Key Sites - South Oxfordshire
Key geological sites: South Oxfordshire.
These are the geological SSSI sites to be found within the civil administrative boundaries of South Oxfordshire District Council.
The geology of the district youngs south-eastward and comprises rocks of Middle Jurassic, Upper Jurassic, Lower Cretaceous, Upper Cretaceous, Palaeogene and Quaternary.
There are nine sites in the district designated as Sites of Special Scientific Interest (SSSI).
Please note that listing on this page does not imply that public access is freely available or has been given. Most sites are not accessible because they are on private land or they may be unsafe. Permission must be sought from the landowner before a visit.
Aston Rowley Nature Reserve SU728972
This 128.5 ha site has been a SSSI since 1973 and much of it is on Upper Chalk, while the harder Middle Chalk has eroded to produce the steep slopes of Beacon Hill and Bald Hill. The hill tops are covered with a layer of Clay-with-Flints up to 6 metres in depth. The grasslands on the steep slopes are on shallow rendzina soils of the Icknield series whilst deeper fine calcareous silty soils of the Coombe series are present in the valley bottoms.
This 4.0 ha site is one of the most famous motorway cutting in the UK, made famous on television by the Vicar of Dibley. It was designated a SSSI in 1986. A stratigraphically important site providing the best Coniacian section in central England, part of the Upper Chalk succession. Above the Chalk rock exposed at the base of the cutting there is a late Turonian to basal Coniacian section of coarse grained nodular chalk, extremely rich in fossils and important in defining the boundary between Turonian and Coniacian age rocks.
Aston Rowant Motorway Cutting SU728965-737965
Chinnor Chalk Pit SU755998
A 66.1 ha, stratigraphically important site on the Lower Chalk and basal Middle Chalk which has been a SSSI since 1986. The site is important for its excellent exposures of Totternhoe Stone, indicating the position of the mid-Cenomanian non-sequence and for its exposures of Plenus Marls and overlying Melbourne Rock. The site has yielded many important ammonites, largely from the Lower Chalk, but also from the basal Middle Chalk.
Highlands Farm Pit SU744813
This 0.6 ha site which has been a SSSI since 1986, is the last available exposure of the gravel flooring the abandoned channel of the Thames between Caversham and Henley (the 'Ancient Channel'), which existed in this area during the Ice Ages, although its relationship to the Thames Terrace sequence is uncertain. It has recently been assigned to the Black Park Terrace which is of Late Anglian age. Palaeolithic flints discovered in large numbers at this site over the last century must therefore be some of the earliest artefacts of their kind known. The uncertainty of the Terrace stratigraphy in the Ancient Channel, and the considerable historical importance of this pit, the most extensively studied and prolific of the palaeolithic gravel exposures in the Ancient Channel, make this a crucial site.
Littlemore Cutting SP532028
This 0.5 ha locality, a SSSI since 1972, shows a remarkable deposit of mid-Oxfordian (Jurassic) age of considerable palaeographic and environmental interest. The cutting has exposures of the limestone and clay units of the Littlemore Clay. This was laid down at the sametime as the Coral Rag reefs which covered most of the Oxford area during the tenuiseratum ammonite zone. The clay was apparently deposited within a narrow channel between the coral reefs of the Rag. Thus here there is an indentation into the northern margin of the Oxford reef and a deposit which can be traced laterally into these reefs. A key site in studies of sedimentation and facies change in the Oxford reef area.
This 1.2 ha locality, a SSSI since 1972, is an old and well known site is of considerable importance in studies of Upper Jurassic stratigraphy. The locality is famous for its ammonite faunas, particularly from the Kimmeridgian wheatleyensis zone and overlying strata, which were collected in considerable numbers by Neaverson and Buckman. The site is the type locality for the wheatleyensis zone and sub-zone, as well as for a number of species of Pectinatites, including P. wheatleyensis. The pectinatus Sandstone above also yielded the type specimens for many of Buckman's species. The Littleworth pit affords an unrivalled section for the study of Kimmeridgian strata and their faunas in the south Midlands
Littlemore Brick pit SP588054
Lye Hill Quarry SP592068
The 3.0 ha SSSI (since 1972) at Lyehill Quarries expose the most extensive sections in the Wheatley Limestone, of mid-Oxfordian age, here only a kilometre from its type locality. This detrital facies, laterally the time equivalent of the Coral Rag reef facies, was deposited as a series of cross-bedded, poorly fossiliferous, fore-reef limestones formed on the northern side of the reef. Their original depositional dip is well seen. Oyster patch reefs represent evidence of the only faunal elements able to tolerate the unstable substrate which prevailed in Wheatley Limestone times. This is a key Corrallian locality in any facies analysis of the Oxford coral-reef area.
Priest's Hill SU700872
A 1.0 ha site and SSI since 1986 where temporary exposures here have revealed Pleistocene organic silts of great importance. These deposits are attributable to an early Middle Pleistocene or a very late Lower Pleistocene interglacial period, probably older than the Cromerian and therefore not previously described in the British Isles. The site, if correctly dated, is unique and of international significance to Pleistocene stratigraphy.
Woodeaton Quarry SP533123
Woodeaton Quarry (6.4 ha) exhibits one of the most complete Bathonian sections (progracilis to ?discus Zones; Taynton formation to Forest Marble Formation) in Oxfordshire and presents the best exposed of two complete and extant Hampen Marly Formation sections now remaining in the county. A full White Limestone succession is also exposed, showing a sequence in many ways more typical of Northamptonshire than of Oxfordshire. The Taynton Formation, Hampen Marly Formation and Shipton Member (white Limestone Formation) were deposited in four shallowing-upwards rhythms, each one with an erosive base and rootletted at the top. The whole section at Woodeaton is of great palaeontological and sedimentological interest. Woodeaton Quarry was first cited in 1975.