As regards the _life_ of the Devonian period, we are now acquainted with a large and abundant terrestrial _flora_--this being the first time that we have met with a land vegetation capable of reconstruction in any fulness. By the researches of Goeppert, Unger, Dawson, Carruthers, and other botanists, a knowledge has been acquired of a large number of Devonian plants, only a few of which can be noticed here. As might have been anticipated, the greater number of the vegetable remains of this period have been obtained from such shallow-water deposits as the Old Red Sandstone proper and the Gaspè series of North America, and few traces of plant-life occur in the strictly marine sediments. Apart from numerous remains, mostly of a problematical nature, referred to the comprehensive group of the Sea-weeds, a large number of Ferns have now been recognised, some being, of the ordinary plant-like type (_Pecopteris, Neuropteris, Alethopteris, Sphenopteris_, &c.), whilst others belong to the gigantic group of the "Tree-ferns" (_Psaronius, Caulopteris_, &c.) Besides these there is an abundant development of the singular extinct types of the _Lepidodendroids_, the _Sigillarioids_, and the _Calamites_, all of which attained their maximum in the Carboniferous. Of these, the _Lepidodendra_ may be regarded as gigantic, tree-like Club-mosses (_Lycopodiaceoe_); the _Calamites_ are equally gigantic Horse-tails (_Equisetaceoe_); and the _Sigillarioids_, equally huge in size, in some respects hold a position intermediate between the Club-mosses and the Pines (Conifers). The Devonian rocks have also yielded traces of many other plants (such as _Annularia, Asterophyllites, Cardiocarpon_, &c.), which acquire a greater pre-dominance in the Carboniferous period, and which will be spoken of in discussing the structure of the plants of the Coal-measures. Upon the whole, the one plant which may be considered as specially characteristic of the Devonian (though not confined to this series) is the _Psilophyton_ (fig. 77) of Dr Dawson. These singular plants have slender branching stems, with sparse needle-shaped leaves, the young stems being at first coiled up, crosier-fashion, like the young fronds of ferns, whilst the old branches carry numerous spore-cases. The stems and branches seem to have attained a height of two or three feet; and they sprang from prostrate "root-stocks" or creeping stems. Upon the whole, Principal Dawson is disposed to regard _Psilophyton_ as a "generalised type" of plants intermediate between the Ferns and the Club-mosses. Lastly, the Devonian deposits have yielded the remains of the first actual _trees_ with which we are as yet acquainted. About the nature of some of these (_Ormoxylon_ and _Dadoxylon_) no doubt can be entertained, since their trunks not only show the concentric rings of growth characteristic of exogenous trees in general, but their woody tissue exhibits under the microscope the "discs" which are characteristic of the wood of