| Description | With plan of boreholes, showing contours of Top Hard Coal and sites of collieries surrounding the Ollerton Coalfield, 2 Apr 1922 and copies of section of the No. 1 Shaft at Clipstone belonging to the Bolsover Colliery Company Limited, showing thickness of strata, description of strata, and total depths of strata from surface down to Top Hard Coal, Apr 1922 |