408 OCCURRENCE OF COAL, &c. 



Coal basin, the comparison fails : the Welsh Coal is, however, of the non-bitu- 

 minous kind, and therefore not so valuable. The circumstances too, here no- 

 ticed, on which, after all, no great stress can be laid, are only found in the neigh- 

 bourhood of this single locality; all the others being far removed from the 

 grey-wacke formation, and having no trap rocks in their vicinity. 



