THE ERIAN OR DEVONIAN FORESTS. 49 



flora, which I was then preparing, and which was pub- 

 lished in 1871. under the name Sporangites Huronensis. 



In 1871, haying occasion to write a communication to 

 the "American Journal of Science" on the question then 



Fig. 15. — Vegetation of the Devonian period, restored. Calamites, Psilo- 

 phyton, LeptopMeum y Lepidodendron, Cordaites, Sigillaria, Dadoxy- 

 lon, Aster opliyllites, PlatypTiyllum. 



raised as to the share of spores and spore-cases in the ac- 

 cumulation of coal, a question to be discussed in a sub- 



