i88i.} Miniature Physical Geography . 635 
river, sand is deposited, and as the river cuts its way down- 
wards this portion is left high and dry. 
But the mischief once begun rapidly spreads. The form- 
ation of one such curve sets the stream a swinging through 
the rest of its course. Now on one side, now on the other, 
are the banks eaten into, until the course has become marked 
by sinuous curves, local conditions causing some of the curves 
to be more pronounced than others. All the curves, however, 
have a tendency to advance down stream. When a curve has 
in this way become comparatively long, the miniature river 
often tends to assume a straighter course ; it recedes from 
its bank cliffs, and soon a tradt of comparatively level dry 
land separates these banks from the stream. This is gene- 
rally due to the lengthening of the curves above. In fadt, a 
little consideration will show that the gradual advance of 
the curves down stream will have a tendency to produce a 
broad valley through which the river will wind. These 
miniature valleys have often beautifully-marked river terraces 
on either side, showing the length of swing of the river on 
each occasion that it oscillates to and fro. There can be 
little doubt that during each swing the river cuts its way 
downwards to some extent, and that therefore the terraces 
formed in succession on the left and right banks are at slightly 
different levels in a descending series ; but this I have not 
been able to see in miniature. 
How marked a feature broad valleys and river terraces 
are on a large scale I need hardly remind the readers of this 
Journal. Memphis, on the Mississippi, stands on such a 
terrace. Sections of any tolerably large river-valley — that 
of the Thames, for example — show this well, but to make 
out a succession of these terraces in a large river valley is 
not easy. They may be more satisfactorily studied in smaller 
tributary streams. I remember an admirable instance near 
Penrith, in Cumberland. But for my own part I confess 
that the study of miniature valleys helped me much in the 
comprehension of this subjedt. 
Very plain are the evidences of the swing of the stream 
in great rivers. No one who has passed down the Missis- 
sippi, for example, can have failed to notice that the opposite 
banks are generally very different in character. The one 
shelves down into shallow water ; the other is cliff-like, often 
20 feet high or more, and has deep water under it. The 
shelving bank is in fadt advancing on the river. The steep 
bank is being undermined by the river. All the settlements 
on the banks of the Mississippi are on the steep side ; there 
are none on the shelving bank. The reason of this is 
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