Aldro earthworks: a cross-dyke on Birdsall Wold, 400m east of Aldro Farm

Reasons for Designation

Cross dykes are substantial linear earthworks typically between 0.2km and 1km long and comprising one or more ditches arranged beside and parallel to one or more banks. They generally occur in upland situations, running across ridges and spurs. They are recognised as earthworks or as cropmarks on aerial photographs, or as combinations of both. The evidence of excavation and analogy with associated monuments demonstrates that their construction spans the millennium from the Middle Bronze Age, although they may have been re-used later. Current information favours the view that they were used as territorial boundary markers, probably demarcating land allotment within communities, although they may also have been used as trackways, cattle droveways or defensive earthworks. Cross dykes are one of the few monument types which illustrate how land was divided up in the prehistoric period. They are of considerable importance for any analysis of settlement and land use in the Bronze Age. Very few have survived to the present day and hence all well- preserved examples are considered to be of national importance.

The cross-dyke is well-preserved over most of its length and is thought to comprise a complete dyke. It was part of an extensive system of prehistoric dykes which has been recorded on Birdsall Wold and has further associations with other broadly contemporary monuments of similar type in the vicinity of Aldro Farm. Parallels are also known from other parts of the Wolds and from the southern edge of the North York Moors. Such associations between monuments offer important scope for the study of the division of land for social, ritual and agricultural purposes in different geographical areas during the prehistoric period.

Details

The monument includes a cross-dyke which lies 400m east of Aldro Farm, at the western end of Birdsall Wold and runs north from Birdsall Dale, over the crest of Birdsall Wold and down the north-facing slope of Birdsall Brow as far as the spring-line in Swinham Wood. Between Birdsall Dale and the crest of Birdsall Brow the dyke takes the form of three 1m deep ditches between four 0.3m high banks; the overall width of the dyke measures up to 25m. As it emerges from Birdsall Dale, the dyke runs in the bottom of a narrow slack across a ploughed field; here, although the earthworks have been buried by a combination of cultivation and natural hillwash, their course can be observed from aerial photographs. North of the modern estate road to Toisland Farm, the dyke continues as an earthwork as far as the brow of the Wold where the outer ditches terminate. A 19th century survey of the earthworks records that these ditches diverted to east and west becoming linear boundaries running for several kilometres along the top of Birdsall Brow, although these have been levelled by cultivation and it is not known how much of the former earthworks survive below ground. The cross-dyke continues down the slope as a single ditch flanked by two banks, having an overall width of up to 18m. Forty metres from the top, a second westwards branch of the ditch indicates the junction of the cross-dyke with another east-west linear boundary which has now been levelled. The main dyke follows the field boundary northwards for a further 300m before it begins to turn gradually north-westwards, finally terminating at the spring-line at the 160m contour. The metalled road surface and fences are excluded from the scheduling, although the ground beneath these features is included.

MAP EXTRACT The site of the monument is shown on the attached map extract. It includes a 2 metre boundary around the archaeological features, considered to be essential for the monument's support and preservation.

Legacy

The contents of this record have been generated from a legacy data system.

Legacy System number:

20470

Legacy System:

RSM

Sources

Books and journals
Mortimer, J R, Forty Years Researches in British and Saxon Burial Mounds of East Yorkshire, (1905)

End of official list entry

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