ROCKS .... THEY'RE NOT WILDLIFE!

Over the last few months the seal pups have been born in caves around the coast. In a few months' time The Lizard will have its distinctive flowers.

So too will the National Nature Reserve of Goss Moor. Further north, harebell, a lime-loving plant, will flower on Pentire Head by Polzeath. Further north still, what is left of the Culm grassland has its own distinctive flora and fauna.

All this wildlife is closely related to the geology. The Lizard, a slab of ocean floor, has very different flowers on the serpentine compared to the schist. The overall flatness of Goss Moor is probably the result of marine abrasion, while the small-scale hummocky ground was the result of miners exploiting the tin ore. Pentire has its harebells because the famous pillow lavas, erupted under water, have been altered to a rock rich in calcium carbonate. But what have seal pups got to do with geology? If you look at the caves around the coast you will soon notice that most are there because the sea has eroded along a fault. So where the seals pup is probably related to a break in the rocks which occurred over 300 million years ago.

Even Breney Common and Red Moor reserves have their origin in geology - marine abrasion again - and man's efforts to work the alluvial tin ore. Earlier this century a tin dredge was working at Breney Common, and gravel was last exploited in 1940. The pools left by these operations are now a major feature of the reserves.

Between the reserves is Helman Tor, not only an impressive landmark but also with a wealth of geological features which make it an excellent teaching site. Helman Tor is one of over 80 RIGS (Regionally Important Geological/geomorphological Sites) in Cornwall. We can think of these as being the geological equivalent of the County Wildlife Sites designated by the Wildlife Trust. Both are the subject of conservation policies in both county and district planning documents. The need to conserve geological features may seem a little strange at first, but just like wildlife sites there are threats. Valuable quarries can be used as informal tips, or for landfill schemes. Coastal exposures can be damaged or destroyed by coast defence schemes (for example at Porthleven and at Fistral, and potentially at Pendower on the Roseland). Mine dumps can be flattened and grassed over: of the new minerals discovered in Britain each year over half are found in Cornwall (and some of these minerals are totally new to science). The RIGS Group is particularly pleased that the National Trust is taking great care not only to preserve the mining structures, such as engine houses, but also the mine dumps in West Penwith.

In places, human needs must take priority over conserving geology - an example is Praa Sands, where coastal erosion was severe. But with the co-operation of district authorities and contractors useful scientific information can still be gained during engineering work.

Quite often geological sites have been damaged through ignorance. As well as identifying suitable sites for RIGS the group runs a large number of guided walks and other events. We hope you will find an event near you which you would like to attend: there are walks from Crackington in the north to Mount's Bay in the west, to Saltash in the east. There are even more events on the salmon-coloured geological events list available from Allet or your local library, or on our Internet homepage. There is also an increasing number of published trails for non-specialists on the market. At present these are scattered thinly from Land's End to Marsland Mouth, and over to Cawsand Bay.

The Wildlife Trust, led by the RIGS Group, is very actively searching for a reserve which combines both geological and biological interest and which we hope will show that both interests can coexist happily and even complement each other.

John Macadam