86 Transactions. — Miscellaneous. 
A still more remarkable result of the flood was presented in connection with 
the lateral valleys which opened on to the terrace of the main river. You 
will remember that I described the front line of each of these valleys, drawn 
from the extremities of the bounding spurs, as presenting the appearance 
of an ordinary river terrace, more or less deeply cut through by its own 
particular stream, and I mentioned that each of these streams had formed, 
at its debouchure on to the surface of the main terrace, a half-cone of 
detritus over which it continued to flow, or through which it had cut a 
channel more or less deep as the case might be. Now, before the flood of 
1868, there was not, in any instance, more than one such half-cone in 
connection with any one valley, the stream from each valley having unques- 
tionably debouched from the same channel on to the main terrace ever 
since the waters of the main river had ceased to run at the level of the 
upper surface of that terrace. But in the case of several of these larger 
lateral valleys, the channels of their streams, though wide and deep, had 
proved to be entirely insufficient to carry off the enormous quantity of 
water which had suddenly poured into them during this flood, the con- 
sequence being that the surplus water overflowed the valley and found 
its way along one or more lower lines on its surface over the edge of its 
frontal-terrace on to the main terrace below. These valley-terraces are, as 
I think I have before observed, composed of loose gravels and silt: Now 
the quantity of surplus water was so great in some instances, that wide 
fresh channels were cut through the fronts of the valley-terraces, and fresh 
half-cones deposited on the main terrace below, some of them being actually 
larger than the old half-cones which had accumulated in front of the 
original debouchures during the immense time which had elapsed since 
they began to be deposited. There could be no mistake about this opera- 
tion. There were the large open gaps freshly cut through the front 
terraces, in some instances extending in depth to the solid rock below. 
There were the great new half-cones, some of them covering several acres of 
the previously level surface of the main terrace, and formed out of the 
materials which had filled these gaps. But no water has ever since flowed 
through these new gaps. The streams of the lateral valleys are again 
flowing in their old channels, and the latter have, in almost every instance, 
been emptied of every atom of the loose material which had previously lain 
in their beds, thus giving largely increased room for the flow of the water. 
Chasms along the line of these streams, in their course across the main 
terrace, in some instances ten and twelve feet deep, the bottoms and sides of 
whieh are clean solid rock, have taken the place of beds of shingle which had 
formerly filled them up to the general level of the ground, the consequence 
being that a considerable number of bridges haye had to be constructed on 
