, about 400 ni of its course passing through lignite tertiary beds. 
‘The character of its valley is very similar. p that al the Missouri. Most of the important 
— "ep udi this river I p g tion of this chapter. Tongue and 
t 
t l tti di d the Big Horn range. Tongue 
River is nearly 150 mile s in length, and flows for the most part through the soft yielding rocks 
of the lignite tertiary. _Po wder. River is. from E 300 — in length, and also flows nearly 
Chapter II. on the * en of Geotepian Pouaiioné in the North- 
west." Chapter XII. on Geological Explorations in Kansas, and Chapter 
XIII. “Tour to the Bad Lands of Dakota," in 1866, will be found of es- 
get value to the student of American Geology. 
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of news interesting to entomologists, and will be useful to all who wish 
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