OLDER POTOMAC OF VIRGINIA AND MARYLAND. 503 



Zamia Washingtoniana Ward/' 

 PL CXI, Figs. 1, 2. 

 1895. Zamia Washingtoniana Ward: The Potomac Formation (Fifteenth Ann. Rep. 

 U. S. Geol. Surv., 1893-94), p. 350, pi. ii, %. 6. 

 Professor Ward, in the work cited, has given an account of this 

 plant, and in pi. ii, fig. 6, has depicted a leaflet and what he regards as 

 its fruit. In his description of the leaflet he regards the narrowed por- 

 tion as the base. In my opinion this is a mistake, it being the termi- 

 nation of the leaf. Several other fragments of the leaflets of this plant 

 were obtained. One of them shows the base pretty well preserved. 

 It narrows like Zamites and seems to have been articulated to the stem. 

 This is indicated also by the fact that all the leaflets are detached. 

 Some of the leaflets must have been very large, much surpassing any 

 leaflet of like form found previously in the Potomac flora. Several 

 of the fragments show a maximum width of 15 mm. One fragment, 

 apparently a little more than half of a leaflet, is 16 cm. long. A smaller, 

 entire leaf, probably from the upper part of the component leaf, was 

 obtained which is only 11 cm. long. This is much smaller than most 

 of the leaflets found. This shows the base slightly narrowed and also 

 thickened. The nerves are not very distinct in the leaflets of this plant. 

 They appear to be comparatively broad and flat. Eleven specimens 

 of this plant occur in the collections, all from the Mount Vernon local- 

 ity. Six of these were collected on November 6, 1892. These are all 

 small fragments. The remaining five, collected on May 14, 1893, include 

 ah those figured and two less complete leaves. 



The above comprise all the fossils found in the Mount Vernon beds 

 up to the present time, 39 species in all. There is little doubt that a 

 good many more might be found in them if sustained search were made. 

 They are" sufficient to show that this horizon is, as Professor Ward 

 maintained, an intermediate one between the Rappahannock and the 

 Aquia Creek beds. 



«Two other fine specimens of leaves of this plant, both in counterparts, were found at the same time 

 and place as the one figured by me, and in view of Professor Fontaine's statements I thought best to figure 

 them The broad one represented in PI. CLXXVI, Fig. 1, is typical, but shows the complete^ tip drawn out 

 to a long narrow, curved point. The other, shown in Fig. 2, is a much narrower leaf, and I was m doubt 

 whether it belonged to the same species. Professor Fontaine returns it without comment with the name on 

 the label as I had written it, I therefore conclude that he considers it a narrow form of this plant. Ihis 

 also shows the tip complete. The crooked shape of the leaf must be ascribed to distortion from pressure.- 

 L. F. W. 



