124 Coal Deposits and Formation. 



That coal is of vegetable origin, no one who has read much on 

 the subject, or personally examined the coal beds, will now deny. 

 Time was, when it was considered a peculiar mineral product, 

 formed in the earth in the same manner and at the same time 

 with the rocks that surround it. The product of its chemical 

 analysis, being altogether vegetable, and the artificial formation of 

 coal from wood by Sir James Hall, have silenced all doubts on the 

 subject. The only mystery now is, how such vast quantities of veg- 

 etable matter could be accumulated and grow on the spot where 

 they were buried. That they grew in general, on the surface now 

 occupied by the coal, appears certain from the perfect state in which 

 the most delicate leaves and stems are preserved. Had they been 

 transported by currents of water, and especially from any distance, 

 it is hardly possible that they should not have received more dam- 

 age. The climate, at that period, must have been both more warm 

 and, more humid than at present, as many of the plants are of those 

 families which now grow only in tropical climates ; and as the laws 

 of nature never change, this may be deemed a correct inference. 

 A similar climate seems to have prevailed in the latitudes north of 

 30"^, both in Europe and in America, many of the same plants be- 

 ing common to the coal strata of both countries, as will be evident 

 by comparing the drawings of several of the species found in the 

 valley of the Ohio, with those exhibited by M. Brongniart, in his 

 work on " Des vegetaux Fossiles," of the European coal beds. 

 South of lat. 30°, but few coal deposits are found, the climate re- 

 quiring but little fuel for the comfort of the inhabitants ; but north 

 of that parallel, naany districts could be but very thinly inhabited, 

 or perhaps not at all, were it not for the wonderful provision of coal 

 laid up in the bowels of the earth for the use of its inhabitants, after 

 the forests were destroyed to make room for cultivation. 



The coal deposits of Britain, by nourishing her manufactures, 

 which have raised her to her present proud attitude among the na- 

 tions, are the principal source of her present greatness. 



In the valley of the Ohio, some of the coal beds, were covered 

 with marine deposits ; in others the deposit was made in fresh water, 

 as is demonstrated from the character of the fossil shells found in the 

 rocks, both over and under the coal. In what manner these chan- 

 ges were brought about, remains for future geologists to determine, 

 after the science has become mature. 



