The Dukinfield Coal-pits. 1 8 1 



illustrated before us, in pictures "of the period," and 

 what is wanting in vestiges of man has its set-off in the 

 profoundness of the antiquity. Far more ancient are 

 these black repositories of extinguished life than the 

 foot-printed sandstone of Lymm. Unlike the Trias, 

 moreover, they point to a period of amazing exuberance 

 of terrestrial vegetation, some of which probably grew near 

 where the remains are now found, while other portions 

 were probably drifted from a distance ; lakes and estu- 

 aries becoming choked with the accumulated debris, and 

 the whole, in course of time, becoming covered up with 



FIG. 26. 

 Calamite. 



FIG. 27. 

 Lepidodendron. 



(All in miniature.) 



FIG. 28. 

 Sigillaria. 



the earthy deposits that pressed all hard and flat, and 

 which now constitute the overlying strata. The general 

 aspect of the plants of the period referred to may be 

 judged of from that of the Tree-ferns, Equisetums, and 



