360 



PALEOZOIC SYSTEM OF ROCKS. 



tudinal section ; and to be those of Conifers by the existence of a dis- 

 tinct bark, rings of growth, and pith (Fig. 458). But the large size of 

 the pith of some seems to ally them with the Cycads. 



Fig. 467. 



Figs. 465-467.— Fruits of Coal-Plants, probably Conifers: 465. Trigonocarpon (after New- 

 berry). 466. Cardiocarpon (after Newberry and Dawson). 467. Rhabdocarpon (after Newberry). 



But the leaves, leafy branches, and fruits are still more interesting 

 and significant. By the study of these, Carboniferous Conifers seem 

 to 'fall naturally into two groups, viz., those with small, spine-like 



