English: Basalt Rock Formation, in the Mull Lava Group of Palaeocene age. Taken on the way to the fossilised tree. I am indebted to Keith Burns for this explanation of the fascinating geological processes involved here :

"On the beach, basalt columns radiate from a central point on the shore near the fossil tree. The columns are formed due to the cooling effect of a standing tree on the lava flowing around the tree trunk. The tree draws heat from the lava. When the lava shrinks, it forms hexagonal shrinkage cracks which form columns whose axes are parallel to the direction of heat flow. So the hexagonal columns radiate from the tree trunk which is drawing heat from the lava.

If lava is in a level slab losing heat to the air above it, it cools from the top down and forms the more familiar vertical hexagonal columns (e.g. Giant's Causeway, Staffa, Sampson's Ribs on Arthur's Seat in Edinburgh).

There must have been a forest that was engulfed by the slowly flowing lava."