100 



LARAMIE FLORA OF THE DEX^'ER BASIX. 



been found in beds above the unconformity- 

 Rhamnus /^aUciformis was described originally 

 from specimens obtained in the Laramie and 

 has subsequently been found in the Montana 

 at a number of horizons. The two species of 

 Ficus are well-marked forms and probably 

 have been correctly identified in both areas. 



In addition to the flora of the Vermejo, 

 which is of course of Montana age, it may be of 

 interest to compare the Laramie flora with the 

 Montana flora as a whole. The following 

 species are common to the two : 



Anemia elongata ( Xewherry). 

 ?Anemia supercretacea HoUick. 

 Sequoia reichenbachi (Geinitz) Heer. 

 Sequoia longifolia i Lesqu'ereux) Knowlton. 

 Sabal montaua Knowlton. 

 Myrica torreyi Lesquereux. 

 Ficus dalmatica Ettingshausen. 

 Ficus praetrinervis Knowlton, 

 Ficus planicostata Lesquereux. 

 Rhamnus salicifolius Lesquereux. 



In addition to the species that are regarded 

 as actually identical in the Laramie and Mon- 

 tana floras, tlierc are two that are obviously 

 related to Montana species, as follows: 

 Palaeoaster? similis, aff. P. inquirenda. 

 Artocarpus liriodendroides, aff. A. dissecta. 



BELATIONS TO THE 'LOWER LARAMIE ' OF 

 CARBON COUNTY. WYO. 



One of the most interesting results brought 

 out by this study is the close relation that is 

 shown to exist between the flora of the Laramie 

 in the Denver Rasin and the flora of the so- 

 called ''Lower Laramie" (now the Medicine 

 Bow formation) of Carbon County, Wyo., and 

 adjacent areas. The flora of the '"Lower Lar- 

 amie" at present known is confined in the main 

 to the lower 300 or 400 feet of beds, and tiiousih 

 it has not yet been fully exploited, the follow- 

 ing forms at least are known to occur: 



Apeibop.si.s discolor Lesquereux. 



Aristolochia sp. 

 *Artocarpus lessigii (Lesquereux) Knowlton. 



Carpites sp. 

 *Ca8sia marshallensis Knowlton. 



Ceanothu.s? sp. 

 *("innainomum afline Lesquereux. 

 *Cyperacites sp.? 



Haphnogene elegans Watelet. 



Diospyros? ficoidea Lesquereux. 

 *Dombeyopsis obtusa Lesquereux. 

 •Dombeyopsis trivialis Lesquereux. 



DryophjUuni cf. D. aquamaruni Ward 



I'ryophyllum bruneri Ward. 



*Dryopteris carbonensis Knowlton. 



Equisetum, tubers of. 

 *Ficus arenacea Lesquereux. 

 *Ficus impressa. 

 *Ficus cockerelli Knowlton. 

 *Ficu8 navicularis Cockerell. 

 *Ficus p!anico.stata? Lesquereux. 

 *Ficus praetrinervis Knowlton. 



Ficus sp., new. 



Ficus? sp. 

 *Sequoia longifolia Lesquereux. 



Geonomites cf. G. ungeri Lesquereux. 

 Ilex? sp. 



*Juglans praerugosa. 

 *I auius wardiana Knowlton. 



Mimosites? sp. 



Mimosa sp.? 

 *Myrica torreji Lesquereux. 



Paliurus zizyphoides? 



Palmoxylon sp., new? 

 *Pecopteris sepulta Newberry cf. HoUick. 

 *Phyllites sp. 



Pistia corrugata? Lesquereux. 



Platanus marginata (Lesquereux) Heer. 

 *Platanus platanoides (Lesquereux* Knowlton. 

 *Rhamnus elegans Newberry. 

 *Rhamnus saliciformis Lesquereux. 

 *Sabal montana Knowlton. 

 *Salix elongata? Al. Braun. 



Salix sp. 

 *Sequoia reichenbachi (Geinitz) Heer. 



Seqiioia sp. 



Woodwardia, new, nearest to W. crenata Knowlton. 

 *Zizyphus minimus Knowlton. 



An analysis of the above list shows that it 

 contains 48 forms, of which 2(3, marked with 

 an asterisk in the list, are named species having 

 a distribution outside this area. Of these 

 26 species no less than 25 are found also in the 

 Laramie of the Denver Basin, and it therefore 

 seems legitimate to conclude that the age of 

 the beds is the same in the two areas. As set 

 forth at length on page 60, the section of "Lower 

 Laramie" rocks has a tliickness of about 6,000 

 feet. According to Veatch. this thick section 

 is separated from the overlying beds (now 

 called ttie Ferris formation) byan unconformity 

 which he regarded as profound, because it was 

 believed to have involved the removal of more 

 than 20,000 feet of sediments. This uncon- 

 formity was presumed to be the same as that 

 which separates the Laramie from the over- 

 lying Arapahoe and Denver formations in the 

 Denver Basin, but as a result of later work 

 Bowen would place this unconformity at tlie 

 top of the Ferris formation and not at its base, 

 though not denying the possibility of an un- 

 conformitv at the base of the Ferris. That 



