12 THE LATER EXTINCT FLORAS OF NORTH AMERICA. 



impossible to obtain the entire outline of a frond, or even of a pinna; the 

 frond must, however, have been of considerable size, and the pinna? 8 or 

 10 inches in length. These last are linear in outline, some of them some- 

 what curved, others quite straight, the difference being doubtless due to 

 their different positions in the frond. The pinnules are usually arched 

 upward, very broad at the base, rounded or obtusely pointed at the summit. 

 Where well preserved, the margins of the larger ones are seen to be finely 

 but distinctly denticulate. The nervation is quite strong, but the frond was 

 evidently thick and firm, and though very prominent on the under side, on 

 the upper the nerves are scarcely visible. The midrib is slightly sinuous, 

 and vanishes toward the summit of the pinnule. The secondary nerves are 

 generally once-forked, but the upper ones are simple, and the lower one on 

 the lower side is often twice-forked, or rather two once-forked nerves 

 spring from the same base. 



Among fossil species this may be compared with A. Filix antiqua, Al. 

 Br. (Heer, Fl. Tert. Helv. Vol. I, p. 35, PI. XI, fig. 1), but though crenulated 

 the pinnules in that species are not denticulate, and they are not curved. 

 The nerves are also less strong and more simple than in our plant. 



Formation and locality: Cretaceous (Puget Sound group). Nanaimo, 

 Vancouver Island. 



Pecopteris (Cheilanthes) sepulta Newb. 



PL LXII, figs. 5, 5a, 6. 



Pecopteris (Phegopteris) sepulta Newb. Proc. IT. S. Nat. Mus., Vol. V (March. 21, 

 1883), p. 503. 



"Frond small, delicate, pinnate; lower pinnse straight, broadly linear 

 in outline, rounded above, attached to rachis by the whole breadth of base; 

 margins strongly lobed by the confluent pinnules; 1 centimeter wide by 5 

 centimeters long; upper pinnules crowded, conical in outline, gently curved 

 upward, with waved or lobate margins; pinnules united by one-third of 

 their length, oblong, obtuse ; basal ones on lower side round, on the upper 

 side flabellate, both attached by all their lower margin to the rachis of the 

 frond; nervation strong and wavy, consisting of one many-branched nerve- 

 stem in each pinnule, each branch once or twice forked; fructification 

 unknown " 



