Wasting effects of the Sea.
Natural History.
It would be a speculation highly interesting to the geologist, to inquire into the probable early history of the Bell Rock, and the changes produced on it by the wasting effects of the waters of the ocean. When we consider the similarity of the red sandstone of this rock with the Redhead of Forfarshire, and opposite shores of Berwick in the neighbourhood of Dunglass, and take into view that there is a ridge or shallower part of the bottom, which extends a considerable way from the Bell Rock in the direction of these shores, we may infer, that the Rock itself had extended at one time much further. We are also enabled to trace the same formation, penetrating to the northward through Ross-shire, and quite across the kingdom, in a southern direction, to Cumberland. At a period indefinitely remote in the history of the globe, we may therefore imagine that one continuous bed of red sandstone had stretched across the Firth , forming a barrier by which the great collection of waters of the Forth and Tay have been pent up.
Proofs of the Sea having occupied a higher level.
In support of this opinion, we have the most unequivocal proofs of the waters of those friths having formerly occupied a much higher level. Of these we may notice the general appearance of their water-worn shores, and a bed of oyster-shells near Borrowstounness, which has been traced to the extent of three miles in length, and about two fathoms in thickness, lying in their natural state, but now upwards of 35 feet above the present level of the sea. Under these circumstances, and many others which might be adduced, it is not improbable that the Bell Rock has at one time been connected with the opposite coasts; and when we consider the general waste of the land, which is apparent in all directions from the impulse of the sea, it may at least be concluded, that at no very remote period, the Rock has been of much greater superficial extent, and above the level of the highest tides. Nor need we be surprised that such changes upon this remote and insulated spot should have been lost sight of, owing to their gradual and almost imperceptible effects, compared with the short period of the life of man, and in absence of all testimony excepting that which is oral.
Plants.
With regard to the marine Plants which grow upon the Bell Rock, we may observe that the lower parts of it are covered with the stronger or larger sorts, as the great tangle, Fucus digitatus, the roots of which rarely appear above the water, while it is seen at the depth of several fathoms, growing with the greatest luxuriance, and has often been observed by the author from a boat in fine weather, as a means for ascertaining, by the direction of the leaf, the changes of the currents of the tide at the bottom. The Badderlock, or Henware, Fucus esculentus, is found only on the north-eastern and south-eastern extremities of the Rock, growing at low water-mark of spring-tides, and seems to prefer the most rapid currents of the sea, and places where the heaviest breach takes place. In such situations it grows in great abundance at the Bell Rock, where it has been measured of the length of eighteen feet, and of proportionally increased breadth. Perhaps some of these plants are of considerable age; but at the works of the Carr Rock Beacon, off Fifeness, it was found that the growth of the badderlock was so very rapid, that the plant attained to the length of seven feet upon the new building, in the course of the winter and spring months. The higher parts of the Bell Rock abound with the smaller fuci, as Fucus mamillosus, and F. palmatus, or common dulse. F. lycopodiodes, alatus, and coccineus, are found on the older stalks of the great tangle, and F. subfuscus and confervoides occupy the smaller pools. In some places, the rocks are rendered slippery with Ulva compressa and umbilicalis; and the higher parts of the Rock, and the basement or lower courses of the light-house, are so covered with Conferva rupestris, as to produce the appearance of a sward of grass.
Animals.
Of the feathered tribe of animals at the Bell Rock, we notice the shag, cormorant, and herring-gull, which sometimes rest upon the Rock when in search of codlings and other small fishes. It also formed the resting-place of numerous seals at the commencement of the operations of the Light-house, but these amphibious animals, as well as the birds, have now almost entirely left it. The common crab and lobster are sometimes found here in the crevices of the rock. The Lepas balanoides, or acorn-shell, the common limpet, mussels of a small size, and the white buckey or Buccinum lapillus, abound on the rock. The Actinia crassicornis, Asterias glacialis and oculata, are common. A minute crustaceous insect, called, by Dr Leach, Limnoria terebrans (Lin. Trans, vol. XI. p. 371.), appeared in great numbers in the submersed wood work of the temporary erections on the Rock.
Insect destructive to Timber.