An Unusual Stone

Picked up this stone on the beach at Lower Largo. It is about 7 centimetres long and heavily pittted. It has a nice pattern, maybe evidence of plant material, but I have very little knowledge of fossils, so not sure whether it's from algae, plant root or fern fronds or even whether the pattern has been hand-carved into the stone. Fife does have locations where fossils from the carboniferous period may be found. East Wemyss a little further along the coast towards Kirkcaldy (about 7miles) is one of the best locations for plant remains.

The stone has some deep holes at one end, perhaps from a rock-boring sea creature.