Area: 20.6 hectares.
Geological Conservation Review Site.
Description and Reasons for Notification:
Trebetherick Point lies at the mouth of the Camel Estuary to the north-east of Padstow. The site is of particular geological interest as it provides an important section in Quaternary deposits, showing a sequence of raised beach, sandrock, ‘boulder bed’ and head deposits resting on a shore platform. The controversial ‘boulder bed’ has been interpreted variously, as a beach deposit reworked from glacial sediments, a solifluction deposit or a till. The sequence at Trebetherick, its wider stratigraphical relationships and implications for Quaternary events and chronology in southwest England have generated considerable interest and debate, making it an important locality for Quaternary studies.
Daymer Bay, to the south of Trebetherick Point, contains excellent exposures of the Harbour Cove Slates (U. Frasnian) and Polzeath Slates (L. Fammenian). Both units are richly fossiliferous which is unusual in this area. The Harbour Cove Slates contain useful palaeocurrent indicators and are consistent with a deep water environment. This is a key palaeontological site whose rich fauna allow precise dating for local Devonian sedimentary sequences.
In addition to the geological interest there is a diverse calcareous cliff top grassland flora on stabilised wind blown sand, and a rich intertidal rocky shore fauna.
The grassland is dominated by red fescue Festuca rubra with frequent calcicolous herbs including cowslip Primula veris, mouse-ear hawkweed Hieracium pilosella, carline thistle Carlina vulgaris and glaucous sedge Carex flacca, in addition to a more maritime community of wild thyme Thymus praecox, common centaury Centaurium erythraea, kidney vetch Anthyllis vulneraria and spring squill Scilla verna.
The rocky intertidal zone at Trebetherick supports a diverse fauna notable for its high population numbers. The Mediterranean mussell Mytilis galloprovincialis, barnacles particularly Chthamalus montagui and C. stellatus and limpets, particularly Patella aspera dominate the community which has representatives of most major intertidal invertebrate phyla present. A notable Cornish element of the fauna is the Celtic sea-slug Onichidella celtica.