North Bay to South Toll House Cliff
Also within
Condition (Natural England)
| Unit | Feature | Condition | Area (ha) | Assessed |
|---|---|---|---|---|
| TA046891 | — | Unfavourable Declining | 1.15 | 2013-02-26 |
| TA048892 | — | Unfavourable Declining | 1.15 | 2013-02-26 |
| TA048894 | — | Favourable | 2.14 | 2013-02-05 |
| TA049894 | — | Favourable | 6.43 | 2013-02-26 |
Climate exposure
This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.
Coastal habitats are exposed to sea-level rise and storm erosion. Where hard sea defences sit behind them, there's nowhere landward to retreat to — a squeeze that keeps compressing the habitat no matter how well it's managed.
Geology & landscape
Landscape processes: Coastal
Description
Description The site comprises both cliff and foreshore exposures which together demonstrate a remarkably complete succession through the Callovian Stage and the Lower Oxfordian Substage. The lowest Callovian rocks exposed are the limestones of the Abbotsbury Cornbrash Formation = 'Upper Cornbrash' of authors which have historically yielded a rich molluscan fauna, including age diagnostic ammonites Herveyi Zone, Lower Callovian. The overlying Cayton Clay Formation = 'Shales of the Cornbrash' of authors is rarely seen but traces can occasionally be found on the foreshore on the north west side of Castle Hill. The Cayton Bay Formation is succeeded by the sandstones and chamosite oolites of the Osgodby Formation. The steep cliff below Queens Parade demonstrates a full sequence of the formation including the component Redcliff Rock = 'Kellaways Rock' of authors, Langdale and Hackness Rock members. Foundered blocks on the foreshore north west of Castle Hill allow the characteristic lithologies of the Redcliff Rock and Langdale members to be examined. The former have yielded age diagnostic ammonites indicating the Koenigi Zone Lower Callovian; the latter are of presumed Coronatum Zone Middle Callovian age. The Hackness Rock Member is best examined at the southern extremity of the site South Toll House Cliff and on the foreshore below the northern tip of Castle Hill. Historically the Hackness Rock of Scarborough has been a rich source of ammonites including the type specimens of several nominal species. Faunas present indicate both the Athleta Zone and the Lamberti Zone Upper Callovian. The Osgodby Formation is succeeded by the silty mudrocks of the Upper Oxford Clay which are well exposed in the lower part of Castle Cliff. Many ammonites have been obtained from near the base of Upper Oxford Clay around Castle Hill and probably include the type specimen of the aptly named Cardioceras Scarburgiceras scarburgense Young and Bird 1828. The fauna indicates the Mariae Zone Lower Oxfordian. Scarborough Castle Hill is capped by sandstones and limestones of the Corallian Group which overlie the Upper Oxford Clay. Various levels in the succession are accessible along the base of the cliff north of the archway below Scarborough Castle. The Lower Calcareous Grit Formation Tenant's Cliff Member and Saintoft Member is well developed and overlain by the Passage Beds and Hambleton Oolite members of the Coralline Oolite Formation. Certain levels in the Corallian Group have yielded important shelly faunas including ammonites indicating the Cordatum Zone Lower Oxfordian and Thalassinoides type burrows are often prominent in fallen blocks. The superb exposure of a remarkably complete and accessible Callovian to Lower Oxfordian sequence have made the cliffs and foreshore exposures of Castle Hill a classic geological locality. The site has great educational potential and is invaluable as a lithostratigraphical reference section. Other Information 1. This site is identified as being of national importance in the Geological Conservation Review. 2. Part of this site was formerly notified under the name South Toll House Cliff+*. * Under Section 23 of the National Parks and Access to the Countryside Act, 1949. + Under Section 28 of the Wildlife and Countryside Act, 1981, as amended.