Fossilised plant?

Fossilised plant?

Observation - Fossilised plant? - UK and Ireland. Description: Light brown stone found in garden, approx. 70x50mm. On one side there is a hollow, in which there is a 'perfectly round' 8mm hole about 3mm deep. At the bottom of the hole is what looks like a fossilised plant with 5 'petals'.

Light brown stone found in garden, approx. 70x50mm. On one side there is a hollow, in which there is a 'perfectly round' 8mm hole about 3mm deep. At the bottom of the hole is what looks like a fossilised plant with 5 'petals'.