ART. 12 FOSSIL PLANTS FROM WYOMING BROWN 6 



ferns, one gets the impression that none of these is definitely deter- 

 mined in terms of living species, and two are assigned to a new genus. 

 Their value, therefore, as habitat indicators is not very great. As 

 for the supposed figs, the fact that two of these species are questioned 

 and the third is identified on the basis of resemblance to another 

 problematical Ficus^ one can be pardoned for not placing great stress 

 on their value as habitat indicators. 



0]3posed to all the uncertainties due to doubtful identification are 

 a few determinations which come reasonably within the limits of 

 certainty. The Aspen species which seem to me to be correctly 

 assigned and beyond serious question are : Nelumho weymouthi, 

 Liquidamhar fontanella^ and Sassafras lyradleyi. If Liquidamhar 

 fontanella alone is correct and if it had the habits of the living 

 species, it would stamp the association as a temperate, perhaps a 

 warm-temperate, one. 



The absence from the Aspen of gymnosperms like the cycads and 

 conifers leaves little for comparison with such older fl^oras as that of 

 the Potomac group, the Kootenai formation, and others. Besides 

 Sassafras hradleyi and Laurus aspensis there are few resemblances 

 to anything in the large and somewhat earlier flora of the Dakota 

 formation. Likewise there are few if any points in common with 

 such floras of later date as that of the Mesaverde formation, Judith 

 River formation, Vermejo formation, and others. The Aspen and 

 Frontier floras, therefore, hold a conspicuous place in the gap of our 

 l<^nowledge of western interior Cretaceous vegetation. 



PTERIDOPHYTA 

 ANEMIA FREMONTI KnowUon 



Plate 1, Figure 3 



Anemia fremonti Knowlton, U. S. Geol. Surv. Prof. Paper 108, p. 84, pi. 31, 

 fig. 6; pi. 32, figs. 1-3, 1917. 



The specimen figured here is similar to those described by Knowl- 

 ton. Exception could be made in respect to the smaller size and 

 the deeper lobing of the pinnules of the Aspen material; but these 

 characters may well come within the variations of the species. 



Plesiotype.—V.S.'NM. No. 39136. 



ASPLENIUM OCCIDENTALE KnowUon 



Plate 1, Figure 5 



Asplenium occidentale Knowlton, U. S. Geol. Surv. Prof. Paper 108, p. 84, pi. 31, 

 figs. 2-5, 1917. 



The specimen figured here is apparently a ternately divided por- 

 tion of a young or deformed frond of the species described by Knowl- 



