BY PROFESSOR STEPHENS. 351 



variations in level, vast volcanic disturbances, and consequent 

 geographical alterations, we again begin to see in a glimmering 

 light the landscape as before, but in a strangely altered state. 

 Subsidence of the land or rising of the sea has opened ways for 

 the cold ocean currents from the west, and the still colder water 

 from the icy south. The maritime i-egions that formerly bore 

 the exuberant jungles of the Lepidodendron flora are now below 

 the sea-level. The climate in general is severe and stormy, 

 modified of course by local conditions. The snow line has 

 descended, and before it the Glossopieris flora has been gradually 

 forced likewise, step by step, to a refuge in the low lands. 



Strange as it may seem, it is nevertheless certain that how- 

 ever extreme the transformation of the landscape may have 

 been, the waters of the sea and their inhabitants underwent no 

 sufficient hardship to alter their character. From the last 

 preceding marine fossiliferous beds we find the following genera 

 and species still surviving, viz. : Cyathophyllura, A7n2olexuSf 

 Syringopora, Favosites, Strophalosia, Chonetes, Orthis, Rhyn- 

 chonella pleurodon, Atryjoa, Spirifer, Teltinomya, Aviculopecten, 

 Pterinea, Dentaliutn, Murchisonia verneuiliana, Pleurotomaria, 

 Eioomplialus, Loxonema, Goniatites, Orthoceras (Report l)ep. 

 Mines, pp. 57-67). I have no doubt that this list will be largely 

 increased by further identifications in the older or Devonian beds. 



This is our third epoch — that of the Lower Marine beds. In 

 the fourth — the Lower Coal Measures — we see the land again 

 emerging, broad valleys opening upon well- watered plains ; a 

 climate, if not warm, at least constantly temperate, moist, and 

 eminently favourable to the growth of the Glossopteris flora, 

 which is now occupying wide areas with the peat mosses which 

 are to be the " Lower Coal " of the future. On the drier eleva- 

 tions we see forests of Araucarias and other conifers. But the 

 snow line is still at a lower level than in the Lepidodendron 

 time, and the glaciers, in consequence of the abundant pre- 

 cipitation of aqueous vapour, descend even lower than in the 

 colder period immediately preceding. Except in the more 



