19".] STEVENSON— FORMATION OF COAL BEDS. 13 



tates to accept the doctrine that coal is product of decomposition 

 of organized bodies. Brongniart exhibits much caution in respect 

 to generahzations but offers these conclusions which he thinks are 

 derivable from actual observation : ( i ) That the coal is a formation 

 contemporaneous with or posterior to the existence of the organized 

 bodies; (2) that this combustible, when it was deposited or formed, 

 was liquid, homogeneous and in a great degree of fineness, which is 

 proved by the frequently parallelopipedonous structure and by the 

 manner in which it is absorbed by the beds which enclose it; (3) 

 that the cause, which has deposited or formed it, was renewed sev- 

 eral times in the same place, with conditions almost the same; (4) 

 that this cause has been the same for almost all the earth, since the 

 coal beds present in their structure and their accessory conditions 

 almost always the same phenomena; (5) that these beds have been 

 deposited without violent disturbances, since the organized bodies 

 which are found in them are often entire and since the leaves, which 

 are impressed on the shales covering the coal, are expanded and are 

 hardly ever rubbed or even folded. 



Parkinson^^ regarded coal as a product of vegetable matter 

 reduced to fluidity by bituminous fermentation ; this fluid suffered 

 modification of its inflammability by deposition of carbon and by 

 intimate admixture with various salts. The vegetable matter had 

 been swept into the sea by the universal deluge. 



Kidd^^ summarizes the doctrine of transport thus, " Powerful 

 floods have swept away forests and subsequently covered them with 

 the ruins of the soil in which they grew ; whence those beds of clay 

 and gritstone which so generally accompany the coal itself." His 

 objections to this doctrine are that remains of trees and shrubs are 

 wanting; that the plants are evidently those of many places; that 

 the mechanical force, which uprooted the forests and swept away 

 the vegetable matter as well as the greater amount of the earthy 

 matter in the shales and gritstones, must have been extreme ; yet 

 the particles of the grit are not rounded and show no sign of attri- 



^*J. Parkinson, "Organic Remains of a Former World," London, 1811, 

 Vol. L, p. 248. 



^"J. Kidd, "A Geological Essay on the Imperfect Evidences in Support 

 of a Theory of the Earth,"' Oxford, 1815, pp. 126, 127, ij8. 



13 



