Cropmarks of two conjoined rectilinear enclosures of possible prehistoric or Roman date, to the east of Poke Holes, Calcethorpe. The enclosures have average dimensions of 30m by 35m. Identified on aerial photography examined as part of the National Mapping Programme. {1} The enclosures lie in the centre of a group of Bronze Age round barrows (see MLI127013 and MLI127014 to the north, and MLI127015 to the south-east), and a Neolithic long barrow (see MLI43179). All of these features have been scheduled, with most in a main group including the intervening ground, with the southernmost barrow in a separate protected area. All of the features are visible as cropmarks on aerial photographs, showing as infilled and buried ditched features. Further features not revealed by aerial photography will also be preserved beneath the present ground surface. The fills of the ditches will contain rare and valuable artefactual and organic evidence, including human remains, relating to the construction, dating, periods of use and religious beliefs of the barrow builders. Environmental deposits preserved in the same features may illustrate the nature of the landscape in which the monument was set. The long barrow is a relatively unusual example displaying a U-shaped ditch thought to be indicative of abandonment before completion. The buried features and archaeological deposits contained therein may confirm this and will provide insights into the early constructional phases which are often obscured in more developed examples. Although the ditched enclosure cannot be dated, its location suggests a spatial relationship with the barrows. Its chronological relationship may be revealed by artefactual evidence from the interior, from the fills of its buried ditches and from the surrounding area. The proximity of the Bronze Age barrows to that of the earlier Neolithic long barrow suggests the location had enduring ritual significance. The long barrow is one of a group focussed on the prehistoric trackway now known as the Bluestone Heath Road, and on the valley of the Waithe Beck. Comparative evidence from all these barrows may have considerable significance for the study of communications, settlement and demography during the prehistoric period. {2} More recent analysis of the aerial photography for this area shows the rectilinear enclosures as cropmarks, located between a Neolithic long barrow and a pair of Bronze Age round barrows. The enclosures are elongated north-east by south-west and have maximum dimensions measuring 72m by 40m. There is no visible entrance, but the south-east element of the enclosure has been heavily truncated by a post-medieval chalk pit. The date of the enclosure is presumably later prehistoric or Roman, though the proximity of the long barrow raises the possibility of a Neolithic date, although additional rectilinear enclosures in the larger area on the same general alignment may suggest it to be a part of a wider complex of Iron Age/Roman activity. {3}