COAL FORMATION. 



43 



according to Ad. Brongniart, probably only the roots of plants, tb 

 body of which is traversed by a ligneous axis surrounded by sou 

 fleshy parts. 



Fig. 46. Sigilla'ria pachyde'rma. 



Fig. 47. Stigma'ria Jicoi'des. 



14. The co'nifers, which, from the consistence of their wood, 

 eeem to have participated largely in the formation of carbonaceous 

 matter in different 



strata, present us, in 

 the different coal- 

 measures, especially 

 in the upper beds, 

 species approxima- 

 ting to the arauca'ria 

 in their spirally-ar- 

 ranged sessile leaves. 

 M. Ad. Brongniart 

 refers the whole of 

 them to the genus 

 Walchia of M. Stern- 

 berg, of which two 

 species, with their 

 leaves and fruit, are 

 here figured, (Jig. 



15. Animal re- 



mains are not very 

 common in coal-mea- 



Fig. 48. a Walchia Schlotheimii. 

 b Walchia Hypnoides. 



Bures ; still some are found, and even in great numbers in certain 



13. What are sigillari ? What are stigmariae ? 



14. What genus of conifers is found fossilized ? 



25 



