'9II-] STEVEXSOX— FORMATION OF COAL BEDS. 639 



tion. Of the other three, two were implanted in a thin mur-like 

 deposit covering the coal ; the roots of one, a SigiUaria, spread out 

 in the clay, but the roots of the other could not be traced. The 

 roots of the third, in the coal, could not be recognized as Stigmaria, 

 but they extended horizontally as clay masses covered with coal. 

 The roots had been filled with sediment. Eight stems were seen in 

 the Louise. Three rose directly from the underlying shale and 

 crossed the mur, which is 60 centimeters thick ; one was cut off 

 abruptly at the coal and the others were broken off just before 

 reaching it. The remaining five are in the roof. One is indefinite, 

 but the others expand at the base and their rootlets are put forth 

 into the shale. These erect trees, throughout, were in situ; all were 

 vertical to the bedding. If they had been transported, they would 

 have been inclined in direction of the current. Transported trunks 

 were seen at various horizons but, in the cases described, the trunks 

 were fixed in place by their roots, wherever the roots were seen. 

 This Lens locality is in the great W'estphalia-France-Belgium field, 

 a paralic area. 



Gosselet refers to conditions in the Banc des Roseaux at Com- 

 mentry, where trunks are seen arranged in all directions, vertical, 

 inclined, prostrate, and he compares them with those resulting from 

 ravages of a hurricane in the forest of ]\Iormal. There, many of 

 the trees were prostrated ; some, held by their roots, were inclined ; 

 while a small number remained erect — the conditions bearing re- 

 markable resemblance to those observed at Commentry. His con- 

 clusion is that, where one sees the mur rich in rootlets of Stigmaria, 

 he may regard it as a soil in which trees spread their roots. If the 

 tree does not rise above the mur, it is because it has been destroyed 

 by carbonization to furnish its elements, in part at least, to the coal 

 bed. When the trunk is cut off sharply at coal or mur, it may be 

 that the deposits were made so slowly that the trunk rotted off" at 

 the water-surface. He quotes Fayol as showing that at times one 

 may prove the presence of erect trunks in the coal itself, but usually 

 they are fused with the mass. 



In this connection, it is well to recall the fact that Potonie^'^'^ 



'"" H. Potonie, " Die Entstehung der Steinkohle," etc., 1910, pp. 134-136. 



237 



