TRANSPORTING POWER OF RIVERS. 
253 
power of streams which, in these respects, fall incalculably 
below the torrents of the Alps. In a flood of the Ottaque- 
chee, a small river wdiicli flows through Woodstock, Vermont, 
a millclam on that stream burst, and the sediment with wdiich 
the pond was filled, estimated after careful measurement at 
13,000 cubic yards, was carried down by the current. Between 
this dam and the slack water of another, four miles below, the 
bed of the stream, which is composed of pebbles interspersed 
iu a few places with larger stones, is about sixty-five feet wide, 
though, at low water, the breadth of the current is considerably 
less. The sand and fine gravel were smoothly and evenly dis¬ 
tributed over the bed to a width of fifty-five or sixty feet, and 
for a distance of about two miles, except at two or three inter¬ 
vening rapids, filling up all the interstices between the stones, 
covering them to the depth of nine or ten inches, so as to pre¬ 
sent a regularly formed concave channel, lined with sand, and 
reducing the depth of water, in some places, from five or six 
feet to fifteen or eighteen inches. Observing this deposit after 
the river had subsided and become so clear that the bottom 
could be seen, I supposed that the next flood would produce 
an extraordinary erosion of the banks, and some permanent 
changes in the channel of the stream, in consequence of the 
elevation of the bed and the filling up of the spaces between 
the stones through which formerly much water had flowed; 
but no such result followed. The spring freshet of the next 
year entirely washed out the sand its predecessor had depos¬ 
ited, carried it to ponds and still-water reaches below, and left 
the bed of the river almost precisely in its former condition, 
though, of course, with the slight displacement of the pebbles 
which every flood produces in the channels of such streams. 
The pond, though often previously discharged by the breakage 
of the dam, had then been undisturbed for about twenty-five 
years, and its contents consisted almost entirely of sand, the 
rapidity of the current in floods being such that it would let 
fall little lighter sediment, even above an obstruction like a 
dam. The quantity I have mentioned evidently bears a very 
inconsiderable proportion to the total erosion of the stream 
