26 THE EVOLUTION OF PLANTS 



The Upper Carboniferous includes the whole 

 of the Coal Measures (Upper, Middle and 

 Lower), together with the underlying Millstone 

 Grit. The Lower Carboniferous is chiefly rep- 

 resented in England by the Mountain or Car- 

 boniferous Limestone of the Lennine chain and 

 the Mendip Hills, and in Southern and Central 

 Scotland by the Calciferous Sandstones. There 

 are considerable differences between the Flora 

 of the Upper and that of the Lower Carboni- 

 ferous, the latter approaching the Devonian in 

 character. Plants of much interest and of quite 

 peculiar types are found in the Calciferous 

 Sandstones of Scotland. 



The Devonian, so well represented in the 

 country from which it derives its name, as well 

 as by the old Red Sandstone of Scotland and 

 elsewhere, is of extreme interest botanically, for 

 it contains the oldest Land Flora of which we 

 at present have any satisfactory knowledge. In 

 OUT own islands it is only at certain places in 

 Ireland that the Devonian is at all rich in fossil 

 plants, but in North America a considerable 

 Flora of Devonian age is known. 



The plants do not on the whole differ very 

 widely from those of the Lower Carboniferous, 

 though some are of course peculiar. They are 

 already very highly organised plants; a vast 

 history must lie behind them, of which, as yet, 



