At various times in its geological history, this region has been covered by water or ice.
A Lower Devonian river system across Angus was home to spiny sharks and shovel-headed cephalaspid fish, arthropods and primitive plants. Several species of fish are known from only a single locality in this region and Perth Museum and Art Gallery holds material from Balruddery Den, Angus, rarely found elsewhere.
In contrast, slabs of sandstone from Dura Den in Fife bearing the large, well-preserved fish Holoptychius, with its recognisable ornamented scales, and Bothrioplepis, a heavily armoured placoderm, are found in most collections, including the Bell Pettigrew Museum in St Andrews and Fife Collections Centre in Glenrothes.
The most recent fossils, from Pleistocene Arctic clays along the Tay Estuary, document warming of the climate in the last 15,000 years following glaciation and can be found in the collections of Montrose Museum, the McManus: Dundee’s Art Gallery and Museum and Perth Museum and Art Gallery.