it*. I therefore published on the 1st of January of the following year (1824) a historical statement respecting the liquefaction of gases †, the beginning of which is as follows: "I was not aware at the time when I first observed the liquefaction of chlorine gas, nor until very lately, that any of the class of bodies called gases had been reduced into the fluid form; but having during the last few weeks sought for instances where such results might have been afforded without the knowledge of the experimenter, I was surprised to find several recorded cases. I have thought it right, therefore, to bring these cases together, and only justice to endeavour to secure for them a more general attention than they appear as yet to have gained." Amongst other cases the liquefaction of chlorine is clearly described. The value of this statement of mine has since been fully proved; for upon Mr. Northmore's complaint ten years after, with some degree of reason, that great injustice had been done to him in the affair of the condensation of gases, and his censure of "the conduct of Sir H. Davy, Mr. Faraday, and several other philosophers for withholding the name of the first discoverer," I was able by referring to the statement to convince him and his friend that if my papers had done him wrong, I at least had endeavoured also to do him right §.

Believing that I have now said enough to preserve my own "honest fame" from any injury it might have risked from the mistakes of Dr. Davy, I willingly bring this letter to a close, and trust that I shall never again have to address you on the subject.

I am, my dear Sir, yours, &c.

Richard Phillips, Esq., &c. &c.

M. FARADAY.

XC. On the Crag of Suffolk, and on the Fallacies connected with the Method now usually employed for ascertaining the relative Age of Tertiary Deposits. By EDWARD CHARLESWORTH, Esq., F.G.S.

To the Editors of the Philosophical Magazine and Journal. GENTLEMEN,

N former communications I treated of the crag as a tertiary formation consisting of separate marine deposits, and

Ibid., p. 236.

Monge and Clouet had condensed sulphurous acid probably before the year 1800. Northmore condensed chlorine in the years 1805 and 1806. † Quarterly Journal of Science, vol. xvi. p. 229. § Lond. & Edinb. Phil. Mag. 1834, vol. iv. p. 261. Third Series. Vol. 8. No. 50, Supplement, June 1836.

3 H

being desirous that the grounds upon which I have adopted this opinion should be fairly placed before those to whom the geological history of our own island is an object of interest, I propose in the course of the following observations to enter more minutely into the merits of that question.

An attempt has been made to explain the relation which the divisions of the crag bear to each other by assuming that the lower or coralline beds constitute the only original deposit, from which the rest of the fossiliferous strata above the London clay in Suffolk and the adjoining counties have been derived, by the operation of diluvial agents.

It may perhaps appear hardly necessary to enter upon the refutation of a theory which is so irreconcilable with recorded facts, but as it is desirable that no stumbling block should lie in the way of future investigation, I shall advert to some of the points which are especially opposed to its reception.

Until the subject was recently brought before the notice of the Geological Society, our available sources of local information respecting the crag and its organic remains were almost entirely confined to the published observations of Mr. R. C. Taylor and Mr. Samuel Woodward, the former of whom had paid great attention to the tertiary deposits of Norfolk and Suffolk, and to whose exertions, I believe, we are indebted for the first list of their characteristic fossils. I might, perhaps, reasonably inquire how far the diluvial character assigned to the red crag is consistent with the results attending my own personal investigation. For the present, however, I am anxious that your attention should be drawn to several passages occurring in the works of the above-named writers, and which are certainly calculated to throw some light upon the point at issue if the matter be really one requiring elucidation.

Mr. Taylor's interesting memoir on the geology of Eastern Norfolk was published in 1827, but his range of observation was by no means limited to the particular district which he there professes to describe. We find, however, no allusion to the Ramsholt stratum, although he had evidently extended his researches into the adjoining county and explored the coral reefs of Aldborough and Orford. A circumstance which appears to have particularly arrested the attention of Mr. Taylor during his investigation of the crag was the natural distribution of its fossil Testacea, the occurrence of which he points out in that part of the formation which we have lately been informed "is decidedly diluvium or disrupted crag." At page 15, he remarks, "it is characteristic of the shells and other organic bodies deposited with the crag, that they are by no means dif

fused in equal numbers and proportions throughout, but occur at intervals in groups and genera. Thus at Cromer the predominant and remarkable shells are Mactræ; at Runton, Cardia; nearer Clay, Murex striatus; at Bawdesey cliff, Murex reversus and Pectunculus; at the Beacon, Venus æqualis; at Felixstow, Pectunculus and Voluta Lamberti; south of Landguard cottage, Murex contrarius and Mya lata; at Bramerton and near Norwich are Murex striatus, Tellinæ, and Balani." There is no reference here made to Ramsholt, Sudbourn, or Aldborough; all the localities named in the above extract are those of the red or diluvial crag.

At page 23, Mr. Taylor observes, "that after the formation of the chalk the waters deposited the marine exuviæ, and gave existence during the long period in which they occupied that portion of its former surface to those remarkable accumulations of crag shells which we now witness." And again, at page 29: "A district bordering a hundred miles upon our eastern coast is occupied by an ancient marine deposit...... point exhibiting groups of shell-fish allied to those of the neighbouring sea, and at another composed of numerous genera which are neither to be recognised living in any part of our globe or assimilated to the fossil shells of other formations."

at one

I need not pursue Mr. Taylor's views any further, but would refer the reader to his work or to his previous papers in the Philosophical Magazine. The above quotations furnish ample proof that he had not discovered the diluvial nature of the red crag, although it was that part of the formation with which he was so intimately acquainted.

In 1833, Mr. Samuel Woodward published an outline of the Geology of Norfolk, in which we are presented with a brief notice of the crag, confirming the previous observations made by Mr. Taylor. At page 19, Mr. W. mentions that "the crag district is a narrow tract running southward from the coast between Cromer and Weybourn, and passing Norwich in its progress towards the Suffolk coast, the great deposit of this formation." Mr. Woodward, without suspecting that the deposit which he is describing is diluvium, proceeds to remark that "this tract appears to us to have been an estuary in the antediluvian period. .....Viewing the thick beds of testaceous remains, we cannot hesitate to admit that the sea occupied for a long period the part of Norfolk now under consideration."

Again, at page 21: "Another point worthy of attention is the apparent agreement in the gregarious habits of the original occupiers of these shells with the recent Mollusca, confining

them to particular spots or habitats; thus we find that the beds of crag shells are not continuous but deposited in patches; and that the shells in the Suffolk beds are in numerous instances generically and in almost all specifically different to those found near Norwich." No traces of the coralline crag have yet been detected in the county of Norfolk; it should therefore be borne in mind that the above observations refer solely to the upper deposit.

We are here furnished with the clearest evidence that Messrs. Woodward and Taylor agree in one important particular; viz. that the fossils of the red crag are not promiscuously jumbled together, but localized very much in the same manner as the Mollusca inhabiting our present seas: both geologists also infer from the great accumulation of these fossils that the ocean must for a long time have remained stationary over that district in which they occur.

In order then to maintain the decisions in reference to this subject which appeared in your Number for November, it will be necessary either to dispute the accuracy of the facts now adduced, or to show that this gregarious distribution of genera and species may exist in a formation resulting from those operations which we designate by the term diluvial. I willingly admit that the views of geologists as to the real nature of these operations are not of the most definite character, and at the present time our opinions respecting the true origin of what are called diluvial deposits are undergoing important modifications; but allowing the utmost latitude for any discordance of this kind, I apprehend that it will require more than ordinary ingenuity to show that the conditions which prevailed at the time when the formation of the crag was going forward can in any way be approximated to that state of things which is generally understood to be the necessary concomitant of diluvial action.

Those who are at all familiar with the geology of Norfolk, cannot fail to have observed that the crag, in common with other formations, has been subjected to the abrasion of diluvial currents. Mr. Taylor remarks that "portions probably from its western edges have been swept away. Their fragments mingled with those of the chalk and preceding formations, piled in enormous heaps, form the cliffs of Cromer and Trimmingham, 250 or 300 feet in thickness upon the original crag which rests in situ at their base.”

I imagine that it would not greatly increase the reputation of any geological observer to infer the diluvial origin of the Norfolk chalk, because its fragments in the shape of detritus occur in the cliffs at Cromer; but a precisely analogous fact has

been brought forward to support a similar opinion regarding the upper division of the crag.

A small series of shells which I had collected at Ramsholt were placed by Mr. Lyell in the hands of M. Deshayes, for the purpose of ascertaining his opinion with regard to the proportion of extinct species. The conclusion he came to was that the per centage of recent shells was the same as in the larger collection, which he had examined when preparing his tables on tertiary fossils, and which were probably obtained from the upper bed.

It is in allusion to this circumstance that a correspondent observes, "If such be the fact, there is an end to the question between my opponent and myself."

Now, the questions which have been under discussion are the presence of corallines in the Ramsholt bed, and the diluvial nature of the red crag. To decide these disputed points by simply ascertaining the per centage of extinct species in the shells of the coralline crag, can only have been effected by a course of induction as novel in its nature as the results which it evolves are important; nor shall I stand alone in anxiously anticipating further information upon the application of a principle, which in some instances may so materially assist the labours of the geologist while prosecuting the investigation of tertiary formations.

I turn however from the consideration of this subject, which is almost devoid of interest from its not having assumed a form that entitles it to serious discussion, to enter upon an inquiry far more comprehensive in its nature and requiring a more profound method of investigation;-an inquiry replete with the highest interest, from the practical suggestions which it offers, and still more so in the field which it throws open for legitimate inductive speculation.

I have on a previous occasion dwelt upon the features which separate the coralline crag from the tertiary strata with which it is connected. The novelty of its general aspect, lithological character, and organic remains when contrasted with the adjacent fossiliferous beds cannot be disputed. But the question may fairly be asked, what is the nature of these changes, and what are the conclusions to be drawn from them? Do they accord with those well-known phænomena which are supposed to register the lapse of ages; or may they not rather be attributed to certain alterations in physical condition, which over a small area may materially affect the existing organization during a comparatively short period?

I am aware that Mr. Lyell in the last edition of his Principles of Geology refers the red and the coralline crag to the