Classic unconformity

Above Helwith Bridge close to the present Arcow Quarry.
Horizontal Carboniferous limestone lies horizontally on Silurian Siltstones which have been bent and twisted. The missing layer (Devonian - about 80 million years)  between the two has been eroded leaving a pretty level surface onto which the Carb Lime has been deposited. The various siltstones are excellent for road surfacing. The rock is taken out by rail and rather large bulk carriers.