158 STEVENSON— FORMATION OF COAL BEDS. [April i8, 



tribnted as to suggest strongly that they belonged to forests, may have 

 no direct bearing on the formation of coal beds, it has an extremely 

 important indirect bearing. It is part of the proof that the region was 

 a land area, covered more or less with vegetation. The other ele- 

 ments of the proof have been set forth with ample detail in Part 

 III. They are, the extraordinary horizontality of the strata in many 

 thousands of square miles, where the disturbing forces have not 

 acted, showing marked resemblance to conditions on the Siberian 

 steppe, described by Belt, or to those on the Gangetic plains, de- 

 scribed by Blanford ; the absence of plant remains in sandstones 

 and shales in great areas ; the presence of coal and shale pebbles in 

 many deposits ; the gradation in size of pebbles, indicating rehandling 

 by streams ; the extreme freedom from fine material along definite 

 lines of coarse rocks, distinct evidence of river selection; the buried 

 valleys, scores to hundreds of miles long; the gullied coal beds; the 

 widely extended sub-aerial erosions: the vast deposits of fine shales, 

 proof of long sub-aerial exposure of the rocks, whence they were 

 derived; the shallow water character of the localized marine lime- 

 stones, which occupy definite areas, resembling estuaries extending 

 into valleys ; the ripple-marks, suncracks and footprints, observed at 

 many horizons. Some of these features, if they existed alone, might 

 be explained in other ways ; but they do not occur alone. They 

 must be considered as a whole. The conditions were such as to 

 favor the accumulation of peat ; the coal beds must have accumulated 

 under practically sub-aerial conditions — unless one accept a flexi- 

 bility of the earth's crust, many times greater than that which some 

 allochthonists imagine is demanded by autochthonists. 



The Peat Deposits Resemble Coal Beds. 



Grand'Eury says that in the coal the plants have been broken up 

 and the parts scattered ; fruits and leaves are separate from their 

 stems; layers of bark have been displaced; the interior portions of 

 stems have disappeared and only the flattened cortex remains ; 

 woody parts have been dispersed as fusain ; stems are split and 

 torn; Cordaites leaves are imperfect; everything, bark or leaf, is 



