Butterley Company correspondence file on the joint leases and sublease from Sir Charles Seely of coal at Birchwood, with plans Coloured plan showing the proposed exchange of coals between the Butterley Company and Sir Charles Seely with corresponding index schedule, Oct 1907. Coloured plan showing the Furnace coal seam at Birchwood Colliery with corresponding index schedule, early 20th cent. Coloured plan showing the Furnace coal seam at Birchwood Colliery, early 20th cent. Jan 1907-Jul 1910