128 CONTRIBUTIONS TO PAL^ONTOLOGY 



Although widely recorded in floras of Cretaceous and Tertiary age, the remains of Equisetum 

 are too generalized to be safely used for purposes of correlation. 

 Occi/rrence— Localities P3853, P3856, P3858, P3859. 

 CoUection—\: . C. Mus. Pal., Nos. 2457, 2458. 



Family SELAGINELLACE.E? 



Genus SELAGINELLA Spring ? 



Selaginella? falcata Lesquereux 



(Plate 6, Fig. 1) 



Selaginellal fakala Lesquereux. U. S. Geol. and Geog. Surv. Terr.. Bull., vol. 1, 365, 1876; U. S. Geol. and 

 Geog. Surv. Terr., Ann. Rept. (1874), 297, 1876; Rept. U. S. Geol. Surv. Terr., vol. 7, 46, only pl. 61, 

 figs. 12-1.5, 1S78. 



Selnginella laciniata Lesquereux, U. S. Geol. and Geog. Surv. Terr., Bull., vol. 1. 378, 1876; U. S. Geol. and 

 Geog. Surv. Terr.. Ann. Rept. (1874), 297, 1876; Rept. U. S. Geol. Surv. Terr., vol. 7, 47, pl. 64, figs. 12, 

 12a, 1878. Knowlton, U. S. Geol. Surv. BuII. 163, 24, pl. 3, figs. 5-8, 1900. Dorf, Bull. Geol. Soc. Araer., 

 vol. 51, 218, 222, 225, 1940. 



There are 5 specimens from Locality P3853 which were at first regarded as SelagineUa 

 laciniata. After consulting the collections at the V. S. National Museum, however, I believe 

 that the two species listed above, which were collccted from precisely the same locality, represent 

 one and the same species in different states of preservation. The distinguishing features of these 

 two species have been the threadlike laciniae of S. laciniata and the narrow leaves of S.l falcata. 

 Both of these features are to be seen on a single stalk in several of the Lance Creek specimens. 

 There are apparentlj' no other comparable specimens reported from Cretaceous or Tertiary floras 

 of North America. 



The reference of this species to SelagineUa is doubtful, as is indicated by the question mark 

 originally inserted by Lesquereux. I have been unable to find anj' Uving species with either 

 aerial or submerged leaves of this particular form. 



Occurrence — Locality P3853. 



CoUection—V. C. Mus. PaL, Plesiotype No. 2459. 



Family GINKGOACE^ 



Genus GINKGO (Kaempfer) Linn6 

 Ginkgo adiantoides (Unger) Heer ? 



Ginkgo adiantoidfs (Unger) Heer, FI. Foss. Arct., vol. 5, pt. 3, 21, pl. 2, figs. 7-10, 1878. Ward, U. S. Geol. 



Surv. 6th Ann. Rept., 549, pl. 31, figs. 5, 6, 1885; U. S. Geol. Surv. Bull. 37, 15, pl. 1, figs. 5, 6, 1887. 



Lesquereux, Proc. U. S. Nat. Mus., vol. 10, 35, 1887. Knowlton, Bull. Geol. Soc. Amer., vol. 5, 579, 1893; 



Proc. U. S. Nat. Mus., vol. 17, 215, 1894; Proc. Washington Acad. Sci., vol. 11, 185, 197, 198, 204, 213, 



1909; Jour. Geol., vol. 19, 370, 1911. Penhallow, Canada Geol. Surv., Pub. 1013, 57, text fig. 12, 1908. 



Berry, Trans. Roy. Soc. Canada, vol. 20, sec. 4, 190, 1926; Canada Geol. Surv. BuII. 42, 96, 1926; Canada 



Nat. Mus. Mem. 63, 18, 1930; Canada Geol. Surv. Mem. 182, 17, 1935. Dorf, Bull. Geol. Soc. Amer., 



vol.51,218, 222, 225, 1940. 

 Salisburia adianloidfs Unger, Syn. PI. Foss., 211, 1845. 

 Ginkgo larajniensis Ward, Science, vol. 5, 496, fig. 7, 1885; U. S. Geol. Surv. 6th Ann. Rept., 549, pl. 31, fig. 4, 



1SR5; U. S. Geol. Surv. Bull. 37, 15, pl. 1, fig. 4, 1887. Knowlton, U. S. Geol. Surv. Bull. 163, 31, pl. 4, 



figs. 7-10, pl. 5, fig. 5, 1900. Brown, U. S. Geol. Surv. Prof. Paper 189, 246, pl. 48, figs. 12-18, pl. 59, 



figs. 1-3, 1939 (see synonymy). 



There is a single specimen from LocaHty P3857 which clearly is a characteristic fan-shaped 

 leaf of the modorn genus Ginkgo. The widespread oceurrences of Tertiary representatives of this 

 genus are usuaiiy referred to thc nominal species Ginkgo adiantoides, whose leaves are identical 

 with those of the living species G. biloha Linn6. Several attempts have becn made by palceo- 

 botanists to distinguish the late Cretaceous Ginkgo leaves as a separate spccies, G. laramiensis. 

 As Berry has pointed out,' the leaf forms shown in specimens of both the Cretaceous and the 

 Tertiary species fail "to disclo.se as much variation as can be selected from a single existing tree." 



> Berry, E. W., Canada Geol. Surv. Mcm. 182, 17, 1935. 



