§ 43. COAL-MEASURES FROM SUBMERGED LANDS. 731 



these rafts, grasses and tender plants are often found entire. 

 Such masses, therefore, might be drifted many hundred 

 miles, and yet the imbedded fragile species, protected by 

 the external network of entangled branches, remain unin- 

 jured; and, undergoing bituminization, while enveloped by 

 the soft mud permeating the mass, might become changed into 

 durable forms, like those which abound in the natural 

 herbaria of the coal-measures. That the conversion of 

 vegetable matter into coal would take place under such 

 conditions we may readily conceive, from what has been 

 advanced in the course of this argument. 



43. Coal-measures from submerged lands. — The 

 theory so ably advocated by Mr. Lyell, and other eminent 

 geologists, of the formation of coal-measures from repeated 

 submergences and elevations of lands covered with dense 

 forests {ante, p. 670), seems to be applicable only to those 

 carboniferous formations which are made up of regular 

 alternations of coal with beds composed of such earthy 

 materials, as to render it probable they were once capable 

 of supporting a luxuriant vegetation. 



But in many of the examples cited in proof of this 

 hypothesis, the bases and roots of the erect trees are in con- 

 tact either with a stratum of rock that never could have 

 been vegetable mould, or with a seam of coal a few inches 

 thick ; and setting aside the improbability of the bed on 

 which they are supposed to have grown, having afforded the 

 nutriment necessary for the support of such trees, the little 

 depth to which the roots extend, proves that the trunks 

 could not have been broken off at the height of a few feet 

 from the ground, while growing on the spot ; for such 

 violence must have rooted them up from the shallow soil, 

 and laid them prostrate. This objection, I think, strongly 

 applies to the examples of upright trees at St. Etienne ; to 

 those in Virginia, where the bases of the trees stand on a 

 seam of coal, resting on granite {ante, p. 520) ; and those 



