I9I3.1 STEVENSON— FORMATION OF COAL BEDS. 157 



of the trees, becoming a thin coal bed overlying the roots and 

 extending to a considerable distance. This too is a familiar condi- 

 tion in modern times. " Upland peat," as Coville has termed it, 

 sometimes accumulates to notable thickness in conifer and oak 

 forests: he reports a thickness of 5 feet in some areas. The writer 

 knows only too well that such peat accumulates to a thickness of 

 more than 3 feet in the forests of gigantic firs within New Mexico; 

 on more than one occasion, his camp narrowly escaped destruction 

 because the peaty material had not been removed to the bottom 

 before a fire was lighted. 



Erect stems in many cases are cut off abruptly at top or bottom, 

 as abruptly as though they had been sawed off. For this condition, 

 which occurs so often in the roof of coal mines, there is no ex- 

 planation aside from growth in situ. The absence of roots to sawed 

 oft" stems in the roof, and of crowns to sawed off stems in the mur 

 can be due only to slipping of the coal, which destroyed the original 

 continuity. 



The great number of erect stems discovered in the narrow ex- 

 posures of mines and on the still more limited space of natural out- 

 crops renders wholly reasonable the suggestion that, if coal were 

 mined by stripping, fossil forests would be found abundantly in all 

 fields, as Binney long ago suggested for the Lancashire region. The 

 stems, which have been found, are associated in many cases with 

 ripple-marked sandstones, the ripples at times resembling the com- 

 plicated forms characterizing dunes or loose sand. Altogether, the 

 evidence showing that the trees, under consideration, grew where 

 they are found, is in every respect as conclusive as is the evidence 

 that the logs between Cape Malagash and Wallace Harbor, described 

 by Dawson, ^^'^ are a petrified raft of driftwood, or that the irregu- 

 larly distributed battered timber found in sandstones is not a growth 

 in place. The reasoning is the same in both cases, an application of 

 knowledge gained by actual observation to explain conditions where 

 actual observation of the process is impossible. 



While the existence of great numbers of trees in situ, so dis- 



^'^ J. W. Dawson, " Some Fossils found in the Coal Formation of Nova 

 Scotia," Quart. Joiirn. Gcol. Soc, Vol. II., 1846, pp. 132-136. 



