112 



CONTRIBUTIONS TO PAL^ONTOLOGY 



the basis of its correlation with the Lance, Colgate-Hell Creek, and Medicine Bow 

 floras, as is shown in the foUowing analysis: 



No outside distribution 57 



Outside distribution 43 (27 in common with type Lance) 



Short-ranging species : 



Montanan 1 



Lancian 22 



Paleocene 



23 



Total number of species 100 



Long-ranging species: 



Montanan-Lancian-Paleocene . 



Montanan-Lancian 13 



Lancian-Paleocene 3 



16 



Species of uncertain range . . 4 



Of the 23 short-ranging species, only 1, Aneimia elongata (Newberry) Knowlton, 

 has elsewhere been known only from deposits of Montanan age. This single dis- 

 cordance is minimized by the serious doubt which Knowlton cast on the identifica- 

 tion of the specimen from the Laramie formation.' The remaining restricted spe- 

 cies, all of which are known elsewhere only from rocks of true Lancian age, are 

 as foUows: 



Anona? robusta 

 Apeibopsis? laramiensis 

 Aristolochites brittoni 

 Asplenium? coloradensis 

 Carpites lakesii 

 Cinnamomum? affine 

 Diospyros berryana 

 Dombeyop.sis trivialis 

 Dryopteris? carbonensis 

 Ficus cowanensis 

 Jugians leconteana 



Juglans newberryi 

 Juglans praerugosa 

 Laurophjdlum coloradensis 

 Laurophyllum wardiana 

 Magnolia lakesii 

 Menispermites cockerelli 

 Palseoaster inquirenda 

 Pistacia eriensis 

 Rhamnus? minutus 

 Saliciphyllum wyomingensis 

 Zizyphus hendersoni 



In regard to the Arapahoe-Denver and Dawson formations, which overUe the 

 Laramic formation, the Lancian age of at least their lowest part has already been 

 estabUshed, on the basis of both Triceratops dinosaurs ^ and Lancian species of 

 plants.' Many of the oldcr plant collections of the Denver region were obtained 

 without due regard to their exact stratigraphic position. As a consequence it is 

 often difficult to determine whether or not a species is restricted to the lower beds 

 of the Arapahoc-Dcnver or Dawson. Pending further work in the region, it can 

 be said at present that at least the following dominant or typical Montanan and 

 Lancian species are known from the lower part of the Denver-Dawson, and not 

 from the upper part, which is beUeved to be of Paleocene age : 



Cercidiphyllum ellipticum 

 Cinnamomum linifolium 

 Cissus? lobato-crenata 

 Cornophyllum wardii 

 Dillenites clcburni 

 Dombcyoi)sis obtusa 

 Ficus coloradensis 

 Ficus planicostata 



' Knowlton, F. H., op. cit., 112. 1922. 

 ' Lull, R. S., op. cit., 3, 7, 1933. 

 » Dorf, E., op. cit.. 34, 1938. 



Ficus? trinervis 

 Laurophyllum coloradensis 

 Myrtophyllum torreyi 

 Nelumbo tenuifolia 

 Qucrcus? viburnifolia 

 Sabalites montaiia 

 Viburnum marginatum 

 Vitis stantoni 



