I.—The Insulation of St. Michael's Mount, Cornwall.
By W. Pengelly, F.R.S., F.G.S.

Read at the Spring Meeting, May 23, 1871.


THOUGH the "Mount" can never fail to be an object of great interest and of pride to Cornishmen, I might, in ordinary circumstances, have hesitated before venturing to make it the topic of a communication even to this Institution, seeing that I have already read three distinct papers on it to as many scientific societies—the British Association, at its meeting at Birmingham, in September, 1865; the Royal Institution of Great Britain, on April 5th, 1867; and the Devonshire Association, during its meeting at Barnstaple, in the following July.

The first was never printed by me or with my knowledge; but, as will presently be seen, a notice of it, and by no means a correct one, appeared in some newspaper. A full abstract of the second, prepared by myself, was printed in the Proceedings of the Royal Institution;1 and the third was printed in extenso, in October, in the Transactions of the Devonshire Association.2

On November 25, 1867, Mr. Max Muller, the eminent Professor of Comparative Philology at Oxford, read to the Ashmolean Society a paper on "The Insulation of St. Michael's Mount," [p.2] which, during the present year, he has printed in his Third Volume of "Chips."3 It was avowedly written to refute a conclusion to which the newspaper seems to have made me come and distinctly enunciate at Birmingham in 1865, but which, as is shown by the manuscript still in my possession, instead of advocating, I declared to be utterly untenable. The erroneous conclusion first ascribed to me by the newspaper, and then treated as mine by Professor Max Muller, was subsequently reiterated by a critic in the Saturday Review;4 and, as it is well known to be difficult, if not impossible, to overtake a misrepresentation, there can be little doubt that it may again and again be given as an instance of the danger of hasty conclusions.

Such are the circumstances which have induced me to write this, my fourth, paper on The Insulation of St. Michael's Mount.

In order to a clear understanding of the precise point on which Professor Max Muller supposed himself to be at issue with me, it may be well at this stage to give a brief summary of my Birmingham paper, read in 1865. Having described the Mount and its position, I formally enunciated the following assumptions:—

1st—That the Old Cornish Name of the Mount was Cara Clowse in Cowse.
2nd—That the Name had been correctly translated as The Hoar Rock in the Wood.
3rd—That the Name was appropriate when it was first given.
4th—(On the authority of Dr. Boase5 and Dr. T. F. Barham6)—

That Florence of Worcester expressly stated that the Mount was formerly five or six miles from the sea, and enclosed with a very thick wood.

Though fully aware that each of these assumptions might turn out to be untrue, I supposed them to have at least a fair amount of evidence in their favour, and therefore came to the inevitable conclusion that the insulation of the Mount must have taken place after the introduction of the old British language into Cornwall. No geologist can for a moment doubt that at a geologically very [p.3] recent time the Mount was permanently a peninsula; or fail to see that its present insulation must be ascribed either to the mere wasting of the coast of the mainland by the action of the waves, or to a more or less general subsidence of the district, attended, perhaps, by such wasting. There is no other alternative. As it was the object of my paper to prove that the latter was the true cause, I proceeded first to show that the rival hypothesis—insulation by encroachment without subsidence—could not be entertained; having been led to this conclusion by a personal visit to the spot and a careful study of its physical geography and geology. It was obvious that though the cliff at Marazion—the nearest point of the mainland—was but little calculated to resist the unbroken action of the waves, it was so effectually protected by the Mount from the only quarter whence very destructive seas could be sent—from S.W. to S.E.—that its recession would in all probability be so slow as to be scarcely appreciable. This conclusion was fully confirmed by the evidence of all the inhabitants with whom I conversed, as they assured me that in their time there had been no wasting of the cliff. It cannot be doubted, however, that the Marazion plain did formerly extend further towards the Mount, and it may possibly have reached it in some very remote antiquity. The former was evident from the fact that the plain terminated, not in a slope, but in a low vertical cliff, consisting of a sub-aerial accumulation of clay and angular stones. The cliff, moreover, was partially protected by a wall : but, on the other hand, though the space between it and the houses was very narrow, the wall itself was so slender as to show that it was neither intended, nor expected to be called on, to resist powerful attempts at encroachment. In fact, it seemed to be a protection against sub-aerial agencies rather than against violent waves. Moreover, several parts of the cliff were entirely undefended, and these had by no means retreated, even to the extent of a single inch, more than those protected by the wall.7


During the visit I encountered an intelligent native, who, though in his eighty-third year, was still active both in mind and in body, and who stated that within his recollection there had been no encroachment on any part of the cliff under the shelter of the Mount; but he added that at a short distance eastward "the sea had destroyed a great deal of land." On going with him to the spot, he pointed out an isolated rock on the tidal strand, which he said was so far in, and concealed by, the cliff when he was a boy of eight or ten years of age, that the portion of it which projected barely furnished him with a foothold from which, when bathing, he had frequently jumped into the sea at high water. From the data thus furnished I came to the conclusion that, where entirely unprotected by nature or art, the retrocession of the cliff had not exceeded twenty feet in seventy-five years; and that to suppose the Marazion cliff, from which the Mount cut off all destructive waves, had retreated at the average rate of ten feet in a century, would be to take a very high estimate. Taking this as a measure, and remembering that the distance from the mainland to the Mount is 1680 feet, it followed that the hypothesis of insulation by mere encroachment would require us to fix the date of the insulation at nearly seventeen thousand years ago. In other words, we should be at liberty to believe that about 150 centuries before the Christian era the permanent connexion of the Mount with the mainland was severed, but that immediately prior to that date it might have been a hoar rock at the end of a wood. To suppose it in, that is surrounded by, a wood, a further demand must be made on antiquity, such as would have sufficed for the wasting of the land from the sea-ward to the land-ward margin of the Mount. In short, on the assumptions laid down at the commencement, the hypothesis of insulation by mere encroachment appeared to demand the belief that at least twenty thousand years ago Cornwall was inhabited by a people who spoke a language which prevailed in the same district to within a very few centuries of our own time, and, from its similarity to the Welsh, might be said to be still spoken by a large population within our own island. Believing this conclusion respecting the antiquity of the old Cornish language to be totally untenable, I at once rejected it, and, with it, as a matter of course, the hypothesis of insulation by encroachment alone ; remarking of the latter that it squandered time most lavishly.


Turning next to the hypothesis of insulation through subsidence—the only alternative consistent with the assumptions made at the beginning—I proceeded to show that there had been a general downward movement of the land in geologically very recent times, and, as evidence of it, described the submerged forests so prevalent on both the north and south coasts of Devon and Cornwall, especially noting the fine and well-known description which, in 1822, Dr. Boasegave of the example in the Mount's Bay.8 I dwelt at some length on the fact that, whilst mere encroachment necessarily destroys and removes the land it wastes, subsidence may leave intact the soil it overwhelms; and, conversely, that when an old vegetable soil is found undisturbed beneath the sea, when the stumps of trees are found projecting vertically through and perpendicular to it, when roots and rootlets ramify from the trunks horizontally through the soil, when the plants are all of kinds still indigenous to the districts, and when such phenomena are met with in numerous localities throughout a wide area, there can be no doubt that there has been a general, tranquil, and in a geological sense, a very recent subsidence of the land.

Next, I pointed out that whilst, on the one hand, this change of level could not have taken place within the last 1,900 years, since, about 9 B.C., the Mount was described by Diodorus Siculus in terms which apply admirably to it at present; on the other hand, the vegetable and animal remains in the forests showed that it was what a geologist would call a very recent event. In short, the evidence then before us, was such as to compel the belief that the insulation of the Mount had taken place before the Christian era, but such also as to permit the belief that the event might have occurred not very long before that time.

The paper concluded thus:—"A careful consideration of all the facts of the case, as well as of the related phenomena, points decidedly to the conclusion that, since Cornwall was inhabited by a race speaking the British language, St. Michael's Mount was a 'hoar rock in a wood,' and that its insulation resulted from a general subsidence of the country."


After reading the paper just sketched, I devoted a considerable amount of attention to the literature of the question, as well as to the physical phenomena in Devon and Cornwall to which it was related; and was enabled to state in the Royal Institution lecture, in 1867, that the tradition of the Mount having been five or six miles from the sea and enclosed in a very thick wood, was first mentioned, not, as I had been led to suppose from the writings of Dr. Boase and Dr. T. F. Barham, by Florence of Worcester, who died in A.D. 1118, and nowhere mentions the Mount, but by William of Worcester, who visited Cornwall about A.D. 1478, or 360 year's further from the period to which the tradition pointed, thus rendering the tradition itself of little or no value; that the alleged old Cornish name assumed so many forms, and there was so much uncertainty about its exact import, as to render it improbable that it had any value as evidence; and that the submerged forest in Mount's Bay was known much earlier than I had supposed, as it was mentioned by Leland (1533-40), who also spoke of the similar forest in Torbay.

The printed abstract of this lecture, prepared by myself, closes with a Recapitulation containing the following passage:—"Nineteen centuries ago it" (the Mount) "possessed a safe harbour, so that its insulation must have been effected long before. It was at one time unquestionably 'a hoar rock in a wood,' but in all probability it had ceased to be so long before any language now known to scholars was spoken in the district. Prior to its insulation was the era of the growth of the forests now submerged along our entire sea-bord," &c.

In the paper read at Barnstaple, in July, 1867, I was able to make the following further corrections:—that the British name of the Mount was neither first mentioned by Carew in 1602, as was commonly believed, nor did it in its earliest known form contain any reference or allusion to a wood, since Norden mentioned it, probably in 1584, and Camden certainly in 1586, both giving it as Careg Cowse, which the first translated Grey rock, and the second rupis cana; that the name occurs in two different forms in Carew—Car a Couz in Clowze and Cara-Clowse in Cowse—each of which he translates in the same way—The hoary rock in the wood;—and that, as there was no Pope Gregory in the year 1070, there must be some error in the following statement made by William of Wor- [p.7] cester:—"Pope Gregory, in the year 1070," granted to "the Church in the Mount of St. Michael in Tumba in the county of Cornwall .... that all the faithful who enriched the Church with their benefactions and alms, or visited it, should be forgiven a third part of their penances." "These words," he continues, "were found in ancient registers lately discovered in this Church," and "they are publicly placed here on the doors of the Church."9

Returning now to the first of these papers—that read to the British Association, at Birmingham, in 1865—it will be remembered that the point of my argument was, that the hypothesis of the Insulation by mere encroachment could not be admitted, because it led to the conclusion that twenty thousand years ago the old British language was spoken in Cornwall, which was absurd. Unfortunately, the newspaper reporter, failing to see that I was using the reductio ad absurdum, with a delightful innocence, supposed, and informed the world, that I had contended for the twenty-thousand years antiquity of the Cornubo-British language. No one who reflects on the facts that scientific language is necessarily technical, and that newspaper reporters are rarely familiar with it, since it is seldom required in their profession, will be unprepared for errors of this kind; and every one who has watched newspaper reports of scientific papers or lectures must be acquainted with many examples of it.

The first intimation which reached me of the error in the newspaper report of my paper was through the Rev. Dr. Bannister of St. Day, Cornwall, who, being so good as to send to Notes and Queries10 a reply to questions I had asked in its pages, concluded thus:—"I should like to ask Mr. Pengelly if he was correctly reported in the newspapers, which made him say at the Birmingham Congress that '20,000 years ago Cornwall was inhabited by a Cornish-speaking people.'" Thinking the matter of little or no public interest, I sent Dr. Bannister a private reply, containing the true state of the case.

The unfortunate newspaper report appears to have fallen into the hands of Prof. Max Muller, who, less cautious than Dr. [p.8] Bannister, at once, and without question, accepted it as correct; as he says, "In his paper read before the British Association .... Mr. Pengelly adduced that very name" (Cara dowse in cowse) "as irrefragable evidence that Cornish, i.e., a Celtic language, an Aryan language, was spoken in the extreme west of Europe about 20,000 years ago."11 So startling a statement was undoubtedly calculated to rouse so eminent a philologer, and, accordingly, he set himself to work to demolish it, not, however, before he must have known that I had been incorrectly reported, or, if not, had recanted, for it is obvious that before writing his paper he had in his possession a copy of the authorized abstract of my Royal Institution lecture in April, 1867, since he avowedly quotes it, though not quite correctly, at the commencement of his paper. Indeed, he states that "In his more recent paper Mr. Pengelly has given up this position" (the 20,000 years antiquity of the Cornish language), "and he considers it improbable that any philologer could now give a trustworthy translation of a language spoken 20,000 years ago."12 Notwithstanding this, however, he proceeds in his work of demolition, and, it must be confessed, with such eminent success as to render it impossible, if any one ever did hold the heresy, for him to do so again. For myself, I am heartily delighted to find that the conclusion which from the first I held to be utterly untenable, has been pronounced by the distinguished Oxford Professor to be one "which would completely revolutionize our received views as to the early history of language and the migrations of the Aryan race."13

Instead of following the learned Professor step by step through his paper, it will be sufficient in this place to state, in passing, that he recognizes the Mount as the Iktis of Diodorus Siculus, remarking that it "was at last admitted even by the late Sir G. C. Lewis";14 accepts the charters of Edward the Confessor (1044),15 and of Leofric Bishop of Exeter (1088);16 declines the assertion of Sir Henry James that there are trees growing on the Mount in sufficient numbers to have justified the ancient descriptive [p.9] name of the 'Hoar rock in the wood';17 and addresses himself mainly to the following topics:—(1) The dense forest mentioned by William of Worcester as having at one time surrounded the Mount, (2) the alleged British name of the Mount, and (3) the translation of the said name. The results of his investigations on the last three points may be best given in his own words:—

"And here we find—

(1) That the legend of the dense forest by which the Mount was believed to have been surrounded existed, so far as we know, before the earliest occurrence of the Cornish name, and that it owes its origin entirely to a mistake which can be accounted for by documentary evidence. A legend told of Mont St. Michel" (in Normandy) "had been transferred ipsissimis verbis to St. Michael's Mount, and the Monks of that priory repeated the story which they found in their chronicle to all who came to visit their establishment in Cornwall. They told the name, among others, to William of Worcester, and to prevent any credulity on his part, they gave him chapter and verse from their chronicle, which he carefully jotted down in his diary."

"(2) We find that when the Cornish name first occurs it lends itself, in one form, to a very natural interpretation, which does not give the meaning of 'Hore rock in the wodd,' but shows the name Cara cowz in clowze to have been a literal rendering of the Latin name 'Mons in tumba,' originally the name of Mont St. Michel, but at an early date applied in charters to St. Michael's Mount."

"(3) We find that the second form of the Cornish name, viz., cara clowse in cowze may either be a merely metamorphic corruption of cara cowz in clowze, readily suggested and supported by the new meaning which it yielded of 'grey rock in the wood;' or, even if we accept it as an original name, that it would be no more than a name framed by the Cornish-speaking monks of the Mount, in order to embody the same spurious tradition which had given rise to the name of 'Hore rock in the wood.'"18

The Critic in the Saturday Review, already mentioned, whilst looking on the Professor's "explanation as perfectly successful," [p.10] takes exception to his recognition of the Mount as the Ilrtis of Diodorus, and to his acceptance of the charters just spoken of: stating that "the Charter of Edward the Confessor referred to in p. 343 is quite impossible, and, if there be degrees in impossibility, those quoted in p. 339 are more impossible still. In them Bishop Leofric and Queen Matilda are made to sign charters some years after their deaths, and Leofric is made to act by authority of Gregory the Seventh, who did not become Pope until after Leofric was dead."19 The question of the Mount and the Iktis will be noticed in the sequel.

The passages in Professor Max Muller's paper which have decided me to write once more on the subject, are the following:—Having referred to the notices of the submerged forest in Mount's Bay, by Borlase in 1757, Carew in 1602, and Leland (misprinted Lelant) in 1533-40, and having pointed out that the first "tells us that these forest trees were not found round the Mount, but midway between the piers of St. Michael's Mount and Penzance, that is to say, about one mile distant from the Mount,"20 he thus proceeds:—"It is quite possible that the remains of trunks of trees may still be found on the very isthmus between the Mount and the mainland; but it is, to say the least, curious that, even in the absence of such stringent evidence, geologists should feel so confident that the Mount once stood on the main- land, and that exactly the same persuasion should have been shared by people long before the name of geology was known. There is a powerful spell in popular traditions, against which even men of science are not always proof, and it is just possible that if the tradition of the 'hoar rock in the wood' had not existed, no attempts would have been made to explain the causes that severed St. Michael's Mount from the mainland.''21

Again: "The only question which, in conclusion, I should like to address to geologists, is this. As geologists are obliged to leave it doubtful whether the insulation of St. Michael's Mount was due to the washing of the sea-shore, or to a general subsidence of the country, may it not have been due to neither of these causes, [p.11] and may not the Mount have always been that kind of half-island which it certainly was 2,000 years ago!"22

The spirit of the passages just quoted will, it is believed, be found in the following queries:—

I. If the tradition of the ''hoar rock in the wood" had never existed, would geologists have ever entertained the idea that the Mount was once permanently a part of the mainland?
II. May not the Mount have always been that kind of half-island it is at present?
III. If at some early period it was severed from the mainland, have not geologists been obliged to leave it doubtful whether its insulation was due to the mere wasting of the sea-shore, or to a general subsidence of the country?

These queries I will now attempt to answer.23

I. It is, of course, not improbable that the tradition spoken of first called attention to the geological causes to which the present geographical character of the Mount was due; nor, on the other hand, is it impossible that the tradition may be a somewhat rudely philosophical interpretation of observed geological facts. The earliest mention of the tradition was that by William of Worcester, and was made in 1478, according to Dr. Oliver.24 Leland, the next author who noticed the Mount, writing about fifty years after, mentions the tradition of loss of area—without, however, alluding to any supposed change in the geographical condition of the semi-island—and states, that "In the bay betwyxt the Mont and Pensants be found neere the lowe Water Marke Rootes of Trees yn dyvers Places as a token of the Grounde wasted;"25 and thus furnishes, whether he understood it or not, good geological cadence of subsidence and an early continental condition of the Mount. It cannot be denied that the tradition, as before hinted, may, perhaps, have [p.12] had this submerged forest as its primary basis; but if it can be shown that the tradition is older than any knowledge of the forest, the fact will in no way detract from the value of the latter as evidence.

II. It is but fair to state that, Professor Max Muller makes no pretensions to geology, and that he does "not venture to touch the geological arguments."26 It is not surprising therefore that the question he puts to Geologists, as such,—"May not the Mount have always been that kind of half-island which it certainly was 2,000 years ago?"—must be met with a clear and an unqualified "Nay.'' In order to a full appreciation of the grounds on which this answer rests, it will be necessary to give here a somewhat detailed account of the geology and geography of the Mount.

It is well known that the Mount is an island at every high water, and, with rare exceptions, a peninsula at every low water. Its distance from Marazion cliff—the nearest point of the mainland—to spring-tide high-water mark on its own strand is 1,680 feet, as Col. Sir Henry James kindly informs me. The tidal isthmus consists of the outcrop of highly inclined Devonian slate and associated rocks, and, in most cases, is covered with a thin layer of gravel or sand. At spring tides, in still weather, it is at high water twelve feet below, and at low water six feet above, the sea-level. In fine weather it is dry from four to five hours every tide; but occasionally, during very stormy weather and neap tides, it is impossible to cross for two or three days together. The Mount is an isolated mass of granite, measuring at its base about five furlongs in perimeter, as I am obligingly informed by Mr. J. P. St. Aubyn; and rising to the height of 195 feet above mean tide, according to Sir H. De la Beche.27 At high water it plunges abruptly into the sea, except on the northern or landward side, where the granite comes into contact with the slate, into which it sends veins and dykes, as may be well seen on each side of the harbour. Here there is a small plain occupied by a village, adjacent to which is the harbour, built in 1726-7, and, as Mr. Johns, the harbour master, has been so good as to write me, capable of receiving ships of 500 tons burthen.


The country immediately behind, or north of Marazion, consists of Devonian strata traversed by traps and elvans, and attains an elevation of about 200 feet. The town stands on a small plain terminating in a cliff from twelve to twenty feet high. Judging from this cliff, the plain is a sub-aerial accumulation of fragments of rock derived from the adjacent hill, and embedded, without any approach to regularity of arrangement, in a yellowish clay, forming probably no more than from 30 to 40 per cent, of the entire mass.

The most important points in the foregoing description, in connexion with our present enquiry, are, 1st. The materials of the Mount. 2nd. The relative level of the isthmus and the sea.

1st. The Mount consists almost entirely of granite; a rock which all modern geologists hold to be of Plutonic or Hypogene origin: in other words, a rock which was not, and could not as such, have been formed at the surface of the earth, but was elaborated beneath an overlying mass of rock of some other kind, which was stripped off by subsequent denudation before any part of the granitic mass could have been exposed at the surface of the earth.

The thickness of this superincumbent mass it is probably impossible even to guess, but Mr. Sorby has, by a very refined method, estimated the pressure under which the St. Austell granite was formed as equivalent to 32,400 feet of rock vertically, that of the mean of the Cornish granite to 50,000 feet, and the granite of Ding Dong Mine near Penzance to 63,000 feet.28 As this pressure was in all probability due to the expanding power of heat beneath or within the granitized mass, it is not necessary to suppose the overlying rocks, the function of which was resistance, had a thickness even distantly approaching these figures. Nevertheless, it must have been very great, and the denudation by which these rocks were removed must have been commensurate.

Should it be objected that, since its solidification, the granite has been thrust up through the rocks which formerly overlaid it, the veins and dykes which, as already stated, it has sent into the surrounding strata, will immediately furnish a conclusive reply in the negative. They can be seen extending in unbroken continuity [p.14] from the central mass into the beds they have invaded, and thus show that the latter have participated in every movement the granite may have undergone.

The geologist, therefore, so far from having the least doubt that there was a time when the Mount was not that kind of half-island which it is at present, cannot but recognize an era when it was completely and deeply encased, and the space between it and the lofty hill behind Marazion was filled, with a very different kind of rock.

2nd. We turn next to the relative level of the isthmus and the sea. From the description already given, it is obvious that if the district were raised 13 feet the isthmus would be constantly above the sea-level, and the Mount a permanent peninsula; whilst, on the other hand, if the district were lowered to the extent of but 7 feet the isthmus would always be under water, and the Mount for ever an island. To prove that the district was once at a greater height above the sea than it is at present, it is only necessary to appeal to the submerged forest long known in Mount's Bay. As has been already pointed out, such a forest is conclusive evidence of subsidence; and it is difficult to suppose that Leland—the first author who mentioned it—could have failed so to regard it.

Indeed, he tells us that "Ther hath been much land devourid betwixt Pensandes and Mousehole. Ther is an old Legend .... a Tounlet in this Part (now defaced and) lying under the Water."29 In other words, a townlet or village, not destroyed by the mere encroachment of the waves, but permanently overwhelmed. We have already seen that he elsewhere mentions "as a token of the Grounde wasted" the occurrence of the "Rootes of Trees, in dyvers Places betwyxt the Mount and Pensants, near lowe Water Marke;" hence, even if the trees originally grew at the sea level, and even if there are none further sea-ward, the district must have been during the growth of the forest 18 feet higher than it is now—an elevation which must have kept the isthmus permanently dry, even if there had been no soil on it, and have deprived the Mount of its present semi-insular character.

The detailed description of this forest by Dr. Borlase, who carefully investigated it in January, 1757, confirms Leland's state- [p.15] ment, for he says that the portion of it which he examined was 300 yards below full tide mark, and at high water its upper surface had 12 feet of water on it.30

For the most minute description of it, however, we are indebted to Dr. Boase, who carefully studied it in the winter of 1825. From his account we learn that the trees were of hazel, alder, elm, and oak; that about a foot below the surface of the bed, the mass was chiefly composed of leaves and hazel nuts in a good state of preservation, the nuts, however, having lost their kernels; that in the bed were found fragments of insects, especially the elytra of beetles displaying the most beautiful colours; that the fishermen asserted that at low water the forest was traceable all the way to Newlyn pier, west of Penzance; that he was of opinion, from the material brought up by ships' anchors, that it extended sea-ward to, at least, Gwavas lake, the well-known roadstead; and that, having observed similar vegetable remains cast up among the pebbles at Lamorna Cove, four miles, in a straight line, S.S.W. from Penzance, he thought it very probable that a wood once covered the whole of the valley which now forms Mount's Bay.31 In short, if Dr. Boase's opinion is even but partially correct—and we shall presently see that it is fully borne out by corresponding facts elsewhere—the Mount, during the forest era, must have been a "hoar rock in a wood;" and it may be repeated that it is possible that the tradition so frequently mentioned was primarily based on the only philosophical interpretation of which the submerged forest was capable.

We have seen, however, that Prof Max Muller demurs to this argument; objecting that he has not been able to discover any proof of the presence of vegetable remains between the Mount and the mainland,32 and that it is, to say the least, curious that, even in the absence of such stringent evidence, geologists should feel so confident that the Mount once stood on the mainland.33

The only aspect of the question in which this objection appears to me to have any force whatever, is that of supposing that the subsidence, unquestionably proved by the submergence of the [p.16] forest, was a mere local slip, in which neither the Mount nor its isthmus participated. To this aspect we will now give attention. We know that a forest of the kind extends continuously from about midway between the Mount and Penzance to Newlyn, and probably sea-ward at least to the well-known roadstead known as Gwavas Lake; that there are indications of another—if, indeed, it is another—as far west as Lamorna Cove; and that a third occurs at Porthleven, seven miles E.S.E. from the Mount;34 hence, were there no further evidence of this kind, it seems impossible to conclude that the subsidence was so local as not to include the Mount. The evidence, however, is far from being so limited, for similar forests are known to exist on all the shores of all the British seas and channels. In 1829, Mr. Colenso, when describing in considerable detail the Stream-works at Pentuan in Mevagissey Bay, stated that at the top of the "tin ground," nearly fifty feet below spring-tide high water, stumps of trees, including oaks, were found having their roots in their natural position, and traceable to their smallest fibres even so deep as two feet;35 and in the same year Mr. Henwood described the Carnon section on a branch of the Fal, and mentioned a vegetable bed containing moss, leaves, nuts, and remains of mammals, at a depth of nearly seventy feet below the high-water level.36 It is well known that such forests present themselves at Millendreth, near Looe, in East Cornwall; and in the Lower St. Columb valley,37 as well as in Padstow harbour, in the north of the county. In Devonshire, too, they are equally well known, as they occur at Bovisand in Plymouth Sound, at Thurlestone Sands in Bigbury Bay, in Salcombe Harbour, at Blackpool near Dartmouth, in Torbay, and in Bideford Bay. They are met with also near Bridgewater and Porlock in Somersetshire, on several parts of the coast of Wales, on the coast of Cheshire, and near Hull. In short, it is difficult to say where they have not been seen.

Some of them are but rarely exposed to view. Thus, the Thurlestone example was seen and described in the spring of 1866, by the Rev. P. A. Ilbert, rector of the parish, who, though he had [p.17] resided there 25 years, and had interested himself in the local geology, had never previously seen or heard of it, though he had frequently noticed that lumps of what proved to be the forest clay were cast up by the waves, and had been much puzzled to account for them. There is a local tradition, however, that an old wood once stood on Thurlestone Sands; and this, in all probability, rests on no other foundation than the submerged forest thus very rarely exposed.38

Again, the splendid instance at Blackpool was seen in 1802 and in 1865, by persons who described it to me; but there is reason to believe that it remained completely buried beneath the sand during the entire interval. It was exposed again in February 1869.39

These forests have been described by so many observers that their literature is quite voluminous. Having devoted a large amount of attention to these descriptions, and having had opportunities of carefully studying the examples at Millendreth, Blackpool, Torbay, Bideford Bay, and the really magnificent one between the Mersey and the Dee, I am prepared to state that they uniformly present the same phenomena. They are everywhere composed exclusively of plants still indigenous to the several localities; the stumps of the trees rise vertically through, and at right angles to, the soil, in which the roots and rootlets ramify horizontally; and there is an entire absence of any indications of local slips.

With such a body of fact before us it may be safely concluded that they are the remains of forests in situ; that they were carried to their present level by a general, uniform, and tranquil subsidence of, at least, Western Europe, including the British archipelago—a subsidence, in fact, similar to that at present in progress in West Greenland,—in which we may feel confident St. Michael's Mount and its isthmus participated, the former being thereby converted into the half-island we now see it.

III. The answer to the third question has been already and obviously indicated, and need not be enlarged on. There may or may not have been some portion of soil on the isthmus, and this may or may not have been occupied by trees but this, in either [p.18] case, would in no way affect the conclusion arrived at:—The insulation was due, not to the mere wasting of the sea-shore, but to a general subsidence of the country.

Should the further question be asked, "What was the date of the submergence?" it must be admitted that at present no definite reply can be given. There are several facts, however,—such as certain statements and allusions in human history, the deposits overlying the forests in some localities, and the amplitude of the existing foreshore—which, on being considered, render it impossible to avoid the conclusion that the date was far removed from our own times.

I. According to Leland the Mount in 1533-40 was in the same condition as, and was no larger than, it is at present;40 William of Worcester's estimation, in 1478, of the distance from the mainland to the Mount differs little from the distance now;41 Bishop Lacy's encouragement to the faithful in 1425 to complete a causeway between Marazion and the Mount for the protection of life and shipping,42 denotes that the exposure was as great then as it is in our day; and as the Confessor's charter in 1044 (assuming it to be trustworthy) describes the Mount as juxta mare—next or by the sea—it may be safely concluded that the insulation had taken place more than eight centuries ago.

The earliest known passage, however, supposed to be descriptive of the Mount, is the famous and oft-quoted one in Diodorus Siculus, about 9 B.C.,43 to the effect that the Britons who dwelt near the Land's End, by reason of their intercourse with merchants, were more civilized and courteous than the others were; that they were the people who dug the tin out of the ground, and cast it into square pieces like a die; that they carried it to a British island near at hand called Iktis, for at low tide all was dry between them and the island, and they conveyed over in carts an abundance of tin in the meantime; and that the merchants exported it thence to Gaul, through which they carried it on horses' backs to the mouth of the Rhone.

It is difficult to see how any one can fail to recognise the [p.19] Mount in this description. It occupies the position and possesses all the peculiar characteristics mentioned; it was capable, and must have been the only spot in the district that was capable, of affording the requisite shelter; it is in the very midst of the most productive tin country,44 and besides it there is no other semi-island to which the author can be supposed to have referred. Nevertheless, many writers, so far from concurring in this view, have advocated the pretensions of other spots, such as one of the Scilly Isles, the Wolf Rock, the Black Rock at the entrance of Falmouth harbour, St. Nicholas or Drake's Island in Plymouth Sound, and even the Isle of Wight. Time will not allow me here to reply to the objections which have been urged against the Mount, nor to dispose of the numerous pretenders. Indeed, it cannot be necessary to do either, as little can be added to the well-known paper on the question by Dr. T. F. Barham.45 It is, perhaps, worthy of remark, however, that those who have studied the Geology of Cornwall espouse the cause of the Mount, whilst most of those who fail to do so appear to have come to the question with their minds imbued with a belief in William of Worcester's statement that there were 140 parish churches submerged between the Mount and Scilly, and accordingly hold that the submergence took place, not only since the time of Diodorus, but since the introduction of the parochial system into Cornwall.

It has been already stated that Professor Max Muller holds the Mount to have been the Iktis, and that his admiring critic in the Saturday Review demurs to his doing so. The latter remarks, "We should like to know Professor Muller's authority for the statement that the identification of the Iktis of Diodorus with St. Michael's Mount 'was at last admitted even by the late Sir G. C. Lewis.' We are specially anxious on this point, as it was the argument of Sir George Lewis in the Astronomy of the Ancients which first convinced us that the Iktis of Diodorus was not St. Michael's Mount."46 The so called argument of Sir G. C. Lewis is contained in the following passage:—"Timaeus mentions an island of Mictis, within six days sail of Britain, which produced tin, and to which [p.20] the natives of Britain sailed in coracles. The Mictis of Timaeus and the Ictis of Diodorus are probably variations of the name Vectis, by which the Roman writers designated the Isle of Wight."47

It would not have occurred to me to have spoken of this passage as containing an argument, or, indeed, anything more than a suggestion. Be this as it may, the passage has been generally, and perhaps not unreasonably, understood to express its author's belief that the Iktis was the Isle of Wight. It does not appear to be so well known as could be wished, that in 1862, Col. Sir Henry James called the attention of Sir Gr. C. Lewis to the sense in which" his words were understood, as well as to the views of Dr. T. F. Barham respecting the Iktis and the Mount, as set forth in the paper already mentioned; and that his reply, dated June 16th, 1862, contained the following statement: "The passage in my volume was not intended to convey the meaning which you attributed to it. All that I meant to say was, that the names Mictis and Ictis were variations of Vectis, and arose from a confusion of that name. My impression was that both accounts were fabulous, and arose from the tendency to multiply islands .... The coincidence of the account of Diodorus with St. Michael's Mount is, however, so close, that it cannot be accidental, and the circumstances mentioned by Dr. Barham, satisfy me that it was the port from which the tin was shipped for the coast of Gaul."48

Though, as we see, the author of the Astronomy of the Ancients never entertained the idea that the Iktis was the Isle of Wight, that idea has been, and still is, held by many; but on what grounds it is difficult to see, except, perhaps, the comparative proximity of the island to the continent. To suppose the Cornubians took their tin by land to the Hampshire coast, is to suppose the existence of bridges and good roads, and such an absence of enmity between the British tribes, as to imply a comparatively high civilization, utterly incompatible with the indirect statement of Diodorus to the contrary. The reason assigned by the old Sicilian [p.21] for the superior civilization and courtesy of the dwellers near the Land's End, was their intercourse with merchants—an advantage which must have been enjoyed by the Vectians in a much higher degree than by the Cornubians, if the Iktis were on the coast of Hampshire, instead of that of Cornwall. Moreover, there is no reason to believe that in the time of Diodorus the Isle of Wight was a peninsula at low water. What evidence there is on the point, is decidedly in the opposite direction. Thus, Bede, who died in 735, calls attention to the same remarkable tidal phenomena in the Solent by which it is at present characterised.49 The accounts which have reached us of its conquest by Vespasian in 43 A.D. do not so represent it; and it is noteworthy that in the earliest traditions respecting the spot it is regarded as an island: Thus, the following is the sixty-seventh of the Historical Triads of Britain:—"The three primary islands attached to the Isle of Britain—Orkney, Man, and Wight. At a subsequent period the sea broke through the land, and Anglesea became an island; and in a similar manner the Orkney Isle was broken, and many islands were formed in consequence, and other parts of Scotland and Cambria became islands."50 Without insisting on the historical value of the Triads, attention may be called to the fact that a tradition, which ventures back to a time when Anglesea was part of the mainland and the Orkneys were one and undivided, recognizes the earliest condition of the Wight as that of an island.

Nor are we without evidence that the relative level of sea and land in other parts of Britain has remained unchanged from the earliest times of history. Mr. Whitley informs me that whilst he found the old Roman embankment at the Wash, from two to four miles inside the outer fringe of the Marsh lands, from the gathering of warp on the outside; it is on the same level as the new embankment built outside to exclude the tide. He properly regards this as strong evidence that no change in the level of the land has taken place since the Roman occupation.51

Again, every reader of Scott's Marmion will no doubt re- [p.22] member the following description of Lindisfarne, or Holy Island, on the coast of Northumberland:—

"The tide now did its flood-mark gain,
And girdled in the Saint's domain:
For, with the flow and ebb, its style
Varies from continent to isle;
Dry shod, o'er sands, twice every day,
The pilgrims to the shrine find way;
Twice every day the waves efface
Of staves and sandalled feet the trace.
                            Canto II., Stanza 9.

This description appears to have been as appropriate in the seventh Century as in the present day, for Bede states that in 635 A.D. the elders of the Scots sent Aidan to be bishop of Northumberland, at the request of the pious King Oswald; and that "the King appointed him his episcopal see in the isle of Lindisfarne, as he desired. Which place, as the tide flows and ebbs twice a day, is enclosed by the waves of the sea like an island; and again, twice in the day, when the shore is left dry, becomes contiguous to the land.52

When it is remembered that Bede was born in the year 673, on the coast between the Tyne and Wear, almost within sight of Lindisfarne; that he spent his entire life from seven years of age in the abbeys of Wearmouth, and of Jarrow on the Tyne, where he died in 735; that he was an ecclesiastic and a writer of ecclesiastical history; and that all the churches from the Tyne to the Tweed, and many of those from the Tyne to the Humber, had their beginning from the Monastery in Holy Island, it cannot be doubted that he had every opportunity and motive to make himself perfectly acquainted with the history and condition of a spot which he must have held sacred. We may safely conclude, then, that there has been no change of relative level of sea and land on the coast of Northumberland during the last thirteen centuries; and that Bede was not aware of any tradition of a different condition of the Holy Island.

II. Though it is not possible in many cases to ascertain the thickness of the materials deposited on the ancient forests so frequently mentioned, thanks to the careful observations which have [p.23] been made and recorded respecting the stream tin works in Cornwall, we have information on the question of a most trustworthy character, and well calculated to impress the mind with the vastness of the time which has elapsed since the subsidence. Thus, at Carnon, Mr. Henwood found the vegetable bed resting on the "tin-ground," and lying beneath a series of distinct beds of sand and silt, having a total thickness of more than 43 feet, and all of them, with the exception of the uppermost bed of river sand and mud, three feet in thickness, containing marine shells.53

Again, Mr. Colenso found at Pentuan the old forest rooted in the "tin-ground," and overlaid with detrital matter 64 feet in aggregate thickness. This accumulation, too, was made up of distinct beds of sand, silt, and vegetable matter; every portion of which had been deposited since the subsidence, for an oyster bed was found on the top of the "tin-ground," the shells being still fastened to some of the large stones and the stumps of the trees.54

When it is remembered that beds of sedimentary origin, like those just mentioned, can no more be deposited at a rate exceeding that at which the pre-existing rocks are abraded, than a wall can, on the whole, be built faster than the stones are quarried or the clay is dug for making the bricks, it will be felt to be impossible to regard the strata under consideration as representing a few centuries merely; and, though we are not, and never may be, able to evaluate them in years, we cannot but feel that they bring us face to face with an enormous amount of time.

Should it be objected that a deposit of great thickness may, by a change in the direction or velocity of a stream, be removed from one place to another and re-deposited in a comparatively short time, it may be replied that the objection is in itself undoubtedly valid, but that it does not, and cannot, apply to the cases before us, as, in each, the successive beds were perfectly distinct and of dissimilar materials, and, at all levels, contained marine shells, which, and particularly the flat ones, Mr. Colenso states were frequently found in rows or layers. They were often double and closed, with their opening part upwards, as if the fish had lived and died where their remains were found.55


III. We have seen that the entire country, prior to the subsidence, stood at least 70 feet higher than at present; consequently the cliffs now assailed by the waves during storms at spring-tide high-water, were then at some distance beyond their reach, or, more correctly, they have been formed by wave action on sites to which the breakers then had no access; whilst the rocks and shoals on which the waves then broke at spring-tide low-water, are now in the quiet depths of the sea. Hence the breadth of the existing foreshore—that is, the entire distance between the line of breakers in the most tempestuous weather at the lowest retreat of the tide, and the cliffs which the waves attack in similar weather at the high water of spring tides—may be taken as the space over which the cliffs have slowly retreated, inch by inch, since the last adjustment of the relative level of sea and land.

It cannot be necessary to remark that this amplitude of the existing foreshore differs much in different districts, for it depends on the materials of which the rocks consist, their structure, the aspect of their exposure, and the prevalent winds. Though the coast from the Prawle to the Start in South Devon is undoubtedly exposed to the almost unchecked fury of the waves sent up channel from the Atlantic, yet, when it is remembered that the rocks of that district are crystalline schists, than which none probably are more capable of resistance, it will be seen that the fact that even they have so far retreated since the submergence of the forests as to form a foreshore fully a quarter of a mile in breath, is one which, to the man of science, betokens that the era of the subsidence must have been in remote pre-Christian times.

Remote, however, as was this era when measured by the units employed in human history, it must have been very modern as a geological event, for, as we have already seen, the plants of which the forests consist are, not only recent species, but such as are still indigenous in the several localities; hence the period of their growth—a period necessarily more ancient than that of their submergence—fails to take us back to the times of extinct vegetation, or to a climate differing much, if at all, from that which at present obtains.

It must be borne in mind, however, that this by no means proves that the animals of the period and districts have undergone no change, for, to say nothing of the influence of man in the [p.25] extermination of at least the larger animals, it is well known that extinction did not result from convulsion, catastrophe, or sudden change; and that lowly organized species are, as a whole, much less affected by changes in external conditions than are those of complex organization. Hence, the value of what may be called the Life of a Species is by no means a constant quantity; and there can be no a priori reason why, though the forests were composed of such plants as now exist in the same localities, the animals which found food and shelter in them may not have been, at least in some instances, extinct species. Indeed, an examination of the ossiferous contents of the forests proves that this was the fact, for, to go no further, there have been found in the Torbay forest remains of the red deer (Cervus elaphus), wild hog (Sus scrofa), horse (Equus caballus) long-fronted ox (Bos longifrons), and mammoth (Elephas primigenius)—the last, if not the last two, being certainly extinct. The evidence of the mammoth is a fine, adult, left, lower molar, dredged out of the peaty mass where there is never less than 30 feet of water.

Remains of the same species were also discovered in 1849, in the submerged forest at Holyhead.56

Though the era of the submergence was, as we have seen, certainly some thousands of years before our time, those who have kept themselves acquainted with the recent progress of Anthropology, will be prepared to hear that it took place since the advent of man in Britain. As long ago as 1829, Mr. Henwood recorded the discovery of human skulls in the forest at Carnon,57 and in 1852 an antler of a red deer, fashioned into a tool, was found nine feet deep in the Torbay forest, and at the same depth below spring-tide high water.58

The connexion of the forests, however, with the Antiquity of Man by no means ends here. They, ancient as they undoubtedly are, must be very modern in comparison with the men whose tools have been found in Windmill Cavern at Brixham, and Kent's Cavern at Torquay. The entrances of these Caverns are in the sides of lime-stone hills, at a height 100 feet in the first case. [p.26] and from 60 to 70 in the second, above the bottom of the adjacent valleys in the same vertical plane; and the implement-bearing deposits which they contain were carried into them when the bottom of the valleys was very little below the entrances. In other words, since the existence of Man in Devonshire, the Brixham Valley has been deepened, by excavation or re-excavation, as the case may be, to the amount of at least 100 feet; and the Ilsham Vale, adjacent to Kent's Hole, to the extent of upwards of 60 feet. But as the bottom of the former, so far as it is known, is not the limestone of the district, nor, in the ordinary meaning of the term, rock of any kind, but an undoubted portion of the submerged forest of Torbay, it is obvious that the time expended in excavating the valley below the level of the cavern, fills but a part of the interval which separates the era of the Cave Men of Devonshire from the present day. In order to obtain the whole, we must add to this part the time represented by the lodgement of the blue forest clay of Devon, or the tin-ground of Cornwall; to this again must be added the period in which the forests grew; to this a further addition must be made of the time during which the entire country was carried down at least 70 feet vertically, by a subsidence so slow, and tranquil, and uniform that it no where, throughout the area of Western Europe and the British Islands, disturbed the horizontality of the old forest soil; and, finally, we must also add the time which has elapsed since—a time which, of itself, thanks to the description of St. Michael's Mount by Diodorus Siculus, we know certainly exceeded 2,000 years, and which the volume of the stratified deposits overlying the forests, as well as the amplitude of the existing foreshore, warrants our believing exceeded it by a very large amount.

To me, the Insulation of St. Michael's Mount in Cornwall has its chiefest interest in this connexion. It is the first, or most modern, of a series of trustworthy stepping-stones leading backwards towards the far reaching Antiquity of the Human Race.


1 Proceedings Roy. Inst. Great Britain, Vol. v, p. 128.

2 Vol. iii, pp. 129-161, 1867.

3 Chips from a German Workshop, by F. Max Muller, M.A., Vol. iii, pp. 330-357, 1870.

4 January 14th, 1871, p. 56.

5 Trans. Roy. Geol. Soc. of Cornwall, Vol. ii, p. 184.

6 Ibid, Vol. xii, p. 105.

7 During a visit to Marazion since this paper was written, I observed the following fact, strongly confirmatory of the belief of the natives that if the cliffs recede at all they do so at a very slow rate. A house standing, it was said, on 60 feet by 60 feet, was in course of erection, on a narrow tongue of the sub-aerial material, having the sea-cliff no more than 12 feet from it on the west, and from 30 to 40 feet on the east. On my remarking that the site seemed a very precarious one, especially for so large and valuable a house, the workmen assured me that there was no risk whatever.

8 "Observations on the Submersion of part of the Mount's Bay; and on the Inundation of Marine Sand on the north coast of Cornwall." By Henry Boase, Esq., Tram. Roy. Geol. Soc. of Cornwall, vol. ii, p. 129, et. seq.

9 Itineraria.

10 3rd Series, Vol. xi, pp. 357-8. May 4, 1867.

11 Page 336.

12 p. 336.

13 p. 354.

14 p. 332.

15 p. 343.

16 p. 339.

17 pp. 331-2.

18 pp. 855-6.

19 Sat. Rev., Jan. 14, 1871, p. 56.

20 p. 334.

21 p. 335.

22 pp. 356-7.

23 A writer in the Westminster Review, in a brief notice of Prof. Muller's papers on Cornwall, says, "In the paper on the Insulation of St. Michael's Mount, we should have been glad to have heard something more of the geological evidence. We should also like to know what Mr. Pengelly .... may have to say in answer from that point of view Many of the questions which Mr. Max Muller has raised can only be solved by the joint labours of the philologist and geologist."—West. Rev., No. lxxvii., January 1871, pp. 277-8.

24 Monasticon.

25 Itinerary, vol. vii., p. 118, 3 ed., Oxford, 1768.

26 p. 356.

27 See Report on the Geology of Cornwall, p. 15, 1839.

28 See Quart. Journ. Geol. Soc, London, Vol. xiv, p. 453, &c., 1859.

29 Itinerary, Vol. iii, p. 17.

30 Natural History of Cornwall, pp. 221-3.

31 See Trans. Roy. Geol. Soc. of Cornwall, vol. iii, p. 166, &c.

32 p. 334.

33 p. 335.

34 Trans. Roy. Geol. Soc. of Cornwall, vol. i, p. 236.

35 Ibid, vol. iv, p. 29, &c.

36 Ibid, p. 57, &c.

37 See De la Beche's Report on Cornwall, &c., p. 405, 1839.

38 See Trans. Devon. Assoc, vol. i, pt. v, pp. 77-9, 1866.

39 Ibid, vol. iii, pp. 127-9, 1869.

40 Op. cit. Vol. vii., p. 118.

41 Op. cit.

42 See Oliver's Monasticon, p. 28.

43 Bk. v., ch. ii.

44 See Dr. Smith's Cassiterides, p. 114. 1863.

45 See Trans. Roy. Geol. Soc. of Cornwall, vol. iii, p. 86, et seq, 1825. Also Trans. Devon. Assoc, vol. ii, pp. 142-55. 1867.

46 p. 56.

47 An Historical Survey of the Astronomy of the Ancients. By the Tight Hon. Sir George Cornewall Lewis, p. 453. 1862.

48 The entire Letter from Sir G. C. Lewis to Sir H. James was printed in the Forty-fifth Annual Report of the Royal Institution of Cornwall, 1863, pp. 34-5, at the request of the latter, in the belief that it would "prevent future writers from quoting the high authority of Sir George Lewis to any contrary opinion."

49 Ecclesiastical History, Bk. iv, Ch. 16.

50 See Notes and Queries, 4th S. vol. iii, p. 23, January 2, 1869.

51 Private letter, August 6, 1867.

52 Ecclesiastical History. B. iii., Ch. 3. (Bohn's Ed.)

53 Trans. Hoy. Geol. Soc. of Cornwall, Vol. iv., p. 57, et. seq,, 1829.

54 Ibid, p. 29, et seq.

55 Op. cit.

56 Lyell's Principles of Geology, 10 Ed., Vol. I., p. 545. 1867.

57 Op. cit.

58 See Trans. Devon Assoc, Vol. i, pt. iv, pp. 36-38. 1865.