would have been some of the largest and most visually imposing Early Neolithic funerary monuments in Britain. Grouped along the River Medway as it cuts through the North Downs, they constitute the most southeasterly group of megalithic monuments in the British Isles, and the only megalithic group in eastern England. The archaeologists Brian Philp and Mike Dutto deemed the Medway Megaliths to be "some of the most interesting and well known" archaeological sites in Kent, while the archaeologist Paul Ashbee described them as "the most grandiose and impressive structures of their kind in southern England". The megaliths can be divided into two separate clusters: one to the west of the River Medway and the other on Blue Bell Hill to the east, with a distance between the two clusters of between 8 and 10 kilometres (5 and 6 miles). The western group includes Coldrum Long Barrow, Addington Long Barrow, and the Chestnuts Long Barrow. The eastern group consists of Smythe's Megalith, Kit's Coty House, Little Kit's Coty House, the Coffin Stone, and several other stones which might have once been parts of chambered tombs, most notably the White Horse Stone. It is not known if they were all built at the same time, or whether they were constructed in succession, while similarly it is not known if they each served the same function or whether there was a hierarchy in their usage. The Medway long barrows all conformed to the same general design plan, and all aligned on an east to west axis. Each had a stone chamber at the eastern end of the mound, and they each probably had a stone facade flanking the entrance. The chambers were constructed from sarsen, a dense, hard, and durable stone that occurs naturally throughout Kent, having formed out of silicified sand from the Eocene epoch. Early Neolithic builders would have selected blocks from the local area, and then transported them to the site of the monument to be erected. These common architectural features among the Medway Megaliths indicate a strong regional cohesion with no direct parallels elsewhere in the British Isles. For instance, they would have been taller than most other chambered long barrows in Britain, with internal heights of up to 3.8 metres (10 feet). Nevertheless, as with other regional groupings of Early Neolithic long barrows—like the Cotswold-Severn group in south-western Britain—there are also various idiosyncrasies in the different monuments, such