Maryland Geological Survey 289 



natural size. The present writer has failed to find any trace of these 

 supposed fructifications. 



This species is not common in the later Potomac, and the specimens 

 from Federal Hill, Maryland, are not perfect enough to determine with 

 certainty their identity with those from near Potomac Run, Virginia. 

 Penhallow has recorded this same form from the Queen Charlotte Isl- 

 ands, and it is frequent in the Shasta of California. The Kootanie 

 occurrence is based on forms described by Newberry as a species of 

 Chiropteris and differentiated from Sagenopteris, primarily because of 

 the infrequency of anastomosis of the A'eins and the consequent elonga- 

 tion of the meshes. This is a feature which is also emphasized in some 

 of the eastern specimens, and also in some of those from California, and 

 it seems quite probable that the Kootanie plant is identical with these 

 others. 



Seward thinks that the American plant may be identical with the 

 European Jurassic species Sagenopteris paucifoUa (Phillips) Ward. Its 

 similarity to Sagenopteris Mantelli (Dunker) Schenk may also be 

 pointed out, the latter usually having the midrib a much less prominent 

 feature than it is in the American plant. In connection with the supposed 

 five pinnules of the present species it is interesting to recall that in Mar- 

 silidium speciosum, a possibly related form, described by Schenk {op. cit.) 

 from the Wealden of Osterwald, the pinnules are considered to be six in 

 number. 



Occurrence. — Patuxent FoRMATioisr. Near Potomac Eun and Kan- 

 l:eys, Virginia. Patapsco roRMATiON. Federal Hill (Baltimore), 

 Maryland. 



Collection. — U. S. National Museum. 



Sagenopteris virginiensis Fontaine 



Sagenopteris virginiensis Fontaine, 1890, Mon. U. S. Geol. Survey, vol. xv, 

 1889', p. 150, pi. cxxxviii, fig. 13; pi. cxxxix, fig. 1. 



Description. — " Frond unknown ; shape of pinnules not seen, probably 

 broadly elliptical or oval; stipe or petiole of pinnules apparently long; 

 midnerve toward the base very strong, dissolving in branches toward the 

 apex; areolation very distinct, formed by lateral nerves which go off 



