The Soom Shale is a member of the Late Ordovician (Ashgill) Cedarberg Formation (Table Mountain Group) in South Africa, renowned for its remarkable preservation of soft-tissue in fossil material.
Deposited in still waters, the unit lacks bioturbation, perhaps indicating anoxic conditions.

It overlies the Pakhuis tillite and is overlain by the Disa Siltstone.

It contains typical Ordovician microfossils, such as chitinozoa

Chitinozoa

Chitinozoa are a taxon of flask-shaped, organic walled marine microfossils produced by an as yet unknown animal. Common from the Ordovician to Devonian periods , the millimetre-scale organisms are abundant in almost all types of marine sediment across the globe...

, acritarch

Acritarch

Acritarchs are small organic fossils, present from approximately to the present. Their diversity reflects major ecological events such as the appearance of predation and the Cambrian explosion.-Definition:In general, any small, non-acid soluble Acritarchs are small organic fossils, present from...

s and spores, and its shelly fauna is also typical of this time period.