CORALLOIDES, or Corals in a fossil state, belonged originally to that class of submarine plants commonly called Lithophyta. The parish of Kilbride affords several varieties. The Junci Lapidei are nor scarce at Philipshill, fig. 12. pl. XIX. They are generally imbedded in lime-stone or till, and lie parallel to one another. Sometimes a mass of them containing many thousands, or rather millions, is found in some quarries. Sometimes they are separable, but frequently not. They consist of perpendicular lamellæ, intersected horizontally, at small distances, which give them a radiated structure. Few specimens are thicker than a goose-quill. Whether fig. 13. is a distinct species, or only a variety, I shall not determine. The specimens are generally flat and branched: some of them retain what seems to be the remains of a cortex, as in the figure. Some specimens of the Astroitæ are found in a field near Crosshill: some of the radiations are about half an inch in diameter. The varieties, fig. 9, 10, 11. are beautiful o account of their denticulations, &c. They are very rare. The Fungites, fig. 6. pl. XX. affords a considerable number of specimens of various dimensions, from a quarter of an inch, to two inches in diameter. Internally they are of a radiated structure, arising from the regular intersection of perpendicular and horizontal lamellæ, of which they are mostly composed. They vary in colour according to the colour of the substance in which they are enveloped; generally the lamellæ are white, and the rest blackish. In their original state they adhered to stones, and other hard bodies in the bottom of the sea: for which reason the basis, or broad end, where the adhesion took place, retains the impression of the shape of the body on which it grew. The only instance I have met with of the adhesion, in a petrified state, is on the fragment of a shell, fig. 5. This peculiarity, as it confirms, without a doubt, the manner of their growth, adds no small value to the specimen from which the figure was taken.
THE Millepore is a very beautiful genus of the coralloides. It abounds in most of the lime quarries, not only in Kilbride, but in the west of Scotland. The specimens are in fragments, and commonly branched. They are from the thickness of a fine hair, to that of a large quill. Some specimens continue to adhere to the shells, &c. on which they were originally formed, as fig. 1. The pores are round, and of different diameters in the same specimen, fig. 2. which is greatly magnified. The extremities of the branches were originally round, as at a. The millepore is frequently spread on the surfaces of shells, entrochi, &c. like the Seratula pumila.
THE Escharæ, Retepori, or Fan coral, is another beautiful genus of Coralloides which abounds in Kilbride. It is found, with shells, &c. among till incumbent on lime-stone; and the specimens are generally lying flat, some of them covering a space of several inches square. They are commonly punctured on one side, as in fig. 3. and smooth on the other, as in fig. 4. Some specimens are very fine and close in the reticulations. Along with them is found a kind in which the whole surface is rough like a rasp or file. It spreads itself on shells, entrochi, &c.
OF these this part of the country affords but a small variety. The Plectronites, fig. 5. pl. XIX. is seldom larger than the figure: some specimens are partly worn away at the point. The Incisores, fig. 7, 8. are found along with the former in some quarries in Kilbride, and at Lochrig quarry1 in the parish of Stewarton. The specimens are seldom larger than the figure, but some of them less. The figures represent both sides. The edge is very sharp, and minutely striated or cut. The colour is generally white: in one specimen, however, it is bluish: the enamel is commonly in high perfection. The root is a dull grayish colour. It is a beautiful and scarce fossil. The teeth delineated fig. 4. are very singular. The fragment of the great tooth, broken off at a, shows a texture extremely compact. The enamel on it, and also on the smaller ones, b b b is of a brownish colour, and perfectly entire. Whether the substance c c is the root of the tooth, or part of the jaw-bone, I shall not determine: it is of a whitish colour, and not very compact. This curious fossil was found among schistus, in the quarry at Philipshill. The fragment fig. 6. is of the same kind of tooth: it is grooved like the other, and is of the same colour and texture. It was found in the till above coal, at Stonelaw. The tooth fig. 1. is probably a molares; specimens are found at the quarry at Philipshill so often mentioned already.2 It preserves little or no enamel, and is not very compact. Fig. 2. is the delineation of a fragment of a crustaceous animal; it retains a fine gloss. The specimen fig. 3. is supposed to be the petrified palate of a fish. The class to which the curious fossil, fig. 7. pl. XX. originally belonged, is not, so far as I know, determined. The specimens are in casts of iron-stone, sometimes found inclosed in iron-stone like a nuceus; at other times found among till along with marine shells, &c. Specimens are very rare.
I SHALL conclude the chapter with a few observations concerning the petrified exuviæ of the ancient ocean.
1. THESE once organized bodies are imbedded in various substances, as till, lime-stone, argillaceous free-stone, iron-stone and soft clay. It has been generally thought, that none of them existed in siliceous substances, or were ever petrified into that kind of earth. Some late discoveries, however, put a negative on that opinion. Several specimens of a siliceous substance, containing great abundance of shells, entrochi, &c. were lately found in the lands of Bogstoun,3 in the neighbourhood of Beith. The shells, which are inseparably united with the stone, are white, of a fine texture, and not of a sparry, but flinty appearance and fracture: the rest of the stone is blackish. Both strike fire copiously with steel. Specimens of a similar nature are found in a quarry at Bathgate.
2. BIVALVE shells, with both valves entire as when in life, are found imbedded in the same stratum, along with univalves, entrochi, &c.
3. BY far the gr4eatest number of specimens retain the shells, and many of them preserve evident marks of violent contusions, which they must have received in a living or recent state: and not a few of them had been worn by attrition, seemingly on the sea-shore.
4. FOSSIL shells, supposed to have been pelagiæ, as the orthoceratites, &c. are found along with shells that are believed to be littorales, as the limpet.
5. THESE remains of the ancient ocean become highly interesting, when we consider them as furnishing us with an undeniable proof, that the earth, in some remote period, underwent a very great change. It is certain that these bodies are not lapides sui generis, produced from the semina of shell-fish, &c. carried out of the sea, up into the air, by vapours, whirlwinds, &c. and afterwards falling down in rain, were deposited in the earth, where they arrived to the state in which we now find them. This was the belief of some naturalists of no small note. (Lithoph. Brit. p. 134.) It is evident, on the slightest attention, that these bodies possessed organization and life, in the same manner that shell-fish and other marine productions do at present. It is almost certain, that most of them lived and died in the places where now found; and that these places were once covered with sea. From this view of them some plausible theories of the earth have been formed; and a multiplicity of arguments drawn to illustrate the causes by which the great revolutions of the earth were brought about. Facts, however, are daily occurring which stand in opposition to most of these theories, and prove them to have been too hastily made. The more enquiries, unbiassed by theories, we make, and the greater number of facts that are undisguisedly related, the more able, surely, will mankind be to discover the phenomena by which the globe of the earth was thrown into its present state. I can say for my own part, that the more attentively I enquire into this subject, and the greater number of theories I consult, the more clearly I perceive the truth of the sacred theory given by Moses.
6. THE serious contemplation of these natural objects affords a great source of pleasure to an inquisitive mind. They exhibit, in clear characters, the wisdom and goodness of the Deity. They lead back our ideas to the most remote ages of time, when these, now petrified, substances answered, by their various functions, some important purpose in the scale of animated existence. It must afford rational pleasure to reflect upon the means by which these exuviæ have, for thousands of years, been preserved, without being totally destroyed: how some fragments as thin as paper, and equally fine with the hairs of our head, still retain their original shape and most minute configurations. A mind led into a train of thinking upon these curious parts of the natural kingdom of God, must enjoy more solid satisfaction, than can be procured from some of the more noisy pursuits in life. These objects, although heedlessly trodden under foot by the rustic and unthinking clown, are far from being useless in medicine, and some of the sciences: they open to the lovers of Natural History an extensive field for the most rational contemplation; and they raise the mind to grand and elevated conceptions of the Great Creator and Preserver of all things.