no.1769. FOSSIL PLANTS OF THE POTOMAC GROl P BERRY. 031 



Montana, and likewise to Acrostichopteris ruffordi Seward a of the 

 English Wealden. On the continent it is represented by the nearly 

 allied and strictly congeneric species Sph nopteris U nellisecta Saporta 6 

 from the Upper Jurassic, and Sphenopteris flabellisecta Saporta c from 

 the Aptien of Portugal. 



Occurrence. Patfxent formation. Duteli (lap. Fredericksburg 

 Trents Reach, Potomac Run, Virginia (not Federal Hill. Maryland). 



Collections. — U. S. National Museum. 



ACROSTICHOPTERIS PLURIPARTITA (Fontaine). 



Baieropsis pluripartita Fontaine, Monogr. U. S. Geol. Surv., No. 15, 1890, 

 p. 208, pi. 89, 6g. 4; pi. 90, figs. 2-5; pi. 91, figs. I. 3, I. 7; pi. 92, figs. I. 2, 

 6.—? Fontaine, in Ward, 19th Ann. Rept. IT. S. Geol. Surv., pt. 2, L899, 

 ]>. 685, pi. 168, figs. 9-12.— Fontaine, in Ward, .Monogr. U. S. Geol. Surv., 

 X,,. 48, 1905, pp. 179, 481, 482, 505, pi. 107, fig. 1. 



Baieropsis pluripartita minor Fontaine, Monogr. U. S. Geol. Surv., No. 15, 1890, 

 p. 20S, pi. 91, fig. 5; pi. 92, figs. 3, i. 



Baieropsis longifolia Fontaine, Monogr. F. S. Geol. Surv., No. 15, 1890, p. 210, 

 pi. 91, fig. 0.— Fontaine, in Ward, Monogr. IT. S. Geol. Surv., No. 48, 

 1905, pp. 505, 517, pi. Ill, tig. 3. 



Description. — Pinnules large in size, inequilateral, fan-shaped, sub- 

 opposite, at an acute angle of divergence, narrowly divided almost to 

 the base into three principal and a varying number of narrow linear 

 subordinate segments. Venation of the usual character in this genus, 

 slender but distinct. The apices are usually, if not always, broken 

 off, so that their character can not be made out. Rachis compara- 

 tively slender. 



This species includes the various indefinite fertile specimens upon 

 which Fontaine based the characters of the supposed fruits in his 

 genus Bau ropsis. These are clearly to be correlated with Acrostichop- 

 teris pluripartita, since one specimen shows a characteristic pinnule 

 of this species. The preservation is poor, and the most that can be 

 made out are oval bodies apparently representing reduced or trans- 

 formed segments of pinnules, all the segments of which are fertile in 

 this case and not merely the basal ones, as is shown in so many 

 specimens of Acrostichopteris longipennis. Fertile specimens of the 

 present species are, on the other hand, very rare and fragmentary. 



This species is present in both the Patuxent and Palapsco forma- 

 tions of Maryland and Virginia. It is also recorded somewhat doubt- 

 fully from both the Lakota and Fuson formations in the Black Hills 

 Rim <»f Wyoming. In Portugal Saporta describes several very similar 

 forms. These include Spin nopU ris cum ijida of the Urgonien-Aptien d 



" Scwanl, Wealden Flora, pt. 1, 1894, p. 61, pi. 6, fig. :'.. 

 b Saporta, Flora Fobs. Portugal, L904, p. 25, pi. 13, fig. 1. 

 cldem, p. 69, pi. 15, figs. 11, 15. 

 <! [dem, pp. 69, 127, pi. 1G, tig. 11, pi. 2:;, fig. 5. 



