Torridonian

The Torridonian is the informal name given to a sequence of Mesoproterozoic to Neoproterozoic sedimentary rocks that outcrop in a strip along the northwestern coast of Scotland and some parts of the Inner Hebrides from the Isle of Mull in the southwest to Cape Wrath in the northeast.

[4] At about the same time Lower Cambrian fossils were found in the sequence above the unconformity, suggesting that the Torridonian was of Precambrian age.

This is consistent with the generally westerly derived pebbly material throughout the thickness of the Applecross Formation, suggesting a constantly rejuvenated sediment source in that direction.

[7] Going back to the late 19th century, geologists had speculated that at least the lower part of the Moine sequence might be a lateral equivalent of the Torridonian, based on similarities in lithology, sedimentary structures and thickness.

The detrital zircon and other geochronological data show that there is major break in the Moine stratigraphy at the base of the Glenfinnan Group and that it can, therefore, no longer be regarded as a supergroup.