causes accumulated in the lower part of the glen. If this took place from the action of former waters flowing through the valley, (and to what other causes can we assign it ?), it must belong to an epoch prior even to the deposits of sharp matter in the upper part; as these must have been otherwise necessarily removed by that cause which deposited the rounded materials in the lower. Here therefore we are again carried back to an æra marked by the action of water, and prior even to the very distant time which appears to have been required for the tedious deposition of the sharp alluvium.
Such are the complicated views derived from a consideration of these appearances, nor is it easy to see how we can avoid the conclusions which must be drawn from them. Although some of them should have their foundation in error, there are still enough remaining to excite our industry in the observation of analogous phenomena, and to stimulate us to seek for a theory of these facts less incumbered with inexplicable results; if indeed it be possible to discover one which shall not be attended with most of the various consequences I have pointed out.
It follows yet, from a general view of these alluvia, that many of them are probably of a formation more ancient than the last great changes which produced the present state of the surface, if we consider the drainage of Glen Roy to appertain to those changes. But we are in danger of being bewildered in the views which open on us when we pursue the operations of Nature so far beyond the limits of our immediate observation.
I have thus, as distinctly as is in my power, stated the whole of the arguments, as well as the difficulties and objections which bear on this question in all the several lights in which it has yet been considered, suppressing nothing which has occurred to me as an
