320 D. WHITE — POTTSVILLE SERIES ALONG NEW RIVER, W. VA. 



fossils, so far as yet observed, goes to show that, although members of 

 the thin sections are usually much expanded in the thick sections, still 

 the greater part of the increase is due to earlier sediments underlying 

 the equivalents of the thinner sections and lithologically belonging to 

 the same series. 



In general, it may be said that, so far as the fossils have been gathered 

 and studied (including those from the type section of the Pottsville in 

 the southern anthracite basin), those from the thin sections are found 

 in the upper portion of the thick sections, those of the moderately thick 

 sections being present in about the same interval, measuring downward, 

 in the much thicker sections, while those from the basal portions of these 

 thicker sections are more or less unique and still farther removed from 

 the flora of the Lower Coal Measures. 



The floras of the middle of the very thick sections of the Pottsville 

 appear to be largely identical with and to present the general facies of 

 the Ostrau-Waldenburg floras of Moravian Silesia, while those from the 

 base of the sections have much in common with the Culm or Carbonif- 

 erous limestone series of the old world. 



Problem of Correlation of Base of Pottsville Series. 



The facts that (1) along the northern rim of the Appalachian coal field 

 and in the Mississippi Valley states the rocks (Pottsville) between the true 

 Coal Measures above and the Lower Carboniferous series with marine 

 fossils below appear to carry only the fossils of the upper portion of the 

 modej'ately thick and very thick Pottsville sections, seeming really to be 

 equivalent, practically, to only the corresponding portions, measuring 

 downward, of the thick sections, and (2) the increasingly unique and 

 ancient character of the lower flora in the very thick sections, stand in evi- 

 dence to show either that there is a time-break between the base of the 

 thin section and the top of the Lower Carboniferous, which break should 

 represent at least the time required for the deposition of the greater por- 

 tion of the thick section, or that the thick section of the Pottsville over- 

 laps in time the Lower Carboniferous in the northern and Mississippi 

 Valley states, the floras of the lower portions of the thick section being 

 in the latter case contemporaneous with marine invertebrates in the 

 Lower Carboniferous of the central states. This problem, as well as the 

 consequent question of the propriety of including the entire Pottsville 

 series or " Conglomerate series " of the southern Appalachian region in 

 the Upper Carboniferous, may be considered to better advantage when 

 the examination of the material from the very thick section of eastern 

 Kentucky and from the southern anthracite field of Pennsylvania is 

 completed. 



