The worlds largest exposed ophiolite is in Newfoundland and a relict of the closing of the ocean which preceded the Atlantic, IIRC. But honestly, just because we live on coastlines we thinbk they are common as mud...we dont know how lucky we have it. I bet there are literally thousands of disadvantaged geologists out there who have never seen an ophiolite. I will trade some to them for a chunk of nepheline syenite.