Marvels of the Universe 



37 



when we pass to consider the early horse-tails, 

 we find instead of a growth of but a few feet 

 high, fossil calamites commonly reaching to sixty 

 or even a hundred feet in height. 



The remarkable point about them is, as in 

 the one previously mentioned, that their method 

 of fruiting remains, in the modern plant, with 

 minor differences, almost exactlj' the same as 

 that which obtained in the times which we 

 are considering, perhaps some two hundred 

 millions of years ago. These plants cannot be 

 satisfactorily examined in the coal itself, but 

 in the shales and sandstones they have under- 

 gone but little change beyond carbonization, 

 and their methods of fruiting have been micro- 

 scopically examined, and wonderful results have 

 been obtained. Much remains yet to be dis- 

 covered, and palaeobotany offers yet many prizes 

 to the searcher. 



The fem-like structures of the coal are many, 

 and have received many fanciful names, generally 

 based on some outwardly noticeable form. One. 

 illustrated on the top of this page, must have 

 been as plentiful in the coal-forests as is the 

 common bracken of our own times. The coal- 

 ferns, as we may call them for convenience sake, 

 present man}' beautiful forms, and any waste-heap 

 from a coal-mine will yield specimens. 



To become coal, vegetation must pass through 

 a number of stages, all dependent on the extent 

 to which the gaseous constituents of vegetation 

 have been allowed to pass away. The result is 

 that coals van,' according to the extent of the 

 purity of the carbon which is left behind. Peat 

 in this respect is but little removed from 

 ordinary vegetation, its carbon being estimated 

 at between fifty and sixty per cent. Lignite, 

 or brown coal, has more carbon, or about sixty- 

 seven per cent. The various coals have from 

 eighty to ninety per cent, of carbon, but when 

 we come to anthracite we find that so much of 

 its volatile products have disappeared that 

 ninety-three to ninety-seven per cent, of carbon 

 is found. Graphite has some ninety-five per cent. 

 of carbon, and if we but knew how to do it at 

 reasonable cost, we might turn our coal-scuttle 

 into a receptacle for diamonds, for the diamond 

 is itself almost pure carbon. But then we should 

 value it the less. 



[/ 1 V iLiU AihPi 



fOSSIl M RN Oh IHF COM BEDS 



A graceful form of which numerous species are found 

 faithfully reproduced in the shale, which can be observed 

 to be flaliing away. 



I'hoto h'l] 



MICROSCOPIC SECTION 



The section wa^ made 

 flowerlcss plant, which had 

 woody. 



[/■;. A. NpireU Arher. 



OF A COAL PLANT. 



across the stem of a fern-like 

 lo pith, the ceniral tissue being 



