THE JUEASSIC FLOKA OF CAPE LISBUKNE, ALASKA. 41 



of Lesquereux's determiurttious and as a final result of his studies gave the following list of 

 species: 



Chondrites filiciformis Lesq. 



Diiksonia saporlana Heer. 



Onychiopsis psilotoides (Stokes and Webb) Ward. 



Cladoplilebis vacrensis Ward. 

 Cladophleliis alata Font. 

 Cladophlebis luittoni (Dunk.) Font. 

 Podozamites distantinervis Font. 



Podozamites grandifolius? Font. 

 Baiera gracilis (Bean) Bunb. 

 Ginkgodium? alaskense Font. 

 Ginkgo digitata (Brongn.) Heer. 

 Ginkgo huttoni (Sternb.) Heer. 

 Ginkgo liuttoni magnifolia Font. 

 Nageiopsis longifolia Font. 



Fontaine discussed this flora at some length, his final conclusion beoig stated as foUows: 

 "The age of the formation yieklmg the Alaskan fossils, as indicated by them, is not older than 

 the Lower Oolite and not younger than the Lowei' Cretaceous but is probably between them.'" 

 On the basis of this statement Ward called the Cape Lisburne plants "Jurasso-Cretaceous." 



In the prelunmary study of Collier's material I took occasion to go over some of the identi- 

 fications made by Fontauie and felt obliged to dissent from several of them. For example, 

 the specimen which Fontaine determined as Podozamites distantinerv-is P^ont., a well-knowni 

 Potomac species. I called P. lanceolatus latifolius, a Jurassic form. It appeared that Fontame's 

 great familiarity with the Potomac flora ha<l led hmi to give undue weight to certam resem- 

 blances between them, and, as it then seemed to me, he made identifications wluch entirelv 

 vitiated the age determiiiation. My conclusion was stated as follows: "I can see no valid 

 reason for regarding this flora as other than Jurassic, or in any event as other than identical 

 with the flora from eastern Siberia, the Jurassic age of which is, so far as I kiiow, universally 

 accepted." I expressed a siniUar view in nn" paper "The Jiu'assic age of the 'Jurassic flora of 

 Oregon' "' and stiU entertain it. 



The following is the complete list of species as given by me in the ]ireliminary report made 

 to CoUier,- with the corre.sponding identifications of the present paper in brackets: 



Cladophlebis huttoni (Dunk.) Font. [=C. huttoni]. 



Dicksonia n. sp.? [=Coniopteris burejeusis]. 



Dicksonia burejeusis Zalessky f=Coniopteris l)urejensis]. 



Tseniopteris parv^ila Heer [=Pityophylhim nordenskioldi]. 



Equisetum sp. [ = E. collieri n. sp.]. 



Podozamites lanceolatus latifolius (Schenk) Heer 1 = P. I. eichwaldi]. 



Podozamites sp. [=P. lanceolatus]. 



Baiera palmata Heer [=Zamites megaphyllus]. 



Phoenicopsis angustifolia Heer [=P. angustifolia]. 



Phoenicopsis speciosa Heer [=P. speciosa]. 



Pagiophyllum kiurii (Pomel) Schimp [=P. kurrii]. 



Stachyotaxns .septentrionalis? (Ag.) Nath. [=P. kurrii]. 



Taxites subzamoides? Moller [=P. kurrii]. 



Ginkgo huttoni Font., n. var. [=G. digitata]. 



This revi.scd list of sjiecies in the ColUer collection is as follows : 



Coniopteris hymenophylloides (Brongniart) Seward. 

 Coniopteris burejon.sis (Zalessky) Seward. 

 Cladoplilebis huttoni (Dunker) Fontaine. 

 ?Cladophlebis alata Fontaine. 

 Equisetum collieri n. sp. 



Podozamites lanceolatus eichwaldi (Schimper) Heer. 

 Po<lozamites lanceohitus (Lindley and Huttoni Braun. 

 Otozamites gigantous Thomas. 

 Zamites megaphyllus (Phillips) Seward. 



Phoenicopsis speciosa Heer. 

 Phoenicopsis angustifolia Heer. 

 Elatides curvifolia (Dunker) Nathorst. 

 Pagiophyllum kurrii (Pomel) Schimper. 

 Pagiopliyllum steenstrupi Bartholin? 

 Pityophyllum nordenskioldi (Heeri Seward. 

 Fieldenia nordenskioldi Nathorst. 

 Ginkgo digitata (Brongniart) Heer. 



AGE OF THE PLANT-BEARING BEDS. 



The bearing of these plants on the age of the beds in which they are found may now be 

 considered. As already stated, the first material from the Capo Lisburne region was studieil 

 by Lescjuereux, who regarded it as probably of Neocomian age. This material, together with 



> Am. Jour. Sri., 4th ser., vol. 30, p. 50, 1910. 2 U. S. Oeol. Purvey Hull. 2TS, p. 29, 190t!. 



