24 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
receive additions where the current is not strong, usually along the 
filling channel and at the up-stream end. Observations upon our 
essentially graded New England rivers show the prevalence of these 
sand-bar islands. The West River as it flows into the Connecticut 
shows three islands of varying sizes and the younger, less mature 
streams that descend from the valley sides into the West and Connecti¬ 
cut Rivers exhibit many such islands. The island though usually of 
systematic sand-bar formation may be accidentally the result of short¬ 
cut. Islands of this type will be considered later. 
The West River is to-day parted by a sand-bar island at the 205-foot 
level (see plate 1). This island is the first of a series by means of which 
the current of the river is adjusting itself to a comparatively recent 
deflection caused by short-cut from the base of the Retreat Meadow. 
The thread of the current and consequently the deeper channel are 
on the right. At low water the left-hand channel is dry, and the 
pebbly, gravelly material covering its floor, grades gradually to the 
level of the island. During the subsiding floods, the up-stream cur¬ 
rent, entering the shallower channel, is more or less checked, and 
therefore deposits, gradually building up the floor of the soon-to-be- 
deserted channel. With continued wash-filling, the old channel will 
be recognized not by a perfect river bed but by a valley-like depression. 
Two other islands occur in the West River before it reaches the 
Connecticut, and the Connecticut is parted by a large island at Brattle- 
boro. The current of the Connecticut flows through the wider right- 
hand channel. At low water, the left-hand channel is almost deserted, 
and inevitably it will be abandoned in the future. The river will then 
have moved materially to the right. Its further progress in this direc¬ 
tion cannot be great because of the artificial constructions. Innu¬ 
merable other instances of partition and the resulting lateral move¬ 
ment of the Connecticut might be cited. The process, however, 
may be studied more simply if reference be made to the younger, 
more energetic side streams. Just before Canoe Brook seven miles 
north of Brattleboro, reaches the main stream, an island, unques¬ 
tionably of sand-bar formation, appears in the middle of its course 
and the water divides to flow around it (plate 10). The thread 
of the current, deflected to the right, has cut down so vigorously 
as to produce a fall of water. Continued erosion of the stream will 
cause the fall to move headwards, and the two streams will exist until 
the waterfall has retreated far enough to acquire the more shallow 
