Question: Are there any rare rocks in Dundalk?

Tiernan answered on 6 Nov 2018:

Ha! Not rare but cool – most of Dundalk sits on rocks that are more than 450 million years old, that formed from sediments settling out on the bottom of a deep ocean that was wider than the Atlantic. If you draw a line from Termonfeckin to Limerick everything north of the line was part of a continent called Laurentia, and everything south of the line was part of Avalonia. Until 100 million years ago the northern part was attached to Newfoundland. Go out to Cooley and the mountains there are volcanic and they formed when the ocean slammed shut 400 million years ago.