average. There is also a great inequality in the width of some zones over others on the same side of the tree; and those on the south are sometimes narrower than on the north: the former inequality is generally thought to be owing to a favourable or unfavourable season; but my own observations tend to discountenance such an opinion. I have several times fixed on a given ring, say the fifth, tenth, or twentieth, counting inwards from the one in contact with the inner bark; and, on comparing it with that of the same year's growth in sections from other trees, have found considerable discrepancies. The alburnum also passes very unequally into the duramen, or heart-wood; different portions of the same or of many contiguous rings being often found in each of these states.

My experiments tend to show that, while De Candolle's average makes old yews to be younger than they are, it gives too great an age to those of more recent growth. For the latter, I think, we should not allow less than 2 lines of their diameter for annual increase, where the trunk has a less circumference than 6 ft.; and even 3 lines or more, if the tree is in a warm situation and a moist luxuriant soil.

I have thought it desirable, at the risk of being tedious, to point out the several sources of error which attend the examination of the yew, that others may avoid them; though I strongly fear that no standard, either for old or young trees o. this species, will ever be found generally applicable, where the nearest approach to truth is required. Actual sections must be resorted to, before we can place any confidence in the result.* (To be continued.)

ART. VIII. Notice of the Occurrence of Volùta Lamberti on the Suffolk Coast; with Observations upon its Claim to rank with existing Species. By EDWARD CHARLESWORTH, F.G.S. It is in the study of fossil organisms, and in the cautious observance of the conditions under which they are presented

In taking the circumference of any old trees, and especially of the yew, whose trunk is often concealed by innumerable little shoots, and is subject to excrescences and inequalities, care should be taken to select that portion which has a medium thickness, and to pass the tape close to the bark; otherwise very erroneous results will be obtained. I had read somewhere that a yew in Llanfoist churchyard, Monmouthshire, had been measured by the writer, and was 33 ft. in circumference; I was therefore disappointed to find that this measurement must have included a great arm or bough that proceeds from the very base of the trunk on the south side, and therefore formed no part of it. Even with this bough, the circumference, at 3 ft. high, is only 27 ft. 6 in.; without it, the circumference of the real trunk, at the same height, is only 21 ft. 6 in.

to examination, in conjunction with those inferences which we draw from our knowledge of zoology and general physics, that the geologist finds the materials on which he speculates as to the changes and revolutions to which the surface of this planet has been exposed, and by which he chronicles the lapse of ages since the period when matter was first endowed with the principle of life. A careful consideration of the present condition of human knowledge, and especially of those departments of research to which our attention is directed, with a view of elucidating many geological phenomena, would seem rather to indicate a narrowing of the boundaries of legitimate induction than an extension of generalisations.

Facts which bear upon any one subject cannot long accumulate without giving rise to numerous theoretical suggestions, and their reciprocal beneficial relation to each other is no longer a matter of dispute. Theory is often the great incentive to observation, the main stimulus to exertion, and the more widely those who are engaged in the prosecution of the same object differ amongst themselves as to the nature of their present conclusions, the greater, perhaps, would be the reliance which we should feel disposed to place in any points of common agreement that may hereafter be attained.

But, although the progress of modern discovery may have a tendency to shake our confidence in some of the inferences which have been based upon the study of organic remains; and though the practical geologist may, perhaps, find that the recognition of contemporaneous rocks through the medium of their embedded fossils is open to wider limits of error than he had previously supposed; still, the zoologist must always find a source of never failing interest in the examination of these records of remote eras, and in the new structures and new types of form which are there presented to his view.

The early readers of this Magazine will doubtless remember a series of highly interesting essays which appeared in its pages upon Fossil Zoology and Botany, in connexion with some general views on Geology, written by a most active and enterprising member of the Geological Society of London, Mr. Richard Cowling Taylor. In now taking up a department in natural history, the importance and interest of which have been so ably illustrated in those papers, my intention is occasionally to notice such fossils contained in my own collection, or the cabinets of others, as appear to me worthy of observation, either from their novelty as specimens, or from their suggesting any new considerations in a geological or zoological point of view.

The Voluta Lambérti of the crag (fig. 7.), one of the most

elegant British tertiary fossils, must be familiar to those who are acquainted with the works of Parkinson and Sowerby; and it therefore possesses no interest on the score of novelty; but there are some very curious points connected with its history which are not generally known, and to which I am particularly anxious attention should be directed. Specimens of this shell are not uncommon in the cabinets of collectors, but I believe that few of the possessors are aware of the sources from which they are generally derived. Nine tenths, or, perhaps, a still larger proportion of the whole number that I have seen, instead of coming, as is usually thought, from the crag, have been taken from the beach along the Suffolk coast, and principally at Walton and Felixtow, two adjoining localities (a few miles east of Harwich), where they are generally found at the time of very low tides.

The mere occurrence of this fossil under the circumstances above mentioned would not in itself excite our surprise, since it is known that rivers in their course carry down to the sea such species of land shells as inhabit their banks; and where the crag is intersected by estuaries, the fossil shells would, from similar causes, be liable to be swept down into the German Ocean, and we should then naturally expect to find some of them washed on shore in common with the shells of recent Mollúsca. But, as the case really stands, there are two difficulties to be explained: first, the great number of these littoral volutes; and, secondly, the different state of preservation which they exhibit, when contrasted with such specimens as are actually taken from the crag deposit. Speaking of this volute, Parkinson says, "the most rare shell of this genus found in this island is the fossil volute of Harwich" (Organic Remains, vol. iii. p. 56.); and certainly it is not by any means a shell of very common occurrence in the deposit to which it is always referred; and, when found there, it is generally in so fragile a state, that tolerably perfect specimens are hardly ever obtained. But from one of the soldiers' wives at the Fort, on the Suffolk side of Harwich harbour, I have obtained more of these littoral volutes, than all the specimens put together that I have seen from the whole extent of the crag formation; and the shells thus found are not only often much larger than those in the crag, but many of them appear to have undergone scarcely any change, save the loss of colour; in fact, were they not almost as strong as recent shells, they would stand but little chance of reaching the shore, unless in fragments, which is, of course, the case with a great many of them.

In a succeeding paragraph to that which I have already

quoted, Parkinson observes, "A very fine fossil shell, bearing much the form of this volute, is found in some parts of Yorkshire; I believe in the neighbourhood of Whitby. This shell is so perfect, and its colours are so well preserved, that a specimen of it having fallen some years since into the hands of Mr. George Humphries, he was deceived into the opinion of its being a dead shell; and being satisfied that it was of a species which was entirely unknown, he cleaned and polished it as a recent shell, and was not undeceived, until, at a subsequent period, he saw another specimen, by which he was enabled to ascertain its being really a fossil."

So long a time has elapsed since the above was written, that I have not been able to gain any more information respecting the shell here spoken of; but I can only conjecture, from Mr. Parkinson's account, that it was one of these fine volutes thrown on shore at Whitby. The fact is certainly highly interesting, considering the great distance between the two localities, unless we suppose that the shell was transported from the Suffolk to the Yorkshire coast. Mr. Humphries is not the only individual who has been misled in this way; a similar instance has come under my own observation; and, indeed, some of these shells have such a recent character about them, that a naturalist totally ignorant of the species indigenous to the British seas might perambulate our eastern coast and meet with a specimen of the Volùta Lambérti without suspecting it to be other than a dead shell of a living mollusc.

Now, it is very possible that those shells, which have undergone so little alteration in character, may have been removed from the crag before the process of mineralisation had taken place to any considerable extent; or we may imagine that there existed a comparatively recent fossiliferous stratum in which this particular species was abundant, and of which all traces are now entirely destroyed. Without entering largely into details to show the plausibility of the latter suggestion, I may remark that, from a careful examination of the deposits upon our eastern coast, I anticipate a considerable change in the opinions which geologists have usually entertained respecting them, when their history shall have been more fully investigated.

The tertiary shells brought from Suffolk and the neighbouring counties have so invariably gone under the appellation of " crag fossils," that it is no very easy matter for a geologist who has not personally examined the numerous localities in which they occur, to divest himself of the impression that they all belong to one definite deposit.

The shells figured in Sowerby's Mineral Conchology were