TO JUNCTION OF (IRANI) AND GREEN RIVERS. 145 



Pteeophyllum kobustum, Newb. 



Plate VI. fiir. 7. 



Leaf large, <> inches or more in width; pinna' strap-shaped, 3 inches in length; 

 bases expanded and coalescing; summit truncated or abruptly rounded; nervation 

 delicate: nerves simple, parallel with the border of the pinnae. 



Two specimens of this singular plant are contained in the collection made l>v Mr. 

 Remond, both imperfect, but both exhibiting the same characters. These are so pecul- 

 iar that, without the evidence of two specimens, I would have said we had here simply 

 a frond of Tcmiopteris torn into strips, with an accidental hut striking regularity. It 

 seems hardly probable, however, though not impossible, that we should find in this 

 small collection two fronds torn in precisely the same way. Besides this, the curvature 

 of the sides of the divisions, where they coalesce at the base, is almost too regular to 

 be the result of accident. They are also too uniform in width to be the effect of 

 mechanical force. 1 have thought best, therefore, to describe this provisionally as a 

 distinct species of /'tcro/il/i/t/an/. 



Formation and locality. — Triassic strata ; Los Bronces, Sonora. 



PODOZAMITES CRASSTFOLIA, Newb. 



Plate VI, ftg. 10. 



I 



Plant large and strong; pinnae long-elliptical or spatulate in form, thick and 

 coriaceous; nervation strong, but somewhat obscured by the thickness of the paren- 

 chyma; nerves parallel with the border, converging at both extremities of the pinnae; 

 a more distinct nerve traverses the central line. 



Only detached pinnae of this plant are contained in the collection made by Mr. 

 Remond, but of these there are quite a number. By their large size and thickness, 

 they are greatly different from those of any species of Podozamites hitherto described, 

 and the distinct median nerve which they show presents a feature not common, if 

 even known, in this genus. It is, therefore, possible that more complete specimens 

 will show it to have characters which should be given generic value. 



Formation and locality. — Triassic strata; Los Bronces, Sonora. 



Alethopteris Wiiitneyi, Newb. 



Tlate Vll.litfs. 1, 1", 1>>. 



Frond pinnate or bipinnate; pinnules of lower portion large, 2-3 inches long, 

 narrowed above, broad below; the lower half of the base attached to, and decurrent 

 on, the rachis; the upper half detached and subcordate; upper pinnules shorter, be- 

 coming at last elliptical and even orbicular; nervation crowded; midrib Strong; lat- 

 eral nerves line and numerous, given oil' at nearly a right angle, simple or once forked. 



The specimens of this plant are too fragmentary and imperfect to permit a full 



and complete description of it. Enough remains, however, to show that it was a 



strongly-marked species, and one quite distinct from any before described from this 



horizon. That portion of the frond contained in the collection made by .Mr. Remond 



19 SF 



