334 LIGNITES. 



and accurate observations than have ever yet been 

 made, but which the present new views will render 

 easy, must determine whether any modifications of 

 this theory will be required for the separate cases of 

 the oolithe and the green sand. 



There is little to add respecting the lignite deposits 

 in the tertiary strata and the alluvial formations ; or 

 at least the reader ought not now to require explana- 

 tions of these. A stratum of peat in the bottom or 

 on the margin of an antient lake is now a bed of lig- 

 nite in a lacustral series; and the marine one of an 

 existing sestuary is the type of a lignite in the plastic- 

 clay. The lignite beds of a marine deposit now re- 

 mote from the present ocean is a submerged Lincoln- 

 shire forest; and if there are scattered lignites in these 

 several situations, there is antient transportation to 

 account for them all, while the type is seen in the 

 floats of wood buried in the alluvia of the great Ame- 

 rican rivers. And such events, in antient times, may 

 also account for some of the lignites in the secondary 

 strata, yet never for those which contain fragments 

 deposited in a regular manner. The alluvial lignites 

 may either have been overwhelmed forests or peat 

 bogs, or they may have been transported and covered, 

 as in the recent cases just alluded to; while their dates 

 and circumstances must be regulated by those of the 

 alluvia. Volcanic ones may be of many ages; while 

 it must not be forgotten that volcanoes erupt tufo and 

 mud as well as lava, and that thus have the papyri of 

 Herculaneum become lignites, approaching to peat, 

 if not pure peat. And whether these more recent 

 ones are to be coal or woody lignite, depends on their 

 ages chiefly, if also possibly on other circumstances; 

 while the further chemical facts necessary to this 

 theory will appear in the next Chapter. 



