No 311                        MARCH 1997              Edited by REVA BROWN


DIARY March 11

What not to do with a Roman mosaic       Stephen Ceosh

Stephen is the Honorary Secretary of the Association for the Study and Preservation of Roman Mosaics (ASPROM). He is a gifted illustrator and is at present working on the monumental task of recording for publication all the Roman mosaics in Britain. He is, therefore, someone who knows what should be done with mosaics, but obviously has some horror stories of what has been done on occasions. Undoubtedly, he will have some lovely slides to show.


April 8                         Claude Graham-White - Hendon Aerodrome Bill Firth

May 13                      Morning Tour of the Garrick Club with Mary O'Connell

May 13                   HADAS Annual General Meeting

Meetings are held on Tuesdays at 8.00 pm for 8.30 pm in the Drawing Room (ground floor). Avenue House. East End Road, Finchley, N3 30E. Members can also take the opportunity to visit the library, both on lecture nights and, presently. most Sunday mornings, when the digging team are there working on finds.

22 March (Saturday)                               34th Annual Conference of London Archaeologists

will be held at the Museum of London Lecture Theatre, 11.00 am - 5.30 pm approximately.

Tickets for non-LAMAS members are £4.00 each. Applications or general enquiries to Jon Cotton, Early Dept, Museum of London, 150, London Wall, London EC2Y 5HN The programme includes progress on Southwark and the Rose Theatre. HADAS will have a display and bookstand at this event.

HADAS weekend in York

4 September (Thursday) to 7 September (Sunday

We have had a good response and the weekend has been booked. More details later.


Barnet and District Local History Society

10 March                Buntingford Railway (Barry Bridges)

At the Wyburn Room, Wesley Hall, Stapylton Road, Barnet. 2.45 pm for 3.00 pm.

Enfield Archaeological Society

21 March                       Excavations at Number One Poultry, London: The history of a Roman,

Saxon and medieval neighbourhood.

At the Jubilee Hall, junction of Chase Side and Parsonage Lane, Enfield, 7.30 pm for 8.00. Cost to visitors: 50p.

The Finchley Society

27 March                          Greenwich places of interest (John Neale)

At the Drawing Room (ground floor), Avenue House, East End Road, Finchley, N3 3QE, commencing promptly at 7.45 pm..

PLANNING APPLICATIONS in the Northern Area                                      BILL BASS

The following sites may be of archaeological interest;

34-38 High Street, Barnet, near to the medieval centre

113-115 High street, Barnet

23 Galley Lane, Barnet, near to medieval pottery finds.

155 Friern Barnet Lane, N20 (land rear of), close to the medieval church and the site of the Friary.

Building work at the Prince of Wales pub in Church Hill Road, East Barnet has uncovered a well, and the pub renovation was halted while building engineers inspect the well. The Prince of Wales and its forerunner The Black Prince seem to date to the mid-19th century and may have been part of a 'National School' before that. Parts of the timber framework suggest that the structure has its roots in the 18th century.

THE BARNETS & HADLEY                                                                           BILL BASS

by the Barnet & District Local History Society

Published by Sutton Publishing Ltd at £9.99

As they say in their introduction: This second volume of photographs, taken from the Barnet Museum's collection, is intended to provide a slightly different slant on the history of our district. As well as photographs of familiar landmarks, it includes groups of photographs on less well-know aspects of our area and devotes a section to the people themselves. Altogether there are five sections. The first three relate to Chipping Barnet, New Barnet and East Barnet. They are followed by a smaller one on Hadley, and finally, the section about people."

The book, although slightly larger in format than the previous one, follows the same style of well-produced photographs (over 250), occasional maps and informative captions showing the dramatic development that has taken place in the area over the last 100 years. One of the people mentioned is Sir John Betjeman, who was a master at Heddon Court, a school which was founded in Hampstead in the 1890s, but moved to East Barnet in the 1920s. Sir John taught here from April 1929 until July 1930. He wrote several poems of the area and his times there, and some are included in the book, together with other anecdotes.


ARCHAEOLOGY AND ALLUVIUM                                                                               ROY WALKER

Our January lecture led us into the world of palaeo-environmental studies Geo-archaeological and, more specifically, alluvium. Dr Martin Bates: our lecturer, head the Institute of Archaeology's Geo-archaeological Service facility, which undertakes evaluations of sedimentary deposits with a view to determining their archaeological history and potential. These evaluations look at how the deposits were accumulated and examine the micromorphology, diatoms, pollens, ostracods, molluscs and so forth. His lecture concentrated mainly on the alluviums and sediments of the Thames Valley and commenced by demonstrating the preservative qualities of his subject by reference to Pepys' diary, which referred to "trees with nuts" discovered twelve feet underground during the excavation of the docks. Similarly, at Crossness in the 1800$: buried oak was preserved sufficiently for furniture to be made from it.

Alluvium is a water-lain deposit which can take many forms. A meandering river would lay down clays and silts on its flood plain, but peats within the ox-box lakes cut off by its meandering. Erosion would occur on the outside of the bends with sands and gravels deposited on the inside. The ice-melt in the last glacial deposited sedimentary gravels. Estuarine deposits would contribute to the alluviums with salt marshes. Martin pointed out that these various deposits from various sources would all be designated alluvium on the geological map. He illustrated other examples - banded hill wash deposits, tufa deposits in Dover and marine sands and gravels.

These deposits extensively spread along the Thames, the Medway, the Essex coast, Dungeness, Romney Marsh and the Wealden Valleys. Yet, there had been little work carried out on these wetlands of southern England, in comparison with other areas. Their importance is a result of their method of accumulation. When rivers overflow their banks, the silts and clays are usually laid gently, with no disruption of artefact scatters, as confirmed at Uxbridge where red deer bone workings were gently sealed some 20 metres from the river. Deposition is close to the water table. creating the anaerobic conditions for the preservation of organics such as wood -note the Roman warehouse at Southwark. Ard marks were preserved at Bermondsey beneath alluvial deposits.

In the Thames area, however, there is a problem. Subsidence in the London Basin at the rate of 1.5 metres per 12,000 years had led to inundations and swamping; creating large depths of peats, clays and silts. The sediments at Tilbury are 13 metres deep, and at Woolwich 5 to 6 metres. Mesolithic remains could be 5 to 12 metres below ground. The problem of such a depth of sediment is compounded by the fact that the water table might only to 1 to 1.5 metres below the ground, leading to deep excavation requiring much waterproofing additionally, aerial photography is of no help in locating such deep archaeology and the SMR tends to be biased in favour of the near surface zone. Field walking is limited to 18t and 19th century history and geophysical survey has only shallow penetration.

These problems are surmounted by the use of boreholes. An interesting range of appliances are used by the research team, from hand augers to motorised commercial drilling rigs. The latter can remove 45 cm long core samples,

undisturbed and bagged ready for further analysis in the laboratory. From a continuous sequence, it is possible to build up a ground model and the basis for the investigation for the archaeological sensitive areas. This is much quicker and cheaper than just trenching.

Martin finished with two examples of work undertaken by his unit. The first was al Dover where essential road building works were cutting through the old town providing the opportunity to investigate the archaeology. The core removed from a borehole in the churchyard revealed gravels on top of peats and tufa with clays, silts and gravels below. The bottom layer was identified as the infilling of the old harbour, the peats and tufa as a prehistoric layer that would be archaeologically significant. The adjacent excavation revealed a large Bronze Age boat within the tufa deposit*. The second site discussed was Chatham dockyard, where the Medway Tunnel was under construction. The tunnelling involved excavating a 10 metres deep hole through gravel which would remove 7:000 years of sediments at one go! Boreholes showed a high chalk area overlooking peats and alluvium. The sequence was saltmarsh deposits above peats, the latter dated to 4,800 bp, Mesolithic, containing one flint, and charcoal signs of some human activity on the floodplain. the chalk bluff proved important. Knapping debris on this was sealed by alluvial deposits which had preserved the Neolithic or Bronze Age flint working. Romano-British ditches and pits had been cut into the alluvium.

Martin's wife, Susan, is a member of HADAS and our first introduction to Martin's sphere of work was at Church Farmhouse in 1993 when, on a brief visit to our excavation, he interpreted one aspect of stratigraphy as being a 'landslip " layer, which enabled us to make more sense of the nature of the site. Martin's lecture, too. has added much more to our knowledge of this specialise aspect of archaeological investigation, for which we thank him very much.

*The full story of the Dover Boat can be read in "Current Archaeology" no. 133 A copy is in the HADAS library, or it can be purchased direct from the publisher - our Chairman!


Archaeologists digging in a cave near Idrija in north-western Slovenia have unearthed a Neanderthal flute made from a bear bone. It probably the oldest musical instrument discovered and is the first indication that Neanderthals did not inhabit a world devoid of recognisable language or, it would seem, of music.