NEW PROTECTION FOR OLD MONUMENTS
One of the final actions of Mr. Callaghan’s Government was to pass through all its Commons stages the Ancient Monument and Archaeological Areas Bill (which had begun life a few weeks earlier in the Lords) between 5.32 and 6.15 pm on April 4; and at 7.03 pm that same evening the Act received the Royal Assent, No. 22 of the final batch of 25 Acts to be passed before the dissolution.
The Act, which contains 65 clauses and 5 schedules, has been hailed by many historical and archaeological bodies as a major legislative advance. When it was introduced in the Commons it was described as striking “an acceptable balance between the need to preserve, or at least to record, our heritage and the requirements of developers, land-owners, farmers, mineral operators and others whose business must inevitably involve a measure of archaeological damage.”
There are at the moment 839 Ancient Monuments in State care; the new Act is the most important measure for their protection since 1913. It introduces, among other things, a system of control for monuments parallel to that for listed buildings, so that “scheduled monument consent” will be needed in future for demolition or alteration on a scheduled site. Another provision is the power to designate “areas of archaeological importance” where 6-month delays can be enforced to allow time for excavation.
The provision which has received most publicity, however, is the one which makes it an offence to use a metal detector without permission either on a scheduled Ancient Monument or in a designated Archaeological Area. In commenting on this clause in the debate, the under-Secretary of State for the Environment remarked that treasure hunting “may be an innocent pastime but in irresponsible hands these devices can lead to irreparable damage and loss of knowledge.”
We hope the new Under-Secretary will feel equally strongly on the subject.
THE SOCIETY’S l8TH AGM
…took place on May 15 under the expert and friendly Chairmanship of Vice-President Andrew Saunders, Chief Inspector of Ancient Monuments at the Department of Environment. Between 70-80 members were present.
The following were elected for the year 1979-8Q; Chairman, Councillor Brian Jarman; vice-Chairman, Edward Sammes; Hon. Secretary, Brigid Grafton Green; Hon. Treasurer, Jeremy Clynes. Committee; Christine Arnott, John Enderby, Peter Fauvel-Clinch, Vincent Foster, George Ingram, Dave King, Daphne Lorimer, Dorothy Newbury, Nell Penny, Ken Vause, Freda Wilkinson, Sheila Woodward and Eric Wookey.
Three official reports were presented on the Society’s activities during 1978-9: the Annual Report, the Treasurer’s Report and the Research Committee Report. Two themes of special importance emerged from them.
The first was that although we now have a small room at Avenue House where we keep books and records and 3 or 4 people can work, we are still without, and still desperately need, a real headquarters. If any member can suggest how HADAS might obtain the use of a large room, with some means of lighting and warmth, available at weekends as well as during the week, will they please, without hesitation, let any member of the Committee know about it? The room needs to be big enough to take 20/25 members at a processing session; and HADAS would have to be the sole occupant, so that the room could be locked when not in use and work in progress left undisturbed.
The second problem is a vital as the first and perhaps, given the help and goodwill of members, it may prove easier to solve. It was set out by our Hon. Treasurer like this:
“It isn’t often you hear a Treasurer asking for money to be spent: but we now have adequate resources which I should like to see put into existing and new projects. But we have a major problem: we are desperately short of human resources, and I appeal to all members to volunteer their help in completing our outstanding” projects and enabling us to launch new ones.”
Do ~ feel you can reply to the Treasurer’s call for help? What the Society needs badly are people prepared to take responsibility for organising, or helping to organise, a project – which may be a long-term, wide-ranging one like the farm or the parish boundary survey; or may be a one-off occasion like a single outing or lecture.
There are also projects already in being whose organisers would like more help – for instance, Sheila Woodward in Edgware, George Ingram for his survey of nonconformist churches, Myfanwy Stewart with site watching.
If you are prepared to offer any kind of help, please let either Jeremy Clynes or Brigid Grafton Green know.
There is one specialised subject on which we would greatly appreciate help – photographic development work. Do any members possess their own dark rooms and developing facilities? If so, would they be prepared to develop prints and transparencies taken by other members for the Society? HADAS would, of course, reimburse their expenses. ===HADAS JUNE DIARY
Sat. June 16. outing with Vice-Chairman Ted Sammes, who will meet us at Slough – and take us through pretty Thames countryside to Maidenhead and Cookham. He will provide a good mixed bag of visits – a Saxon burial mound; the Henry Reitlinger Museum, with collections of pottery, sculpture and drawings; the Stanley Spencer gallery, devoted to the works and memorabilia of the artist; and Courage’s Shire Horse Centre. If you want to take part, fill in the form enclosed with this Newsletter and return it as soon as possible to Dorothy Newbury.
All Weds, Sats and Suns in June except June I6. Digging at. West Heath, 10 am-5 pm. We have much to do this year, so please come as often and as long as you can.
Proposed Dig at Church Crescent, Finchley. We are still marking time here, waiting for problems of sale and ownership of the site to be resolved. If you have already notified Paddy Musgrove of your interest, you will be informed as soon as a date is fixed for the start of the dig.
NEW SHIRE PUBLICATIONS
Prehistoric Stone Circles, by Aubrey Burl. Price £1.25
Aubrey Burl, author of this new volume in the “Shire Archaeology” series, has produced a very readable summary of facts and current theories about the origins, purpose, development and regional variations of these dramatic monuments.
He considers the inspiration for their origin to lie in the large circular burial mounds of Eastern Britain which often covered deep circular ditches or rings of stones or posts. The earliest stone circles, however, lie round the coasts of the Irish Sea and were, he thinks, built by the stone axe traders. Their association with celestial events was, he considers, symbolic rather than practical and pointed to their use as seasonal ceremonial meeting places for some form of ancestor cult.
The stone circle reached its zenith in size and form in its middle phase (the period of metallurgy and the beaker) when some were huge and all Were elegant. Oval was the predominant shape and there is evidence that, regardless of size, different regions used preferred numbers of stones and, indeed, developed their own architectural forms. Every inhabited area had its own stone circle.
The late period produced small clusters of circles, possibly the product of individual families, with distinctive district characteristics. There is no evidence of stone circles after 1200 BC.
Profusely illustrated, this stimulating little booklet is an excellent introduction to Aubrey Burl’s major work “The Stone Circles of the British Isles,” and is very handy to slip into the pocket. D.R.L.
Roman Roads, by Richard W Bagshawe. £1.50
In the same series is this booklet by an engineer who has included many new photographs taken in the course of field work as well as an excellent selection of air photos and reproductions from early maps. After a brief history of Roman road studies, in which pride of place of course goes to the work of that king of amateur archaeologists, Ivan Margary, the author gives notes on Roman road construction (illustrated by sections), a chapter on maps and documentary evidence, suggestions for tracing unknown Roman roads and information on how to record them when found. He provides a select bibliography and ends with – for this size book- a magnificent 30 pages of illustration.
This is a good, clear introduction to a fascinating aspect of archaeology which has provided many field archaeologists with the interest of a lifetime. B.G.G.
Clay Tobacco Pipes, by Eric Ayto. Shire Album 37, 60p
The author of this very readable 32-page booklet, Eric Ayto, has himself manufactured clay pipes as a craft potter since 1972.
The Album starts by tracing the origin and development of the clay pipe from the 16th c. until its decline after the first world war. It goes on to describe the pipe-makers themselves and the various techniques and stages of manufacture. Finally it describes how to date pipes, how to collect them and how to trace the makers.
The booklet is well written and well illustrated, and should be of great interest to anyone who has ever found a clay tobacco pipe, either in the back garden or on an archaeological excavation. J.C.
The three books here reviewed can be obtained from the Hon. Treasurer, Jeremy Clynes. Please add l5p to your order for postage.
THE LOCAL TROLLEYBUS
By Bill Firth.
The current exhibition at Church Farm House Museum, which lasts until June 24, has been arranged by the London Trolleybus Preservation Society and recalls with pictures, maps and relics the time when the trolleybus was an everyday form of transport in what is now the London Borough of Barnet.
The first trolleybuses ran in the area in July 1936 and the last in January 1962, so that the period covered is only just over 25 years and its end is less than 20 years ago. This comes as a surprise to many who used trolleybuses regularly when they were the new, modern transport.
The exhibition can be viewed from three standpoints, all well covered within the restricted confines of the Museum. (No attempt has been made to display an actual trolleybus, but there are models). The technical aspect is covered by frogs or switches, insulators and other apparatus from the overhead (as the wires are technically known) together with wiring layouts and some vehicle equipment. Of most interest is the chance to look closely at items from the overhead which, because of its elevated position, remained a mystery to most of us.
The operating angle again is illustrated by items which the general public does not normally see -vehicle time cards, time and duty schedules, fault delay records, overtime dockets, licences, regulations, bye-laws and so on. One item which caught my eye here was the tester for dud coins – do bus conductors still have them, or are our coins now of so little value that they are not worth counterfeiting?
Lastly there are the nostalgic items, route maps, fare schedules, tickets and in particular photographs, all of which are of scenes in the Borough of Barnet. The fare schedules are a harsh reminder of what declining traffic and inflation have done to fares: in 1947 one could travel from Holborn to North Finchley by a rather roundabout route via Finsbury Park, Turnpike Lane, Wood Green and Friern Barnet or, more directly, from Moorgate to Barnet via the Angel, Highgate and Finchley, for lOd (about 4p).
The photographs will have most appeal to anyone who is not a trolleybus enthusiast. It was good to see that the 1909 trials at Hendon (later Colindale) depot were not forgotten and there is a particularly good series of the terminus at North Finchley, but everyone will surely find something here to please them.
HADAS TO THE “RESCUE”
Every HADAS member who has taken part in a Society digs – Burroughs Gardens, Church Terrace, West Heath, Finchley Rectory – has helped on a rescue dig and thereby retrieved, before it was too late, information which enabled an ‘i’ to be dotted or a ‘t’ crossed in the history of the area. This has been because HADAS has acted as a watchdog and local authorities, the Borough of Barnet and the GLC, have shown wisdom and understanding. Such is not, however, the inevitable practice and there are areas where whole chapters of our past will remain unwritten forever because the evidence has disappeared under the ravages of time, weather and, above all, man.
‘Rescue’, the British Archaeological Trust, was formed to try to do for the whole country what HADAS tries to do in Barnet. Rescue also tries to do a bit more: it is instrumental in the formation of local units, provides scholarships to train archaeological personnel, acts as a super watchdog, seeks funding and aid for archaeological projects and plays an active part in the education of the public (young and old) in the appreciation of their fast disappearing heritage.
To have any effect at all, Rescue needs every bit of support and help it can get. With this Newsletter is a form for membership and/or donations. I do most earnestly urge all members who feel they can make a contribution, however small, to do so. Our future may be rooted in our past but, today, the bulldozer and the ‘fast-buck’ are loosening those roots. DAPHNE LORIMER ===THE DAY THE COACH ‘BLEW UP’ Jacqueline Hall describes how HADAS met with triumph and disaster in North Kent.
The Society outing on May 12 had one unforeseen and unusual feature – coach trouble, something that no HADAS outing has suffered before.
Disaster struck before we had reached our first objective, Oldsbury Hill Fort near Ightham in North Kent. The engine of the coach overheated and boiled dry. When the radiator cap was removed to pour in some water (borrowed, in a watering can, from nearby field sprinklers) clouds of steam poured out. We limped down to Wrotham and rang home for a relief coach to meet us further along the way.
The delay meant some rapid re-thinking by Sheila Woodward and Wendy Page, who were organising the trip. They decided to cut out the hill fort and make instead for our second objective, Coldrum long barrow at Trottiscliffe. This was reached by a pleasant walk along a country footpath. It must once have been most impressive in its proportions, having originally measured 70 by 55 ft. The mound has disappeared, leaving the four huge sarsen stones of the burial chamber standing exposed to wind and weather. Some of the bones of the 22 skeletons found in the chamber arc to be seen in the small and isolated Trottiscliffe Church.
After lunch our rogue coach set off for Chiddingstone along delightful rural roads. After looking at the beautifully preserved 16th/17th c. houses, owned by the National Trust, and the nearby quaintly-shaped “chiding” stone, we moved on to Penshurst, where our relief coach was expected. However, the “relief” had beaten’ us to it. It had not only arrived before us but, not finding us there, had returned promptly to London.
Penshurst P1ace, however, put every worry about coaches, rogue or relief, out of our heads. We explored the intricacies of this medieval house with its Tudor additions; and its notable Great Hall dated 1340 with a central hearth. The gardens, too, were a joy, with miles of perfectly trimmed yew hedge and many goldfish pools.
Our coach returned us safely to London after a memorable outing. Special thanks are due to Sheila and Wendy for coping with crisis so calmly and competently, and to our coach driver, who never lost his cool even when his coach did!
HENDON’S FIRST CENSUS
Historians who study Census returns usually begin in 1841, considering that Census the first which gives real detail about individuals. In many areas that is true. In our Borough, however, we are fortunate: for the parish of Hendon (not, alas, for any other part of the Borough) we have the original returns (not just microfilm copies) from three earlier Census, containing a good deal of information.
(NOTE – the following appeared in Newsletter 101 in July 1979 —
C0RRECTION. In the article on Hendon’s First Census, when discussing Rufus King, reference was wrongly made to the American War. This should, of course, have been to the War of Independence.
End of NOTE)
The first Census countrywide was taken on the night of March 10, 1801, when there was no Civil Service to mastermind it. This and the Censes of 1811, 1821 and 1831 (the last is the only one for which we have no Hendon returns) were taken by parishes. The Overseers of the Poor took charge of the count. Questions were oral, not written and, from a modern historian’s point of view, were not really the right questions – they did not deal, for instance, with age or marital or family status.
From 1841 the whole thing became more streamlined. Registration districts (which had come into being under the 1827 General Registry Act for the registration of births, deaths and marriages) were subdivided into Census Enumeration districts; in that year there were 35000 Census Enumerators, and the questions became more searching.
In general the figures of the four earliest Census are considered of doubtful historical value. The three sets of Hendon returns, however, are reasonably detailed. They are contained in small, paper-covered books – not quite as large as modern school exercise books – the unlined pages of which have been ruled up by the assessors in faded ink. They are divided into Hendon North End and South End – the way the parish was administered for Vestry purposes.
The 1801 Census occupies four small books with only, on average, 5 pages used in each book. The two South End books give a total of 1177 persons. The enumerators (Thomas Littlewood and James Goodyer for one book, William Geeves for the other) have carefully totted up the numbers of people on each page. The North End enumerators (William Dell and William Buckingham) do not add up each page. The total for the North End districts appears to be 695, making a total of 1872 inhabitants for the whole parish in 1801.
The way the questions were posed also differed between North and South End. Obviously this was the start of the project, before the formula had been clearly worked out and laid down.
Both North and South Ends start with columns for “number of house” and “name of occupier.” Both have -though not in the same position on the record – columns for “number of fami1ys” in each house and total “number of persons.” In the South End books “persons” are subdivided into male and female and there is a final column “how employed” which is in turn subdivided into “agriculture”, “trade” and “unoccupied.”
The North End books are more complicated with more columns. They have a “trade or occupation” column following “name of occupier.” This is not subdivided, so that ,instead of type you get the actual occupations – farmer, housekeeper; labourer, gardener, Gentleman, carpenter, “taylor”, smith, mantua maker, “poor” (in which poignant category are 8 persons, all widows), stagemaster, captain in the Navy, baker, attorney, carrier, dealer, wheelwright, bricklayer, Army agent, builder , shoemaker, merchant, postman (not our kind of postman) and shopkeeper.
There are also separate columns in these books for children, male and female; servants, male and fema1e; and one for servants’ employment, , not always filled in. When it is the commonest occupations are gardener, footman, groom, coachman and “boy”! The servants column also apparently includes living-in apprentices. John Lodge, smith, has 2 male servants who are also “smiths; farmers have servants who work in agriculture; a baker has a baker servant; and a carpenter with 3 servants (2 male, one female) puts the word “Prentices” against their occupation.
There are also columns headed “inmates, male and female” and “inmates occupation”. This category may cover lodgers, some of whom are perhaps permanent like those of the mantua maker, whose house harbours 3 “inmates” besides herself – and others who may be birds of passage (3 publicans’ houses have “inmates” on the night of the Census). There arc sometimes children, noted as such, among the “inmates, ” which may mean children boarded out by the parish.
More information can therefore be wrung from the North End books, but it is not as clear nor easy to interpret as that in the South End books.
A word about that column “number of house.” It does not mean a street number. No streets are either numbered or named, so there is no way of tolling where you are, either in South or North End, except that in Mr. Geeves’ South End book two entries give some, clue – one for the Almshouses, which must be Daniel’s Almshouses (where Church Road joins The Burroughs); and, another for the Workhouse at the end of The Burroughs (where Quadrant Close now stands). The workhouse is entry 46. It contains 19 males and 38 females – 4 employed in agriculture, 24 in trade and 29 unoccupied. The entry following, No. 47, must surely apply to some adjunct to the Workhouse, though it is merely called “Mr. Goodyers;” in it there are 52 males and 4 females, with 6 persons employed in trade and 50 unoccupied. (Incidentally, Nicolls Almshouses in Mill Hill – that is, in North End – are not identifiable in this Census). The “number of house” goes through each book seriatim. There are 379 inhabited houses in Hendon parish in 1801.
On the last page of each book is given the number of uninhabited houses on Census night: 5 in South End, 10 in North End. For each un-occupied house the name of the “proprietor” is given; and a column headed “l’ occupier” stands for “late occupier.” Here again is a clue to where we are in the parish. In South End one uninhabited house is “Mr. Coore’s Ivy House.” There is today, on the north corner of The Burroughs On Watford Way, an interesting group of 4 18th c. houses, Nos. 9, 11, 13 and 15, of which No. 13 is still called Ivey House. Was this, perhaps, Mr. Coore’s, uninhabited on the night of March 10, 1801?
Two entries are of themselves particularly interesting. One is totally unexpected. It is for house no. 121 in North End, and it is for “His Excellency Rufus King, American Minister, ” living with one male and one female servant. Perhaps some HADAS member with a taste for documentary research might care to ferret out who exactly this gentleman was. Was he, only 25 years after the American Civil War, the first Minister to be appointed to Britain? Is it known where precisely his house was in Hendon? Did it serve as his office as well as his home?
The other entry is bizarre – and a commentary on social mores. It occurs in South End and is the entry for house No. 69. The occupier is Mr. Lockier, the number of “familys” is 1 , the persons are male .2, female 22, making a total of 24, one of whom is engaged in agriculture, two in trade and 21 are unoccupied. What a family, by any standards!
We hope to discuss in later Newsletters the other early Hendon Census of 1811 and 1821.
MILESTONE FOR THE NEWSLETTER
This is the 100th issue of the Newsletter, which began life in October, 1969, with a slim l 1/2 pages, a circulation of under a hundred and the promise of appearing at “about 6-weekly intervals.” Towards the end of 1971 it began with an occasional hiccup to arrive almost monthly and to be a full 2 pages.
There have been other milestones. No. 20 (Sept. 1972) was the first 4-pager; July 1974 saw us dressed up with a printed heading and the now familiar HADAS logo; in October 1975 we conformed to up-to-date usage, changing from foolscap to A4 size. April 1976 was the first 6-page issue; and in May 1978 we crept up to 8 pages:. This month we are a bumper 11.
Another innovation – thanks to the professional skill of Freda Wilkinson – was the institution of an Index in 1977. The first one covered issues 1-70, Oct. 1969-Dec. 1976. Since then Mrs. Wilkinson has kindly put her talents at our disposal annually, providing separate indices for 1977 and 1978. These, being an essential tool’ for researchers, have added a new dimension to the use of the Newsletter, particularly in libraries. Incidentally, any member who would like to have these indices can, by letting our Hon. Secretary know, do so at a cost of 5p a page.
This seems a very proper moment to announce further extension of the Newsletter’s scope. From now on we hope sometimes to include line illustrations – maps, sections, plans, the occasional page of drawings of pottery and small finds. You may have noticed that we had a successful trial run for this new venture last month, when we included a reproduction of a 19th c. advertisement.
With this Newsletter comes our first map, to accompany the opening article in ~ series by HADAS members which we shall publish on different aspects of archaeology in the Borough. Mike Purton, a recently joined member, starts the series with the article which follows, on Geology in the Borough of Barnet. He hopes in a later paper to describe how geology has affected human occupation and activity in the area.
THE GEOLOGY OF THE BOROUGH OF BARNET
By Michael Purton
Introduction. The accompanying map shows the outcrops of geological deposits in the area and this article attempts to describe briefly their character and the history of their formation. The time scale involved is considerably longer than that for archaeology and extends over 50 million years. Considerable changes have taken place during this time, starting from when the area was below the sea level when the London Clay was being deposited and continuing through periods of uplift and several glacial periods to the present day.
London Clay. The oldest deposits exposed in the area are those of the London Clay which was laid down about 50 million years ago. It is present over the entire area and has a maximum thickness of over 400 ft. All the other deposits in the area can be considered as lying above the London Clay.
The London Clay is a stiff brown clay when exposed at the surface but can be seen to be dark-grey or bluish-grey when freshly exposed in cuttings. The colour change is due to the chemical action of weathering which also tends to dissolve fossils. As a consequence, fossils are rare at the surface but many have been recorded in the past during the cutting of the Archway Road and the construction of cuttings and tunnels when the railways were being built. These fossils included mammals, reptiles, birds, fishes and plant remains (including palms and sequoia) which indicated a sub-tropical climate at the time of deposition. The deposits are interpreted as being formed from the mud from a large river and laid down, in estuarine or marine conditions.
Claygate Beds. The London Clay is succeeded by Claygate Beds which are composed of alternations of sand, loam and clay and are regarded as being transitional between the London Clay and Bagshot Sand. The change in character is interpreted in terms of the shallowing of the sea after the deposition of the London Clay.
The Claygate Beds are exposed on higher ground in the area at Hampstead, Highgate, Mill Hill, Totteridge, Arkley and Elstree.
Bagshot Sand. The Bagshot Sand occurs only in the area capping the high ground at Hampstead and Highgate. The deposits were laid down some 45 million years ago and are composed of 60-80 feet of white and yellow sands with layers of loamy material, occasional layers of small rolled flint pebbles and a bed of ironstone. The base of the series is taken at the top of the first prominent underlying clay bed and is marked by springs, including that giving rise to the Leg of Mutton pond.
The Bagshot Sand represents a further shallowlng of the sea following the deposition of the Claygate Beds. There are no further marine deposits in the area following the Bagshot Sand. An extremely long time gap of over 40 million years occurred before subsequent Pleistocene deposits were laid down in the area. During this time the whole area was lifted above sea level and the beds were gently folded to give the present saucer-like configuration of the London Basin with the Chalk outcropping at the margins (the Chilterns and the North Downs). These changes occurred only very gradually and it is only because of the long period of time involved that the effect appears so great.
During the Pleistocene period, which covers the last two million years, the land was above sea level and the geological history is interpreted in terms of climatic changes, glaciations and changes in sea level. For a complete understanding it is necessary to correlate deposits with those outside the area and this requires contributions from many disciplines. Active work relating to the Barnet area is still in progress.
Most of the Pleistocene deposits in the area are river deposits laid down on valley floors. These occur at different levels which arc related to changes in past sea levels. When a fall of sea-level occurs, rivers will cut down through the old valley floors leaving the original deposits as terraces on either side of the new valley floors. Several terraces hove been identified in the Thames Valley and the Vale of St. Albans and these reveal a complicated history against which the deposits in the Barnet area must be considered.
Pebble Gravel. The oldest of these deposits is the Pebble Gravel which, due to subsequent erosion, now occurs as a thin capping over the highest land in the area at Stanmore, EIstree, Arkley, Barnet and Totteridge, with small remnants at Mill Hill and Hampstead. The Pebble Gravel is composed mainly of flint pebbles, some reaching the size of a hen’s egg. There are a number of minor constituents which indicate a source to the south in the weald. Thus it is concluded that the deposits were laid down by a river (or rivers) which drained northwards and that there was no river on the present course of the Thames.
Dollis Hill Gravel. The next oldest deposits arc those of the Dollis Hill Gravel, which occur at Dollis Hill, Hendon, Finchley and Southgate. It can be shown that at this time, some 600,000 years ago, the Thames (or, more strictly, its precursor) ran through the Vale of St. Albans past Watford, St. Albans, Hatfield and Hertford to the east. Careful analysis of the structure and composition of the Dollis Hill Gravel shows that it was a river deposit (not glacial, as indicated on geological maps) formed from a river following the present course of the Wey and Mole in Surrey which then flowed north-eastwards in a valley between Hampstead and Mill Hill to join the proto-Thames near Hoddesdon.
At about this time the period of the Anglian glaciation occurred; this was the only glaciation in which the ice reached the area. A glacier flowing from the main ice sheet to the north crossed the Chalk outcrop through the Stevenage gap, flowed into the then Thames valley and into the valley of the Dollis Hill Gravel. This had the effect of blocking the outlet of water from the valleys so that lakes formed into which fine sands and silts were deposited. When the lakes eventually overflowed they cut new drainage channels to the south east. The effect of this was to divert the Thames to its present course and completely to reverse the drainage in the Brent Valley from a northeast to a southwest direction.
Boulder Clay. The maximum advance of the ice was as far as Finchley, where the terminal moraine is left today as a mass of boulder clay stretching from Whetstone to Finchley, East Finchley and Muswell Hill, overlying the Dollis Hill Gravel and the thin lake deposits.
The boulder clay is a tough bluish clay containing pebbles and larger fragments of flint, chalk, Jurassic rocks from the Midlands and occasional igneous rocks from Scandinavia, indicating a northerly and easterly origin of the ice sheet from which the glacier flowed. The boulder clay also contains lenses of sand and gravel.
Subsequent geological history follows the general pattern of the present with rivers flowing in their present valleys but at lower levels so that a series of river terraces have been formed. Two terraces (Boyn Hill and Taplow) occur in the Brent Valley and Neolithic implements from terraces of the same age at Yiewsey in West Middlesex have been described by Desmond Collins. During the time in which these deposits wore being 1aid down there were two glacial periods, the Wolstonian some 200,000 years ago and the Devensian 30-40,000 years ago (in general, it is not possible to correlate these glaciations with the classic Alpine sequence). The ice sheets in these glaciations did not reach so far south and consequently, did not have such a drastic effect on drainage in the area.
(EDITORIAL NOTE – The reference above to Neolithic implements should read PALAEOLITHIC – see correction on page 10 of Newsletter 111 – May 1980)
The latest deposits are those of alluvium in the floors of the present river valleys.
SOURCES R L Sherlock, British Regional Geology: London & Thames Valley. HMSO, 1960
H B Woodward, Geology of the London District, Mem. Geol. Surv; 1909
P L Gibbard, Middle Pleistocene Drainage in the Thames Valley; Geol. Magazine; 1979, 116 (1), 35-44
Hampstead Scientific Society, Hampstead Heath, Its Geology and, Natural History. T Fisher Unwin 1913, 41
This account is based on a limited examination of the available literature, not on first hand experience.
Tho London and Thames Valley booklet gives a general background; a detailed local description is given in the Hampstead Scientific Society publication, chapter II.
Further information came from H B Woodward’s 1909 account of the geology of the London area which was based on mapping carried out before the area became built over.
The Pleistocene Geology is less straightforward to decipher than the Tertiary and the account relies heavily on a recent Paper by P L Gibbard in which temporary deposits in the Finchley area have been of decisive importance in the interpretation of the history of the drainage in the Thames Valley. This work emphasises that it is not only local archaeology but also local geology which depends on the examination of temporarily exposed sections.
Geological maps were also used, as were the facilities of the Geological Museum library. This library is open to the public (10 am- 4 pm weekdays) who may also consult members of the Institute of Geological Sciences (HADAS members have in fact been able to use this service in connection with West Heath finds).
Theo Museum itself is worth a visit. On the first floor a large scale model shows the geology of the Thames Basin. More recent displays are on the ground floor, but on the upper floors some older displays dealing with mineral workings are of as much interest to industrial archaeologists as they are from the geological point of view.
Finally, the author wishes to thank Dr. J C Robinson of University College, London, for introducing him to the more recent literature.
(EDITORIAL – For accompanying map, select the following link)