Coneybury Henge

Coneybury Henge is a henge which is part of the Stonehenge Landscape in Wiltshire, England. The henge, which has been almost completely flattened, was only discovered in the 20th century. Geophysical surveys and excavation have uncovered many of its features, which include a northeast entrance, an internal circle of postholes, and fragments of bone and pottery.
Location.
Coneybury Henge is around 1.4 kilometres east-by-southeast of Stonehenge, which can be seen from the site. The location has extensive views southeast across the Avon valley, and west towards Normanton Down. The henge is difficult to identify on the ground, having been levelled by ploughing, but has been identified on aerial photographs, geophysical survey, and by excavation. The absence of any mention of the henge in historical records suggests that it may have been levelled in medieval times or soon after, and this theory is supported by ridge and furrow marks visible on some aerial photographs.
Discovery and excavation.
The site was first noted from the air in the 1920s and thought to be a disc barrow. Later aerial photographs gave strong indications it was a Class I henge. The photographs show an oval ditch, around 45 metres by 55 metres in diameter. The entrance is on the longer axis on the northeast side. Traces of an external bank are said to be visible. 
The henge was excavated in 1980 as part of the Stonehenge Environs Project. The excavations revealed a broad oval ditch around 4 metres wide by 3 metres deep defining the henge. Excavation of internal features included a few pits and postholes, numerous stakeholes, and an arc of postholes inside the inner edge of the enclosure ditch which may have represented a post circle. Some of the internal features may pre-date the henge. Finds included pottery ranging from the early Neolithic to middle Bronze Age, as well as animal bone and a human cremation.
Coneybury Anomaly.
Around 12 metres northwest of Coneybury Henge, evidence suggesting a unique cross-cultural feast has been found. The Anomaly is a pit containing a large amount of early Neolithic pottery together with a large quantity of animal bone, and flint tools of both Mesolithic and Neolithic types. The bones included at least ten cattle, plus several roe deer, two red deer and a pig. The material was radiocarbon dated to 3980-3708 BCE, before the henge was constructed and within three centuries of the introduction of Neolithic technology to Britain. It is interpreted as the result of a single event, not a long occupation or recurrent use. 
The ceramic assemblage included bowls and cups, all of rather similar manufacture. Many of the fragments were large, indicating that they have not been trampled after they were discarded, and thus that a single, relatively short event led to the Anomaly.
The cattle were not butchered in the same way as the roe deer; most limbs of the cattle are absent - possibly redistributed among participants - while the deer bones remained in the pit. Isotope ratios in the bones indicated that all the animals came from within 20km of Coneybury. They included at least three groups of cattle, each from a different place and comprising individuals of multiple ages, while the deer all came from the immediate neighbourhood. The cattle were all female and had grazed on open ground; they had not eaten straw from manured cereal plots. 
The primary pit ﬁll includes both Neolithic and Mesolithic tool types. There is no obvious source from which residual Mesolithic material could be derived, and no evidence of differential weathering. The blades/blade-lets must therefore be part of the event that caused the Anomaly. This intimate mixture of Neolithic and Mesolithic tools is unique, and seems to indicate a single event attended by two different cultural groups. 
The excavators suggest that the Coneybury Anomaly represents the material remains of a gathering organized by a regional community, with participants coming from different areas. One group of attendees provided deer instead of, or in addition to, cattle. This group may have been hunter-gatherers who survived alongside farmers, engaging with them in a solidarity feast which requires equivalent contributions from participants and maintains community cohesion. If this is correct, the regional feasts that have been suggested for the later causewayed enclosures were already taking place in the earliest Neolithic phase, albeit on a smaller geographical scale.