Report of a reconnaissance from Carroll, Montana Territory, on the upper Missouri, to the Yellowstone National Park, and return, made in the summer of 1875 . way, the material being carried on by ^;the current. Upon the opposite side of the stream, at c, the current \ is weaker, the water shallow and eddying, and the shore runs out crfacrou?.to meet the water in a long low sand-bar. At 6, there is a higli ? bank of alluvial clays, 10 feet or more above the stream, deposited f ^^ long before in time of flood, but now being rapidly torn away. Stillagain at a the water washes at the foot of the o
Report of a reconnaissance from Carroll, Montana Territory, on the upper Missouri, to the Yellowstone National Park, and return, made in the summer of 1875 . way, the material being carried on by ^;the current. Upon the opposite side of the stream, at c, the current \ is weaker, the water shallow and eddying, and the shore runs out crfacrou?.to meet the water in a long low sand-bar. At 6, there is a higli ? bank of alluvial clays, 10 feet or more above the stream, deposited f ^^ long before in time of flood, but now being rapidly torn away. Stillagain at a the water washes at the foot of the older bluffs, whileopposite is the never-failing sand-point. Thus the river winds on its course, touching the hills, which formthe true limit of its valley, only here and there. For the greaterpart of its course, it is confined between the alluvial banks. It issafe to say that, except in the «pring, the river deposits compara-tively little solid matter, and this, chiefly on the sand-spits andbars, where the force of the moving water is small. The workof the river is at this season one of destruction more than deposition, tearing down what it has13 w. 98 EECONKi^ISSAHOE FEOM CARROLL, MONTANA, itself previously built up, and also to a less extent carrying away the older deposits. It actsalone, unaided by any minor tributary streams; for they are dry except in the early season. Evenduring the summer, however, the channel is constantly changing. The mud-and-sand bars whichare everywhere formed do not long retain their positions, but are moved on down the river andheaped up again in other places. Thus the process is one of gradual transferral down the stream;the solid matter going to make one alluvial bank after another until it is finally deposited in theGulf of Mexico. It is interesting to note, in this connection, the explanation recently given by Prof. JamesThomson (Proc. Royal Society, 1876) of the origin of the windings of rivers in alluvial plains. Heshows that, upon hydrauli
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