[sir J. w. DAWSON] ON THE GENUS LEPIDOPHLOIOS 7S- 



Y. Eelations op Lepidophloios to the Accumulation of Coal. 



On tbis subject it is not necessary to say much, as what is noted of 

 the Lepidodendra in my papers on the Accumulation of Coal, in the 

 Journal of the Geological Society (1865), and in the chapter on that 

 subject in Acadian Geology covers nearly all that can be said of Lepido- 

 phloios. 



I may merely state that such specimens as I possess, in a flattened 

 and carbonized state, show that in ordinary circumstances the outer bark 

 and leaf-bases have yielded a film of compact coal, perhaps y^th of th& 

 thickness of the i*ecent stem, and that the woody axis will appear usually 

 as mineral charcoal of the same character as that of the Lepidodendra 

 The large cones and their contained sporangia and macrospores must 

 have contributed to the mass of such material which enters into the 

 coarser layers of coal, but can, until the microscopic structure of these 

 organs is better known, scarcely be distinguished from the similar parts- 

 of other Lepidodendroid trees. The trees of the genus Lepidophloios 

 were associated in the Carboniferous swamps with Sigillaria, Lejndoden- 

 dron, Calamités, etc., and were most plentiful in the Middle and Upper 

 Coal Formations, but do not seem to have been so abundant as either of 

 these genera in any locality in which I have studied them. 



