310 MESOZOIC FLORAS OF UNITED STATES. 



tana beds. This form of cj^cad, which is so highly characteristic of the 

 Lower Cretaceous, differs in so many essential points from the Zamites 

 of the Jurassic, which find their type in Z. Fe7ieonis (Brongn.) Ung., 

 that it does not seem proper to unite them in one genus. If ever plants 

 are to be made generically different from characters of foliage, it would 

 seem that the Jurassic and Lower Cretaceous types of so-called Zamites 

 ought to be so considered. As the form of the Lower Cretaceous is 

 always and markedly pectinate in shape, Pedinizamites would appear 

 to be a proper generic name. 



Mr. Weed's collection contained a few forms of a Zamites that 

 seemed from the imperfect specimens obtained to be new, and the name 

 Zamites Weedii was proposed for it in the preliminary report. These 

 are represented in PL LXXIII, Figs. 1 and 4. This collection showed 

 also one or two imprints of a smaller Zamites, which, in the same report, 

 was supposed to be a different species and compared with an unnamed 

 Zamites of Dawson from the Kootanie of Canada. The numerous speci- 

 mens of Z. arcticus above described show that both of these forms fall 

 easily within the limits of variation of that species, and hence the^^ 

 must be regarded as identical with it. 



PL LXXIII, Fig. 1, represents the .basal portion of one of the 

 leaves, with wider leaflets, and shows the shortening of the leaflets 

 toward the base. No doubt lower down on the leaf the leaflets are 

 wanting, giving a naked petiole. Fig. 2 shows a fragment of a leaf 

 from its middle portion, with leaflets of the larger size, but not quite 

 so large as some that were seen. Fig. 3 represents a small fragment 

 from the middle portion of a leaf, showing some of the largest leaflets 

 seen. Fig. 4 gives a small fragment of a leaf from its middle portion, 

 showing leaflets of the smallest size. Fig. 5 represents a fragment 

 from the middle portion of a leaf that shows the narrowest tj'^ps of 

 leaflets that possess an average length. Fig. 6 gives two of the leaflets 

 of Fig. 5 enlarged four diameters to show details. 



Genus CYCADEOSPERMUM Saporta. 



Cycadeospermum montanense Fontaine n. sp. 



PI. LXXIII, Fig. 7. 



A single nut-like seed was found in the Geyser beds, which seems 

 to be a C,ycadeospermum, probably a new species. But there is not 



