GEOLOGY IN THE UNITED STATES 4Q 



remains found in coal beds indicate that palms, phenogams, 

 or flowering trees, and conifers, or plants of the pine tribe, 

 attained a colossal size. It is impossible for the imagina- 

 tion to conceive of the gorgeousness that then clothed mother 

 earth. There must have been great numbers of immense 

 floating islands, carrying groves, in the inland seas that the 

 marsh regions enclosed, and the warm humid atmosphere 

 was no doubt heavy with the perfumes of myriad flowers 

 of gigantic proportions. 



When the plants and trees died their remains fell to 

 the ground of the forest, and soon became decomposed into 

 a black pasty mass, to which was added year by year the 

 continual accumulation of fresh carbonaceous matter. Thus 

 this process of decay and disintegration went on among 

 the shed leaves and trees until a bed of uniform thickness 

 would be formed over a wide area. The eras of verdure 

 during which these plant beds were in progress were alter- 

 nated by periods of inundation by salt water from the oceans, 

 that destroyed all terrestrial life. The accumulations of 

 thousands and thousands of years of vegetable growth and 

 decay became covered up with deposits of sedunent. Then 

 the continental surface, or wide portions of it, would again 

 slowly emerge and a new era of verdure appear. Thus the 

 alternations continued until all the successive coal beds 

 were formed. The ever increasing pressure of the accumu- 

 lated strata above them compressed the sheddings of a whole 

 forest into a thickness in some cases of a few inches of coal, 

 and the action of the internal heat of the earth caused them 

 to part, to a varying degree, with some of their component 

 gases. The coniferous trees, such as the living larches, pines, 

 firs, etc., gave rise for the most part to the mineral oils, their 

 sheddings having been subjected to a slow and continuous 

 distillation, the oil so distilled accumulating in troughs in 

 the strata, or finding its way to the surface in the shape 

 of mineral oil springs. The nature and property of the 

 coal to be formed depended upon the original substances 

 of the living plant. One of the most remarkable things in 

 connection with coal is the state of purity in which it is 

 found . Owing to the fact that the forests must have abounded 



Vol. 7-i 



