312 PROCEEDINGS OF TEE NATIONAL MUSEUM. vol.41. 



each other and with those ferns in the European Wealden which are 

 referred to dadopJileUs alhertsii. The adcUtional fragments of 

 Potomac ferns which are referred to this species are not common and 

 are equally unimportant botanically and stratigraphically. The two 

 CladopMeiis, sp., Fontaine are clearly enough referable to tliis species. 

 CladopMeUs pacJiypTiylla is considered as an anomalous pinna, with 

 thicker, more remote pinnules, which are contracted at the base. It 

 was founded on a single fragment from Fredericksburg, Virginia, and 

 if not an example of this species is simply a distal aberrant pinna of 

 one of the other described species from that locahty. The specimen 

 which was the basis for the presence of Aspidium oerstedi Heer in this 

 flora is the merest fragment without significance in any way. 



The fertile pinnae of Cladophlehis alhertsii agree with those of 

 CladopJdehis parva and other Potomac species in the general character, 

 form and arrangement of the sori, the nature of the material precluding 

 any more detailed information on this point. The sori appear to be 

 confined to the basal part of the proximal pinnules. The present 

 species is closely related to the contemporaneous form Cladophlehis 

 virginiensis Fontaine. 



It is common in the Wealden of England and Germany and prob- 

 ably in homotaxial beds in Austria and Russia. It has been recorded 

 from the Cenomanian of Bohemia and from the Atane beds of Green- 

 land, but both of these determinations may be considered as very 

 doubtful. In this country it is definitely known only from the 

 Potomac group. It has been recorded from the Patapsco formation 

 at Vinegar Hill, Maryland, but the single specimen is referred by 

 the writer to CladopJdehis virginiensis which is abundant at this 

 locality. 



Occurrence. — Patuxent formation : Potomac Run, Telegraph Sta- 

 tion (Lorton), Dutch Gap, Trents Reach, Fredericksburg, Virginia. 

 Arundel formation: Arlington, Hanover, Bay View, Maryland. 



Collections. — United States National Museum, Goucher College. 



CLADOPm^EBIS BROWNIANA (Dunker) Seward. 



Pecopteris browniana Dunker, Monogr. Norddeutsch. Wealdenbildung, 1846, 



p. 5, pi. 8, fig. 7. — Fontaine, Monogr. U. S. Geol. Survey, vol. 15, 1890, p. 



88, pi. 22, figs. 10, 11; pi. 23, figs. 2-7; pi. 26, figs. 3, 13; Proc. U. S. Nat. 



Mus., vol. 15, 1892, p. 492. — Dawson, Trans. Roy. Soc. Can., vol. 10, sec. 



4, 1893, p. 84, fig. 3.— YoKOYAMA, Journ. Coll. Sci. Japan, vol. 7, 1895, 



p. 218, pi. 24, figs. 2, 3; pi. 27, figs. 1-5. 

 Alethopteris reichiana Ettingshausen, Abh. k. k. geol. Reichs., vol. 1, Abth. 3, 



1852, p. 17. 

 Alethopteris browniana Schimper, Pal. Veget., vol. 3, 1874, p. 502. 

 Cladophlebis browniana Seward, Wealden Flora, pt. 1, 1894, p. 99, pi. 7, fig. 4. — 



Ann. S. Afr. Mus., vol. 4, 1903, p. 10, pi. 2, figs. 1-4, 6. — Knowlton, Smiths. 



Misc. Coll., vol. 4, pt. 1, 1907, p. 108, pi. 11, fig. 1.— Knowlton, in Diller, 



Bull. Geol. Soc. Amer., vol. 19, 1908, p. 386. — Fontaine, in Ward, Monogr. 



U. S. Geol. Surv., vol. 48, 1906, pp. 272, 510, 517, 538, 544, 547, 557, 572. 



