Gneiss at Crocodile Rock, Rosemarkie

I had always associated gneiss with Lewis so I was a bit confused to find it on the east coast at Rosemarkie. Lewisian gneiss is the oldest rock in the UK. The rocks are called Pre-Cambrian because they predate the first named geological era. That means they are over half a billion years old. Gneiss is a metamorphic rock that has recrystalised due to heat and pressure. I think the original rock here was granite, which would account for the pink colour. And how did it end up here? Well, it turns out that we were on a continuation of the Great Glen Fault - plenty of heat and pressure as the north of Scotland scraped against the Highlands but also the possibility of bringing deeper rocks to the surface. And the rock on the beach really does look like a crocodile!