Found in the North Esk, Penicuik, Midlothian Polton Coal Company Limited – Brick and Fire Clay Manufacturer, Bonnyrigg, Lasswade, Edinburghshire. 1878 – Hugh Rigg, Manager Canmore Canmore Below – a better quality brick seen in the Dalkeith Museum
28/02/1883 – Glasgow Herald – Midlothian colliery and brickworks for sale – The Polton Colliery and Brickwork with the tenants part of the lease and the whole machinery, plant and miners dwelling houses connected therewith……………………..The pits have won 5 workable seams of coal, 4 of which rest on good clays which are cheaply got and well suited for the manufacture of all kinds of fire clay goods and the other is worked in connection with an excellent oil shale. The machinery and plant are in good order and there has been recently erected a new pumping engine made in the most improved system. The brickwork is extensive and capable of turning out all kinds of fire clay goods. Reduced upset price £4500. Mr Gilchrist will be at the Company’s office close to Bonnyrigg Railway Station for the purpose of showing the works to intending purchasers……. For further particulars, application may be made to……Hugh Rigg, Edmonstone Colliery, Millerhill.