Colwick Cutting is the only Geological SSSI within Nottingham City Council boundary.
This site is the type section of the Triassic Colwick Formation, a major rock unit comprising mudstones, siltstones and thin sandstone arranged in coarsening-upwards units. A variety of sedimentary structures including ripple marks, wavy bedding, halite pseudomorphs and abundant desiccation cracks are seen. The facies probably represents marine intertidal conditions, an environmental interpretation consistent with the discovery of the brachiopod Lingula elsewhere in the formation. The age of the formation is probably Anisian-Ladinian and it can be correlated with other 'Waterstones' facies in the English Midlands.
Information from a citation by Natural England.