Penn, Esq. London, 1825.

[42] "Statesman and Record," October 6th, 1846.

[43] Sir Charles Lyell's statement is by no means so express or definite
as it is represented to be in this passage, in which I have taken the
evidence of his opponents regarding it. What he really says (see his
"Principles," second edition, 1832) is what follows:--"_If_ the ratio of
recession had never exceeded fifty yards in forty years, it must have
required nearly ten thousand years for the excavation of the whole
ravine; but no probable conjecture can be offered as to the quantity of
time consumed in such an operation, because the retrograde movement may
have been much more rapid when the whole current was confined within a
space not exceeding a fourth or fifth of that which the Falls now
occupy." In the eighth edition of the same work, however, published in
1850, after he had examined the Falls, there occurs the following
re-statement of the case:--"After the most careful inquiries I was able
to make during my visit to the spot in 1841-42, I came to the conclusion
that the average [recession] of one foot a year would be a much more
probable conjecture than that of one and a quarter yards. In that case
it would have required _thirty-five thousand years_ for the retreat of
the Falls from the escarpment of Queenston to their present site. It
seems by no means improbable that such a result would be no exaggeration
of the truth, although we cannot assume that the retrograde movement has
been uniform. At some points it may have receded much faster than at
present; but in general its progress was probably slower, because the
cataract, when it began to recede, must have been nearly twice its
present height."

[44] "Scottish Christian Herald," 1838, vol. iii., p. 766.

[45] The substance of this and the following lecture was originally
given in a single paper, before the Geological Section of the British
Association, held at Glasgow in September 1855. So considerable have
been the additions, however, that the one paper has swelled into two
lectures. Most of the added matter was at first thrown into the form of
Notes; but it was found, that from their length and frequency, they
would have embarrassed the printer, mayhap the reader also; and so most
of the larger ones have been introduced into the text within brackets.

[46] A curious set of these, with specimens of the smooth-stemmed fucoid
collected by Mr. John Miller of Thurso,--a meritorious