[39] See "Primary and Present State of the Solar System, particularly of our own Planet;" and "Exposure of the Principles of Modern Geology." By P. M'Farlane, Author of the "Primary and Present State of the Solar System." Edinburgh: Thomas Grant.
[40] One of the more brilliant writers of the present day,—a native of the picturesque village in which this anti-geologist resides,—describes in a recent work, with the enthusiasm of the poet, the noble mountains which rise around it. I know not, however, whether my admiration of the passage was not in some degree dashed by a few comic notions suggestive of an "imaginary conversation," in the style of Landor, between this popular author and his anti-geologic townsman, on the merits of hills in general, and in especial on the claims of those which encircle Comrie "as the mountains are round about Jerusalem." The two gentlemen would, I suspect, experience considerable difficulty in laying down, in such a discussion, their common principles.
[41] "Comparative Estimate of the Mineral and Mosaical Geologies." By Granville 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 laborer in the geologic field,—were exhibited at Glasgow to the Association. The larger stems were thickly traversed in Mr. J. Miller's specimens by diagonal lines, which seemed, however, to be merely lines of rhomboidal fracture in the glassy coal into which the plants were converted, and not one of their original characters.
[47] I must, however, add, that there was found in the neighborhood of Stromness about fifteen years ago, by Dr. John Fleming, a curious nondescript vegetable organism, which, though equivocal in character and appearance, was in all probability a plant of the sea. It consisted of a flattened cylinder, in some of the specimens exceeding a foot in length by an inch in breadth, and traversed on both the upper and under sides by a mesial groove extending to the extremities. It bore no external markings, and the section exhibited but an indistinct fibrous structure, sufficient, however, to indicate its vegetable origin. I have not hitherto succeeded in finding for myself specimens of this organism, which has been named provisionally, by Dr. Fleming, Stroma obscura; but it seems not improbable that certain supposed fragments of wood, detected by Mr. Charles Peach in the Caithness Flagstones, but which do not exhibit the woody structure, may have belonged to it.
[48] I figured this species from an imperfect Cromarty specimen fifteen years ago. (See "Old Red Sandstone," first edition, 1841, Plate VII. Fig. 4). Of the greatly better specimens now figured I owe the larger one ([Fig. 120]) to Mrs. Mill, Thurso, who detected it in the richly fossiliferous flagstones of the locality in which she resides, and kindly made it over to me; and the specimen of which I have given a magnificent representation ([Fig. 12], p. 55) to my friend Mr. Robert Dick. I have, besides, seen several specimens of the same organism, in a better or worse state of keeping, in the interesting collection of the Rev. Charles Clouston, Sandwick, near Stromness.