measures decline rapidly to the S.E.; but in traversing the lower grounds, where the greater portion of them have been actually proved, by boring, to lie in regular stratified order, they dip but about five inches in the yard to the above point of the compass. In regard to the quantity of coal, I may adduce the single fact of the vestigia of certain of its concomitants, of considerable thickness (say from three to eighteen feet), proved in the deep, being found throughout the whole of the longitudinal line of the bassets, bearing a proportion short of the coal vestigia there scattered. Reasoning from this fact*, in conjunction with coexisting evidence, it is demonstrable to a certainty that the latter are portions of a very considerable and valuable stratum of coal, occupying its individual station, as a part of the mass of stratification partially explored, and whose bassets, or vestigia, were evidently deposited at the same period and by similar means. As a concurrent proof that these vestigia have been carried but an extremely short distance from their respective beds, I need only remind the initiated (who are aware of the extraordinary chafing or decomposing power which impetuous waters exert upon some of even the hardest minerals brought from any distance) that the various freestones, shales, coal, &c., found at the crop, are not in the slightest degree worn by attrition: even of the binds, which are of an extremely friable, tender, and soluble nature, I have numerous specimens, whose angles and asperities are of the most acute description.

About 400 yards beyond the first basset another coal appears to the day; which, in some places, has been discovered two feet thick, and also accompanied by its immediate con

* An exactly analogous line of coal vestigia, and all its concomitants, varying from about 10 yds. to 30 yds. wide, traverses the new Leicestershire coalfield, in a direction due N.E. and S. W.; which vestigia are thrown up to the surface through the red marl formation; a very considerable thickness of which entirely conceals the superficies of the substrata (carboniferous) over a great extent of country. The important characters of these bassets were first noticed, examined, and appreciated by Mr. Williamson (an experienced practical coal discoverer and miner), who, placing that implicit confidence in them which experience in exactly similar evidence (or laws of nature) had taught him to entertain, was thereby encouraged to persevere in a long and tedious trial (by boring) for coal in Bagworth Lordship (made a few hundred yards to the west of the above line), which, after penetrating through about 103 yards of red marl, ultimately led to the discovery of the vast stores of coals now working there; and other collieries subsequently opened in the immediate vicinity. Accompanied by Mr. Williamson, the discoverer of the above coalfield, I have recently traced and very minutely examined the aforenamed carboniferous bassets, and found them, in every peculiar and essential character, precisely analogous to those which traverse this district.

comitants, and resting upon a clunch, the usual pavement of coal this has also an almost vertical dip to the S.S.E. Here, as in the first bassets, confusion and disorder are apparent; but this, as Williams asserts, in his History of the Mineral Kingdom, is common to all strata which, as in this instance, come in contact with the base of hills or other previously formed elevations.

In reference to the measures proved by boring, it may be necessary to state, that men of unquestionable judgment have not only recognised them as the identical strata represented by their vestigia at the surface or line of bassets, but pronounced them to possess, collectively, precisely the same mineralogical characters, &c., which so definitely distinguish the old coal formation. It may be important to remark, that, in the course of our penetrating the upper beds of this formation, marine exuvia were found tolerably abundant, but decreased until we arrived at, apparently, the old coal formation, where they entirely disappeared, and were succeeded by those of vegetables alone. The carbon, which gradually increased in the measures, was, in the last fifteen or twenty yards, extremely abundant; indeed, quite equal in quantity (as proved by the common process of washing) to any of the strata in the immediate vicinity of the coal beds of the explored coalfields. This lower series also contained two or three thin veins of coal, commonly called breeders. Can any thing be more clearly demonstrative of the total absence of the red marl (in this vicinity) from its assigned geological position? However, there appears nothing extraordinary in this circumstance, when we take into consideration the extremely variable thickness of all the secondary formations, and particularly the red marl, or new red sandstone, which, it is well known, is frequently found terminating abruptly, forming thin beds, or swelling into considerable thickness, in the comparatively short space of a square mile or two.

To revert to the fact of the bassets of the coal and all its concomitants, accompanied by the characteristic fossils of the old coal formation, traversing this district in a direct line: whether they result from igneous or aqueous causes; whether they are calculated to break or disarrange the concatenations of the modern system, or whether they can be reconciled thereto, I leave to the learned to determine. That the

After this interesting enquiry had been prosecuted to the depth of more than 100 fathoms, it was unfortunately terminated by the introduction, by some malicious person, of a quantity of iron and steel into the boring-hole.

facts are substantial and stubborn ones, I am fully prepared to prove, and I shall also be most happy to give ocular demonstration of all that I have advanced respecting the geology of this neighbourhood.

In the contemplation of unanticipated or unpalatable truths, the determined sceptic and uncompromising systematist should ever bear in mind that there are many phenomena in the magnificent arcana of nature which the accumulated wisdom of ages, even to the end of time, shall fail to demonstrate; that "the book of nature," as Bishop Pontoppidan observes, "contains many leaves which no mortal ever yet perused;" and, consequently, it behoves the votaries of system, who aim at perfection, so to construct their scientific temples that the admission of any of the unexplored truths contained in her sacred pages may not sap their foundation, nor disturb the general harmony of the structure. That this would be a hard task is admitted; but, in contemplating the extreme jealousy and pertinacity sometimes evinced by the privileged few who are permitted to assume the banner of science, one can scarcely resist the inclination to indulge in such reflections. In a complex subject like geology, the abstruse disquisitions of the theoretic must ever remain subservient to the actual discoveries of the practical. However at variance such discoveries may happen to be with the previously adopted notions, prevailing opinions, or vested interests of individuals or societies, they will ultimately, despite of every disparagement, prevail, and find their way into the stores of public knowledge; where unshackled liberal and inquisitive minds will appreciate them according to their worth, and where, perchance, they may occasionally merit to be received as new data, whereon to found speculations and enquiries which may ultimately tend to the farther developement of science and the extension of national wealth.

Coplow House, Leicestershire,

Nov. 18. 1833.

J. HOLDSWOrth.

THE Geological Museum of Gideon Mantell, Esq., of Lewes, of which an account is given in III. 9. to 17., VI. 75., is about to be transferred to Brighton. Mr. Mantell, after twenty years' extensive and successful practice in the medical profession in the eastern side of Sussex, is removing to Brighton; where we trust that, consistently with his professional engagements there, he will make some arrangements which may allow scientific enquirers to visit his museum, without any sacrifice of his own time.--ttt

ART. XI. Some Observations on a very interesting Aurora Borealis, witnessed at Hull on the Evening and Night of October 12. 1833. By GEORGE H. FIELDING, Esq. M.R.Č.S.L., Member of the British Association for the Advancement of Science, Treasurer and Hon. Curator of Comparative Anatomy to the Hull Literary and Philosophical Society, &c. &c.

On the evening of Saturday, Oct. 12. 1833, we had the most brilliant exhibition of the aurora borealis I have ever seen. The evening was remarkably bright and clear; the sky presented a deep blue tint, and the stars were uncommonly brilliant; the air felt sharp, the temperature being about 40°; the pressure of the atmosphere 29.832; the wind rather brisk, and from the north-west. At half past 8 P.M. there was a broad, irregular, semicircular belt of vivid white light, stretching across the northern hemisphere of the heavens. The span of the arch was from 70° to 80°, its upper edge reaching as far as the star Eta in Ursa Major, about 18° above the horizon; and the breadth of the belt, which varied, I should state to be about 5°. It was exactly similar to a rainbow in shape, but of pure white light.

Below the bow I at first thought there was a dark black cloud; but, on minuter investigation, I found this to be a deception, caused by the extreme brilliancy of the aurora, which threw the surrounding medium into shade, and obscured the lustre of the fixed stars so much as to make them seem blue. By degrees the arch extended itself towards the zenith, and included the whole constellation of Ursa Major: it also gradually filled up the concavity down to the horizon, until it finally presented the magnificent appearance of an arc of an immense globe of fire.

During the whole time of my observation, brilliant radii were shooting up towards the zenith from the convexity of the arch, sometimes broad, sometimes narrow, sometimes vanishing immediately, and at others remaining visible for a minute or more, to an altitude of 60° or 70°, and seeming like pillars of flame. The radii mostly disappeared at or before they had attained, an altitude of 90°, but might occasionally be traced in very narrow wavy streaks into the southern hemisphere.

The most extraordinary appearance, however, was a rapid undulatory motion, accompanied with frequent brisk flashes*,

* These flashes resembled, both in duration and colour, the silent lightning frequently seen in the horizon on warm summer evenings, apparently at an immense distance, and when not a cloud is visible.

I cannot but consider the aurora as an electrical phenomenon, and think that, were it not at such a remote distance, we should have explosions audible as in a thunder storm. This, however, is mere conjecture; but I

which extended through the whole length of the curve. These immense flashes reached an altitude of 80° or 90°, and were often divided into numbers of square portions, or flashes, separated by broad dark lines. This singular phenomenon I should judge to be owing to the intervention of patches of dense vapour between me and the aurora; and, as not a cloud was visible during the interval between the flashes, and as the stars preserved their brilliancy, the height of the aurora must have been immense.

As a diagram, however rough, excels description in these matters, I add a slight sketch (fig. 22.) of the appearance when the square masses were given off.

I think the exhibition was the most splendid about 10 P.M., although it continued very beautiful till after 2 A. M. There was not the slightest corresponding appearance in the south, nor could I distinguish any sound I could attribute to the aurora: in fact, the latter is perhaps hardly to be expected, as the mean distance of the aurora from the earth, as calculated from the observations of twenty different philosophers in the same century, is, according to Sir Richard Phillips, 500 miles; the distance observed varying from 100 to 1000 miles.

With respect to the very remarkable changes in the weather, and especially in the temperature, which immediately followed this certainly uncommon exhibition of the aurora in these latitudes, and which I am about to detail, a large share, in the absence of any other known cause, may fairly be attributed to this phenomenon. During the night the temperature fell to 34°, being the lowest degree of cold I have registered

hope soon to see the matter fully explained, as Captain Ross (whom I had the pleasure of seeing immediately on his arrival at Hull, after his long absence and perilous adventures) himself informed me he had obtained ample and satisfactory information respecting it and its causes.