Hill Gravel Research Articles

The Palaeogene Haldon Formation of South Devon

The Haldon Formation comprises a sequence of Palaeogene gravels and clays occurring on the summit of the Haldon Hills in South Devon. The Tower Wood Gravel Member is a residual gravel derived from the solution of the Chalk Group in place, comprising large flints, frost-shattered but not fluvially abraded, in a matrix of sandy clay. This member is dominated by well-ordered kaolinite and this must have been introduced by a river or rivers flowing from the Dartmoor area. The formation of the member occurred between the very latest Cretaceous, at the earliest, and the Late Paleocene. The Buller's Hill Gravel Member is a fluvial gravel with abraded flints in a matrix of clayey sand. The clay mineralogy is a mixture of well-ordered and disordered kaolinites. The gravels correlate with the Poole Formation of the Hampshire Basin, and possibly also with the Reading Formation. The Haldon Clay Deposit exists only as a series of clay bodies within the Buller's Hill Gravel Member. These bodies are believed to have been incorporated by processes of cryoturbation and solifluction. The clay mineralogy of the Haldon Clay Deposit comprises disordered kaolinite and illite, which will have come from supergene weathering of sediments, probably from the Carboniferous and Devonian strata to the north or north-west of Haldon. It is considered most likely that the unit is lacustrine in origin, having formed as a sheet of clay overlying the Buller's Hill Gravel Member, but it may possibly be fluvial.

Results of geological and archaeological observations at Switchback Road Pit, Maidenhead, Berkshire

Gravel extraction at Switchback Road Pit, Maidenhead, which lay between Cannoncourt Farm, Furze Platt and Lower Mount Farm, Cookham - two of the most important locations for Palaeolithic handaxes in the middle Thames Valley - was monitored as an archaeological condition of planning consent. Extraction at Switchback Road has now ceased and the results have identified the probable northern extent of the Furze Platt implement scatter and an additional discrete cluster of Palaeolithic handaxes within an otherwise low density distribution of material. Most of these implements are in a slightly rolled condition, indicating that they have not moved far from their original point of deposition. Lithological analyses have confirmed the geological deposits as part of the Lynch Hill Gravel, which was probably deposited between Oxygen Isotope Stages 10 and 8 (350 000-250 000 bp ).

Correlation of Thames terrace deposits between the Lower Thames, eastern Essex and the submerged offshore continuation of the Thames—Medway valley

A modified correlation of terrace deposits between the Lower Thames and eastern Essex is proposed, based on a reconsideration of the available evidence and correcting earlier published versions. It is suggested that the Rochford Gravel and Rochford Channel of the Southend area are not separate features within the fluvial record, but belong, instead, within the Southend Channel-Southchurch Gravel aggradational sequence. A correlation between the onshore terrace system and three submerged terraces recognized beneath the southern North Sea is proposed here for the first time. An important implication of these new correlations is that all terrace deposits lower than the Lynch Hill Gravel are below ordnance datum east of Canvey Island.

Significance of a molluscan fauna to the physiographic history of the Calgary area, Alberta

A newly discovered molluscan fauna provides an approximate age for a previously undated gravel sequence capping Nose Hill, a relict plateau adjacent to the Bow River in Calgary, Alberta, and constrains the age of the physiographic relief in the area. The fauna consists of a mixed terrestrial–aquatic assemblage whose composition indicates a paleoclimatic regime similar to that of the area today. The fossiliferous sediment, interpreted as a pond deposit, is a pebbly mud within a thick braid-plain gravel sequence. Isoleucine epimerization in the molluscs is not inconsistent with an Early Pleistocene or older age for the deposit. The Nose Hill gravels and an equivalent sequence capping another outlier (Broadcast Hill) located on the other side of the Bow River define an originally extensive paleo-plains surface. Fluvial dissection of the surface, including 175 m of incision by the Bow River and resultant separation of the two outliers, occurred within the last one to two million years.

Recent investigations of Pleistocene sediments near Maidenhead, Berkshire, and their archaeological content

Recent archaeological and geological assessment of Thames terrace deposits to the north of Maidenhead has been undertaken. The principal site investigated was at Furze Piatt, incorporating the important Palaeolithic localities of Cannoncourt Farm Pit and Cooper's Pit. The deposits form part of the Lynch Hill Terrace, although later sediments occur in addition to gravels deposited by the Thames. These later sediments comprise a predominantly fine-grained colluvial deposit (‘brickearth’) which is locally overlain by a tributary gravel. A temperate climate soil has been recognised in the ‘brickearth’ beneath this later gravel. Palaeolithic artefacts of predominantly Acheulian type occur within the Lynch Hill Gravel. Later artefacts, of probable Neolithic age, have been recovered from the ‘brickearth’.

Middle Pleistocene stratigraphy in the lower Waveney valley, East Anglia

The Middle Pleistocene deposits of the lower Waveney valley have been investigated by drilling and bulk-sampling and a regional stratigraphy has been established. The variations in the thickness and distribution of the drift deposits can be attributed, in part, to a relief developed on the underlying Crag sediments. Remnants of quartzite-rich sand and gravel, preserved on the highest parts of the Crag, are thought to be the oldest surviving Pleistocene fluvial deposits of the region. It is believed that they were laid down during the Beestonian or earlier, by a proto-Waveney that flowed eastwards from the Chalk escarpment. This river may have developed contemporaneously with an ancestral Thames. Lithological evidence suggests that the two systems remained separate: one flowing east-north-eastwards towards Corton, the other sub-parallel with it south of Saxmundham. Successive marine transgressions during the Cromerian Stage affected only low-lying areas on the surface of the Crag and led to re-working of quartzose material and deposition of a restricted suite of intertidal sands and clays. With the onset of glacial conditions in early Anglian times, ice advanced into the area from the North Sea and deposited the North Sea Drift. This group of sediments is here redefined as comprising a till (or tills), a hitherto unrecorded proximal outwash phase (Leet Hill Sands and Gravels) and a series of distal outwash sands (Corton Sands). The Leet Hill Sands and Gravels are poorly represented in the Anglian stratotype at Cotton but are widespread inland where they have an optimum development in a linear depression in the Crag surface. The overlying Corton Sands are believed to have been derived entirely from wastage of the North Sea Drift ice. They accumulated in three fining-upwards cycles of which only the lowest is seen at Corton. A tentative correlation with the north Norfolk coastal succession suggests that the cyclicity may have developed in response to oscillations in the position of the ice margin. A period of erosion intervened before a separate ice advance came into the area from the west and deposited the overlying Lowestoft Till. Spreads of sand and gravel, derived from wastage of the Lowestoft Till ice, flank the Waveney valley and mark the course of a major meltwater channel which is believed to extend beneath Lowestoft.

Age and origin of clayey silt ‚brickearth’︁ in west London, England

AbstractThe loamy ‚brickearth’︁ deposits overlying coarse cold climate Kempton Park, Lynch Hill and Taplow Gravels of the R. Thames in west London are dated by thermoluminescence and mineralogical comparisons with loesses of three known ages. Although much of the ‚brickearth’︁ resembles loess, it often contains more sand or clay than typical loess, and the mineralogical studies suggest that even the coarse silt (16–63 μm) fraction is rarely similar in composition to any known English loess. The thermoluminescence measurements suggest that most of the ‚brickearth’︁ on the Taplow and Lynch Hill Gravels was deposited in the late Devensian, whereas that on the Park Gravel is mainly Flandrian. It is suggested that the latter is mainly floodloam, whereas the earlier ‚brickearth’︁ is a mixed aeolian sediment derived from various local sources in and close to the Thames Valley.

Tertiary weathering profiles in the plateau deposits of East Devon

A complex of superposed weathering profiles forms the dominant feature of the geology of the East Devon tableland. In the Palaeocene, a lateritic weathering profile, the Combpyne Soil, formed as Chalk deposits underwent dissolution beneath their Tertiary overburden. The profile is well differentiated and polygenetic. The Peak Hill Gravels represent reworked pallid and mottled zones and occur extensively over the tableland. Red earths survive in isolated pockets in the subsequent land surface and traces of laterites occur. In the Sidmouth area. following earth movements in the early Eocene, the Seven Stones Soil was formed. Chemical weathering was less intense than in the older profile. Silcrete formed in both profiles in the Sidmouth area. During the later Tertiary but especially in the Pleistocene these earlier profiles suffered erosion and local redistribution to form the Mutters Moor Gravels. Quaternary soils are developed on fresher Permo-Triassic rocks where the tableland is deeply dissected and are also superposed at various levels of erosion in the older profiles on the plateau surface.

The Clay Mineralogy of the Haldon Gravels

AbstractThe less than 10 μm and less than 3 μm fractions of the heterogenous Haldon Gravels have been examined by X-ray diffractometry. Kaolinite of high to low crystallinity is the dominant clay mineral, with variable amounts of illite (clay mica) ; quartz, a little feldspar and anatase also occur. The kaolinite has been ranked using the crystallinity index of Hinckley and also by indices derived from the ratio of peak height to background height for the 10 and 11 peaks.Clay from the matrix of the psaphitic members of the Buller's Hill Gravel contains intermediate grade kaolinite with a little illite, but clay bodies included in this formation contain only low grade kaolinite with a high, but variable proportion of illite. The Tower Wood Gravel contains two distinct populations; one is identical to that of the Buller's Hill Gravel, the other consists of high crystallinity kaolinite with a little illite. Head Gravel formed from the Buller's Hill Gravel by solifluction contains intermediate to low crystallinity kaolinite.

The haldon gravels of South Devon

The Haldon Gravels comprise four components, three Eocene and one Pleistocene. The Tower Wood Gravel, of early Eocene age, contains weathered but unabraded flints in a clay matrix of well-ordered kaolinite with little illite, and was formed from in situ solution of the Chalk. The overlying Buller's Hill Gravel contains abraded flints and exotic pebbles in a matrix of kaolin clay and sand; it was formed largely by fluvial reworking of the Tower Wood Gravel on a wide flat plain during approximately Reading Beds to Bagshot Beds times. Bodies of ‘ball-clay’ kaolin now found within the Buller's Hill Gravel but differing from it in their clay mineralogy originated as a sheet of clay overlying the gravel, deposited on a river flood-plain or in a coastal lagoon and tentatively correlated with the Bracklesham and Barton Beds. Downwarping of the Bovey Basin prevented further, sedimentation in the area. During the Pleistocene the Haldon Gravels were affected by periglacial processes; the flints were frost-shattered, the gravels mixed by cryoturbation and solifluction to form Head Gravel, and the overlying sheet of clay broken up and incorporated as masses of clay in the Buller's Hill Gravel.

Intraformational Periglacial Structures in the Nose Hill Gravels and Sands, Calgary, Alberta, Canada

A gravel and sand sequence at Calgary, Alberta, resting unconformably on Paskapoo sandstone and overlain by a late Wisconsin till, has within it two distinct horizons of structures attributable to periglacial activity. The lower horizon shows involutions and deranged and frost-shattered pebbles, while the upper horizon shows fossil ice wedges. A periglacial environment probably existed in southwestern Alberta at least twice during the gravel and sand deposition, and the sequence is probably of Pleistocene age, although predating the earliest Laurentide ice advance in the area. The average annual temperature in the Calgary area was approximately 9°-14° C. cooler than at present.

THE PLEISTOCENE DEPOSITS OF HOLDERNESS, EAST YORKSHIRE

Summary The Holderness tills are described, and grouped into two series: the Basement Series below, and the Drab-Purple-Hessle Series above. The Basement Till is shown to underlie (and not overlie as was formerly supposed) the Sewerby raised beach, which is considered to belong to the Last Interglacial. The Basement Till was therefore deposited during the Saale Glaciation or earlier, and the Bridlington Crag (which has been rediscovered after being hidden for sixty years) may thus be of Holstein (Great Interglacial) age or earlier. The Drab-Purple-Hessle Series is considered to have been deposited from one composite ice sheet of Würm age, probably Main Würm, and the “moss silts” which underlie it at Dimlington are placed in a Würm interstadial. The Early Würm may be represented by the solifluction bed at Sewerby. The Kelsey Hill Gravels, the Kirmington silts and the Speeton Shell Bed are reassessed, and their position in the chronology is discussed.

A Clactonian flint industry at Little Thurrock, Grays, Essex

A site, rich in artifacts of the Clactonian flint industry, exists at Little Thurrock, Grays, Essex. The industry is contained within a thin deposit of fluviatile gravel which is found at a height of forty-nine feet O.D. and is a fragment of an almost completely denuded terrace of the Thames. The relationship of this gravel deposit to the fossiliferous Grays' brickearth and the gravel to the north, which is mapped by the Geological Survey as Boyn Hill Gravel, has been examined and the flint industry considered in detail.

A Shaped Bone from Warren Hill, Suffolk

During a recent visit to the famous gravel-pits at Warren Hill, Suffolk, one of the workmen handed me the bone which is described in this note. He evidently attached little importance to the specimen, which had been kept merely because it was a bone—as such are rare in the Warren Hill Gravel. The finder informed me that the specimen came from the concreted gravel—a very compact and chalky layer in the Warren Hill deposit. This claim is borne out, first, by the white, chalky appearance of the bone, which corresponds with the condition of others from the same horizon; and, secondly, by the fact that the medullary cavity of the specimen still retains some of the gravel in which it was embedded. The bone is clearly fossil, but, like others from Warren Hill, this condition is not accompanied by an addition to the weight of the specimen. The bone, in fact, probably now weighs less than it did in its pristine state—a condition of affairs, however, by no means uncommon in ancient specimens. It has assumed a consistency similar to that of chalk, and its surfaces can easily, though roughly, be scraped, or cut, by a knife.

Palæolithic Implements of the Warren Hill Gravel

A SELECTION from nearly 1,300 flint implements in the Sturge Bequest, from the gravel on Warren Hill, near Mildenhall, Suffolk, is on special exhibition at the British Museum, Bloomsbury, and will remain there for about three months. It will be found at the head of the main staircase, and is arranged in two desk-cases, one containing representatives of the main types and the other the specimens illustrated in the Sturge volume, with exceptional pieces showing the remarkable local patina and other special features. The exhibition is intended to show the sequence or association of implements in the same gravel, and to direct attention to the deposit, which is a geological puzzle. The long hill between Mildenhall and Ickling-ham lies at right angles to the River Lark near its south end, and was evidently formed before the valley was cut. The gravel seems to belong to an interrupted line of high-level deposits in a curve from Lakenheath to Snail well, following the southeastern boundary of the Fens. It is now generally held that this gravel bank is a glacial moraine; but there were thousands of implements included in it, and some in an unrolled condition enable a limiting date, if not a sequence, to be supplied on archaeological grounds. The collection shows that, besides first-class hand-axes of St. Acheul character, there was also a striking proportion of flake-implements resembling in form those from High Lodge near the north end of the same ridge; and these are now thought to mark the third stage of the Clacton industry. Their horizon elsewhere is evident, but at Warren Hill it remains to determine the relation between the Clacton and St. Acheul series, and to identify the glaciation producing this apparently homogeneous gravel, which must have been derived from an area, once thickly inhabited, in the neighbourhood. There is now a good opportunity to draw on the archaeological material for a solution of the geological problem.

VII.—Note on a Section in Probable Bagshot Beds on Shooters Hill, Kent

In 1905 trenches for electric mains were carried up the northeastern slope of Shooters Hill, along Shrewsbury Lane to “The Bull”, and thence down the western hill-slope along the Dover Road. From about 350 O.D. in Plum Lane to 424 O.D. at “The Bull” the trench ran for nearly two-thirds of a mile along the junction of the London Clay with the overlying group of sands, pebbles, and clayey gravels which form the ‘gravel cap’ of Shooters Hill. Neither the exact age of these superficial deposits nor their mode of formation—whether marine or fluviatile beds—is as yet known, but the general coarseness of the sands, the presence of pebbles of Lower Greensand chert, and the very stiff clayey matrix of the gravel distinguish them from typical Bagshot Beds, and moreover throughout the greater part of the section a sharp and irregular junction could be traced between them and the brown London Clay. At a few points, however, the top of the London Clay was seen to pass into pale-brown and yellowish sandy clays, sometimes of significant thickness. Thus in the Dover Road, about 100 yards above Christ Church, below the thick red clayey gravel of the ‘cap’, lay about 3 feet of yellow loam, the lower part of which became a pale-brown clay passing quite gradually into normal blue or brown London Clay with septarian nodules. In the same series of excavations (1905) a trench at the junction of Shrewsbury Lane with the Dover Road showed the Shooters Hill gravel resting irregularly on a bed of fine clean yellowish sand quite unlike anything previously noted in the numerous pits and trenches opened upon the Hill, but as unfortunately the trench was only a few feet deep the relation of this fine sand to the London Clay could not then be made out.

On another Section in the so-called Interglacial Gravels of Holderness

The Kelsey Hill Gravels, opened several years ago, are, I think, well known to all glacialists, but unfortunately the gravel pits at which Messrs. Phillips, Wood and Rome, Prestwich, Reid and others worked are now to a large extent overgrown, and nearly all the sections recorded by those gentlemen are no longer visible. When the gravels first began to attract the attention of geologists the general opinion was that they had been deposited during a mild inter-glacial period, during which a lower bed of boulder clay was to some extent denuded, and the range of gravel hills, of which Kelsey Hill is one, was formed from the material washed out of this clay. The scarcity of scratched stones and other similar evidences of ice-action being the ground for this supposition.[*][1] The few ice-scratched boulders noticed had the scratches almost entirely obliterated, and it was thought that these stones were first enclosed in the lower boulder clay, and the subsequent denudation was answerable for the grooves being removed. The numerous animals, mammoth, deer, rhinoceros, bison, &c., the remains of which were found in the gravels, were also supposed to be the inhabitants of this area during the time between the two Glacial Periods. More recently the late Professor Carvill Lewis visited these gravels, and, though he stated that there was a lack of evidence in support of an inter-glacial period, he expressed the opinion that “ Kelsey Hill is not a mound, and has not the aspect of a moraine,”[*][1] and ... [1]: #fn-1

On some Hill Gravels north of the Thames

On some Hill Gravels north of the Thames

V.—Theoretical Remarks on the Gravel and Drift of the Fenlands

Summary1. The brown Boulder-clay corresponds with the brown Clay of the Eastern counties, and is oldest.2. Then the hill gravel, the blue Boulder-clay, and perhaps the shell bed of March corresponds to the contorted drift.3. As elevation progressed, the Fenlands would become one great fiord, ramifying at the Cambridge end up the southern valleys in the Chalk. First the coarse gravels of low levels were formed, and finally, during a long period—for the flints are wonderfully worn—the fine gravel of the plains. After which the country was elevated, and the sea denuded the superficial beds and retired. This corresponds to the Upper Boulder-clay and coarse gravel of the Norfolk section.4. Now rivers cut their channels, and there commenced luxuriant vegetable growth, which corresponds with the excavation of the Mundesley river and the Mundesley peat.5. Then a depression, during which was formed the Buttery-clay the Fens. This corresponds with the Upper Sands and Gravel of Mundesley.6. And, finally, comes the second peat and the present state of nature.I believe this succession is true for a far larger area than the Fenlands, perhaps for all Great Britain.