LANCE FLORA OF EASTERN WYOMING 111 



below the top of the Triceratops zone. The analysis of the floral assemblage is 

 as foUows: 



No outside distribution 13 



Outside distribution 51 (28 in common with type Lance) 



Total number of species ... 64 



Short-ranging species: Long-ranging .species: Species of uncertain range . . 4 



Montanan Montanan-Lancian-Paleocene . 1 



Lancian 26 Montanan-Lancian 17 



Paleocene Lancian-Paleocene 3 



26 21 



As has already been pointed out in my report on the Medicine Bow flora, its 

 resemblance to the Lance flora is striking. Out of a total of 51 species with outside 

 distribution, it has 28 species (55 per cent) in common with the type Lance flora. 

 Its reference to Lancian age is amply corroborated by a study of its component 

 short-range species. Not a single species has previously been known only from 

 deposits of Montanan or Paleocene age. In contrast, there are 26 (51 per cent) 

 which have been found previously only in deposits of Lancian age, as follows: 



Apeibopsis? laramiensis LaurophyHum coloradensis 



Carpites walcotti Laurophyllum meeki 



Cinnamomum? affine Magnoha dakotana 



Cinnamomum linifolium Magnolia lakesii 



Cissites lobatus Magnohophyllum cordatum 



Dombeyopsis trivialis Menispermites cockerelli 



Dryopteris? carbonensis Palaeoaster inquirenda 



Ficus coloradensis Pisonia? racemosa 



Ficus cowanensis Pistacia eriensis 



Grewiopsis saportana Sabalites eocenica 



Juglans leconteana Viburnum marginatum 



Juglans newberryi Zingiberites dubius 



Juglans prserugosa Zizyphus hendcrsoni 



The temporal relations of the Medicine Bow formation, as here interpreted, 

 are shown in figure 3. The inckision of the upper Medicine Bow and overlying 

 lower Ferris in the Lancian age is based entirely on the reported presence of Tri- 

 ceratops remains in these beds. No plants are now known from this part of the 

 sequence. 



Laramie-Denver-Dawson floras — The flora of the Laramie formation of the 

 Denver basin of Colorado has been described by Knowlton.^ Although I beheve 

 it is somewhat overspeciated, there are apparently about 100 recognizable species. 

 The plant-bearing beds lie between the Sphenodiscus-heaTing Fox HiUs sandstone 

 below and the top of the Triceratops zone of the overlying Arapahoe and lower 

 Dawson formations,- and are thus clearly of Lancian age. The testimony of the 

 floral assemblage, even without other evidence, supports the same conclusion on 



' Knowlton. F. H., U. S. Geol. Surv. Prof. Paper 130, 1-168, 1922. 



' Lull. R. S., Mem. Peabody Mus. Nat. Hist., vol. 3, pt. 3, 3, 7, 1933. Hatcher, J. B., and Lull, R. S., U. S. Geol. 

 Surv. Mon. 49, 182-184, 1907. 



