ture is quite obliterated, and the ligneous origin can barely be inferred from very slight traces of annual rings. Some parts have a fibrous structure, and are white and opaque. The fibres cohere so slightly in some portions, that they may be reduced to powder between the finger and thumb. In general, however, the fibres cohere more firmly as they approach the translucent part, and then the vegetable structure becomes very apparent.

In addition to the above specimens, I have in my possession other two from Van Dieman's Land. These are both Coniferæ, so that out of nine specimens seven are Coniferæ, and only two true Dicotyledons. As far as these nine specimens go, we may therefore infer, that in Van Dieman's Land the growth of coniferous trees at a period antecedent to the present state of things, was more frequent than that of the Dicotyledonous kinds. The same may be said with regard to the Coal and Lias formations of this island. In these deposits numerous specimens of petrified wood have been found, and, from a careful examination of these, I will venture to assert that the whole belong to the coniferous tribe. This opinion you will probably remember I mentioned to you, Mr Witham, and others, in the course of last summer, and I was then led to speak on the subject with some degree of confidence, from a recent investigation of the structure of the different kinds of trees at present growing in all the different climates of the globe. In order to obtain the requisite knowledge, I found it necessary to cut transverse sections of a great number of trees, and of such a degree of thinness, that the cellular, as well as the vascular, system might be distinctly seen. This labour I was obliged to submit to, in consequence of finding all the sections of wood figured in such works on vegetable anatomy as I could lay my hands on so imperfect, that no precise idea could be formed on the subject.

The structure of the Coniferæ differs so widely from that of the true Dicotyledons, that a single glance will in general enable us to distinguish the one tribe from the other. In the Coniferæ there is only one regular system of pores, resembling a piece of the most delicate network. Each mesh is bounded by straight lines crossing each other at nearly right angles, and the concentric lines of the meshes almost always approximate each other at the outer edge of each annual layer of the wood. This struc

ture is uniform throughout the whole tribe of Coniferæ, the only perceptible difference consisting of the dimensions of the meshes, trees of slow growth, as Taxus Baccata, having the finest texture. It may be right to mention, that in some of the Coniferæ, (not in all), there are occasionally circular openings to be seen, known to botanists under the name of Lacunæ. These, however, are very irregular in their distribution, sometimes occurring frequently, at other times not at all.

The structure of the true Dicotyledons consists of a system of vessels separated from one another by masses of cellular matter. The vessels or pores are always bounded by curve lines. In some trees they are circular, in others they are elliptical, and the degree of eccentricity of the ellipses in different trees is remarkably different. The elliptical pores are sometimes divided by one or two transverse partitions. In some trees the vessels are empty, and in other trees they are filled with a resinous or gummy-resinous matter. The size, form, number and arrangement of the vessels or pores differ so widely in different trees, that one species may be as clearly distinguished from another by the organic structure as by the shape of the leaves or the florification. As in the Coniferæ, the vessels generally become smaller as they approach the outer edge of the annual layers. In some kinds of trees the vessels are numerous, in other kinds they are sparingly bestowed; and it is worthy of note, that, in some kinds of wood of great strength and durability, as the oak, they are not only numerous, but also of very large dimensions.

The cells constituting the cellular portion of Dicotyledonous trees, have different forms and different dimensions in different kinds of wood. In the coarser kinds of mahogany for instance, the cells have a rhomboidal form. In some trees they are spherical, and in others the form is very irregular; but however the form may differ, it will in general be found that the smaller the cells the greater will be the strength of the timber. This is very strikingly the case with regard to the different kinds of elm. In the Scotch Elm the cells are smaller than in the English Elm, and these, again, are smaller than in the Dutch Elm; and it is generally known the timber of the Scotch Elm is better than that of the English, and that the Dutch Elm is good for nothing.

With regard to the two specimens of petrified wood from the tertiary formation of the Isle of Sheppey, I have only to remark, that they both belong to the coniferous family. One of them displays the concentric rings surrounding the pith very distinctly, but throughout the greater part of the mass there are only fragments of the reticular texture to be seen intermixed with calcareous spar, in the form of stellular radiated concretions. In the centre of many of these concretions there are a few meshes of the net-work of the wood, and which have probably disposed the calcareous matter to assume its present form.

These specimens, when in the woody state, have been penetrated by worms in a manner similar to what takes place at the present day, and the cavities so formed have been filled with calcareous spar and sulphuret of iron. Yours faithfully,

Professor Jameson, College Museum.

EDINBURGH,

March 5. 1831.

WM. NICOL.

Account of the Discovery of Bone Caves in Wellington Valley, about 210 miles west from Sydney in New Holland.

DR LANG of Sydney *, at present in this country, having communicated to us the following particulars, in regard to the remarkable bone-caves of New Holland, we hasten to lay them before our readers, as they are highly interesting in a geological view. A description of the collection of bones from these caves, mentioned in the following communication, will be given in our next Number. Among these remains of a former mammiferous creation, are bones of an animal very much exceeding in size any of the existing races in New Holland.

SIR,

Sydney, 21st May 1830.

I beg you will allow me to inform your readers that a discovery, which will doubtless excite very considerable interest

* We are delighted to learn that a College Academy is about to be established at Sydney. With such a man as Dr Lang as chief, it cannot fail to flourish, and prove beneficial to the Australian world.

in the scientific world, both in Great Britain and on the continent of Europe, has just been made in the interior of this Colony, by that very respectable Colonist and Magistrate, George Rankin, Esq. of Bathurst. The discovery I allude to is that of a great quantity of fossil bones, in a cave near the penal settlement of Wellington Valley, and about 210 miles west from Sydney.

The country in the neighbourhood of Wellington Valley is of limestone formation, and the limestone ridges are perforated by numerous subterranean caverns, branching off in every direction, and forming chambers of the most grotesque, and at the same time of the most imposing appearance. This remarkable feature in the physical conformation of that part of the territory is not peculiar, however, to the limestone ranges of Wellington Valley. Similar caves are met with in Scotland, in Yorkshire, and in other parts of Great Britain, on the continent of Europe, in North America, and in short, wherever limestone abounds.

In a late excursion to Wellington Valley, Mr Rankin visited and explored a remarkable cave, about two miles from the settlement, the existence of which had been known for a considerable time, and the entrance of which is in the face of the limestone range, on the south side of the river Macquarrie, by a gentle declivity. Immediately beyond the entrance, the cave in question expands into a lofty and spacious chamber, the roof of which is beautifully ornamented with stalactites, many of which, however, have unfortunately been broken off by the scientific barbarians of the neighbouring settlement. In beating gently with a hammer on the sides of the cavern, the sound in one part of it indicated the existence of another chamber separated from the first by a thin partition; and accordingly, on breaking through the thin dividing wall of limestone, a second chamber was discovered, though of smaller dimensions than the first. At the farther extremity of the first chamber, Mr R. discovered a downward passage, which he determined to explore, and which he found terminated in another cave or chamber, the entrance into which was by a precipitous descent. On lowering himself down into this third chamber, into which no mortal man had ever entered before (for the aborigines have a superstitious repugnance to entering any cavern, saying, Koppa, the spirit of

the caves in the aboriginal mythology, Koppa sit down there), Mr R. observed, to his very great surprise, a piece of bone lying on the floor of the cavern. It struck him at first that it might have belonged to some bush-ranger who had attempted to hide himself in the cave, and had subsequently died; but on a more minute examination, he discovered a vast number of other bones of various sizes, and generally broken, some strewed on the floor of the cave, but the greater number imbedded in a sort of reddish indurated clay along its sides. The rope by which he had lowered himself into the cavern had been fixed to what appeared a projecting point of the solid rock, but on its breaking off in consequence of the weight attached to it, it was ascertained to be a large fossil bone-the thigh bone, I conceive, of some quadruped much larger than the ox or buffalo, and probably of the Irish elk, the rhinoceros, or elephant.

Mr Rankin collected a small quantity of the bones, or rather fragments of bones, and has brought them to Sydney, with a view to their being forwarded to Professor Jameson, of the University of Edinburgh. They will doubtless excite much interest among the geologists of Great Britain, and will probably lead to interesting results, in regard to the geological history of this vast island. It may perhaps be deemed presumptuous for an individual, who has little acquaintance with the science of comparative anatomy, and none whatever with that of fossil osteology, to anticipate these results. But the discovery in question has developed certain facts of the utmost interest in regard to the past history of the continental island, from which certain inferences, which it would be difficult to dispute, are clearly deducible. These facts and inferences I shall therefore take the liberty to submit to your readers.

1. It is quite evident that the greater number of the bones in question are not those of animals of the species at present inhabiting this territory. The aborigines are very good authority on this point in the absence of such men as Professor Jameson, or Professor Buckland, or Baron Cuvier; for when shewn several of the bones, and asked if they belonged to any of the species at present inhabiting the territory, they uniformly replied, Bail that belongit to Kangaroo, Bail that belongit to emu, &c. &c.