316 GENERAL OBSERVATIONS. 



to all the coal beds hitherto known ; and no doubt the antediluvian 

 forests were far more extensive and luxuriant. — As trees are often 

 found lodged at a great depth, in the channels of rivers, and at the 

 bottoms of lakes, we need scarcely inquire, how the masses of wood 

 could be deposited at the bottom of the ocean, instead of all floating 

 at the top. Yet we may notice, that the trees being torn up with all 

 their roots, branches, and leaves, would naturally become much 

 clogged with the mud or clay of the soil in which they grew ; and 

 this clay would not only facilitate the deposition of the vegetable 

 masses, but supply materials for the shale beds which uniformly 

 accompany coal. The leaves and small plants, floating in the upper 

 part of the mass, would occasion those vegetable impressions found 

 in the coal shale, immediately over each bed of coal; and often in the 

 coal itself. Some of the thinner seams of coal, as the Maybecks 

 seams, appear to owe their origin to floating masses of branches, 

 shrubs, and small plants. The process by which such vegetable 

 matter might be converted into coal, is well described by Mr. 

 Parkinson, in the First Volume of his Organic Remains. The coal 

 beds would be formed by successive floating masses of wood, beds 

 of clay or sand being interposed between them. 



The exuberance of animal life in the ancient world, may be pre- 

 sumed to correspond with that of vegetation. Immense quantities of 

 shell-fish, with the exuviae of those of former ages, being strewed 

 along the shores of the seas and the rivers, would, at the breaking 

 up of the strata, be swept away by the waters ; intermixed with the 

 sand, marl, or clay, on which they reposed, now destined to be their 

 matrix ; and masses of animal matter, including shells, remains of 

 fishes, &c., after floating for some time, would be deposited in the 

 beds, and become the nuclei of future nodules of stone. 



Some may be ready to ask, Why are the beds so regular, ami in 

 many instances so homogeneous? Why do we not find them presenting 



