A glossary of geological terms used on this site
This page is under construction. For a full glossary document open the .pdf document below. This will appear in a new window.
Geologists are (in)famous for their long words and sometimes impenetrable terminology! This page may help you understand the site better. Where definitions refer you to the Geology Chart, please click HERE. The main Building Stone page will then open in a new window.
Ashlar: Building stone, rectangular, finely dressed (cut or sawn) with smooth external face and sides for close fitting
Bath Stone: Middle Jurassic limestone widely used in church windows and quoins
Bridport and Yeovil Sands: Geological formation extending from Dorset coast to Yeovil. See Geology chart
Bartonian: Geological time period. See Geology chart
Beer Stone: Local limestone once quarried in SE Devon. See Geology chart
Bembridge Limestone: Local limestone once quarried on Isle of Wight. See Geology chart
Bembridge Stone: Local limestone once quarried on Isle of Wight. See Geology chart
Binstead Stone: Local limestone once quarried on Isle of Wight. See Geology chart
Bioclast: Broken fossil shells, components of many limestones
Bivalve: Mollusc with two halves to its shell: clams, scallops, oysters, etc .
Blue Lias: Basal Jurassic Limestone, thin beds. Quarried in SW Dorset & Somerset. See Geology chart
Burr: Local limestone quarried on Isle of Purbeck. See Geology chart
Calcarenite: A limestone composed of sand-sized grains of calcium carbonate, usually shell debris.
Calcite: Calcium carbonate, defining component of all limestones.
Carboniferous: Geological time period. Rocks of this age not exposed in Dorset. Imported limestones used.
Chalk: Soft very fine-grained limestone. Geological formation widespread in S & SE England
Chert: Very hard rock composed of silica replacing sandstone or limestone in patches.
Cenomanian: Geological time period. See Geology chart
Chilmark: Area west of Salisbury where Portland Limestones quarried.
Clavellata: Species name of fossil bivalve. Geological formation name - See Geology chart
Concretions: Hard, dense, ovoid or spherical rock within a softer sedimentary rock layer.
Cornbrash: Middle Jurassic shelly oolitic limestone used as building stone. See Geology chart
Corallian: Upper Jurassic shelly limestone used as building stone. Geological Group - See Geology chart
Cretaceous: Geological time period. See Geology chart
Crinoid: Fossil marine animal related to starfish, also known as "Sea Lilies"
Current bedded: Sedimentary layers which were deposited inclined rather than horizontal; cross-bedding.
Cypris: A genus of ostracod (qv)
Dolomite: A mineral or rock largely composed of Calcium Magnesium Carbonate
Dressings: Building stones cut to a smooth face for windows, quoins, string courses
Echinoid: A Sea Urchin - a type of marine animal living on or within the sea bed
Eocene: Geological time period. See Geology chart
Featherbed: Very shelly local limestone once quarried on Isle of Wight. See Geology chart
Featherstone: Very shelly local limestone once quarried on Isle of Wight. See Geology chart
Ferroan: Containing iron minerals usually oxidised to an orange-brown colour; ferruginous
Ferruginous: Containing iron minerals usually oxidised to an orange-brown colour; ferroan
Flint: Very hard rock composed of silica replacing chalk in patches
Forest Marble: Middle Jurassic shelly limestones & sandstones used as building stone. See Geology chart
Freestone: Any rock which can be cut in any direction for building use
Fuller's Earth: Middle Jurassic clay with some limestones used as building stone. See Geology chart
Gastropod: A type of Mollusc, e.g.. Snail, which can live on land, in freshwater or in the sea
Glauconite: A green mineral formed from volcanic ash deposited in marine conditions
Ham Hill Stone
Yellow Ledge Stone Band