Found by Heather McHaffie in the West Lothian area. This example is not in my possession. Thistle DCI or Thistle DC 1 Stein, Castlecary Fireclay Works, Castlecary, Stirlingshire. Stein, Manuel Firebrick and Refractory Works, Whitecross, Stirlingshire. Stein & Co, Anchor Brickworks, Denny, Stirlingshire. Milnquarter Fireclay & Gannister Works, Bonnybridge, Stirlingshire.
An example of this brick is still to be found however the leaflet depicted below confirms its existence. It is not known if the brickmark will show 60 or Sixty.
Bonnybridge Silica & Fireclay Co Ltd, Bonnybridge, Scotland
Bonnybridge Brand – for general steel use.
Calder L – Manufactured exclusively for use in steelworks ladles.
Calder – A first class Scotch firebrick with superior spalling resistance
Octo – For highest heat duty in the firebrick range – combines slag resistance with good resistance to spalling.
Novo Fifty – These are finding themselves more applications in the severest temperatures zones of modern furnaces.
Novo Sixty – These are finding themselves more applications in the severest temperatures zones of modern furnaces.
Novo – Sillimanite – These are finding themselves more applications in the severest temperatures zones of modern furnaces.
BSF ( Semisilica ) – recommended for reheating furnace roofs and similar applications.
Bonsil Plastic Refractories – growing field of application for monolithic and in situ construction.
Boncrete Refractory Castables – growing field of application for monolithic and in situ construction
BS Refractory Mortars & Cements – For all refractory jointing purposes.
Hepworth Ceramic Holdings plc (GR-Stein Refractories Ltd. parent co) bought the Bonnybridge Silica & Fireclay Co. Ltd in 1972, closed Bonnybridge works in 1973 and closed Chapelhall in 1980. Therefore between 1972 and 1980, GR-Stein Refractories probably continued to manufacture bricks with this trademark for a time.