.^O COAL. 



Cciii jj ckiscd by geologists among the secon- 

 dary rocks or substances, and is found in regions 

 ot' secondary formation arranged in horizontal 

 strata. Tbe whole western country is of ihi;^ 

 character. 



Again. — Its accompamments, shale and sand 

 stone are tho^ principal rocks, besides lime and 

 gypsum. 



Black shale 7,'hkh burns in the fire, and which 

 derives its coior from the bitumen with which it is 

 impregnated, is to be seen in various places. 



BitumiiiOus springs and oil stones exist in this 

 country. 



Hydrogen ga-, or burning springs, are also 

 found in this region, issuing from strata of schist, 

 and are of the same nature, in several respects, 

 with the gas obtained from the distillation of coal. 

 Sir Humphrey Davy ascribes the quantity of gas 

 thus spontaneoasly extricated, to the consolidation 

 of this coal, ctTected under a great pressure; and 

 even when this substance ov/es its. origin in some 

 measure to other causes, it Is in a degree always 

 identified with coal. For the inflammable gas of 



marshes consists of hydrogen and charcoal. 



Whenever I see this gas in a state of ignition, or 

 issuing from the earth in its usual state, I setdov/a 

 i^s origin in some ir^casure to coal. 



