27 



1. Sigillarife and Calamodendrese. 



Favularia, (in part)? 

 Sigillaria proper, (in part)? 

 Calamodendron, (in part) ? 



2. Cycadese. 



Rhiptozamites. * 



3. Nceggerathiss. 



Noeggerathia. 



Poroxylon. 



Dolerophyllum. 



Whittleseya. 



Saportea. 



Medullosa? 



Colpoxylon ? 



Ptychoxylon. 



4. Cordaitese. 



Dictyocordaites. 

 Cordaites. 

 Dorycordaites. 

 Poacordaites. 



5. Taxinex. 



Psygmophyllum. 

 Baiera ? 1 

 Ginkgophyllum. 

 Tylodendron. 

 Walchia, Voltzia, etc. 

 Dadoxylon. 



6. Conifers. 



It would thus appear : 



1. That the nearest structural affinities of the Palaeozoic 

 gymnosperms with the higher Cryptogams lead toward all 

 the groups of Acrogens, viz. : Sigillariae, Calamitese, Lepi- 

 dodendrese and Ferns. 



2. That the present dominant groups of Coniferse proper 

 and Cycadacese are absent or slenderly represented in the 

 Palaeozoic. 



3. That the dominant Palaeozoic families are Ihe Noegge- 

 rathiae, Cordaitese and Taxineae, and that these occupied 

 a prominent and important place, and culminated in the 

 Palaeozoic and early Mesozoic periods. 



1 Permian , of Russia, Schmalhausen. 



