Cleveland Ironstone Formation

Cleveland Ironstone Formation
Stratigraphic range: Pliensbachian PreꞒ Ꞓ O S D C P T J K Pg N
Exposure of the Cleveland Ironstone Formation near Skinningrove
Type	Geological formation
Unit of	Lias Group
Underlies	Whitby Mudstone Formation
Overlies	Staithes Sandstone Formation
Thickness	up to 25 metres (80 ft)
Lithology
Primary	Mudstone, Siltstone, Ironstone
Other	Sandstone
Location
Region	Europe
Country	UK
Extent	Cleveland Basin
Type section
Named for	Cleveland, England
Location	cliffs near Staithes

The Cleveland Ironstone Formation is a sequence of marine ironstone seams interbedded with shale and siltstone units which collectively form a part of the Lower Jurassic System of rocks underlying Cleveland in North Yorkshire. Exploitation of the ironstone seams became a major driving force behind the industrialisation of the Teesside district during the mid- to late-1800s.^[1]

Based on the stratigraphy of the formation, the Cleveland Ironstone was found to belong within the Upper Pliensbachian (Domerian) universal stage. Ironstone seams and accompanying shales may be highly fossiliferous with remains so abundant in parts as to form well-developed shell-beds. Analysis reveals a wealth of shallow-water marine species, some in life position, along with trace fossils including Rhizocorallium burrows well exposed at Old Nab, east of Staithes.