Stone in Archaeology Database


Purbeck: Broken Shell Limestone

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Local Name(s): Purbeck: Broken Shell Limestone. Example of Purbeck: Broken Shell Limestone
Stone Group: Sedimentary
Stone Type: Limestone
Geology:
Era:   Mesozoic
Period:   Jurassic
Epoch:   Upper
Geological Sub-Divisons:

Upper Purbeck

General Colour Description:

A grey/brown colour.

Hand Specimen Description:

A coarse grained, very hard, bioclastic limestone which is poorly sorted with a rough feel. The bivalve shells (neomiodon) in the 'Burr' are broken and tumbled in every direction, while the limestone matrix has weathered away into cavernous holes. This weathering is so characteristic that it is possible to recognise isolated pieces of 'Burr' in the remains of Medieval buildings (Thomas 1998: 61). Bioclasts include neomiodon, unio and viviparus with fragments of fish and turtles.

General Comments:

This stone was known as 'Burr' by the quarrymen and masons.

Stone Identifiers: Calcareous,  Fossiliferous.
Reacts dilute to HCl? Yes