224 MESOZOIC FLORAS OF UNITED STATES. 



DESCRIPTION^ OF THE SPECIES. 



Phylum I^TERIDOPHYT^ (Ferns and Fern 



A.llies). 



Order FILICALES (Ferns). 



Family fYATHEACEvE. 



Genus DICKSONIA L'Heritier. 



DiCKSONiA PACHYPHTLLA Fontaine n. sp. 



PI. LXV, Fig. 1. 



1894. Aspleniopteris pinnafifida Font.? in Diller & Stanton: Bull. Geol. See. Am., 



Vol. V, p. 450. 

 1895 [1896]. Aspleniopteris pinnatifi.da Font.? in Stanton: Bull. U. S. Geol. Surv., 



No. 133, p. 15. 



A single imprint of a fern in fruit was found at locality No. 9. It 

 shows the terminal portion of what appears to have been an ultimate pinna. 

 The amount of material is too small to permit its positive determination. 

 It is, however, much like a plant from Cascade County, Mont. Professor 

 Ward and Mr. Weed recently made a considerable collection of fossil plants 

 in Cascade County, Mont., a few miles from the town of Geyser. These 

 fossils appear to occur in the same system of beds as those yielding the 

 fos: Us of Great Falls. They are of Lower Cretaceous age, belonging to the 

 Kootanie or Lower Potomac phase of that flora. For the sake of descrip- 

 tion I have named the strata yielding these Cascade plants the Geyser 

 beds. The description of these plants is published in this paper. 



Among the plants from the Geyser beds two small bits of a fruiting 

 fern were found. They apparently belong to a new species of Dicksonia, 

 but as the amount of material is very small and the specimens are very 

 imperfect, I did not venture to do more than describe it as a doubtful new 

 species, giving it, for the sake of reference, the name Dicksonia pachy- 

 'phylla. The plant now in question, from the Shasta beds, is much like 

 the Geyser fossil, and my sole reason for doubtfully identifying it with that 



" It happened in the progress of the work that the collections from the Kootanie of Great Falls, Mont., 

 were sent to Professor Fontaine before those from the Shasta formation were ready, and he reported on them 

 first.— L. F. W. 



