[1] The successions represented by these two groups have also been referred to as the Eastern Longymndian and Western Longmyndian respectively, forming as they do the bedrock of the east and west parts of the Long Mynd in Shropshire.
The rocks have since been folded due to fault movements and plunge gently to the south.
The Longmyndian deposits rest upon Uriconian rocks but different sections are exposed exclusively between the Church Stretton Fault and the Pontesford-Linley Lineament.
Topmost of the group, the Portway Formation, consists of braided fluvial deposits with marine incursions.
The Ragleth Tuff Formation is the basal unit of the Stretton Group and the supergroup sequence.