NO. 2158. JURASSIC FLORA FROM ALASKA— KNOWLTON. 459 



Occurrence. — 6698. Upper Matanuska Valley, Alaska, about | 

 mile up the next to the lowest creek entering the East Fork of Boulder 

 Creek from the south. 



NILSSONIA POLYMORPHA Schenk. 



Plate 81, fig. 4. 



Nilssonia polymorpha Schenk, Foss. flora Grenzschichtens d. Koupers u. Lias 

 Frankens, 1867, p. 127, pi. 29; pi. 30, figs. 1-5.— Nathorst, Bidrag till 

 Sveriges foss. flora, Kongl. Svenska Vetenskaps-Ak. Handl., vol. 14, 1876, p. 

 40, pi. 8, figs. 2-15; pi. 9; pi. 10; pi. 11. 



This species, as may be seen in the two papers above quoted by 

 Schenk and Nathorst, is an extremely variable one, showing a great 

 range in size and outline of the leaf; in fact, the diversity is so great 

 that it would seemingly do no hann to divide the species up at 

 least into a number of well-marked forms, as, indeed, had been done 

 before the species was defined by Schenk, especially if it could be 

 shown that there were any stratigraphic relations estabhshed for the 

 several forms. But, be this as it may, there are no data available in 

 this country that would make such a course possible; in fact, the 

 only specimen contained in the present collection is the one here 

 figured which is a mere fragment from the middle of a medium-sized 

 leaf with entire margins. 



Occurrence. — 6700. Upper Matanuska Valley, Alaska. Crest of 

 spur between first and second tributaries entering East Fork of 

 Boulder Creek above its mouth. Elevation, 4,780 feet. 



PAGIOPHYLLUM FALCATUM BartoUn. 



Plate 81, fig. 1. 



P agio phy Hum falcatwn Bartolin, Nogle i den bornholmske Juraformation fore- 

 kommende Planteforsteninger. — Moller, Bildrag till Bornholms fossila flora, 

 Gymnospermer, Kongl. Svenska Vetenskamps-Ah. Handl., vol. 36, 1902, p. 

 32, pi. 5, fig. 13. 



The Alaskan material includes a number of small branches and 

 branchlets that appear to be best referred to this species. They are 

 shghtly smaller than the original species given by Bartolin, but are 

 indistinguishable from the fragments figured by MoUer, who, how- 

 ever, has questioned their reference to Bartolin's species. 



Occurrence.— 6700. Upper Matanuska Valley, Alaska. Crest of 

 spur between first and second tributaries entering East Fort of 

 Boulder Creek above its mouth. Elevation, 4,780 feet. 



