CONTEMPORANEITY OF THE IDENTICAL FLORAS 175 



ranes of the Allegheny series have no representatives or contemporaries 

 in the Kanawha formation except in the 'upper, lesser, portion of the 

 latter, the entire lower half of the formation being older, or (/>) the Ka- 

 nawha and Allegheny are essentially equivalent, the respective floras 

 being homotaxial, not contemporaneous. The question is whether, if 

 there be no unconformability at the base of the Allegheny series in the 

 Pennsylvania sections, the upper beds of the Pottsville formation have 

 changed their distinctive lithologic characters so that the lithologic 

 boundary between the Allegheny series and the Pottsville formation 

 diagonals in time in passing from the Allegheny valley to the Kanawha 

 river, or whether the successive floras existed in Pennsylvania long before 

 they reached southern West Virginia. 



In support of the first hypothesis, we have (1) the existence, in the 

 lower Kanawha group, of floras by composition and relations distinctly 

 antecedent to those in the Allegheny series ; and (2) the presence of the 

 typical floras of the Allegheny series occurring in characteristic compo- 

 sition, and apparently in regular sequence, in higher beds, above the 

 older floras, in the same section along the Kanawha river. In proof of 

 the second hypothesis, there is the well founded presumption, based on 

 stratigraphic demonstration in certain more northern portions of the 

 great basin, that the several formations preserve their characters as well 

 as continuity along the Appalachain trough ; and (2) the testimon}^ of 

 several of the stratigraphic geologists, including one of the most dis- 

 tinguished authorities, who have studied the Virginian region, in favor 

 of the persistent characters of the beds. 



The supposition that the paleontologic differences between the two 

 formations are due to diagonalling in time on the part of the floras in- 

 volves the further supposition that a maximum thickness of over 600, 

 perhaps over 900, feet of sediments, including several calcareous beds 

 and at least four workable coals, were laid down in the Kanawha region 

 while well defined and characteristic groups of plant species were mi- 

 grating from Pennsylvania to southern West Virginia. This I believe 

 to be absolutely untenable for the following reasons : (a) The mi- 

 gration, if occurred, was made along a continuous coast bordering the 

 eastern margin of the Upper Carboniferous sea ; (6) a presumably low 

 coastal plain offered a direct and easy route; (c) the prevailing direc- 

 tion of the currents at the close of Pottsville time, as indicated by the 

 bedding of the sandstones along portions of the trough, was from north 

 to south, thus favoring a speedy journey ; (<i) the fruits of many of the 

 types appear to have been so constructed as to withstand drifting for 

 some time ; (e) practically the entire plant association must have mi- 



