REASONS FOR DESIGNATION
A small number of substantial and defensible boundary features have been identified as frontier works marking territories in the early medieval period. Up to 50 examples are known with a fairly wide distribution across England, including examples in southern England, East Anglia, Yorkshire, Derbyshire and along the Welsh border. Identified remains extend over distances from as little as 300m up to as much as 240km in the case of Offa's Dyke. They survive in the form of earthworks and as buried features visible as cropmarks or soilmarks on aerial photographs. They appear often to have been constructed across the natural grain of the landscape and, although many examples consisted of a single bank and flanking ditch, to vary considerably in their form and dimensions, even along different stretches of the same boundary, depending upon local topography. Evidence from contemporary documentary sources, excavation and survey suggests that they were constructed in the early medieval period between the fifth and eighth centuries AD. Some were relatively ephemeral, perhaps in use for only a few years during periods of local strife; others, such as Offa's Dyke, constructed between Wales and Mercia, have formed long-lived territorial and/or military boundaries in use for several centuries. As a rare monument type of considerable importance to the study of early medieval territorial patterns, all surviving examples are identified as nationally important.
The cross ridge dyke 800m east of Bleaklow is important because it is one of only two defensive or demarcation measures from this period which relates to the limestone areas of the Peak District.
The monument includes a double ditch and bank earthwork situated on a limestone ridge overlooking the village of Calver. It occupies a defensive or demarcatory position across the ridge on the edge of the limestone plateau of the Peak District. Such earthworks are often referred to as 'dykes'. The earthwork is orientated north-south and comprises a central bank approximately 4.5m wide with a ditch of similar width to either side. The whole earthwork is about 14m wide and rises approximately 2m from the base of the ditches to the top of the central bank. Although truncated by a trackway, there appear to be traces of a further bank on the eastern side. The earthwork survives in relatively good condition for about 60m from a trackway which defines its northern end. The trackway may have truncated the northern extent of the earthwork, but this is uncertain. At its southern end, the earthwork has been disturbed by mineral extraction to the extent that its original length is unknown. At approximately 40m from the northern end of the earthwork is a break in the banks which may have been original: the earthworks curve slightly inwards at this point. Although there is now no trace of an approach from the eastern side, a hollow way rises from the break to the west which appears to pre-date the enclosure of the surrounding land. The earthwork is interpreted as a defensive or demarcation measure constructed across the ridgeway during the post-Roman period. Its location on the edge of the limestone region of the Peak is similar to that of The Grey Ditch, near Bradwell, which is dated by archaeological means to this period. Historical and archaeological evidence indicates that the earthwork separated land to the west, occupied in the 'Dark Ages' by the Pecsaetna, from that of the North Mercians. All modern walls, gates, fences and posts, and the metalling of trackways, are excluded from the scheduling, although the ground beneath these features is included.
Book Reference - Author: Barnatt, J and Smith, K - Title: The Peak District - Date: 1997 - Page References: 53-5 - Type: DESC TEXT