THE AGE OF THE WYE, 179 
about five and a half miles an hour^ at which time the water is 
heavily laden with sediment. 
The stream, it may be observed, winds backwards and 
forwards across the alluvial land from cliff to cliff, in “ bends” 
of a peculiar form and curvature, wearing away its outer banks 
and the cliffs themselves wherever it reaches them, as shown 
by the dark marginal lines already alluded to, and leaving a\ 
deposit on the inner banks so as always to maintain its average 
width. 
The curvature of these bends ” evidently depends upon the 
magnitude of the stream. If different streams of various sizes, 
large and small, be carefully inspected, either on the ground or 
on a correct map, it may be observed that they all wind 
backwards and forwards across their alluvial lands in a similar 
manner ; and that the radius of the curvature of their bends,” 
though it does not, so far as I know, admit of exact measurement, 
yet clearly and evidently bears a definite ratio to the size of the 
stream. 
Looking now at the “ general course ” of the river on the 
portion shown on the wall map, and starting from the Hole-in- 
the-Wall, it will be observed that, after having rounded the 
abrupt turn above the Hole-in-the-Wall, its general course” is 
nearly straight till it arrives at Backney. The consequence has 
been that the “ cliffs ” on the two sides are of about the same 
height, which indicates that the wear has been about equal on both 
sides. But when it arrives at Backney the general course ” 
makes a bend to the east, and here we see, as might have been 
expected, that the force of the waters has been thrown against 
the west or salient cliff and has worn it largely, wLile the east 
or retreating cliff is comparatively little worn. 
Again, proceeding down the river, we find that at Boss there 
is a westward bend in the “ general course,” and that this is 
