THE ALLEGHENY SECTION 147 



Allegheny series in the bituminous basins of Pennsylvania or northern 

 West Virginia and those in the corresponding portions of the Kanawha 

 series in southern West Virginia. It needs but a casual inspection of 

 the floral succession in the southern Virginian district to show that the 

 characteristic plants of the Allegheny series in the type region of Penn- 

 sylvania first appear only in the upper portion of the section along the 

 Great Kanawha, the greater portion of the latter, including the most im- 

 portant coals, containing plants of manifestly earlier age. 



The purpose of this paper is to present a preliminary statement of the 

 general characters of the floras of the Allegheny series, the position of 

 these floras in the Virginian section, and a characterization of the floras 

 of the lower portion of the Kanawha series. Some general paleobotanic 

 correlations will be given, together with a brief statement of the changes 

 in stratigraphy and conditions of deposition which appear to be indi- 

 cated by the distribution of the fossil plants. 



Floras of the Allegheny Series 

 type sections of the series, and its subdivisions 



The Allegheny series * or the Lower Productive Coal Measures f (XIII), 

 as it has earlier and more commonly been known, is typically repre- 

 sented in the fourth, fifth, and sixth bituminous basins in the Allegheny 

 valley of western Pennsylvania. It comprises approximately 300 feet 

 of shales, sandstones, and coals, with several thin limestones, lying be- 

 tween the Homewood sandstone (conglomerate), the topmost member 

 of the Pottsville formation (XII), and the Mahoning sandstone (locally 

 conglomerate), which forms the base of the Conemaugh series or Lower 

 Barren Measures (XIV). This series, which is comparatively uniform 

 in this region, has been described and abundantly illustrated by columnar 

 sections in the reports on Butler, J Armstrong,! Clarion, || Jefferson,^[ 

 and Clearfield** counties, and in the Summary Final Report ff of the 

 Second Geological Survey of Pennsylvania. 



Typical sections are also described in Rogers's "Geology of Pennsyl- 

 vania' 1 and Doctor I. C. White's memoir " Stratigraphy of the Bitu- 

 minous Coal Fields of Pennsylvania, Ohio, and West Virginia. "J! In the 



*Bull. U. S. Geol. Survey, no. 65, pp. 65, 99. 



f Rogers : Geology of Pennsylvania, vol. i, part 1, p. 109. Sections described, vol. ii, part 1. 



X Second Geological Survey of Pennsylvania. Report of progress in the Beaver River district of 

 the bituminous coal fields of western Pennsylvania, by I. C. White. Report Q, 1878. Northern 

 townships of Butler county, by H. M. Chance. Report V, 1879. 



g Report of progress in Armstrong county, by W. G. Piatt. Report H 5 , 1880. 



|| Report of progress in Clarion county, by H. M. Chance. Report VV, 1880. 



% Second report on Jefferson county, by W. G. Piatt. Report H 6 , 1881. 



** Second report on Clearfield county, by H. M. Chance, Report H 7 , 1884, 



ft Vol. iii, part 2, Harrisbur'g, 1883. 



JJ Bull. U. S. Geol. Survey, no. 65, 1891. 



