GEOLOGY. 313 



My conviction is, that the beds of coal were deposited from crater, under 

 the same circumstances as the other beds between which the coal is found. 



The numerous analyses of coal show that no timber now existing 

 contains within itself the pruper quantity of ingredients to form coal. It 

 must, therefore, acquire its ingredients in part from some other source, or 

 a part of those existing in wood or woody fibre must be deposited, and 

 another part of the ingredients remain in excess. There is very little 

 vegetable matter that contains nitrogen, and woody fibre has none. In 

 coal, nitrogen is found in notable quantities, at almost every analysis. 



Woody fibre seldom furnishes more than 50 per cent, of carbon coal 

 has from 70 to 90 per cent. The inference that coal was once in a vegetable 

 state arose at first from the fact that the impressions or petrifactions of 

 leaves and trees are abundant in coal strata. 



As the impressions of the same trees and leaves are found in the shales 

 and sandstones that overlie and underlie these strata, this fact is equally 

 strong proof that the sandstones" and shales are of vegetable origin. 



Bitumen is similar in its elements to coal, and it pervades rocks of all 

 ages. It is found as abundant in the Silurian and Devonian strata as in 

 the Carboniferous, and is even seen in the igneous rocks. It exudes 

 from the earth in immense quantities, as at the Dead Sea, in Trinidad, on 

 the McKenzie River, and in the Birman empire. 



The limestones of Seyssel, in France, that are newer than the carbon- 

 iferous, and those of Ohio, Michigan and Wisconsin, that are older, equal- 

 ly produce bitumen enough, if concentrated, to form heavy beds of 

 coal. No vegetable remains are found in these rocks. 



If the diffusion of bitumen, extending from the tertiary and lias down 

 to the Cambrian strata, does not entitle it to the name of a mineral, why 

 should the oxides or sulphurets, that have no greater range, be regarded 



as minerals ? 



The advocates of a supply of timber, to be formed into beds of coal, as- 

 sert that it was collected on the shores of ancient seas, borne by oceanic 

 currents over the whole surface, settled to the bottom in layers, and was 

 covered with sediment that did not enter the interstices, beneath which it 

 was carbonized. No sea or lake, now in existence, collects from its shores 

 such immeasurable supplies of timber ; but, on the contrary, all seas cast 

 their floating trunks upon the strands to rot. The trees brought down by 

 rivers like the Mississippi, the Amazon and the Ganges, come singly, and 

 not in floats or layers ; they are, if sunk, buried in silt, and either pre- 

 served in kind or decay and disappear. No authenticated case is known 

 of a layer of timber, self- transported, and intombed in mud, that has 

 been converted into coal. It is therefore necessary to attribute to ancient 

 seas and rivers qualities that ours do not possess, and that are purely 

 imaginary, and even contrary to nature. Most of the coal rocks are of 

 marine origin, and the great examples of buried timber, in the deltas of 

 rivers, are in fresh-water deposits. 



The advocates of a supply from peaty matter, originating in marshes, 

 H 



