//. Bassler — Cycadophyte from the Coal Measures. 23 



uppermost Stephanian and which Sterzel'* and Potonief both 

 consider referable to the lowermost Autunian or Rothliegenden 

 (Permian). This horizon will be referred to as Permo-Car- 

 boniferous in the sense that it probably occurs in the narrow 

 zone of passage from the Stephanian to the Autunian. 



The material from Maryland falls well within the limits of 

 this species as described by Zeiller, for, while the leaflets are 

 rather less bluntly terminated than is the case with the Alsatian 

 specimens or with the one from Longpendu, they are distally 

 somewhat less attenuate than that from Commentry. The 

 rachis of the Maryland specimen, unlike the rather poorly 

 preserved rachises of the material figured by Zeiller, instead of 

 being terete as these appear to have been, is flattened above, is 

 rather coarsely but somewhat indistinctly lineate and is 

 traversed longitudinally by a shallow median channel. The 

 manner in which the base of the pinnules obliquely half en- 

 circles the rachis and the evidence near the base, of the torsion 

 of these leaflets during fossilization, out of the plane they 

 occupied during life, is well seen in the accompanying figures. 



The better to show the nervation with its rather infrequent 

 dichotomies and the spinulose denticles into which the nerves 

 are produced, I have added a somewhat diagrammatic line 

 drawing. The nerves occur to the number of 10 to 13 in each 

 half centimeter. 



Associated with Plagiozamites Planchardi in Europe are 

 two species of Pteridosperms — Linopteris Germari (Geibel) 

 Potonie and Odontopteris genuina Grand'Eury — which I 

 believe do not anywhere range lower:}: and it is a matter of 

 considerable interest to know that these three species are like- 

 wise found associated in Maryland. 



If we are not yet prepared to correlate the beds of the 

 middle Conemaugh of the Appalachian basin with the Permo- 

 Carboniferous of Europe, then the horizon which has yielded 

 the plant here considered is lower than any other from which 

 zamitoid cycadophytean fronds have yet been collected. The 



* Sterzel, 1899, Flora des Eothl. von Oppenau, Mitth. d. grossherz. Badisch. 

 Geol. Landesanst., Bd. 3, p. 340 et seq., also Sterzel, 1893, Flora d. Eothl. 

 in Plauensehen Grnnde bei Dresden ; Abhandl. k. Sachs. Gesell. Wiss., vol. 

 xix, pp. 157, 159. 



f Potonie, 1893, Die Flora des Eothl. von Thiiringen ; Abh. kgl. Preuss. 

 Geol. Landesanst., neue Folge, Heft 9, Theil ii, p. 224. 



:£To the species Odontopteris genuina Grand'Eury I would assign only 

 material the pinnules of the more distal pinnae of which are obliquely 

 ovate-triangular in shape with the upper margin straight or slightly concave, 

 thus excluding the plant figured under this name by Kidston in 1901, in 

 Flora Garb. Period, Proc. Yorksh. Geol. and Poly tech. Soc, vol. xiv, pt. ii, 

 pi. xxviii, fig. 1, from the Middle Coal Measures of England and that by 

 Potonie in 1904 in Abbild. u. Beschreib., Lief, ii, No. 22, fig. 1, from the 

 Westphalian of the basin of the Saar, forms which appear to have more in 

 common with Odontopterisbrittanica Gutbier. 



