Pillow lavas, together with metamorphosed sediments, occur in the Ardwell bridge area, Banffshire, northeast Scotland, and have recently been examined petrographically. It appears that these rocks, probably near the base of the upper Dalradian, were originally syntectonic biotite- albite-sphene-iron ore schists that have been metamorphosed to amphibolites. Chemically, they are rich in both soda and potash, and low in calcium, and therefore might be considered intermediate between potash and normal spilites.

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