186 ON THE ORIGIN OF COAL. 



like our European field, seems to require an 

 ocean for its formation. This ocean would be 

 of a very dilBPerent character to any now known 

 to cover the surface of the globe, exhibiting an 

 uniformity and shallowness unknown at the pre- 

 sent time ; and such circumstances would doubt- 

 less influence the tidal wave and produce pheno- 

 mena unlike those observed at this day. 



As the present ocean and its tides will not, 

 therefore, account sufficiently for the different 

 deposits of the Coal measures, allow me to direct 

 your attention to vertical sections of those strata, 

 and show the materials of which they are com- 

 posed, and how they change and graduate into 

 one another. 



The size and nature of the particles composing 

 the different beds give us some idea of the cur- 

 rents of water that brought them. I propose to 

 ascertain the rate of subsidence from the same 

 source, and to attempt to show that the currents 

 are but the effects of such subsidences. 



The diagram, plate III, figure 1, represents a 

 section of part, and the richest portion, of the 

 lower Coal-field at Staly-bridge, near Man- 



