The Lewisian complex or Lewisian gneiss is a suite o Precambrian metamorphic rocks that ootcrop in the northwastren pairt o Scotland, forming pairt o the Hebridean Terrane an the North Atlantic Craton. These rocks are o Archaean an Paleoproterozoic age, ranging frae 3.0–1.7 Ga. They form the basement on whit the Torridonian an Moine Supergroup sediments war deposited. The Lewisian consists mainly o granitic gneisses wi a minor amount o supracrustal rocks. Rocks o the Lewisian complex war caught up in the Caledonian orogeny, appearing in the hanging wa's o mony o the thrust faults formed during the late stages o this tectonic event.