36 



Marvels of the Universe 



FOSSIL-FERN FOUND IN COAL. 



This fern is very common in coal, and its fossilized 

 parts somelimes stand out very clear and distinct, as a 

 film of black carbon. 



The 



ANOTHER COAL-FERN. 



wedge-fern 



has lobed leaRets, and the thick 

 stem is particularly well preserved. This specimen was 

 ifrom the sandstone roof of a coal-seam. 



to form a future seam of coal, provided the 

 necessary physical conditions followed. But we 

 can see no evidence of such conditions as being 

 likely to follow. The country would ha\'e to 

 be let down to the bottom of the sea ; de- 

 posits of sand and clay would have to be laid 

 down upon it ; long periods of heat and pressure, 

 and consequent chemical action, would also have 

 to follow before our black mud would become 

 coal. 



Making allowance for differences in the forms 

 of vegetation, a peat-bog forms a very good ex- 

 ample of a bed ready to be changed into coal. 

 But it would not become coal so long as it 

 was exposed to the action of the atmosphere. If 

 the peat deposits of Ireland were to disappear 

 beneath the sea, and be acted upon by all the 

 agencies which accompany marine sedimentation, 

 there might be, in ages to come, rich deposits of 

 coal. 



The vegetation of the modern peat- bog, which 

 might in future ages become coal, is very different 

 from that of the old coal-forest growth. We 

 look in vain in coal for our familiar trees or for 

 the wild flowers of the country-side. Flowers with 

 pretty petals there were none, as the insects, such 

 as they were, had not learned to be attracted by 

 highly-coloured appendages. The nearest approach 

 to our forest trees which had then appeared were 

 some cone-bearing trees. Most of the forest trees 

 of those far-away times have, in succeeding ages, 

 dwindled down to the horse-tails of our marshes, to 

 the little creeping club-mosses of our mountains ; 

 these, with many fern-like structures, form the bulk 

 of the coal-forming plants. 



The modern club-moss closely resembles the 

 giant coal-plant except in size, for the fossil 

 genus in many cases reached one hundred feet 

 in height. When the fruiting has taken place, 

 the spore-cases open, and the microscopic spores 

 are scattered far and wide, to provide for future 

 generations. 



Similarly, in those ages that are long past, the 

 giant club-moss, with the enormous area which it 

 covered, must have scattered its spores literally 

 in showers, and we know that certain coals of the 

 best kind are made up almost entirely of these 

 spores and their spore-cases, which are saturated 

 with resin and make a good blazing coal. Again, 



