OXFORDSHIRE, a midland county of England, is bounded N.E. by Northamptonshire, E. by Buckinghamshire, S. by Berkshire, W. by Gloucestershire, and N.W. by Warwickshire. It lies between 51° 23' and 52' 10' N. lat., 0' 50' and 1° 44' W. long. The county is very irregular in form. The longest straight line that can be drawn on the surface of the county measures 51 miles, and extends from the War wickshire border near Upton House to the Thames at Lower Caversham. The area of the connty is 739 square miles, or 472,887 statute acres. The population in 1841 was 163,127; in 1851 it was 170,363.
Surface and Geology.—The surface of Oxfordshire is for the most part level or gently undulating. A long range of hills runs from the left bank of the Evenlode, in the west of the county, northward to Chipping Norton, and thence eastward to the neighbourhood of Doddington. A low offset runs north-westward near Great Rollwright, and connects the range with a group of hills that occupies a consider able district on the north-west boundary, and forms part of the water shed between the Severn and the Thames. Broom Hill, one of the highest of these, and the most north-western point in the county, is 836 feet high. The most southern part of the county is occupied by the Chiltern Hills. The north-western slope of these hills is the steeper. Nettlebed Hill, near Nuffield, is 820 feet high ; Nuffield Common has an elevation of 757 feet. The Chilterns were formerly occupied by a forest or thicket of beech-trees, which are the trees best adapted to the soiL A large part of the surface is now occupied as amble land or as sheep-walks. The only other hills worth mention in the county arc those to the cast of Oxford, between the Cherwell and the Thames. Shotover Hill, the highest of these, has an elevation of 509 feet.
The Chiltern Hills are composed of chalk ; from their northern base the lower formations of the cretaceous group crop out. The upper green-sand is almost lost in the chalk marl which overlies and in the gault which underlies it : the gault has been sometimes designated Tetsworth clay, from the village of Tetsworth, near Thame. The upper division of the oolitic series, comprehending the Purbeck, Port. land, and Kimmeridge beds, crops out from beneath the iron-sand.
To the east of Oxford the coral mg, one of the formations of the middle division of oolitee, forms the elevated platform between the valleys of the Cherwell and the Theme. This formation extends across the Thamea into Berkshire. The blue thy, or Oxford clay, which separates the coral rag from the lower oolites, occupies the middle part of the county. On the eastern side of the county the Portland bed, of the upper series of oolites rest Immediately on the Oxford clay.
The rest of the county, except the valley of the Cherwell above Banbury, is occupied by the lower division of the oolites. The forest
marble, another formation of this division, has obtained Its mune from Whichwood Forest, near Burford, where it is found. It is a limestone susceptible of a tolerable polish, and occasionally used as a coarse marble. The calcareous slate of Stonesfield, near Woodstock, is remarkable for the singular variety of its orgenie romaine, among which are the spoils of birds, land animals, A mphibia, sea-shells, and vegetables. The great oolite is quarried near Burford, and these quarries supplied the stone of which St. Paul's cathedral (London) is built. The lower division of the oolites forms the mats of a well defined range of hills rising from the valley occupied by the Oxford clay. The greater part of the county north of Deddington and Chipping Norton is occupied by ferruginous sands and sandstone, denuded of the great oolite which usually caps them. The district occupied by these oolitic and arenaceous formations contains some of the highest hills In the county.
Ilydrography and Communications.—Oxfordshire belongs almost entirely to the basin of the Thames. The Stour, an affluent of the Upper Avon, rises just within the north-western boundary at Drayton ; and the Ouse, in the upper part of its course, skirts the north-eastern boundary, and receives the Ousel, one of its smaller tributaries, from that part of the county. The Thames first touches the county a little below Lechlado in Gloucestershire, where the navigation com mence,, and quits it a little below Henley. The length of its course along this county is about 70 miles. [Trusses.] The Windrush rises iu the Cotswold Hills, and after flowing through Gloucestershire enters Oxfordshire, passes Burford and Witney, and flows by several channels into the Thames. The Erenlode rises near Moreton-in-the•Marsh in Gloucestershire, and enters Oxfordshire about 9 miles from its source, having previously skirted the border for a short distance : its course through Oxfordshire is generally south-east and south. It falls into the Thames about a mile and a half east of Ettsham. The Glyme, one of the tributaries of the Evenlode, after passing Woodstock flows through Blenheim Park, where it expands into a large sheet of water. The Cherwell, or Cherwell, rises near the village of Charwellton, in Northainptonshi e, and flows southward into the Thames at Oxford. It receives a number of small tributaries. The Theme rises at Stcwkley, between Aylesbury and Fenny Stratford in Buckinghamshire, and flows south-west to the town of Thame, where it touches the border of Oxfordshire; for about 5 miles farther it skirts the border, and then entering the county flows through it about 10 miles into the Thames at Dorchester. It is navigable from Theme to Dorchester.