THE JURASSIC FLOK.\ OF CAPE LISBURXE, ALASKA. 47 



generic idenlity it may bo well enough to retain the form under Coniopteris. It has usually 

 been assumed that these plants belong to the family Cyatheaceac, but of this more will be said 

 later. 



The salient features of Coniopteris hurejensis are described by Seward as follows: 



Frond bipiiinate or jirobably tripiiuiate; pinna" linear-lanceolate, attached to a comparativ'ely slender racliis 

 along the margins of wliich the pinnae axes and the lamina of the basal pinnule on llie lower side of the pinna are 

 decurrent. The pinnules may be oval and serrale. like those of C. hijmcnophylloides, or longer and narrower, the linear 

 lamina being serrate, or more deeply dissected into small oval .segments; the latter form appears to be identical with 

 that of some of the specimens described by Heer as Dicksonia gracilis and D. glehniana. In the larger examples the 

 rachis is broader: the more widely separated pinnae give a more open habit to the leaf, in marked contrast to the more 

 compact form. The venation is of the Sphenopteris type. 



In spite of Seward's elaborate explanation of the diversity in form and appearance of the 

 sterile fronds referred to C. hurejensis, it is difficult to believe that all are correctly referable 

 to a single species. The long, narrow pinnje with linear serrate laminte (cf. figs. 18 and 20 

 of Seward's PI. Ill) may very well be the sterile portions of the form that bore the fruitmg 

 specimen, but it would seem that the longer, oval, slightly serrate pinnules such as are shown 

 m his Plate III, figure 19, are too different to have come from the same species. However, 

 the collection may have contained many specimens that were not figured and some of these 

 may^ bridge the apparent differences. 



The fine fruitmg spccmien from Cape Lisburne shown in Plate V of the present paper 

 is referred with much certauity to C. hurejensis. It is a frond of large size, beuig probaljly 

 between .30 and 40 centimeters m length and at least 20 centimeters broad. It is tripinnatified, 

 or quadripinnate. The maui racliis, which is over 3 millimeters in diameter and slightly zigzag, 

 was evidently very stiff and rigid. The primary pmnis are remote, alternate, at irregular 

 distances, and spreading at the tips, giving the frond a very open, spreadmg effect. The rachis 

 is relatively strong and somewhat angled. The secondary pinnce are also alternate, sessile, 

 lanceolate ui general outline, and cut into numerous linear, deeply cut pinnules. The sori 

 are terminal on slightly reduced lammse. 



The sitigle specimen referred by Fontaine ' to Cladophlehis vaccensis Ward, a species first 

 described from the Jurassic of Oregon, is at best very obscure. It does not have the nervation 

 ascribed to C. vaccensis, though in the shape of the pinnules there is not much difference. It is 

 undoubtedly the same as the form shown in Zalessky's Plate III, figures 1, la, and refigured 

 by Seward in his Plq,te III, figure 19, and is to be referred to Coniopteris hurejensis. 



CoNioPTEUis IIY.MEXOPUYI.LOIDES (Broiigulart ) Seward. 

 Plate V. figure 2. 



Coniopteris hymenophylloides iBrongniarl ) Seward. Juras.sic flora of the Yorkshire coa.st, p. 9,S, PI. XVI, figs, 4-6; PL 

 XVII, figs. A. 6-8; PI. XX, figs. 1. 2: PI XXL figs. \-i. 3a. 4. 4a. 1900; Fontaine, in Ward. U. S. Geol. Survey Mon. 

 48, p. 59, PI. VIII. figs. l-:5, 190.5. 



Sphenopteris hymenophylloides Brougniarl. I'ii«lriiine. pp. 51. 198 [nomenj. 1828; Histoire des v^g^laux fossiles. ]>. 189, 

 PI. I.VI, fig.s. 4, 4b, 1829. 



Adiantites amurensis Heer, Flora fcwsilis arciica, vol. 4, pt. 2. p. 94. PL XXI. figs. 6a, b; enlarged, figs, (i, '■, d. 1876. 



This is one of the most ahunthmt and widely distributed of Jurassic plants, having been 

 repoi'ted from the Antarctic, many locaUties tlu-oughout the Ai-ctic, Siberia, China, Japan, 

 Germany, France, England, and Oregon, and now from Alaska. As might be expected from 

 tiie mnnber of students wlio liave liandl<>d it, it has been reported under several generic names 

 (Sphenopteris, Thyrsopteris, Dicksonia, Adiantites, etc.), but it all seems conspecilic and is 

 best included under the somewhat noncommittal name Coniopteris. 



This species is represented in the Cape Lisburne material })y the single piinia figured, but 

 fortunately this fragment is excellently preserved and there can be no doubt as to (lie correctness 

 of its identification. It is, for itistance, not to be distinguished from a specinuMi from the 

 Jurassic of Yorkshire, England, figured by Seward.^ 



' Fontaine, W. M., U. S. OeoL Sun-cy Mon. 48, p. 157, PI. XXXIX, figs. 7, 8, l!)0.'i. 

 ' Seward, .\. C, Jurassic fiora of the Yorkshire coast, PI. XVI, fig. 6, 1«00. 



