The Windermere Group of rocks is the name used to define the type of geological formation found in the Windermere region of the English Lake District. The Windermere Group of sedimentary rocks has a base of Coniston Limestone which is a group of calcareous sediments that rests unconformably on top of the Borrowdale Volcanic Series. This is then succeeded by a series of shales and then by grits and greywackes. Compression from the NW or SE buckled the strata into anticlines and synclines and caused slaty cleavage in some sediment beds. This formation was laid down in the Silurian period. In North America, the Windermere Group of rocks is a Neoproterozoic suite of clastics and volcanics up to 8,000 meters thick in western Montana, Idaho, and British Columbia. [1]
