56 STEVENSON— FORMATION OF COAL BEDS. [April 21. 



small in coalification. That the air was damp and warm is proved 

 by the aerial roots of Psaroiiiiis and Calaiiiodoidroii ; and the heat 

 of the climate appears from the dense resinous bark, which often 

 dominated the wood. Strong light, great heat, excessive humidity, 

 great marshes in which plants grew quickly and died, explain condi- 

 tions not easily explained by conditions of the present time. The 

 residues falling into the marshy bottom of the forest, underwent 

 aqueous rotting; they were then transported to the areas of deposit, 

 which preserved them from complete destruction. 



Grand' Eury published much relating to this subject and in 

 I90O'''* he summarized all the results of his long studies in a memoir 

 presented to the geological congress. 



He describes fossil forests /// situ, which show that the Car- 

 boniferous plants, though arborescent, were forms of marsh-habit 

 like those of the Dismal Swamp, the foot and adventive roots in 

 the water, but the stocks and rhizomas creeping on the bottom. The 

 forests were very local. Growing in stagnant water and fixed by 

 few roots to the ground, they were destroyed by slight causes and 

 the roots alone remained. This would give a "soil of vegetation" 

 as described by Dawson— a feature as familiar at Saint-Etienne as 

 in Canada. 



Coal is stratified, evidently deposited under water. There is no 

 evidence that roots ever traversed the parallel laminse of which it 

 is composed. The stocks and roots, descending in the roof, spread 

 out on the coal but never penetrated it. This condition is constant 

 and is due to the circumstance that slowly deposited vegetable mat- 

 ter, undergoing fermentation, is opposed to the introduction of roots, 

 which, being unable to live in it, instinctively refuse to pierce it. 

 Similarly there is no relation between stocks and overlying coal. 

 Their roots are often enclosed in coarse twisted coal composed of 

 overturned stems, with leaves, branches, which, however, is con- 

 tinuous with overlying laminated coal. The elements are the same 

 in both and they are identical with those in the adjacent shales, so 

 that transportation from a distance is impossible. There is then in 

 some coal beds evidence of formation in place or almost in place. 



■"'C. Grand" Eury, "Du liassin de la Loire," Coiiipt. Rcndiis I'llI'"" 

 Congrcs Gcul. Intern., Paris, 1901, pp. 521-538. 



56 



