THE CARBONIFEROUS SYSTEM. 



703 



every portion of its surface. The effect is heightened by the contrast of the coal-black 

 colour of these vegetables, with the light ground-work of the rock to which they are 

 attached. The spectator feels himself transported, as if by enchantment, into the forests 

 of another world ; he beholds trees of forms and characters now unknown upon the surface 

 of the earth, presented to his senses almost in the beauty and vigour of their primeval 

 life ; their scaly stems, and bending branches, with their delicate apparatus of foliage, 

 are all spread forth before him; little impaired by the lapse of countless ages, and bearing 

 faithful records of extinct systems of vegetation, which began and terminated in times of 

 which these relics are the infallible historians." It is not in the coal itself that the 

 distinct forms of vegetable matter are most numerous, but in the layers of shale, 

 sandstone, and ironstone which intervene between its seams ; and besides plants, the coal 

 formation contains the organic remains of marine fishes, with molluscous and crustaceous 

 reliquiae, supposed to be of fresh-water or estuary origin the latter, a new feature in 

 the earth's story of organic life. 



The following are some of the most common and interesting vegetable remains in the 

 coal measures. 



Ferns. Of these flowerless plants there are now existing about fifteen hundred species. 



They are often subterraneous and 

 creeping, but become arborescent 

 and leafy above the ground, espe- 

 cially within the tropics, to which 

 zone the arborescent ferns are now 

 confined, with the exception of some 

 in the islands of the southern he- 

 misphere. Those of Europe are of 

 diminutive size, but towards the 

 equatorial regions they often attain 

 the height of forty or fifty feet, the 

 magnitude of trees, as in the ad- 

 joining figure. On the staircase 

 of the British Museum there is an 

 example of a Bengal species forty- 

 five feet high. The fossil ferns of 

 the coal formation, amounting to 



__ one hundred and twenty species and 



Tropical Ferns. upwards, include nearly half of its 



flora, and almost all of them belong to the arborescent tribe, from which Brongniart in- 

 fers that the conditions of heat arid humidity, which 

 now favour their growth, more especially obtained, 

 and that in high northern latitudes, during the 



carboniferous pe- 

 riod> They are 

 arranged in ge- 

 nera, according to 

 the shape of the 

 leaves, their mode 

 of attachment to 

 the stem, and the 



Annularia brevifolia. Sphenophyllum dentatum. manner in which 



the veins of the leaves are distributed. While the foliage of these ancient ferns occurs 



