LEPIDODENDRON 135 



I. Secondary Wood not observed 



1. Lepidodendron Harcourtii, Witham ; Coal-measures. 



2. L. parvulum, Williamson ; Coal-measures. 



3. L. macrophyllum, Williamson ; Coal-measures. 



4. L. Hickii, Watson ; Coal-measures. 



5. L. aculeatum, Sternb. ; Coal-measures. 



II. With Secondary Wood 



6. Lepidodendron breznfolium, Williamson ; Calciferous Sandstone 



series, at base of Carboniferous formation. 



7. L. {Lepidophloios ?) Wunschianum, Williamson ; also from 



Lower Carboniferous strata. 



8. L. selaginoides, Carruthers ; Coal-measures. 



9. L. {Lepidophloios) fuliginosum, Williamson ; Coal-measures. 

 10. L. intermedium, Williamson ; Coal-measures. 



n. L. obovatum, Sternb.; Coal-measures. 



L. mundum, Will., formerly included in this list, 

 has now been shown by Mr. Lomax to be the stem of 

 a Bothrodendron (see p. 200). 



Now, of all these forms, there are only two which are 

 known to have attained any considerable size without 

 showing secondary growth of the vascular tissues ; 

 these species are L. Harcourtii, the first Lepidodendron 

 discovered with its structure well preserved, and 

 L. Hickii, recently recognised as a distinct species by 

 Mr. D. M. S. Watson. The original specimen of 

 L. Harcourtii was found in 1832, in the Hesley Heath 

 Colliery, Northumberland, and was first described by 

 Witham of Lartington, 1 who named it Harcourtii after 

 its discoverer. Our first minute knowledge of the 

 structure of this fossil was due to the great French 

 palaeobotanist, Adolphe Brongniart, who gave an 



1 Internal Structure of Fossil Vegetables, Edinburgh, 1833. 



