276 APPENDIX. 



(3) The Millstone Grit Sub-Flora : 



In this formation the abundance of plants and the number of 

 species are greatly diminished.* Trunks of coniferous trees of the 

 species Dadoxylon Acadianum, having wide wood-cells with three 

 or more series of discs and complex medullary rays, become charac- 

 teristic. Calamites undulatum is abundant and seems to replace C. 

 Suckovii, though C. cannceformis and C. cistii continue. Sigillarice, 

 become very rare, and the species of Lepidodendron are few, and 

 mostly those with large leaf -bases. Lepidophloios still continues, and 

 Cordaites abounds in some beds. The ferns are greatly reduced, 

 though a few characteristic coal-formation species occur, and the 

 genus Cardiopteris appears. Beds of coal are rare in this formation ; 

 but where they occur there is in connection with them a remarkable 

 anticipation of the rich coal-formation flora, which would thus seem 

 to have existed locally in the Millstone Grit period, but to have 

 found itself limited by generally unfavorable conditions. In Ameri- 

 ca, as in Europe, it is in the north that this earlier development of 

 the coal-flora occurs, while in the south there is a lingering of old 

 forms in the newer beds. In Newfoundland and Cape Breton, for 

 instance, as well as in Scotland, productive coal-beds and a greater 

 variety of species of plants occur in this formation. 



The following would appear to be the equivalents of this forma- 

 tion, in flora and geological position : 



1. The Serai Conglomerate of Rogers in Pennsylvania, &c. 



2. The Lower Coal-formation Conglomerate and Chester groups 

 of Illinois (Worthen). 



8. The Lower Carboniferous Sandstone of Kentucky, Alabama, 

 and Virginia. 



4. The Millstone Grit and Yoredale rocks of northern England, 

 and the Culmiferous of Devonshire. 



5. The Moor rock and Lower Coal-measures of Scotland. 



6. Flagstones and Lower Shales of the south of Ireland, and Mill- 

 stone Grit of the north of Ireland. 



7. The Jiingste Grauwacke of the Hartz, Saxony, and Silesia. 



(4) The Carboniferous Limestone Series : 



This affords few fossil plants in eastern America, and in so far as 

 known they are similar to those of the next group. In Scotland it 

 is richer in plants, but, according to Mr. Kidston, these are largely 



* " Report on Fossil Plants of the Lower Carboniferous and Millstone 

 Grit of Canada," 18Y3. 



