BRITISH ASSOCIATION. 



were found, and to which they owed their preservation, were 

 due to drifting by wind. 



On the Great Lancashire Coal Field, by Mr. E, W. Binney, 



The Lancashire Coal Field commences with the lower 

 millstone girt, and extends upwards into the limestone of 

 Ardwick, near Manchester, now generally considered the 

 highest portion of the coal measures, hitherto observed in 

 England. The author divides this series into three groups 

 in descending order. 



1 . The Manchester Coal Field, containing the limestone of 

 Ardvdck^ and the isolated coal measures of Clayton and 

 Bradford, near Manchester, occupying the low tract of 

 country adjoining the new red sandstone plains. 



2. The middle field, comprising the thick coal seams of 

 Poynton, Ashton, Middleton, Worsley, Wigan, &c., occupy- 

 ing the rising ground between the new red sandstone plains, 

 and the higher parts of the country, and containing the 

 richest portion of the field. 



3. The lower coal-seams, found in the elevated parts of the 

 country, along the sides of the Penine chain, and the moor- 

 lands of the northern parts of Lancashire ; comprising those 

 of Whaley Bridge, Mellor, Glossop, Rochdale, Todmorden, 

 Colne, Blackburn, Chorley, &c. Seams of no great thickness, 

 but valuable from their quality and position, and remarkable 

 from their adjoining shales containing remains of the genera 

 Pecten, Goniatites, Posidonia, and other shells of marine 

 origin. The total thickness of the deposits varies in different 

 parts of the field ; in a line from Manchester through Ashton, 

 to the limestone shales of Hollins Brook, the thickness is 

 about 2000 yards ; and there are 75 beds of coal exceeding 

 one foot in thickness, forming altogether 150 feet. In a line 



