Can anyone help ID this fossil found on a coastal path in the Isle of Man?

[celestialIvy]

This rock was found on a Coastal path in the Isle of Man. Any idea what this could be? 

Edited April 6, 2019 by celestialIvy

[erose]

Corals seen in cross section.

 

[ynot]

Horn coral.

[Rockwood]

Rugose coral.

[TqB]

I agree, it's part of a rugose coral colony from the lower Carboniferous, a species of Siphonodendron, maybe Siphonodendron scoticum.

The growth form of this species and a few others is interesting, with corallites often joined in chains for a while before separating.

[Rockwood]

6 minutes ago, TqB said:

corallites often joined in chains for a while before separating.

I knew that had to be a deep rooted habit.