The important observations made by Mr. Lamplugh among the “crush-conglomerates” of the Isle of Man suggest that the phenomena described by him may have a much wider range than had previously been supposed. Ever since I had the opportunity of going over his Manx evidence with him, I have suspected that some of the fragmental rocks which I myself have regarded as volcanic agglomerates might prove to be due, not to volcanic explosions, but to the same kind of underground movements which have undoubtedly given rise to the enormous masses of “crush-conglomerate” in the Isle of Man. The breccias of Anglesey seemed to me likely on renewed examination to prove to belong to the latter series. Accordingly I recently took occasion to revisit these rocks, both in the centre and along the north coast of the island. The result was entirely confirmatory of my suspicions. The breccias in question are, I now feel convinced, true crush-conglomerates.