Concretion

Snuff box?

A concretion is a hard lump of sedimentary rock. This one is named after its resemblance to an old-fashioned snuff box. These disc-shaped rocks developed when algal growths trapped sediments, and their colour is due to the presence of an iron mineral called limonite. 

Find out more on the rocks and pseudofossils page.

Common name

Concretion

Type

Rocks and Pseudofossils


Strata

Inferior Oolite

Time period

Middle Jurassic

Age

170 million years

Where found

Bonscombe Quarry, Shipton Gorge

Found by

E M Samuel in 1968

Museum

Dorset County Museum, Dorchester

Accession number

DCM.G.01484