NV. 8. Shaler—F luviatile Swamps of New England. 213 
plains of New England. Here and there also we find low but 
sharp kame ridges which are equally characteristic of this class 
of deposits. These contours are of themselves sufficient to 
prove that these areas have never been the flood plains of 
any river. Other evidence is found in the fact that these kame 
bearings terraces have bowlders scattered over them; usually 
these erraties are of small size, but occasionally they have a 
mass of twenty cubic feet or more. The materials which form 
the kame plains consist in the main of sand and pebbles 
deposited in an irregular, cross-bedded way quite different from 
the structure of fluviatile terraces. Again the kame plains 
may be traced completely beyond the valleys into positions 
where it is evident that they have no relation to river action. 
Below the level of this kame terrace the valleys of the rivers 
which flow from south to north show no other benches until 
we descend to the level of the present flood plain. This is 
always, as is shown in the diagram, in direct communication 
with the present margin of the river so that a very slight flood 
sends the water over the whole of its level. Even in the times 
of ordinary low water the river extends through sedgy flats for 
some distance from the margin of the flowing stream. The 
whole of this alluvial plain is swampy; so far as I have seen 
none of it is exempt from floods, and there is, at no point, any 
indication of down-cutting on the part of the stream bed. This 
absence of a distinct lowering of the drainage level in these 
basins may possibly be accounted for in part by the fact that 
they are all more or less obstructed by mill-dams. Still making 
all allowance for these obstructions and considering only the 
conditions which remain when the water is drawn away from 
the pools, it is clear that there has been in these channels an 
entire absence of that swift down-cutting which is so marked 
a feature in the rivers which flow from north to south. . 
It is moreover clear that the reverse process is now rapidly 
in action; none of these northward flowing streams have, at 
the present time, sufficient currents to clear their beds of the 
detritus brought into them. by floods from their tributaries. 
Hyven in the time of floods they discharge no coarse detrital 
matter ; only the small amount which is held in suspension by 
a slight current is carried to the sea. The result of this failure 
of the streams to exercise any general erosive effect is that the 
process of deposition is constantly going on not only on the bot- 
toms of their channels but upon a wide field on either side of the 
waterways. ‘The deposition of coarse sediment is taking place 
not only along the bottoms of the streams but in the form of small 
deltas where the brooks from the higher ground are arrested in 
their speed at the margins of the swamp lands. These deltas 
are inconspicuous; in part because the greater number of the 
