It is the lowermost part of the Windermere Supergroup, which was deposited in the foreland basin formed during the collision between Laurentia and Avalonia.

[6] The early Paleozoic geology of northern England records the convergence and eventual collision of the Avalonia microcontinent with the continent of Laurentia.

The underlying Borrowdale Volcanic Group formed in an island arc, caused by the southerly subduction of the crust of the now vanished Iapetus Ocean.

At the end of active arc volcanism, the area began to subside, allowing deposition of the shallow marine Dent Group.

The final closure of Iapetus occurred during the Devonian Acadian orogeny, with the resulting continental collision causing deformation of the Ordovician rocks, including folding, thrusting and cleavage development.