302 D. WHITE — AGE OF LOWER COALS OF HENRY CO., MISSOURI. 



tending to lead from the Valenciennes series (Westphalian) to the Ste- 

 phanian.* The presence of these types in the Henry County beds, as 

 well as the comparative absence from them of the species more char- 

 acteristic of the Middle zone of the Valenciennes basin, indicates for our 

 flora a greater and more significant affinity with that in the terranes suc- 

 ceeding, in time, the zone of Bully-Grenay than with that of the beds 

 below this zone. Hence, taking all things into consideration, we will 

 perhaps be warranted in concluding that the Missouri flora represents a 

 stage close to, but below, the upper limit of the Westphalian. 



SUMMARY OF CONCLUSIONS RESPECTING THE STAGE OF THE MISSOURI FLORA 



IN THE OLD WORLD BASINS. 



In passing, it should be noted that the Transition series in Britain and 

 the zone of Bully-Grenay, to both of which our flora seems to refer us,t 

 have been quite independently correlated with each other by Zeiller and 

 Kidston. So also the tendency of the Missouri flora toward that succeed- 

 ing the upper zone of the Valenciennes series appears to harmonize with 

 the reference made bv Zeiller t of the Mazon Creek flora to the zone of 

 Bully-Grenay. 



The study of the distribution of our flora in other European basins 

 indicates an approximately contemporaneous stage in the Geislautern 

 beds near the top of the Saarbriick series of the Rhenish coal regions, 

 in the upper part of the Schatzlar series, and in the Radnitz series in 

 central Bohemia. 



General Considerations as to the early Carboniferous Flora. 



The study of the geographic distribution of the Mesocarboniferous 

 floras throughout the northern hemisphere shows (1) so striking a gen- 

 eral parallelism in the succession of the floras, (2) so high a degree of 

 uniformity in the elemental composition and relations of the floras of 

 the respective stages in the different basins, and (3) so large a proportion 

 of the genera, and species even, that are identical and in similar general 

 sequence, both with respect to their associates and with regard to their 

 relative period of existence, not merely in the basins of the same conti- 

 nent, but between Europe or Asia and north America,§ as not only to 



* Several of our species are more nearly related to forms in the Commentry flora (Stephanian) 

 than those forms from the Franco-Belgian field tabulated above. 



f As remarked above, it may be slightly later than either. 



t Op. cit., p. 195. 



g Forty-one of the 44 genera present in the Henry County flora are also found in the European 

 coalfields, while the proportion of identical species may, even with the refinement of differenti- 

 ation that now prevails in Paleozoic paleobotan}', ultimately be found to comprise far more than 

 one-half of the entire flora. 



