DAVIS: RIVER TERRACES IN NEW ENGLAND. oak 
clear how a wandering stream will behave up and down valley from a 
fixed node. Several suppositions may be made. 
First, the meanders will sweep down the meander belt, and the - 
meander belt will swing to and fro across the valley, but the ampli- 
tude of both movements will be decreased as the node is approached, 
and extinguished as it is reached. So far as my observations go, this 
condition is more appropriate down-valley than up-valley from a fixed 
node. Below the node, slight curves may be formed ; these may develop 
into normal meanders, Figure 37 (the river flows to the right), as they 
sweep away from the sill; but such development will probably be grad- 
ual, and hence the valley floor will widen gradually in that direction. 
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Fie. 37. 
Second, the meanders may continue almost in full force as they 
approach the node from up the valley, merely changing in the lowest 
part of their course that leads directly to the sill. This might involve 
the introduction of a “kink” into the meander system, at the point 
where a change is made from the normal down-sweeping curve to the 
constrained course that leads to the ledge. That such a sharp bend is 
possible seems to be shown by certain peculiar forms in the meanders of 
the Theiss on the plain of Hungary; it being probable that bends of this 
kind result from the faster down-sweeping of some meanders than of 
others. The considerable breadth of flood plain often observed next up- 
stream from a node supports this supposition. 
Third, the fixed node may perhaps induce the formation of free nodes, 
evenly spaced from the ledge of superposition ; then between the fixed 
node and the free nodes, the stream might vibrate as a stretched string 
vibrates when it is lightly “stopped” at a third or a quarter of its 
length. Symmetrical free terrace cusps would result from this process. 
So systematic a movement would seem to be possible only in rare 
