DURHAM, a county of England bounded north by Northum berland, east by the North sea, south by Yorkshire, and west by Westmorland and Cumberland. Area 1,014.6 sq. miles. The Derwent, a tributary of the Tyne, forms part of the northern boundary with Northumberland, while the Tees in the south forms almost the whole of the boundary with Westmorland and York shire. The county is divided into a highland west and a lowland east. No clearly marked contour separates these regions but geologically the Permian scarp, forming the right bank of the middle Wear and continuing north-north-eastwards to just south of Tynemouth is a suitable dividing line. West of this the Car boniferous limestone series prevails, a succession of thick beds of limestone with intervening sandstones and shales. This series forms the high ground of the north Pennines which are the back bone of the western section of the county. It is, however, broken by intrusive dykes and sills of basalt, especially in the Tees valley above Middleton ; one of these, the Great Whin Sill, extends 120 miles. The Cockfield dyke and Little Whin Sill are similar intru sions of basalt. Millstone Grit caps many of the higher points in the west as at Muggleswick and Walsingham commons. On these plateaux, Bolts Law reaches 1,778 ft. and Fatherly hill 1,504 feet. The outcrop of the Millstone Grit broadens eastward until it is covered by the Durham coalfield which occupies the centre of the county from Newcastle and South Shields to Barn ard Castle. There are some small Silurian outcrops near Cronk ley on the Tees, once famous for its slate pencils. South and east of the Permian Scarp the newer rocks are exposed and dip east wards or south-eastwards. The Permian magnesian limestone reaches from the Tees to South Shields in a broad tract and occupies the coast between that town and Hartlepool. The south eastern corner of the county is low-lying with Triassic and Jurassic material—red marls and sandstones with beds of gypsum and rock salt.
The drainage system as represented by the major streams, the Wear, Derwent and Tees, bears a curious relation to the geology. When flowing over the older rock of the west they follow a general north-west to south-east line, well marked in the Upper Wear and Tees, but, once they enter the newer rocks, the general direction of the drainage runs almost at right angles south-west to north east. Of additional interest is the final section of the Wear from Chester-le-Street to the sea. In pre-glacial times the south-west to north section of the middle course continued and the Wear was a tributary of the Tyne entering it just to the west of Gateshead. The blocking of its former lower course by glacial debris caused it to turn at Chester-le-Street to the eastward and it cut through the low Permian scarp and found the sea at its present mouth at Sunderland. Between the Wear and lower Tees is the strange valley of the Skerne. This river flows on Permian rock in an opposite direction to the general trend of the larger rivers and enters the Tees just as it changes its course (near Darlington) from the upper north-west to south-east section on the older rocks (where it takes advantage of important fault lines) to its lower course on newer rocks in a broad open valley with wide stretches of sand near the coast.
Glacial deposits containing derived material from the Cheviots and Pennines obscure the older rocks. There are evidences from sunk meanders in the middle courses of the Wear and Tees, raised beaches, and submerged forests off the coast at West Hartle pool and other points of post-glacial earth movements. Except in the western moorlands only a few scraps of the county have been left in their natural state. The ballast-hills at Shields, Jarrow and Hartlepool, have many foreign plants elsewhere unknown in England. Stockton was almost the last retreat in England of the native black rat. Peatbog remains testify to the former abund ance of deer, wild ox and boar, which appears to have existed in the reign of Henry VIII. ; records of red deer are found in the i8th century.
In the 6th century Northumbria was divided into Bernica and Deira, separated by the Tees, the latter including the district afterwards known as Durham. The post-Norman palatinate grew around a grant of land originally made by Egfrith to St. Cuth bert on his election to the see of Lindisfarne in 684. On the transference of the see to Chester-le-Street in the 9th century, Guthred the Dane endowed it with the whole district between the Tyne and the Wear, stretching west as far as Watling street, a grant confirmed by Alfred; the endowment was again enriched at the establishment of the see at Durham in 995. The ravages of the Danes caused much disruption in this area in the 9th century when the Tees formed the northern boundary of the Danelaw. Durham continued, however, to form part of the earldom of Northumbria, and it was not until after the purchase of the earl dom by Bishop Walcher in that the bishops began to exer cise regal rights in their territory. The term palatines is applied to the bishop in 1293. At the time of the Conquest the bishop's possessions included nearly all the district between the Tees and the Tyne, except Sadberge, and also the outlying districts of Bedlingtonshire, Norhamshire, Islandshire and Crayke, together with Hexhamshire, the city of Carlisle, and part of Teviotdale. Henry I. deprived the bishopric of the last three but made over to it three vills of the earldom of Northumberland. The wapen take of Sadberge was purchased by Bishop Pudsey in 1189, but continued independent in administration. The division into the four wards of Chester-le-Street, Darlington, Easington and Stock ton existed in the 13th century. The diocese was divided into the archdeaconries of Durham and Northumberland.
The palatinate was administered by a steward with a sheriff. coroners, chamberlain and chancellor. The palatine assembly represented the whole county and dealt chiefly with fiscal ques tions. The bishop's council, consisting of the clergy, the sheriff and the barons, regulated judicial affairs. The prior of Durham had his own court. The repeated efforts of the crown to check the powers of the palatinate bishops culminated in 1536 in the Act of Resumption, which deprived the bishop of much of his judicial power. In 1596 further restrictions were imposed and in 1646 the palatinate was abolished. It was revived, however, after the Restoration, and continued with much the same power until the Act of 1836, which finally vested the palatine jurisdiction in the crown. The most important palatinate barons of the i 2th century were the Hiltons, the Bulmers, the Conyers, the Han sards and the Lumleys. The Nevilles owned large estates in the county, which they ruled from Raby castle. Owing to its isolated position the palatinate took little part in the great rebellions of the Norman and Plantagenet period. On the outbreak of the Civil War Durham inclined to support the cause of parliament, and in 164o harboured the Scottish army. In 1642 the earl of Newcastle organized the western counties for the king, but in 1644 the palatinate was again overrun by the Scottish army, and after Marston Moor fell entirely into the hands of the parliament.
See W. Hutchinson, History and Antiquities of the County Palatine of Durham (3 vols., Newcastle, 1785-1794) ; R. Surtees, History and Antiquities of the County Palatine of Durham (4 vols., 1816-40) ; B. Bartlet, The Bishoprick Garland, Collection of Legends, Songs, Ballads . . . of Durham (1834) ; J. Raine, History and Antiquities of North Durham (1852) ; Perry and Herman, Illustrations of the Mediaeval Antiquities of the County of Durham (1867) ; G. T. Lapsley, The County Palatine of Durham (New York, 1900) ; Victoria County History, Durham. See also the Surtees Society's Publications and Transactions of the Architectural Society of Durham and North umberland.