I9IIJ STEVEXSOX— FORMATIOX OF COAL BEDS. 15 



The manner in which the plants are preserved in rocks accompany- 

 ing coal beds as well as the presence of vertical stems in normal 

 position are most convincing. He cannot attribute the formation of 

 coal beds to accumulation of vegetable detritus transported from 

 a distance and deposited in the condition of pulp (bouillee) as was 

 supposed by Sternberg and Boue. In fact it would be difficult to 

 understand how the causes, which reduced to a kind of pulp the 

 plants which have formed the coal itself, failed to change the plants 

 found in the neighboring beds; how it is that the coal formed in 

 the sea contains no marine debris ; how, finally, a substance thus 

 deposited shows no more inequalities in thickness of the bed. He 

 accepts De Luc's conception of vast swamps as best agreeing with 

 observed conditions. The intervening rocks originated during pe- 

 riods of elevation of the sea-level or depression of the land. 



Ure'-- could not believe that coal beds are the remains of up- 

 rooted forests or shattered trees. Reeds and ferns atTorded most 

 of the material and they grew not far from the place where the coal 

 is found, as is shown by the state of preservation. The vegetable 

 matter was reduced to a pasty condition, elaborated in the tepid 

 waters of the primeval globe and was deposited in a semi-fluid con- 

 dition where now found. The proof of this hypothesis is found in 

 the great extent of very thin coal beds, the parallelism of the oppo- 

 site faces, in the existence of narrow fissures filled with coaly mat- 

 ter, as well as in 'the homogeneous substance and texture and the 

 cubical division in coal beds. The conversion of the buried matters 

 into coal might continue ripening during many ages bv percolation. 



AlacCulloch'--^ devoted many years to actual investigations in both 

 field and closet, the results being given in numerous brief papers. 

 The outcome of his completed studies is presented in an elaborate 

 discussion of the origin of coal and the formation of coal beds. 



Peat, lignite and coal form a continuous series, the transition 

 being sufficiently perfect. The character of the plants, the presence 

 of tree trunks, their bark converted into coal, show that the plants 

 from which coal was formed were terrestrial, not marine. Those 



~ A. Ure, "A Xew System of Geology," London, 1829, pp. 163-174. 

 ^J. MacCulloch, "A System of Geology with a Theory of the Earth," 

 London, 1831, Vol. IL. pp. 311, 312, 336. 337, 339, 341, 359. 



15 



