186 Physics and Hydraulics of the Mississippi River. 
succession of mountain vere and enormous cafions 
etween the 
110° 30’ and lat. 44° 30’, the Upper Yellowstone has its on 
in a lake, as yet only visited by trappers and Indians, whence! 
lunges through an impassable gorge to the highest point vis! 
y Capt. Raynolds’ party. From this point, where it is two hun 
dred yards wide and six feet deep, it winds to the northeast, 
through a narrow valley, to the mouth of Clarke’s fork. In this 
distance it is characterized by many islands, and by bold, swe? 
ing curves, Seoenily impinging upon the hills. Betwee? 
Clarke’s fork and the mouth of the Big Horn, the river 18 from 
500 to 600 yards in width, unobstructed by rapids, and flow! 
with a swift current of some three or four miles per hour. 
Below Big Horn river, to Powder river, the width increases 
to 800 or 900 yards, and the river becomes turbid, resembling 
From Powder river to the Missouri the banks are low on 
caving, and the river assumes the characteristic appearene sred 
the Mi , containing numerous sand bars, densely 
‘islands, &c. There are also some rapids and shoals. be 
Capt. Raynolds is of the opinion that the Yellowstone ca? 
