494 FOSSIL PLANTS FROM MONTANA—FONTAINE. 
amount of material is not sufficient to permit positive identification, 
but in any case this fern is very near the Potomac plant and is of the 
same type. 4 
Thyrsopteris rarinervis Font. 
oe 
This fern shows numerous imprints. Some of them are very fine, 
being much better than any from the Potomac beds. Some of the forms _ 
approach more nearly Heer’s Asplenium dicksonianum than do those 
of the Potomac fossils. The resemblance was seen in the latter fossils — 
but, as stated, it was not so marked as in some of the Great Falls im- 
prints. i 
Sequoia ambigua? Heer. 
The collections contain three small and poorly preserved fragments — . 
of a conifer which is most probably Sequoia ambigua. Some of the 
leaves are preserved and are identical with those of that species. The 
amount of material does not permit a positive determination. 
Sequoia rigida Heer. 
There are in the collections four pretty well preserved impressions— 
of a conifer that can not be distinguished from Sequoia rigida. 
Sphenolepidium virginicum, Font. 
Eight impressions of a conifer identical with Sphenolepidium virgin-- 
icwm of the Potomac formation were obtained. Most of them are poorly ~ 
preserved and show a good deal of maceration, as if they had been | 
floated long in water. To judge from the number of impressions ot 
this plant that were found it must have been somewhat common in the 7 
Great Falls flora, standing next to Taxodium ramosum. 
Taxodium (Glyptostrobus) ramosum Font. 
This conifer shows twelve specimens. They are the best preserved 
of the coniferous fossils, giving in most cases the character of the plant 
quite distinctly. The specimens of it are more numerous than those 
of any other conifer of the Great Falls flora. It occurs along with me 
two preceding conifers and with Tha oe rarinervis and Aspid- — 
ium montanense, in a sandy shale. . | 
. 
Zamites montanensis sp. nov. 
Pl. LXXxIVv, Fig. 4. 
Mr. R. 8. Williams, of Great Falls, loaned Mr. Knowlton a beautiful 
imprint of a cyead which seems to be new. A drawing of it was made 
and is given in Pl. Lxxxtv, Fig. 4, of this paper. 
I have not seen the original, ha the drawing gives the character a 
distinctly that a description can be given from it. The description is 
as follows: The leaf (compound) is narrowly elliptical in outline and 
small. Itis abruptly pinnate, with a stout rigid midrib. The lowe 
leaflets are lancet-shaped, short, remote, and stand at right angles with 
