LIFE OF THE PERIOD. 167 



and continuity of the physical agencies that mould and mo- 

 dify the face of nature, that interest becomes immeasurably 

 enhanced when we associate the results of these old-world 

 operations with the necessities of the present, and trace in 

 them an obvious provision for the social and intellectual 

 advancement of man. 



"We come next to consider the Carboniferous system as a 

 life-period, and though there must necessarily be consider- 

 able differences between the fossils of its respective divi- 

 sions carboniferous shales, mountain limestone, and coal- 

 measures yet in a sketch of this kind the aim is more 

 an outline of the whole than the consideration of specific 

 minutiae, which can only be appreciated by the professed 

 palaeontologist. Perhaps the most remarkable feature of the 

 period is its Flora a flora remarkable not only for its vast 

 exuberance, but for the peculiar character of its plant-forms, 

 which bear, in most instances, but a faint resemblance to 

 those of the present day. This vegetation is for the most 

 part converted into coal, but here and there, scattered 

 throughout the shales and sandstones, we find leaves, fruits, 

 stems, trunks, and roots, which indicate its nature, and 

 from these the botanist must construct the aspects of the 

 carboniferous flora. Sea-weeds, marsh-plants like the equise- 

 tums, reeds, and rushes, a vast variety and exuberance of 

 gigantic ferns and clubmosses, pine-like trees with their 

 leaves and cones, and a still greater number perhaps which 

 cannot be assigned to any existing order, may be said to 

 constitute the bulk of the coal vegetation. Fragmentary, 

 and converted into coaly or stony matter, the botanist has 

 no easy task in reading these old- world forms, and all that 

 he can in many instances do, is to trace a resemblance and 

 give a name founded on some external peculiarity. It is 

 for this reason that we find in lists of carboniferous plants 



