The Wolds are formed largely from a series of pure marine limestones formed during the Cretaceous period, known collectively as the Chalk Group. The chalk overlies a series of other sedimentary strata of late Jurassic/early Cretaceous age. The strata dip gently to the east and form a scarp which runs southeast from Barton upon Humber via Caistor before it loses its identity north of Spilsby. To the north of the Humber Gap, the same formations continue as the Yorkshire Wolds. The rock succession in stratigraphic order i.e. youngest/uppermost first, is this:
The thin Hunstanton Chalk and the Ferriby Chalk formations form much of the west facing Wolds scarp but it is the overlying Welton Chalk Formation which forms the greater part of the easterly dip-slopes with the Ferriby Chalk extensively exposed within the dry dip-slope valleys. The Burnham Chalk Formation forms an indistinct secondary scarp to the east of the main scarp between Barton and Louth. In the north between South Ferriby and Grasby, the lower part of the scarp is formed from the Kimmeridge Clay Formation. A series of other rock layers intervene from the Caistor area southwards, uppermost of which are the green-brown Carstones: Lower/early Cretaceous
Carstone Formation
Roach Formation
Tealby Formation
Claxby Ironstone Formation
Upper/late Jurassic
Spilsby Sandstone Formation
Kimmeridge Clay Formation
The numerous dry valleys cut into the dip-slope are typically floored by head, locally derived clay, silt, sand and gravel. The western valleys were created during recent glacial periods through the action of water over frozen ground whilst many in the east represent subglacial drainage. During the last ice age, ice encroached upon the Wolds from the northeast and entered the Humber gap from the east but did not cover the Wolds, hence ther is no Devensian age glacial till on these hills. However an earlier ice age left extensive spreads of till across the central and southern areas. Sections of the main scarp, notably at Saxby All Saints and between Nettleton and Walesby have been subject to landslip.
Geography
The Wolds comprise a series of low hills incised by characteristic dry open valleys. The Lincolnshire Wolds can be divided into four distinct areas:
The Lincolnshire Wolds were designated an Area of Outstanding Natural Beauty in 1973, and are managed as such by the Lincolnshire Wolds Countryside Service. The Wolds AONB covers 560 square kilometres, while the Countryside Service recognises a wider Lincolnshire Wolds Character/Natural Area which incorporates the AONB and the neighbouring areas of the Wolds to the north and south. The Wolds AONB cuts across the council boundaries of Lincolnshire County Council, East Lindsey District Council, West Lindsey District Council and North East Lincolnshire Council. The boundaries of the AONB are marked by tourist signs incorporating stylized hills and trees, placed on roads leading into the area.
People and places
The Wolds are sparsely populated and have a rural character. They are 'ringed' by several small market towns that lie around their edge:
Alford
Horncastle, billed on tourist signs as the "gateway to the Wolds", lies just outside the south end of the AONB
Louth, "the capital of the Wolds"
Market Rasen
Caistor
Spilsby
Many of the place-names in the Wolds indicate a strong Viking influence in the area's history. There is also an abundance of mediaeval 'lost villages' – settlements abandoned due to changes in land use, soil exhaustion and disease. Several notable roads and paths run over the Wolds. Caistor High Street, the path of a Roman road and now the route of the B1225, runs from Caistor to Baumber near Horncastle. The ancient Bluestone Heath Road follows the course of an ancient drove road from west to east across the Wolds, and several "A" roads also run through the AONB. The Wolds are now promoted as a tourist destination: the area's connection with Tennyson is being exploited, and farmers are being encouraged to diversify into the tourism industry. The roads of the Wolds are particularly popular with motorcyclists, and the area is home to Cadwell Park, one of the UK's top race circuits. The area is also popular with hikers: the Viking Waylong-distance footpath runs from Barton-upon-Humber in North Lincolnshire across the Lincolnshire Wolds and into Rutland, and there is a youth hostel in the middle of the Wolds at near the village of Tetford.