This famous Upper Jurassic building stone is one of the most important in the country having been used for iconic buildings including St. Paul’s Cathedral and the Cenotaph. It is easily recognised by its pure white or grey colour – lacking the buff or orange tinges of Bath and Cotswold Stone – and its fine grained oolitic character. Its most common usage in Herefordshire and Worcestershire is for monuments, particularly war memorials.
There are three main beds used. The ooidal Whit Bed contains common shells, whereas the Base Bed is generally less shelly in character. The fossiliferous Roach Bed is the most distinctive of the Portland limestones as it exhibits large, open, biomoldic pore spaces. These relate to the leaching out of examples of the large gastropod Aptyxiella portlandica (known informally as the ‘Portland Screw’) and the bivalve Myophorella incurva (‘’Osses Heads”).
The stone was and still is quarried on the Isle of Portland, Dorset, where there are 35 named quarries from which stone was loaded directly onto boats and exported countrywide. Only a few are still being worked.
Portland Stone Details
|Geological Name||Portland Stone Formation|
|Age||Upper Jurassic (Tithonian: 152.1 ± 4 Ma to 145.0 ± 4 Ma)|
|Area of use||Herefordshire & Worcestershire|
|Era of use||Mostly 19th Century and onwards|