at Perton, near Stoke Edith Park, and an account of his discovery of some splendid specimens of a Eurypterus, which has been named after him. Shales of a similar character, and occupying the same relative position, have been found wherever the junction between the Silurian and Old Red series has been exposed to view.

The question here presents itself, under what conditions this very interesting and instructive district has assumed its present conformation. It is perfectly obvious that a force from beneath has upheaved the strata from their originally horizontal position, and that subsequently the great dome thus produced has been removed by denudation. But was this upheaval a gradual or sudden one, and were the denuding forces of a violent nature or the gradual effects of the atmosphere, such as we this day witness on all hands? And lastly, what has become of the material of which the dome was formed?

66

The answer to this last question is found in the considerable deposits of drift, referred to by Sir R. Murchison, and described in much detail by Mr. Merewether in an excellent paper read before this club in the year 1870, who thus summarises the information that his long residence in the neighbourhood and careful observation had enabled him to collect. These drifts "are found," he says, at Mordiford, by the side of the road leading to Woolhope, through Haugh Wood, then the high and long bank of drift opposite the bridge leading to Holme Lacy; the drift at the turn of the road, about 300 yards further on; the great mass of drift on the right hand side where the river approaches close to the road, in the village of Fownhope, between a bridge over a small stream of water and a draper's shop, nearly opposite the Green Man Inn." And he mentions finding among the gravels a considerable number of specimens of the fossils peculiar to the rocks of the Woolhope valley, so that there can be no doubt as to their origin. But much difference of opinion has been expressed as to the mode in which these accumulations have taken place. The opinions of earlier geologists were in favour of some sudden and violent upheaval and the action of enormous volumes of water rushing over the torn and dislocated masses of shattered rock. In 1866 Mr. Symonds speaks of earthquake motion as having been the operative cause of the disturbance (though I have every reason to believe that in later years he would have expressed a very different view). In Sir Roderick Murchison's description of the district we continually meet with such expressions as "violent extrusion," "great convulsions near Dormington," and he writes as follows:-"What agency, I ask, except that of very powerful currents of water, could have removed every fragment of debris that must have resulted, whether at one or several periods of elevation, from the destruction of all the once superposed arches of rock, and have scooped out all the detritus arising from such destruction, from the circling depressions, the central dome, flanking ridges, and former cover of those Silurian strata? And if that water had not been impelled with great force, caused by the sudden uprises of these rocks from beneath the Old Red Sandstone, what other agency will account for so complete a denudation, the broken materials having only found issue by one lateral gorge, which was, we see, opened out by a great transverse fraction of the encircling ridges?" (p. 492, Siluria). We have here an eloquent and picturesque description from the pen of a firm believer in

what is called the convulsionist theory of geology. And, indeed, if but the limited space of a few thousand years be all that we are justified in allowing ourselves to account for what has here evidently happened, a deus ex machinâ in the form of some such mighty convulsion as Sir Roderick has pictured, is manifestly demanded. But as experience and observation have extended recourse to sensational hypotheses involving such violent action has been seen to be unnecessary and unfounded; and I believe that all competent geologists of the present day maintain that only on the clearest evidence ought they to be admitted. It is seen that, allowing sufficient time, the forces called into play by frost and rain, breaking up the rocks, first into larger and by degrees into smaller masses, are amply sufficient to effect all the phenomena which we here behold. If e.g. you visit the huge quartzose masses of rock that rear their giant forms above the moorland that covers the ridge of what are called the Stiperstones in Shropshire, you will not fail to wonder at the large blocks of stone which strew the ground in long lines down the slopes of the ridge. Starting from the foot of each large mass these stretch away in gradually diminishing size, and tell, as plainly as rocks can speak, of a history of extremely slow movement, resulting from the descent down the hill of the soil on which they lie, and that as they proceeded on their way they have been broken up by atmospheric agency into ever smaller portions, until, at last, they are reduced to the condition of sand and clay. And that this motion of the soil is no myth you will be convinced, if you observe the way in which the edges of strata which dip inwards towards the centre of a hill are bent by the continued friction of the surface earth upon them as it slowly moves downward. Given many millions of years for the continuous action of the forces now in operation, what may not be effected? Some observations made several years ago, which at the time attracted the attention of some of the members of the Woolhope Club, upon the quantity of sediment annually carried down by the waters of the Onny, showed that the denudation of its basin would probably amount to about a foot of the ground's surface in 400 years. I should hardly venture to quote this result as sufficiently trustworthy, since the observations were not continued long enough to make them quite satisfactory, but that I have lately had the pleasure of seeing the estimate confirmed by a passage in Mr. Wallace's splendid work on "Island Life," in which he gives the average arrived at by a very large number of observations of the same kind made in other parts of the world. Now, the area of the basin from which the waters of the Onny are supplied measures about 84 square miles, and taking the average height of the surrounding hills, at the very moderate estimate of 400 feet, I find that a valley of such dimensions would, at the above rate, be worn down in about two million years, though this is probably far below the mark, since denudation would be much slower when the land was first emerging from the ocean than afterwards. Various estimates have been made, founded on data, that I cannot now discuss, as to the time that has elapsed since the commencement of the deposition of the sedimentary rocks. Of these the most probable, as well as the most moderate, appears to be that of Mr. Wallace in the book I have alluded to, and this amounts to no less than 28 million of years. Now, such being the vast spaces of time involved in geologic change, it can hardly be thought excessive

to assign two millions, which, although a small portion of the whole, is inconceivably great, as the period required to move the mass of solid material that once extended over the place where we now stand, assuming that a valley of 84 square miles by 400 feet deep may have been excavated during that interval.

And what, on the other hand, are the evidences of any exceptionally violent action? The small mass of intrusive diorite at Bartestree suggests a certain amount of volcanic disturbance in the neighbourhood; but its effect must have been quite insignificant. Then there are the beds of drift and gravel. Did they indeed contain a large number of angular fragments torn from the living rock, and great irregular masses such as we know to be among the ejectamenta of volcanoes in the present day, and swept into their present position by waters of a mighty deluge, something might be said in favour of such a hypothesis. But if, on the contrary, they are largely made up of rounded and smooth and water-worn stones the evidence would point the other way. Such rounded pebbles and gravel can only have been formed by attrition, and tell quite clearly of the lapse of a lengthened period of time for their production.

That from time to time storms of great violence have visited this district, as elsewhere is of course true. An account of one such storm was given in the Hereford Journal of May 29th, 1811.* Floods like these have no doubt swept before them large quantities of detritus such as are found in the beds of drift; the valley has moreover been probably elevated above the waters of the ocean, and again plunged beneath them more than once; and, as Mr. Merewether suggests, the tract between this and Dinmore and Holme Lacy may have been a vast lake, and doubtless all these changes have left their marks on the geologic features of the district; but I cannot concur with him or others in supposing that they afford any proof that Woolhope has been the scene of any exceptional convulsion.

I hope I may be excused for dwelling so long on this point. I have done so since, in the many interesting papers which I have consulted in your Transactions, I do not find that it has been discussed from this point of view. In conclusion, it may be of interest to notice that in comparison with the thickness of the different members of the Silurian strata to the west, their representatives here show a marked diminution or thinning out. I have been unable in the various papers recorded in the Club's Transactions to find any clear statement upon the actual thickness of the various strata at Woolhope, a want which I venture to suggest it might be desirable for some member to supply. In a paper, indeed, by the Rev. Robt. Dixon, read in 1867, he gives certain measurements, but they appear to have been deduced from the section of the survey and not from original observation. In this statement the thickness of the Wenlock series is estimated at about 1,400 feet, while I find in Woodward's geology that the same beds measure at Malvern, not very far distant, only 790 feet. There is, I imagine, some inaccuracy here which would be well worth clearing up. In Shropshire, these Wenlock strata are some 2,400 feet thick, and it is probable that a regular thinning out in their dimensions, as in those of the higher strata, will be found to have occurred as we trace them to the east. The relative thickness of beds in different

* Transactions, 1867, p. 167.

localities is one of the most interesting and important questions that can engage the attention of a geologist, since much light is thrown by its determination on the configuration of the land in distant epochs, and on the primæval history of the earth.

Upon the conclusion of Mr. La Touche's paper, the President, on behalf of the Club, suitably thanked him. Then some business of the Club was transacted, including the election of the Rev. J. O. Bevan, of Vowchurch, as delegate to the British Association for the advancement of Science at their meeting to be held this year at Cardiff.

The following gentlemen were elected members of the Clnb:-Mr. C. G. Blathwayt, of Walney House; Rev. C. S. Hagreen, Vicar of Marden; and Rev. Plaskitt C. Lewis, of Oldcastle.

The following few remarks, entrusted to the charge of the Honorary Secretary, were prepared by Mr. George H. Piper, F.G.S. :

The chief object of the excursion to-day is to familiarize ourselves with the geological structure of the Woolhope Valley, and while using the science of Palæontology in detecting the rock formations which come uuder our notice, we must not lose sight of the fact that our present pursuit is physical geology.

When we call to mind that amongst other eminent geologists Sir Roderick Murchison and the Rev. William S. Symonds have made this valley the object of their research, and have written fully upon it, I must ask you to acquit me of plagiarism when you find that in the following short remarks I have made free use of their valuable books on the subject. Murchison describes Woolhope as being the most symmetrical valley of elevation in the British Isles. There the limestone, as seen in the diagram (of which I have made copies for your use), forms the exterior coat of a central dome marked C, in which the summit of the Upper Llandovery (or May Hill Sandstone) is barely visible. Sections of this formation may be seen near to the village of Woolhope. From this rock the Woolhope limestone, D. 1, dips away on all sides to pass under the Wenlock shale, D. 2. Quite near to the Church there is a large open quarry of Woolhope limestone. The Wenlock limestone, D. 3, plunges under the Ludlow rocks, E. 1, 2, and 3, and Old Red Sandstone, F, as displayed in the diagram. In short, you have before you on either side of the central dome of Haugh Wood a full exposition of all the Upper Silurian rocks, from their base to their summit.

The phenomena of this most remarkable elliptical mass. insulated and raised up through a great area of overlapping Old Red Sandstone, were first described in the "Silurian System." The term " Valley of Elevation" does not convey an adequate idea of this wonderful geological scene, for within the encircling ridge of Middle Ludlow rocks (or Aymestrey limestone), E. 2, there is one parallel surrounding valley in the Lower Ludlow Shale, E. 1, and another in the Wenlock Shale D. 2, or between the ridge of Wenlock Limestone D. 3, and the Woolhope Limestone D. 1. Thus, by the elevation of the various strata around a common centre, and by the subsequent excavation of their softer members, the hill or dome