NORTHAMPTONSHIRE, an east midland county of Eng land, bounded north by Lincolnshire, north-west by Rutland and Leicestershire, west by Warwickshire, south-west and south by Oxfordshire, south-east by Buckinghamshire, and east by Bedford shire, Huntingdonshire and Cambridgeshire. The area is 1,003.1 sq.miles.
The underlying structure of the county is very simple. It forms part of the Jurassic es carpment, here known as the Northampton uplands. All the rocks are of Jurassic age, the dip being in a general way to the south east, and the strike from south-west to north-east. The oldest, and most westerly belt consists of Lias formations which cover a large surface in the south-west and centre, around Banbury, Day entry and Market Harborough, and they are also exposed along the rivers near Towcester, Northampton, Wellingborough and Kettering. The marlstones of the Middle Lias were formerly much used for building material ; the Upper Lias is worked for bricks at Easton Neston (Towcester), Blisworth, Gayton, Heyford, Northampton, Wellingborough, Rushden, Irthlingborough, Ketter ing and Corby. Through the middle of the county, north-east to Northampton, Rockingham and Peterborough, is an elevated tract of Oolitic rocks, which formerly supplied stone, of which many of the villages are built, as well as lime and marl. The New Duston quarries have several varieties of good stone, the dis trict around Northampton a limestone known as Pendle, and Weldon (Lincolnshire Oolite) a noted freestone ; Barnack Rag (near Stamford) is no longer worked. The great Oolite lime stone, though unsuitable for building material, owing to the ease with which it weathers, was largely used in the past, Culworth, Blisworth and Cosgrove quarries being famous. At the base of the Inferior Oolite, Northampton sands yield iron ore, which is worked at Duston, Culworth, Towcester and at numerous locali ties north-east of Northampton. Certain hard shelly beds in the Oolite rocks have been polished and used as marble.
On the south-east border of the county, a belt of Oxford clay occupies the surface, good exposures occurring in the brick fields about Peterborough. Boulder clay is widely distributed over the
uplands and in the east of the county, and glacial and river gravels are also plentiful. The south-west portion of the county forms the principal watershed of the Midlands ; the Cherwell, the Avon, the Leam, the Welland, the Nene have their sources in this region, and all form sections of county boundaries. The position of Day entry as a wireless station and a meeting place of roads is also related to this fact of centrality and elevation. The longitudinal river Nene flows in a north-easterly direction along the foot of the uplands, draining them to the Wash.
In primitive times the waters of the North sea reached almost to the foot of the North amptonshire uplands. The immigrants of the end of the Stone age seem to have penetrated up from the coast, and Peterborough has yielded important finds of early pottery. Some Beaker pot tery occurs, chiefly on the uplands. There are a few material ob jects of the La Tene I. culture and the La Tene III. culture. During the Iron age, the uplands offered defensible sites, and many hill camps were made, Hunsbury (II m. S.W. of North ampton), being one of the most famous. In Roman times, iron, stone and clay were worked, and Towcester was an important station on the Watling street route to the north-west. At some time in the 7th century the district suffered a simultaneous inva sion (West Saxons from the south, Anglian tribes from the north), finds show a mingling of races, but West Saxon influence never spread farther north than a line from Daventry to War wick, and with the extension of the Mercian kingdom under Penda and the conversion of the midland districts, ceased altogether. The abbey at Medehamstede (now Peterborough) was begun by Penda's son, Peada, in 655, and about the same time foundations were established at Peakirk, Weedon Beck, Castor and Oundle. In 87o the district was overrun by the Danes, and Northampton was one of the five Danish boroughs, until in 921 it was recovered by Edward the Elder, who fortified Towcester in that year.