Maetland Geological Survey 251 



CladophleMs parva Fontaine, 1906, in Ward, Mon. U. S. Geol. Surv., vol. 



xlviii, 1905, pp. 225, 280, 510, 538, pi. Ixv, figs. 5-8. 

 CladophleMs parva Knowlton, 1908, in Diller, Bull. Geol. Soc. Am., vol. 



xix, p. 386. 

 CladophleMs parva Berry, 1911, Proc. U. S. Natl, Mus., vol. xli, p. 316. 



Description. — Fronds large, bipinnate or tripinnate. Eachis very 

 stout. Pinnae linear-lanceolate, becoming somewhat falcate in outline 

 distad, and passing from alternate to subopposite. Pinnules relatively- 

 wide, falcate, acuminate in the sterile forms, but obtuse in the fertile, 

 variable in size, according to their position, the distal pinnules which 

 represent the reduced pinna lower down on the frond are larger and 

 relatively more slender than the pinnules of the lateral pinnae, which 

 are almost as wide as they are long, and falcate. Between the two orders 

 there is every gradation on each frond through pinnatifid pinnae to simple 

 pinnule-like forms. Margins entire or slightly crenate, especially in the 

 fertile pinnules, which are wider than the sterile. Sori large, reniform 

 in outline, in three or four pairs on either side of the midvein at the 

 end of a distal branch of a furcate vein. The structure or arrangement 

 of the sporangia cannot be made out, but the spores are preserved in 

 abundance. They are small, ranging from .083 mm. to .05 mm. in 

 diameter, with very thick walls, the outer surface covered with fine 

 granulations not visible with magnifications of 200 diameters or less. 

 The tetrad scars are very distinct. In form as well as size these spores 

 are variable, the smaller possibly immature spores are trigonal in out- 

 line while the larger are more nearly spherical. Their varying appear- 

 ance is well shown in those which are figured. Lateral veins usually 

 but once forked, sometimes simple. Texture coriaceous. 



This is a large and handsome species and is represented in the col- 

 lections by very fair material of both the sterile and fertile fronds. It 

 ranges from the bottom to the top of the Potomac deposits and outside 

 the Maryland- Virginia area is recorded from the Shasta beds of the 

 Pacific Coast, the Kootanie of Montana and the Lakota formation of the 

 Black Hills. There are a number of European Wealden species which 

 are similar to CladophleMs parva, but it is believed to be quite distinct 

 from its contemporaries, although small fragments of almost any of the 

 species of CladophleMs are likely to be confused. 



