Area: 32.0 hectares.
Description and Reasons for Notification:
This site, which includes a stretch of cliff along the north side of Poole Harbour of high geological interest, also holds dry and wet heath with a rich associated flora and fauna.
Included in the SSSI is one of only two sites yielding fossil plants from the Dorset Pipe Clays, of lower Eocene age. This is of considerable significance as these deposits are the probable fluviatile (‘river-lain’) facies equivalents of the marine London Clay with its world famous flora. Fossil plants occur here at several facies throughout the geological site. Foreshore exposures allow the observer to understand the geological context of the plant bearing strata, making this site a valuable one. The flora from the geological site consists mainly of angiosperm fruits and seeds, many of which represent tropical trees and lianas. Over seventy fossil species have been recorded here of which thirty species and three genera are restricted to this site in British Tertiary floras, whilst many are unique in the world’s Tertiary deposits. It is also the type locality for four genera and forty-four species and is critical for studies of European Tertiary palaeobotany and palaeocology.
Dry heathland occurs on the higher ground, the railway embankment and slopes of old mineral workings. Dominated by ling Calluna vulgaris and western gorse Ulex gallii, it is typical of the heathlands north of Poole Harbour. Other associated plants are bell heather Erica cinerea and bristle bent Agrostis curtisii and lichens of the genus Cladonia are frequent. Common gorse Ulex europaeus and bracken Pteridium aquilinum locally form dense stands.
In wetter areas on lower ground purple moor-grass Molinia caerulea and cross-leaved heath Erica tetralix are the dominant plants, but where there is flushing by ground water from above, common cottongrass Eriophorum angustifolium, bog asphodel Narthecium ossifragum, star sedge Carex echinata, marsh lousewort Pedicularis palustris and royal fern Osmunda regalis occur. There are small quantities of the bog-mosses Sphagnum tenellum and S. fimbriatum and, in places, the mosses Campylium stellatum and Warnstorfia fluitans. Other low-lying wet areas support common reed Phragmites communis, common sallow Salix cinerea and downy birch Betula pubescens.
The dry heathland supports strong populations of the rare sand lizard Lacerta agilis and Dartford warbler Sylvia undata, a rare heathland bird, breeds here. The former clay workings now form a lake which is of general interest for birds and supports a number of dragonfly species including the scarce small red damselfly Ceriagrion tenellum.