"Although there is no dramatic scenery in Oxfordshire, no sea cliffs or craggy peaks, the rocks beneath the gentle surface have largely determined the pattern and character of human settlement through water supply, soil type and the provision of building materials."
H. Philip Powell
President, Oxford Geology Group
Author of The Geology of Oxfordshire
CHURCHILL & SARSDEN
DRY STONE WALL
The solitude of its high calcareous grassland and beech hangers, its sheltered valleys and long vistas are all cherished aspects of the Cotswolds landscape of northern Oxfordshire. The escarpment and plateau of the wolds dominate the north-west of the county. These gently rolling hills are formed in Jurassic limestones, clays and sands. It is the warm, buff and yellow building stones that give the signature ‘chocolate box’ Cotswold architecture and countryside its distinctive character.
The underlying geological formations influence the landscape features that develop above. The White Limestone Formation, for example, often forms plateau and caps the cuestas and valley slopes. Whereas the Sharp's Hill and Hosehay formations usually form hollows between the more resistant Chipping Norton Limestone and Taynton Limestone formations.
The Thames Valley
The upland gradually dips southwards to the Thames and Oxford vale, which is lined by the heavy Middle & Upper Jurassic clays.
The Midvale Ridge
Immediately to the south of Oxford and running between Faringdon and Thame, a low ridge separates the Thames valley from the Vale of White Horse to the south. This ridge is formed by the Upper Jurassic limestones and clays and is overlain at its eastern end by the Portland and Purbeck limestones. The higher hilltops along the ridge, such as Boars Hill, are capped by rocks of Cretaceous age.
The Vale of White Horse and Chilterns
The Vale of White Horse has been cut into the thick, bluish-grey Cretaceous Gault Clay. It is restricted to the south by the impressive escarpment of Lambourn Downs and the southern end of the Chilterns. This line of hills is formed in the Upper Cretaceous chalk, which supports characteristic species-rich grassland and beech woodlands. Evidence for the periglacial conditions that dominated the area during the ice ages of the last two million years is provided by the dry valleys, such as the Manger and Devil’s Punchbowl which occur along the chalk cuesta.
GREAT COXWELL TITHE BARN
BELOW FOLLY HILL
AN EXPOSED AMMONITE