A banded amphibolite occurs at Durcha, near Invercassley, in northern Scotland, which has been interpreted at one time or another as either igneous or sedimentary in origin with subsequent metamorphism. Investigation of the dark and light portions of the striped rock separately, chemically and petrographically, leads to the conclusion that the dark, hornblendic portion probably represents a pre-orogenic dolerite sill in Moine psammitic sediments. Metamorphism then resulted in a series of s-planes, along which lit-par-lit injection of quartz-feldspathic material took place. The origin of other occurrences of striped rocks in Scotland that have been described as similar to the Durcha rocks is considered. One new chemical analysis and trace element determinations on the amphibolite and on the Ben Vrackie epidiorite are included.