112 SMITHSONIAN MISCELLANEOUS COLLECTIONS [VOL. 50 



There is so little of this specimen available for examination that 

 it is impossible to make out its real form or its position on the frond. 

 It is possible that it is only an extremely auricled form of, for instance, 

 Cladophlebis constricta Font., 1 though in Cladophlebis the pinnules 

 are supposed to be attached by their whole bases, whereas in the 

 one under consideration the attachment is probably by only a minute 

 portion of the base. As this species cannot be referred to Cla- 

 dophlebis, I have placed it tentatively under Dryopteris, but we must 

 await fuller material before it can be definitely placed. 



Locality. — Meridith mine, 3 miles southeast of Nollar's ranch and 

 6 miles southwest of Geyser, Cascade County, Montana. 



ADIANTUM MONTANENSE n. sp. 

 Plate XII, Figs, i, 2 



Outline of frond unknown; pinnules apparently opposite or sub- 

 alternate, relatively large, short-petioled, reniform, margin cut into 

 numerous large rounded lobes; primary nerves numerous (a dozen 

 or more), equal, radiating, several times dichotomous. 



This form is represented by a few fragments only, the best being 

 figured. In the one shown in figure 1 there is seen to be a rather 

 slender rachis with one pinnule attached by a very short petiole and 

 another some distance above and on the same side which is not at- 

 tached, but is possibly in nearly its original position. The other, 

 shown in figure 2, exhibits two pinnules on opposite sides of the 

 slender rachis, only one of which, however, shows the petiole at- 

 tached. The outlines and nervation are very well shown in the 

 figure. 



This species is undoubtedly very closely allied to Adiantum formo- 

 sum Heer, 2 from the Lower Cretaceous (Kome) of Greenland, 

 though Heer supposed his species to be simple — that is, he found no 

 evidence to show that the pinnules (or fronds) were ever attached 

 to a rachis — whereas in the Kootanie form the frond was clearly 

 compound, having the pinnules attached by a short petiole to a 

 slender rachis. In size, shape, degree of marginal lobation, and 

 nervation they are certainly very similar, and a well preserved suite 

 of specimens might show even closer agreement. Neither Heer's 

 species nor the one under consideration shows any trace of fruit, 

 and hence the reference to Adiantum is based entirely on form and 



1 In Ward, Monog. U. S. Geol. Survey, No. 48, pi. lxxi, fig. 26. 



2 Fl. Foss. Arct, vol. 3, 1874, p. 35- pi- hi, figs. 1, 2. 



