Valley of the Lackawanna and of Wyoming. 323 



matter may have prevailed still more, and then the deposit is a carbo- 

 naceous slate — and lastly, the carbon may have been supplanted by 

 the earthy matter, and then seams of slate v.^ould be formed as we 

 actually find them in the coal beds. Without some such process, it 

 seems difficult to account for the varying proportions of earth and 

 carbon, which we tind blended in the anthracites ; the extremes be- 

 ing the purest coal on the one hand, and slate on the other, and be- 

 tween these there appear to be innumerable mixtures or combiimtions 

 of earth and coal in different proportions. 



Perhaps the reason why the vegetables found in the slate retain 

 their organized form, is found in the fact, that the fine sedimentary 

 earths, the silicious and argillaceous, of which the slate is composed, 

 may have enveloped the plants too suddenly, to permit them to un- 

 dergo decomposition, and thus to exhibit an impalpable carbon ; while 

 their forms would, of course, be distinctly impressed upon the yield- 

 ing plastic matter of the slate, rendered soft perhaps by diffusion 

 in water. Pressure is also to be taken into account in reasoning up- 

 on the probable obliteration of the organic structure ; this force would 

 operate in proportion to the progress of the accumulation whether 

 of coal strata, or of those of superincumbent rock. 



Many other considerations present themselves in relation to this 

 subject ; such as the time when, and in which, these deposits were 

 made, the original position of the strata whether flat or inclined ; if 

 flat, by what force raised or depressed ; if inclined, how the mate- 

 rials were prevented from accumulation in thicker masses at the low- 

 est curvature or point of declination, &c. Internal fire may have 

 raised and distorted and modified the coal beds, after they were form- 

 ed, but it seems more difficult to admit, that coal strata have been in 

 actual ignition. 



fJonclusion. 



But, dismissing theoretical considerations, Uie coal is in our power 

 and it is destined to produce great results in the United States. In- 

 cluding the bituminous and the anthracite coal of the various regions, 

 there is in our territories, enough to supply the world,* and the coun- 

 try on die Susquehanna and its tributaries will, when the commu- 

 nications shall be duly opened, rise to a degree of importance, at 

 present, not easily realized. It is hoped that the spirit of speculation, 

 so productive of extravagant and erroneous expectations, will not be 

 here substituted for a regular course of industrious exertion, which, 



* Not to mention the coal bf^yond the Mississippi and that in Nova Scotia. 



