I became quite interested in Geology in my youth so thought that I’d compile a little list of online sources for anyone who might be interested in learning something of that aspect of the Western Isles and especially of South Harris:
Scottish Geology (portal): Hebrides:
Images of rock samples from Harris at The Hunterian Museum and Art Gallery, Glasgow
A brief overview of South Harris plus Outer Hebridean intrusions:
South East Harris Igneous Complex:
These last two are particularly technical but I guess it’s not called the ‘South Harris Igneous COMPLEX’ for nothing!