076 J. W. BEEDE BEDS OF APPALACHIAN AND WESTERN SECTIONS 



likely that conditions were unfavorable to them. At the same time it is 

 possible that this fauna exists there, but has not been collected, though it 

 hardly seems probable. 



In the light of the foregoing evidence it would seem that, so far as the 

 evidence furnished by the invertebrate faunas of the Appalachian and 

 western interior regions, the successions are not difficult to correlate. In 

 the second place, that the evolution of the faunas was slow until the base 

 of the Neva limestone or its equivalents elsewhere have been approached, 

 when the evolutionary processes were remarkably quickened and new 

 faunas were developed. 



SUCCESSION OF THE FLORAS AND CORRELATION OF THEIR HORIZONS 



On account of the widely distributed plant beds in the Pennsylvanian 

 and the Permian systems, the record of the floras of these periods is of 

 great value for purposes of correlation, and it will be interesting to com- 

 pare correlations based on these floras with correlations based on the 

 invertebrates. 



In the Appalachian region above the Pottsville series, the flora is well 

 known nearly to the top of the Conemaugh, and is the type section for 

 comparison of upper Pennsylvanian floras of America. Without going 

 into too great detail, it may be stated that the post-Pottsville plants fall 

 into two groups, as found in the Allegheny and Conemaugh stages re- 

 spectively. Skipping the uppermost Conemaugh and Monongahela series, 

 the flora of the Dunkard series of the lower Permian has also been rather 

 fully described. 



Beginning with the Cherokee formation of Kansas and Missouri, the 

 lowest Pennsylvanian formation occurring in the State of Kansas, we 

 find a flora which was described by White 7 as Allegheny in age. This 

 Allegheny flora extends upward to the unconformity in the upper part 

 of the Pleasanton shales. In other words, it corresponds with the Des 

 Moines stage of the western Mississippi Valley. 



Concerning this flora, White remarks : 



"The Lansing [Cherokee shales] horizon is certainly not lower than, and 

 probably not so low as, the lower coal-bearing division of the Arkansas Coal 

 Measures. . . . The flora seems to correspond to that of the Middle Coal 

 Measures of Great Britain and to the uppermost portion of the latter or to the 

 transition series above the Westphalian of the continent of Europe." s 



Speaking of the flora of the Le Roy (Weston and Lawrence) shales of 

 Series III of Kansas, he states : 



7 David White: U. S. Geol. Survey Monograph xxvii, IS!)!). 

 S U. S. Geol. Survey Bulletin ZTL. 1903, p. 111. 



