Hampshire Basin Research Articles

The Horizons of Bryozoa (Polyzoa) in the Upper Eocene Beds of Hampshire

I. I ntroduction . This communication is for the purpose of describing the horizons on which Bryozoa (Polyzoa) occur in the Upper Eocene Beds (marine clays and sands) of Hampshire. No claim is made to establish special zones with particular species confined to them, but those beds are indicated that contain a relative abundance or deficiency of bryozoan remains, within the three broad divisions of the Upper Eocene (Lower, Middle, and Upper Barton Beds). The geology of this portion of the Hampshire Basin may first be briefly reviewed. The Barton Clay and Barton Sands form part of the well-known Hampshire Syncline, and are exposed at Christchurch Bay, and also at Alum Bay and Whitecliff Bay, in the Isle of Wight. The type-section at Barton Cliffs on the mainland consists of sandy clays in the lower part (50 feet), dark sandy clays and stiff drab clays in the middle part (56 feet), and clayey sands and light-coloured sands in the upper part (96 feet). (Total = 202 feet.) Corresponding Upper Eocene Beds in the Isle of Wight attain a greater thickness. At Alum Bay, the western end of the island, they reach a total of 338 feet. At Whitecliff Bay, at the eastern end of the island, they reach a total of 368 feet (9, p. 108). Even these thicknesses may fall short of the maximum totals in the Isle of Wight, owing to the high angle of dip, and to the compression to which so many of the strata have clearly been

Some Aspects of the Hampshire Plateau Gravels

Before proceeding to consider the special features of the Hampshire Basin, and their bearing on palæolithic problems, I should like to say a few words on more general subjects. It is very well known, but perhaps not always remembered, that scarcely one of our commonly accepted conclusions regarding the geological position of the early palæoliths rests on a secure foundation; in almost every case we have to content ourselves, not with a sound logical deduction, but with the most probable of several possible inferences from inadequate and conflicting data. And as an example of what I mean, let us glance at some points in the history of river terraces. First of all the word terrace usually connotes two distinct structures, a basal rock-shelf, and a series of deposits resting on it; and although it is generally assumed that the two are so intimately bound together as to be practically contemporaneous, yet that is not a sure inference, since it is equally possible that there may have been, in some cases at least, a long interval between them. The importance of this possibility to archæologists will be evident when I remind you of the contention of several eminent authorities that the different human cultures of the Pleistocene belong rather to such intervals than to the period of accumulation of the drift to which they are generally referred.

On Cycles of Sedimentation in the Eocene Strata of the Anglo-Franco-Belgian Basin

Landenian.—The Landenian is represented by the Thanet Sands and Woolwich and Reading Beds. The former seem to correspond to the two lower zones of the French Landenian, whilst the marine Bottom Bed of the Woolwich Series corresponds to the zone of Cyprina scutellaria. The present writer. has given reasons for believing the pebble-bed separating the two to be due to a movement of uplift in the Wealden area.1 In the east of the London district the marine Bottom Bed passes up into clays and marls crowded with estuarine fossils (Woolwich Beds); to the west into unfossiliferous mottled clays and fluviatile sands (Reading Beds). The extensive transgression at the time of the zone of Cyprina scutellaria is noticeable in the London Basin as it is in the Paris and Hampshire Basins.

II.—The Geology of the Isle of Purbeck

The “Isle” of Purbeek includes part of a heathy tract underlain by the Tertiary beds of the Hampshire Basin, a central ridge formed by the Chalk which rises abruptly from beneath those beds, and, in its southern part, a hilly region underlain by Wealden, Purbeck, Portland, and Kimmeridge strata, and terminated by bold cliffs. Each formation gives rise to characteristic features in the landscape, the Portland Stone especially forming a dominant escarpment and vertical sea-cliffs.

The Clay with Flints

I have the pleasure to submit for your information some conclusions which I have arrived at after two years' work among the flints of Hampshire, in a district contained between the Meon, West Sussex, and the south of the Isle of Wight. The point I wish to urge is that in very great probability the earliest pages of the History of the Stone Age will be found written, not in pits of transported gravel but at the fountain head and parent source of these gravels—the Clay with Flints of the chalk downs. That has been my hypothesis, and as I went along I found things fitting into it. I feel convinced that Professor Prestwich had some such idea when he recommended Mr. Benjamin Harrison to devote his attention to the flints of the North Downs at their highest points.I would ask you to undertake a flight of imagination and to place yourselves in some modern aerial contrivance a few hundred feet above Alton in Hampshire, and to survey the horizon north, south and west. You will find below you the western extremity of the Wealden Pericline in the form of a truncated cone fading away to the horizon of Tertiaries which once wrapped round and spread over it, but which now have shrunk away to form the London and Hampshire Basins north and south of the Pericline. What was once a deposit of Reading Beds became in Eo., Mio, Plio. and Pleistocene time a smear of Remanié over the entire surface, before the excavation of the chalk valleys, a residue which we call Clay with Flints, and which is known in France as the Argile à Silex.

On the Geology of the Neighbourhood of Seaford (Sussex)

The following paper deals with that part of the South Downs which adjoins the coast between Beachy Head and Newhaven. Its primary object was to investigate the variations of the dip and strike of the Chalk strata in that area, with the view of discovering the interpretation of the sudden westerly dip of the Chalk at Seaford Head. Incidentally, the geological features of the surrounding country and their relation to the surface-contours are discussed, and reasons are given for the view that the true eastern extremity of the structural area known as the Hampshire Basin lies within this district. With regard to previous literature on this part of Sussex, the whole question is summed up by Mr. Jukes-Browne in the following statement, published in 1904:— ‘At Newhaven the beds are nearly horizontal, so there must be a quick recovery from the steep inclination which they show in Seafurd Head. Whether they are re-curved or faulted we have no means of knowing.’

On the Probable Occurrence of an Eocene Outlier off the Cornish Coast

During the new geological survey of the Hampshire Basin fresh evidence was discovered of the westerly extension of certain of the deposits, in the form of Eocene river-gravels. This evidence tended to link more closely the Eocene deposits of Devon with those of the Hampshire Basin; but it did not seem to throw any light on the Eocene geology of Cornwall, nor of any part of the area west of Dartmoor. Some years since (in 1897) during a holiday-visit to the Lizard, I was much impressed by the character of the material which forms the extensive shingle-beach at Gunwalloe, on the western side of the Lizard promontory, not far from Mullion. The shingle, which was being extensively carted away for gravel, was so perfectly rounded, and in appearance was so unlike anything that I had expected to find in Cornwall, that I examined it closely, taking away samples to give to the Museum of Practical Geology, Jermyn Street. The coarser beach proved to consist largely (about 70 per cent. by weight.) of Chalk-flint and Greensand-chert, only 30 per cent. being Palaeozoic at the spot where it was examined. A large quantity of the fine shingle yielded :— At the time, I was unable to carry the matter further; for, although well aware that scattered Chalk-flints were not uncommon in Cornwall, I could not understand why so many had collected at this spot, almost to the exclusion of the local rocks. The absence of Chalk-flints from the Pliocene gravels of St.

On a peculiarity in the course of certain streams in the London and Hampshire Basins

On a peculiarity in the course of certain streams in the London and Hampshire Basins

The Geology of the Isle of Purbeck and Weymouth

ANY ONE travelling from London to the South Coast may see how the gentle southerly inclination of the chalk, which has carried it under the Tertiary beds, changes on the south side of the trough, bringing the chalk up again with a steeper slope, but now with a northerly dip; how it then folds over the axis of the Wealden anticlinal, only to fall to the south more rapidly than it did before, and pass under the waters of the Channel. If we make our traverse further west, there, in consequence of the strike of the rocks being oblique to the trend of the coast, we find still more southerly folds brought into view, and the chalk, after passing rapidly under the Tertiary beds of the Hampshire basin, reappearing in the Isle of Wight, with the strata vertical or even thrown over beyond the vertical. Along this line of disturbance older and older Mesozoic rocks turn up in the anticlinal folds.

On the Occurrence of Pebbles of Schorl-rock from the South-west of England in the Drift-deposits of Southern and Eastern England

A set of twelve representative specimens, consisting essentially of quartz and tourmaline, have been examined by Prof. Bonney, who informs the Author that they consist mainly of felspathic grits, schorl-rock, etc., similar rocks to which occur in the South-west of England. The most westerly point at which the pebbles have been detected is on Great and Little Haldon Hills, 800 feet above Ordnance datum, where they are of larger size, more abundant, and coarser-grained than elsewhere. Thence they are traced to the north and south sides of the Thames Basin, and into East Anglia at Walton-on-the-Naze, Aldeburgh, etc. There is a general decrease in height in the deposit in which the pebbles occur, in passing from west to east, and the pebbles appear to have taken two main courses—one along a peneplain west to east from Dartmoor, the other from south-west to north-east across England. The pebbles are absent from the Weald and from the district around Bagshot, from the Hampshire Basin and its bounding hills (with the exception of the extreme south), and from the highest and presumably oldest gravels north of the Thames. D iscussion ( on the two foregoing P apers ). Mr. C. Reid pointed out that irregular decalcification or settlement in gravels tends to cause the longer axes of the stones to become vertical, and that this vertical position, therefore, must not be taken as evidence of glacial action. With regard to Mr. Salter's specimens of schorl-rock, he was sorry to see that the Author still insisted on confounding

III.—The Origin of the Vale of Marshwood in West Dorset

The great sheet of Chalk which, with the subjacent Greensand and Gault, stretches through so large a part of Southern England and underlies the whole of the Hampshire Basin, terminates abruptly in West Dorset. There is no doubt that the Upper Cretaceous rocks once spread continuously over the Jurassic hills east of Bridport and across the Vale of Marshwood, and were united to the corresponding beds in East Devon, where the Chalk and Greensand are so conspicuous in the cliffs near Beer Head.

The Eocene Deposits of Devon

In a paper read before this Society in 1896 I gave a short description of the Eocene Deposits of Dorset, and remarked that ‘It is noteworthy that the new evidence discovered in the western end of the Hampshire Basin strongly supports the idea that the pipeclays of the Bagshot Series are derived from the weathering of the Dartmoor Granite, and that the Bovey Tracey outlier, so like the deposits around Bournemouth, is, as maintained by Mr. Starkie Gardner, of the same age and deposited in the same basin, though in Devon Eocene rest directly on Palæozoic rocks.’ Since these words were written I have had occasion to re-examine the Bovey basin on behalf of the Geological Survey, with the result that light can now be thrown on several obscure points in the geology. As my notes on the Bovey area will complete the general description of the western end of the Hampshire Basin, it will be useful to lay before the Society the results, especially as much detailed work remains to be done and it will be at least 3 years before any general memoir can be published. In the year 1875, when Mr. H. B. Woodward was revising the geology of the Bovey basin, and I was engaged in mapping the Greensand and plateau-gravel of Haldon, we were much exercised as to the age and relationship of the deposits, but then had no clear evidence to permit us to go contrary to the received ideas, though liar. Woodward published

The Eocene Deposits of Dorset

The new survey of the western end of the Hampshire Basin having necessitated certain modifications in the geological map, it may be useful to lay the principal results before the Society. If the alterations were mere matters of detail, this would scarcely be worth while; but the more accurate mapping has led to the discovery of a sudden westerly change in the character of the Lower Bagshot Sands, and of a well-marked overlap at their base. The mapping of the Tertiary strata proves also that there is evidence of other periods of earth-movement in southern England, besides those already known, and that we are dealing with one of those regions where folding affects the same area again and again. When the Eocene strata are followed westward through Sussex and Hampshire into Dorset, one finds constant local changes in the lithological character of the deposits, though these changes seem all to tend in the same direction. Marine beds become less conspicuous, coarser, more estuarine, and estuarine deposits become truly fluviatile. Thus the London Clay, which exceeds 300 feet in thickness to the east, dwindles to less than 100 feet in Dorset, and becomes more sandy and pebbly, though still apparently of marine origin. The Woolwich and Reading Series—fluvio-marine at Newhaven and Portslade, and slightly so at Lancing— becomes more fluviatile westward, lenticular patches of subangular gravel appearing in it west of Wareham. To what extent the Reading Series rests unconformably upon the Chalk is difficult to say, though overlap is clearly

The Palæontology of Sturgeons1

THE palæontological history of the Acipenseroid fishes is at present very imperfectly known. In the existing fauna, only two families are recognizable—that of the Acipenseridæ, with series of bony dermal scutes upon the trunk, and that of Polyodontidæ, destitute of any such armour; both these occupy so low a position in the scale of organization, that considerable evidence of numerous extinct allies might naturally be expected to occur among the fossils of the older rocks. Such evidence, however, can as yet be only slightly recognized. Remains of typical members of the two existing families seem to occur as low in the Tertiary series as the Eocene formation. Pectoral spines and dermal scutes, indistinguishable from those of the living Acipenser, are met with in the Upper Eocene of the Hampshire Basin, and the London Clay (Lower Eocene) of the Isle of Sheppey; and Prof. E. D. Cope has described a fish (Crossopholis) from the Eocene Green River Shales of Wyoming, U.S.A., differing only from the typical Polyodontidæ in the possession of rudimentary scales upon the sides of the trunk.

Further Observations on the Correlation of the Eocene Strata in England, Belgium, and the North of France

It is not my intention to reopen the whole question of the position and correlation of the Eocene strata of England and France, but merely to bring again before the Society such portions of them as involve some yet unsettled points of classification and some necessary rectifications of my own work. The synchronism of the Thanet Sands with the Lower Landenian, of the London Clay with the Lower Ypresian, of the Bracklesham Beds with the Calcaire Grossier, and of the Barton Beds with the Grès de Beauchamp is now perfectly well established. But with respect to the exact relation of the Sands of Bracheux and of the Soissonnais to the English Series, of the Oldhaven Beds to the Woolwich Series, and of the Lower and Upper Bagshots to equivalent strata in the Paris Basin, there are still differences of opinion and some open questions. Since'the publication of my early papers on the Eocene strata, the important monographs on the Eocene Mollusca of Edwards* and Searles Wood† in this country, and the last great work of Deshayes‡ in France, have made large additions to the Eocene faunas of the English and French Tertiaries. At the same time, the work of the Geological Survey and others in the London and Hampshire Basins §; of MM. Hébert ∥, Dolfuss ∥, De Mercey ∥, and others in the Paris Basin; of MM. Gosselet ¶, Ortlieb, and Chelloneix ** in the North of France; and of MM. Briart and Cornet M. Dewalque, MM. Rutot, Van

V.—London Clay in the Vicinity of Southampton

The outcrop of the London Clay to the north of Southampton, near the edge of the Hampshire basin, beyond Bishopstoke, Romsey, etc., was mapped by the officers of the Geological Survey many years ago.

The Oligocene Strata of the Hampshire Basin

The Oligocene Strata of the Hampshire Basin

VII.—Suggestions for a Revised Classification of the British Eocenes

Since the British Eocenes, especially of the Hampshire Basin, were mapped by the Survey, a portion of them have been separated by several writers as Oligocene. The utility of the change is not apparent in our country, where the break is seen to be purely artificial; but in other parts of Europe the Oligocenes, which embrace formations previously known as Lower Miocene, are of great importance. This change, absorbing the entire Upper Eocene fromation of the Isle of Wight, would seem alone to necessitate a reconsideration of the classification of the remainder. But the classification of the Eocene formation, invented and often modified when the beds composing it were imperfectly known, is throughout arbitrary and artificial, and scarcely yet on a scientific basis. Most of the present divisions comprise under one name the very distinct deposits formed by river, sea, or estuary, though these have been brought from quite opposite directions, and are perhaps by no means contemporaneous.

On the Relations of the Eocene and Oligocene Strata in the Hampshire Basin

Conclusion The Lower Tongrian, as is well known, has no marine representative in the Paris basin, the great freshwater gypseous series occurring on this horizon; but in the small basin of the Cotentin, as M. G. Dollfus has so well shown, the Lower Tongrian or Brockenhurst series is represented by the “argile à Corbules”. The Headon series, including both the sands and overlying clays, contains a fauna which, by Hébert, Sandberger, Mayer, and other authors, has been recognized under the name of the zone of Cerithium concavum . The Brockenhurst series contains a fauna which has been quite as universally recognized as agreeing with that of the continental Tongrian or Lower Oligocene. Now, if my interpretation of the section be the true one, the beds containing the Tongrian fauna in the Hampshire basin overlie those containing the fauna of the zone of Cerithium concavum and this is the relation which is believed to exist between their continental representatives. Most geologists, indeed, group the zone of Cerithium concavum with the Upper Eocene or Bartonian, and the representatives of our Brockenhurst series with the Lower Oligocene. But, according to the views of Messrs. Keeping and Tawney, the beds which in this country contain the Lower Oligocene fauna form a thin and very inconstant bed in the midst of the strata containing the fossils of the zone of Cerithium concavum .

IV.—Woodwardian Laboratory Notes

The district to which the following notes refer is that which lies between Bagshot, Woking, Aldershot, Farnborough and Ascot. It consists mainly of heath-land, and seems but little known to geologists; in fact, the only authority for the beds included in this area is Professor Prestwich, who, in his paper on the Bagshot Beds [Q.J.G.S. vol. iii. (1847), p. 278], has supplied all the information about the district that is at present known. He divided the beds into an Upper Sandy series, a Middle Clayey series, and a Lower Sandy series. The Middle series he grouped with the Braeklesbantts of the Hampshire basin. The Upper he placed between the Bracklesham and Barton ; our present object is to show that it is more nearly related to the latter.