First post in the new geology blog.
Just to get started, here is a picture of an erratic boulder on the south east side of Iona - a large piece of Ross of Mull Granite from the other side fo the Sound of Iona, brought there by the ice 12 - 15000 years ago.
The grey heart shaped thing is a xenolith - a piece of country rock that has been caught up in the molten granite before it solidified at depth
The hammer is for scale - it is about 10" long.
There are lots of erratic boulders of granite in Iona - all over the island. Will have more pics of them on the actual geology web site once it gets up and going
JW, January 2016