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bourhood, together with some of granite, gneiss, and porphyry, that must have been transported from a distance of not less than fifty miles. The position of these

stones, relatively to the masses from which many of them have evidently proceeded, indicates decidedly a current flowing with considerable force from west to east. Masses of sand, too, accumulated in various places, exhibit that waved stratification which evidently proves the existence of a former current. In the diluvium around Edinburgh, few or no traces of the remains of mammalia have been found; but to the westward, about Alloa, and in Stirlingshire, the ivory tusks of the elephant, and the horns of ruminating quadrupeds allied to the elk, have been from time to time discovered. All these circumstances, joined to the appearances already pointed out at Burdiehouse, lead to the conclusion that land has existed to the westward, that from thence has proceeded one or more large rivers, and that the situation where Edinburgh now stands may have been the bottom of some estuary."

Niddry quarry is about two miles south-east of Edinburgh, and is formed by the tilting up of the northern edge of the Mid-Lothian coal measures, by means of the greenstone rocks, which intersect these deposits. The strata, as seen in this section, are nearly vertical, and consist of alternate layers of shale, sandstone, and seams of coal.

Immediately above the strata thus elevated, is superimposed the diluvium c, c, a mass of clay, five feet in depth, with fragments of sandstone and boulders, of the same nature as those which prevail in the surrounding district. The sharp unworn edges of the sandstone and shale, exhibiting the same appearance which they must have borne when newly severed from the connecting layers, proves that the superposition of the diluvial matter immediately succeeded this elevation; and the

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a, a, Sandstone. b, Shale. c, Diluvium with boulders. d, Present soil.

mass of diluvial matter which penetrates about two feet into the fissure at e, evidently shews that no denuding current had swept away any newer strata which might have been deposited above; for such newer strata, if it had existed, must have pre-occupied this fissure.

In this same diluvial covering, at Clifton Hall, near Falkirk, fifteen feet below the surface were discovered some years ago, two tusks of a fossil elephant, and several other fragmentary remains of mammalia are occasionally, though rarely, met with. Now, the question is, Was the elephant a contemporary of the diluvial clay in which its tusks were imbedded? and was this diluvium contemporaneous with the coal measures above which it lies? If these questions are admitted in the affirmative, then we have the fossil elephant a contemporary of the coal formations. But we have the megalichthes, and many other species of extinct fishes and shell mollusks, in the coal and subjacent limestone, which would also, in this way, claim a contemporary era with the mam.. moth.

* Mr Bald. Wernerian Transactions, vol. iv.

NOTE II. p. 37.

"Within the last ten years, three large trees have been found in Craigleith quarry, near Edinburgh, which have excited great attention, and have been minutely investigated. In 1826, a tree was exposed, measuring thirtysix feet in length, and three feet diameter at the base; and, in November 1830, one still more remarkable was displayed to view. This tree was found about the centre of the quarry, at a depth from the surface of about one hundred feet. A considerable portion of the top was broken off and destroyed when first discovered; but more care having been observed afterwards, the whole. was exposed in such a manner, that its form and size and position, could be well ascertained.

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The entire length of this tree was forty-seven feet, exclusive of the top, which was broken off, and supposed to be about twelve feet. Its breadth varied from two to one and a half feet. Its greatest diameter, near the base,

was, in one direction, five feet. It was of a compact solid structure, its original shape apparently well preserved, with the exception of part being somewhat flattened, probably by the unequal pressure caused by one portion becoming consolidated before another, and thus the softer parts giving way. The external surface was incrusted with coaly matter, varying from a quarter to half an inch in thickness, which was evidently the outer portions and bark converted into bitumen. The tree lay in a slanting direction, with its lower end dipping to the south-east. It lay across several strata of sandstone and shale, the upper beds of which rested in an unconformable position on the lower- the latter forming a sort of hollow trough. There were no traces of either branches, leaves, or roots, attached to this fossil; both its upper and lower ends were evidently rounded, and worn smooth by attrition. About a third from the top, it was bent and somewhat flattened; distinct elevations were seen at intervals on the trunk, corresponding to the places where branches may be supposed to have grown.

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A branch was discovered a little to the south of the position of this tree in the same year; and, in 1833, another large trunk was exposed in a deeper part of the quarry, about fifty yards to the westward.

This tree lies at an angle of forty-five degrees, and rests on strata, dipping to the east by north. Upwards of thirty feet have been already exposed; the greatest diameter is about three feet; irregular swellings or rings are distinctly visible on the trunk, and two distinct hollows where branches have grown out."-Geology of the Environs of Edinburgh, p. 52.

When the first fossil tree was discovered in Craigleith quarry, near Edinburgh, various conjectures were formed regarding the class of plants to which it belonged. According to the canons of Brongniart, then in full force, its position in the lower fossiliferous beds ranked it among the arborescent ferns: then, when its structure clearly indicated that it was a tree, a new specific name was given to it, and it was henceforth pronounced an extinct fossil. It might, in this way, according to the prevailing theories, have been for ever, to use an expression of Swift, "kicked out of creation," had not Mr Nicol, after much labour and patient induction, and aided by the lucky chance of receiving a spar of New Holland pine which had been brought to Leith spliced to the mast of a vessel, detected its exact conformity with a recent species. Thus this splendid fossil, instead of obtaining a niche in the archives of a preexisting world, was found to be identical with a species of araucaria, at present flourishing in the islands of the South Sea.

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