Recent archaeological excavations at Dryleaze Farm in 2008 and 2009 in advance of gravel extraction revealed a range of archaeological deposits, mostly typical of Iron Age occupation found on the terraces of the Upper Thames. It is though, the discovery of a more unusual monument type, discovery that has prompted this note.
This particular part of the extraction area lies adjacent to an old river channel, now in-filled with silt and peat. It probably last flowed as a channel in about 1500 BC before changes to drainage patterns (rivers move!) caused it to block off and infill. But this is geology. What makes the site of interest (to archaeologists) is the presence here of monuments called “burnt mounds”. There are five of them, created, perhaps successively over several generations. These monuments are typically simple heaps of fire-cracked flint, 5-10m across and often to be found with a crescentic plan. They are usually to be found close to water. In southern Britain, they are now only to be found 0.3-0.5m high - reduced by ploughing, These sites are not especially common in Southern Britain and are rare in Gloucestershire but their big brother examples, of which there are quite literally thousands, are to be found in Highland Britain. In Ireland where they are called Fulachta Fiadh and can be 2m high or more. link to Ireland
The reason for the distinctive crescent form is that the focus of attention was a water-containing trough with which hot stone is used to boil the water it contained. When the thermal shock has caused the stone to fracture into unusable pieces, it was simply dumped adjacent to the trough. At a time in later prehistory when sheet metalwork had not been invented, experiments have shown that the use of hot stones to boil a large volume of water in a trough was quite efficient.
It is thought that they are the remains of communal cooking places. There is very little archaeological evidence to support this but we are fortunate in that old Irish literature (which stretches back to early Christian times, and perhaps beyond) describes them thus.
The examples at Shorncote here are likely to be of Bronze Age date, c.1500 BC but radiocarbon dates are awaited.