The Mariner's Rock (or The Hall Door Rock)

At the edge of Lough Foyle, at a certain point, lies an elegant distinctively shaped anvil-like rock, a little offshore. In the winter months especially, its dark form can at times be glimpsed jutting above the breaking waves illuminated by clear winter sunlight.

Why is it called The Hall Door Rock? I was reliably informed by one of the Shorepath walkers that in days long past this distinctive rock was utilized by local mariners- during adverse weather conditions they would align the boat with the rock and a door of one of the grand residences along the shore-Carnagarve House, in order to navigate a straight course safely to shore.
Available for purchase at Frame Masters, Letterkenny.