Appin Group

The Appin Group is a thick sequence of metamorphosed Neoproterozoic sedimentary rocks that outcrop across the Central Highlands of Scotland, east of the Great Glen. It forms a part of the Dalradian Supergroup.

It is divided into three subgroups each consisting of multiple named formations. In stratigraphic order i.e. youngest at the top, these are:

Blair Atholl Subgroup
 * Islay Limestone Formation
 * Mullach Dubh Phyllites Formation
 * Lismore Limestone Formation
 * Cuil Bay Slates Formation

Ballachulish Subgroup
 * Appin Phyllite & Limestone Formation
 * Appin Quartzite Formation
 * Ballachulish Slate Formation
 * Ballachulish Limestone Formation

Lochaber Subgroup
 * Leven Schist Formation
 * Glencoe Quartzite Formation
 * Binnein Schist Formation
 * Binnein Quartzite Formation
 * Eilde Schist Formation
 * Eilde Quartzite Formation

This whole succession reflects alternate periods of deepening and filling of the sedimentary basin.