With regard to these crustaceous mosses in general, it is worthy our regard, that in the economy of nature they answer singular and important uses. To an unobserving eye, no class of vegetables may appear more insignificant, or less adapted to advantageous purposes in the creation than these. This vulgar estimation of things is frequently erroneous; and it is certainly so in the instance before us. These minute and scemingly insignificant mosses serve, under some circumstances, to valuable purposes. No sooner is a rock left bare by the sea, but these lichens lay the foundation for its future fertility. Their seeds, which are presently brought thither by the winds, soon cover it all over. These corrupting, presently afford a soil sufficient to nourish other smaller mosses; which in their turn form one deep enough for larger plants and trees; and thus the rock becomes a fertile island.*

5. LICHENES FOLIACEI SCUTELLATI.

Such as consist of a more lax and flexible matter, formed into a foliaceous appearance, having the parts of fructification in the form of scutellæ.

Some of the plants of this division are interspersed with the former in some of the systems of botanic authors. In general this division contains the whole first series of the 2d order of lichenoides in Dillenius; the first division of the 2d series, and the latter part of the 2d division, of the same: it comprehends the lichenes imbricati and umbilicati of Linneus; and many of the placodium of Hill. The plants of this order are many of them not less common in England than the foregoing, on rocks, stones, old pales, trees, &c. Some adhere very closely to what they grow upon, and seem to be only foliaceous about the edges: others adhere but loosely, and are much expanded and divaricated, so as to form something like ramifications.

It was remarked, from Linneus's observation, that one of the crustaceous lichens was scarcely ever found growing but upon limestone rocks. On the contrary, the same author has observed of a foliose lichen belonging to this order, that it will thrive on all kinds of rocks except limestone rocks. This species Dillenius calls the common grey-blue pitted lichenoides. It is very common with us upon trees, old wooden pales, &c. as well as upon rocks and stones. It is the usnea cranii humani of the old materia medica. Linneus adds, that it will dye a purplish colour.

Hither likewise must be referred the cork or arcel, which is used by the

* Vide Econom. Natur. in Amæn. Acad. vol. ii. p. 17.-Orig.

+ Lichenoides vulgatissimum cinereo-glaucum lacunosum et cirrhosum Hist. Musc. p. 88. Lichenoides crusta foliosa superne cinereo-glauca, inferne nigra et cirrhosa scutellis nigricantibus. R. Syn. p. 72.-Orig.

‡ Lichenoides saxatile tinctorium foliis pilosis purpureis Raii Syn. p. 74, No. 70. Hist. Musc. p. 185. Lichen petræus purpureus Derbiensis Park. Theat. p. 1315. Lichen omphalodes Lin, Spec. Pl. 1143.-Orig.

Scotch and others to dye a purple or scarlet colour. The preparation of it is by powdering, and making it into a mass with urine. Parkinson tells us * the poor people in Derbyshire scrape it from the rocks, and make the same use of it. Mr. Ray adds to this account, that the Welsh, who call it kenkerig, have long been acquainted with this property, and have it in common use. The colour from this moss is but very dull; but if the same methods were taken to improve it as have been with the orchel, it would doubtless be rendered much better, and more durable. Linneus relates that there is an immense quantity of this moss about the rocks of the isle of Aland in the Baltic; where the good women themselves make a yellow dye with it from a simple decoction of the plant, without the addition of any saline article. He adds, that those who would heighten the colour, add a small quantity of roucou § to the decoction.

6. LICHENES ERECTI RAMOSI PLANI.

Such as consist of a firm tough matter, disposed into flat and thin ramifications growing erect, and bearing their scutellæ on the edges, surfaces, and at the extremities.

This division comprehends the flat branched tree-mosses of authors; many of the 4th order of Haller's lichens; the first part of the 2d division of series the 2d in Dillenius; and the platisma of Hill. The plants of this division grow upon old trees, especially in thick and unfrequented woods; some of them on rocks: they are many of them extremely common in England on all kinds of trees. As they were some of the most obvious, so they were some of the first lichens noticed by the old writers, by whom they were called lichenes arborum. The mosses of this order were substituted instead of the usnea in the composition of the pulvis cyprius. The very species, which was most frequently used for this purpose, was the channel-leaved lichenoides of Dillenius, || on account of its being easily reduced into a fine powder, of a good white colour. Yet others are doubtless as well adapted to the same purposes: and if it was of importance enough to employ them to any purposes of the like nature in our own country, they might be procured in sufficient plenty.

One of the plants of this order is applicable to the same uses as the Canaryweed, and is reckoned not much inferior to it: and as it is found in the same places, it is very often packed up with it in considerable quantities. Dillenius

*Park Theat. Botan. p. 1315.-Orig.

Flor. Lappon. p. 343. V.-Orig.

+ Raii Hist. Plant. p. 116.-Orig.

& Otherwise called arnotto.-Orig.

| Lichenoides coralliforme rostratum et canaliculatum. Hist. Musc. 170. Lichenoides arboreum ramosum angustioribus cinereo-virescentibus ramulis. Raii Syn. 75. Lichen calicaris Lin. Spec. Plant. 1146.-Orig.

It is truly

calls it the flat dyers lichenoides with longer and sharper horns. * and properly a plant of the lichen genus, though the older writers of the last century called it a fucus. They were led into this mistake by its having flat ramifications, and from its growing on the rocks by the sea-side. It is found in the East Indies upon trees, and is frequent on the coasts of the Mediterranean, as well as about the Canary Islands.

7. LICHENES PELTATI.

Such as consist of a tough or coriaceous matter, disposed into a foliaceous appearance; on the edges of which, in general, the parts of fructification are placed, in the form of flattish oblong bodies, in these mosses called shields or pelts.

This division contains the 3d series of the 2d order of Dillenius's lichenoides; the lichenes coriacei of Linneus; and several of the placodium of Hill.

That celebrated and well-known plant, the ash-coloured ground liverwort† of Ray belongs to this order. It is very common all over England on dry and barren ground; and indeed almost all Europe, and America too, seems to afford it in sufficient plenty, as we find it observed by almost all the botanic writers since Ray, who was one of the first that described it. The earliest account we have of its use for the bite of a mad dog is in the Phil. Trans. vol. 20, p. 49; (or vol. iv, p. 232 of these Abridgments) from Mr. Dampier, in whose family it had been a secret for a number of years. It was communicated first to Sir Hans Sloane, as a kind of fungus, or Jew's-ear; and at the request of Dr. Mead was some years afterwards received into the London Dispensatory. Scarcely any of the boasted specifics of former ages ever acquired so great reputation as this plant has done in modern times, for its prevalence against the bite of a mad dog; and the patronage of the late learned Dr. Mead made it sufficiently known throughout all the world. Happy would it be indeed if it fully deserved the high encomiums which have been bestowed on it. A great and eminent physician has doubted its efficacy at all in such cases; and it is well known that Boerhaave even laughed at it. Dr. Mead had certainly a high opinion of it: he tells us it never failed, through the course of 30 years experience, where it was duly given before the hydrophobia came on. Later instances have showed that it is not infallible, and Dr. Van Swieten's supposition is but too likely to prove

Lichenoides fuciforme tinctorium corniculis longioribus et acutioribus, Hist. Musc. 168. Platysma corniculatum, Hill Hist, Plant. 90. Lichen fuciformis, Lin. Sp. Pl. 1147.-Orig.

+ Lichenoides digitatum cinereum lactuca foliis sinuosis, Dillen, Hist. Musc. 200. Platysma sinuosum scutellis ovato-rotundis, Hill Hist. Pl. 89. Lichen caninus, Lin. Sp. Pl. 1149.-Orig. Dr. Van Swieten. See Comment, in Boerh. Aphor. § 147.-Orig.

§ Mechanical Account of Poisons, ed. 4th, p. 156.-Orig.

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true. It must be confessed that Dr. Mead's exhibition of it seems too much complicated with other means to leave room for judging fully of its real efficacy; and it may really be questioned whether bleeding, pepper, and cold bathing, have not had more to do in the case than the lichen.

The muscus pulmonarius officinarum, * tree-lungwort, or oak-lungs, belongs to this order. It is found about old oaks, and on rocks and stones overgrown with moss, in many of our thick woods in England; but not in any great plenty. Few perhaps of the antiquated simples were in more repute in their day than this plant. It was celebrated for ages, on account of its supposed prevalence in pulmonary complaints of almost all kinds; and yet on inquiry into the original of its use in such cases, it would probably appear that it arose more from a fancied resemblance they found in the plant to the lungs themselves, than from any real and well-grounded proofs of its efficacy. As a gentle astringent, like most other species of the family, it would doubtless contribute to relieve in many cases where the lungs were affected, as in hæmoptoes, and some others: but it does not seem by any means to deserve that high character in medicine which has been given to it.

CONCLUSION.

Dr. W. remarks, by way of conclusion, that we have in this genus of plants a convincing instance of the utility which may result from the study of natural science in general, and even of its minuter and hitherto most neglected branches. From a view of the foregoing memoir it is evident that the economical uses of the lichens, in the various parts of the world, are already very considerable and important; and though it does not appear that the sensible qualities of any of them, or the experience of former ages, will warrant our ascertaining any singular powers to them in a medicinal way, yet posterity will doubtless find the means of employing them to many valuable purposes in human life to us unknown. XCII. On the Fossil Bones of an Alligator, found on the Sea-shore, near Whitby in Yorkshire. By Capt. Wm. Chapman. p. 688.

In Jan. 7, 1758, was discovered on the sea-shore, about half a mile from Whitby, part of the bones of a large animal. The ground they laid in was what they call alum-rock; a kind of black slate, that might be taken up in flakes, and was continually wearing away by the surf of the sea, and the washing of stones, sand, &c. over it every tide. The bones were covered 5 or 6 feet with the water every full sea, and were about 9 or 10 yards from the cliff, which was nearly perpendicular, and about 60 yards high, and was continually wearing

Lichenoides pulmonium reticulatum vulgare marginibus peltiferis, Dill. Hist. Musc. 212. Lichenoides peltatum arboreum maximum, Raii Syn. p. 76. Muse. pulmonarius C. B.-Orig.

away, by the washing of the sea against it; and to judge by what had happened in his own memory, it must have extended beyond these bones less than a century ago. There were several regular strata or layers of stone, of some yards thickness, that ran along the cliff, nearly parallel to the horizon and to each other. He mentioned this to obviate an objection, that this animal might have been upon the surface, and in a series of years might have sunk down to where it lay; which would appear impossible, at least when the stones, &c. had taken their present consistence.

Where there is only the superior maxilla remaining, there are no teeth; but the sockets are visible and deep, and at the same distances from each other as the teeth in the other part of the jaw. The tip or extremity of the bill was entire for 4 or 5 inches, having both maxilla, with their teeth, and towards the point large fangs. Part of the bill and head were covered with the rock.

There were 10 vertebræ, from 3 to 4 half inches in diameter, and about 3 inches long, some of them separated in taking up. They were about 2 inches in the rock. There was observed something like bone to stretch from the vertebræ, and intending to take it up whole, begun to cut at what they thought a proper distance; but found they cut through a bone; and with the vertebræ brought up 3 or 4 inches of the os femoris, with the ball, covered with the periosteum : but the animal had been so crushed hereabouts, that they could make little of the socket or os innominata. Several of the ribs came up with the vertebræ : they were broken, and laid parallel to the vertebræ; but not quite close, there being some of the rock between them. The periosteum is visible on many of the bones. There were 12 vertebræ remaining in the rock, with which they are almost covered, especially towards the extremity.

The place where these bones lay, was frequently covered with sea-sand, to the depth of 2 feet, and seldom quite bare; which was the occasion of their being rarely seen: but being informed that they had been discovered by some people 2 or 3 years before, they had one of them with them on the spot, who told them that when he first saw it, it was entire, and had 2 short legs on that part of the vertebræ wanting towards the head. Though they could not suspect the veracity of this person, they thought he was mistaken; for they had hitherto taken it for a fish. But when they took it up, and found the os femoris above mentioned, they had cause to believe his relation true, and to rank this animal

among those of the lizard kind: by the length (something more than 10 feet) it. seemed to have been an alligator.