knowlton] TERTIARY PLANTS OF NORTH AMERICA. 247 
Zizyphus microphyllus Lx. Mem. Mus. Coinp. Zool., vol. vi, no. 2, p. 
28, pi. viii, f. 9, 1878. 
Miocene: Chalk Bluffs, California. 
Zizyphus piperoides Lx. Mem. Mus. Comp. Zool., vol. vi, no. 2, p. 28, 
pi. viii, f. 10, 11, 1878. 
Miocene: Chalk Bluffs, California. 
Zizyphus serrulatus Ward. Bull. U. S. Geol. Surv., no. 37, p. 73, pi. 
xxxiii, f. 3, 4, 1887. 
Fort Union group : Burns's Ranch, Montana. 
Zizyphus Townsendi Kn. Proc. U. S. Nat. Mus., vol. xvii, p. 229, pi. 
ix, f. 8, 9, 1894. 
Eocene?: Herenden Bay, Alaska. 
Zizyphus sp., Kn. Bull. Geol. Soc. Am., vol. viii, p. 134, 1897. 
Fort Union group : Lightning Creek, Converse County, Wyoming. 
Zizyphus sp., Kn. 'Bull. Geol. Soc. Am., vol. viii, p. 148, 3897. 
Laramie group: Rock Springs, Wyoming. 
Zonarites digitatus (Brongn.) Gein. 
Ficoides digitatus Brongn. Lx., Ann. Rept., op. cit. ; p. 421, 1872 [1873] ; Hist, 
d. Veg. Foss., p. 69, pi. ix, f. 1, 1828. 
Dakota group : Kansas. 
Zostera marina L. Paisley, Can. Nat., 2d ser., vol. vii, p. 270, 1875. 
Post-Pliocene: Batnurst, New Brunswick. 
