Richard Osgood and his team found an ovoid stone in their recent dig at Boles Barrow.
So a fossil echinoid is very likely, a natural flint nodule quite likely and a river pebble brought onto site as a hammer stone a possibility but it appears to lack percussion marks. Other suggestions such as a stone curlew egg can be dismissed.
Fossil echinoids are not archaeological, but they can be found in archaeological sites. They are formed when a sea urchin dies and its hard shell is buried in sediment. Over time, the sediment hardens into rock, and the urchin's shell is preserved as a fossil.
Fossil echinoids can be found in many parts of the world, including Europe, Asia, and North America. They are often used to study the evolution of sea urchins and to understand the ancient environments in which they lived.
There are a few cases where fossil echinoids have been found in archaeological sites. For example, in 2016, a team of archaeologists found a fossil echinoid with an Anglo-Saxon inscription on it in London. The inscription was interpreted as a religious symbol, and the discovery suggests that early Christians may have used echinoids as religious objects.
However, fossil echinoids are not typically considered to be archaeological artifacts. They are more commonly seen as geological objects that can provide insights into the ancient world.