COMPARATIVE STAGE OF MISSOUEI FLORA. 287 



PROBABLE STAGE OF THE LOWER COALS OF MISSOURI IN EASTERN SECTIONS. 



A review of the preceding table shows (1) that nearly all the species 

 from Missouri which have a relatively restricted A'ertical range ha^-e also 

 been collected from near the horizon of coal B near Morris or Mazon Creek, 

 Illinois, or in the Kittanning coals of Ohio and Pennsylvania, and that the 

 plants from the Lower Coal Measures of Missouri, especially in Henr}- 

 County, appear to be most nearly related to those floras; (2) that the greater 

 portion, or nearly two-thirds, of these species are present in the floras of 

 Mazon Creek and Morris; (3) that over one-half of them have been gathered 

 from the Kittanning (chiefl)' the Darlington and Middle Kittanning) of Ohio 

 and Pennsylvania, and (4) that nearly one-half are also present in the 

 collections from coals D and E (the "Marcy" and "Pittston" coals) in 

 the Northern Anthracite field. 



If we take into account the stratigraphic occurrence of the species most 

 nearly related to those that are peculiar to the ]\Iissouri flora the projjortions 

 will not be materially changed. Thus Oligocmym alabamensis Lx., the 

 nearest American ally of 0. Missouriensis, is found in the upper beds of the 

 Pottsville series. The fern figured b}^ Lesquereux^ as Pecopteris abhreviutaf 

 Brongn., the Lepidodendron Wortheni Lx., and Lepidopliyllum ovatifoUitm, 

 which are correspondingly related to Sphenopteris opMoglossoides, Lepidoden- 

 dron Brittsii, and Lepidophijllum Jenmyi, respectively, are found at Mazon 

 Creek; Tmiiopliyllimi' deflexum Lx., Lepidophylliim Mcmsfiekli, and Lepido- 

 phloios dilatatus Lx., the relatives of'T. latifoliiim, Lepidophyllum Missouriense, 

 and Lepidophloios Van Ingeni, are typically from the Darlington coal at 

 Cannelton, while Pecopteris oreopteridia, P. pennceforniis (as seen in some 

 American collections), related to P. Jenneyi and P. pseudovestUa in the 

 Missouri flora, are abundant in the E and D coals, respectiveh', of the Lack- 

 awanna antln-acite field. On the other hand, little information of immediate 

 use in correlation is to be derived from the distribution, of the species 

 excluded from the table, on account of their great stratigraphic range, except 

 the very important fact that most of them have not yet been discovered 

 below coal B of the northern bituminous fields. 



If we assume, then, that the table fm-nishes a fair representation of the 

 average or mean vertical distribution of our flora, it becomes quite apparent 



' Coal Flora, Atlas, p. 8, pi. slvi, figs. 4-6. 



