RIGS Group

Trust's first geological reserve

Many people will now be aware from the media that the Trust has its first geological reserve. This is Harvey's Pit at St Erth - not any old Tom, Dick or Harvey but the Harveys of Hayle, the great builders of Cornish engines. The pit was the source of their moulding sand, and so has very great significance for the industrial archaeology of Cornwall. Not much is visible now - a rusting piece of rail, tips of waste sand, and the main working face, but all so overgrown with over 60 years of oak, hazel, brambles, nettles, moss - hardly a geological site at all - so why are we excited?
Well, firstly, it's the first, and the negotiations by the Trust's solicitors have been protracted. The site was originally offered to the Royal Geological Society of Cornwall who generously turned it over to the Trust as a body with experience of managing reserves. We hope that this experience will soon include managing several geological reserves.
Secondly, the pit is not any old sandpit but is an SSSI in the St Erth Beds, thought to be the only material of its age in Britain, though there is material of the same age preserved in North West France (as well as beneath the Atlantic). The age is late Pliocene, a mere two million years ago or slightly less, and a marine clay in the nearby Vicarage Pit, owned by the Church Commissioners, has yielded abundant fossils many of which indicate a Mediterranean climate and a shallow water depth (maybe less than lOm). Since the St Erth Beds are found at a height of 37-50m, this suggests a sea level at the time of probably about 45m higher than today. Much of the scientific work was done in the early 1970s (and Professor Frank Mitchell who led it has deposited his field papers, and much else, in the St Erth archive at the Trust) but there are many questions still unanswered - and new scientific techniques to be used.
The undisturbed sand, at the edges of the pit, is the material which will need to be studied and of course this is a finite resource: clean off a face and within a year it will be smeared with soil and being colonised by plants, and need cutting back again. For this reason all cleaning of the faces needs to be science-led, and we hope researchers will want to decipher more of the story from the St Erth Beds.
In the meantime the Trust has as its first geological reserve a site of international importance, with the potential for adding more information to the history of the climate and sea levels of the last few million years, an area of major research interest and, of course, of public concern for whatever light it may throw on potential future changes.


At our AGM on 13th November, Dr Roger Jones will be talking about making Postcards from the Past and the work of the BBC Natural History Unit. If you cannot make it at 3.OOpm at Camborne School of Mines, he is also talking at Bodmin Community College at 7.OOpm. Both talks are Geological Heritage - please collect one from Allet or ask for one to be sent to you.

John Macadam

Look out for Cornwall's Geology and Scenery - an Introduction by Professor Cohn Bristow. This new book explaining local geology for the layman is ava ilable from book shops in the county at 13.99 paperback or 17.99 hardback.

Otter Group

The next meeting of the Otter Group will be held at Five Acres on Saturday 12th October from 1045am until 500pm. The morning session will deal with otter survey methods and during the afternoon there will be an opportunity to visit local rivers to look for signs of otters. If time allows, there will be slides on Californian sea otters. Anyone interested in otters, and particularly in recording, is very welcome. Please bring your own lunch - tea and coffee will be provided.

David Curtis

Reptile and Amphibian Group (CRAG)

Amphibians and reptiles continue to hit the headlines Bhs Frogwatch, newt pond restoration at Hayle, a rare neotenous newt - one which grows to adult size but remains a tadpole - at Pencalenick School and terrapins at Swanpool have all helped to raise the Trust's profile. We've recently set up a partner group - DRAG - with the Devon Trust, but we're still desperately short of volunteers willing to do the survey work so essential to conserving our own native herptiles.

Mark Nicholson

Mark Nicholson
Trust Education Officer Mark Nicholson shows Swanpool visitor Tristan Peck, aged four, what a 50p-sized baby terrapin from a pet shop (left hand) will eventually become. Photo Sion Brackenbury.

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