474 PAIwEOBOTANY. 



The remains of Plants appear for the first time, so far as yet 

 known, in the Lower Cambrian series (jhtEophyton of the Fucoi- 

 dal Sandstone of Sweden) ; and from this time onward they are 

 never absent altogether from any of the great geological forma- 

 tions. The affinities of this earliest known plant are so dubi- 

 ous that it cannot be employed as proving the first appearance 

 of any of the great groups of plants. The Upper Cambrian 

 and Lower Silurian Rocks have yielded various remains of an 

 unquestionable vegetable nature, but of doubtful affinities re- 

 ferred, however, with more or less probability, to Sea-weeds 

 (" Fucoids "). In the Upper Silurian Rocks have been detected 

 various Sea-weeds (Spirophyton, &c.), the spore-cases of Lyco- 

 podiaceous plants (Pachytheca}, Lepidodendron, and remains of 

 the remarkable generalised type Psilophyton, which is in some 

 respects intermediate between the Lycopodiacece (Club-mosses) 

 and the Ferns. In the Devonian period as we now know, 

 from the researches of Dr Dawson of Montreal in particular- 

 plants are very abundant, and belong to varied types. The 

 great group of the Gymnospermous Exogens is here represented 

 by remains of various Conifers (Dadoxylon, Ormoxylon, and 

 Prototaxites}. The Ferns are represented by numerous species, 

 in many cases not far removed from types now in existence ; 

 and it is interesting to notice that Tree-ferns (Psaronius and 

 Caulopteris) are not wanting amongst these. The Lycopodiacea 

 or Club-mosses are represented in the Devonian Series by nu- 

 merous remarkable types, such as Lepidodendron, Lcpidophloios, 

 Cordaites, and Lycopodiies. The Sigillarioid plants, regarded 

 by different authorities as being Coniferous, or Lycopodiaceous, 

 or as being intermediate between the Acrogens and Gymno- 

 sperms are represented by species of Sigillaria itself, with its 

 Stigmaria roots. The Horse-tails or Eqnisetacece are repre- 

 sented by species of the remarkable genus Catamites. The 

 genus Antkolithes, commonly supposed to be the spike of fruc- 

 tification of some phanerogamic plant, and now known to bear 

 the probably Gymnospermous fruit, Cardiocarpon is repre- 

 sented by two species in the Devonian Rocks. Lastly, the 

 Devonian formation of the State of New York has yielded the 

 remains of an Angiospermous Exogen, which has been described 

 by Dr Dawson, under the name of Syringoxylon mirabile. 



We thus see, even from such an imperfect summary as the 

 above, that we must abandon the old view that nothing like a 

 general and varied flora existed in times anterior to the Coal- 

 measures. We see that at a point of Palaeozoic time as early 

 as that represented by the Devonian formation, the earth ex- 

 hibited a far from scanty vegetation, composed of true land- 



