DESCRIPTIONS OF FOSSIL PLANTS FROM THE MESO- 

 - ZOIC AND CENOZOIC OF NORTH AMERICA. I. 



By F. H. KNOWLTON 



With Two Plates 



I. Two New Fossil Chain-fdrns (Woodwardia) from Oregon 



AND Wyoming 



WOODWARDIA MAXONI, sp. nov. 



Plate LXIII, Figure 3 ; Plate LXIV, Figures i, 2 



Outline of whole frond unknown; pinnae lanceolate, broadest at 

 base, narrowly acuminate at apex, cut ^ or more of distance to the 

 rachis into numerous, approximate, oblong, obtuse, often slightly 

 falcate lobes which are finely serrate-toothed at apex, the basal lobes 

 with small oblong or triangular auricles on the lower side; rachis 

 very strong; midvein relatively strong, with a single series of elon- 

 gate, or elliptic — oblong, slightly oblique, areoles on each side, the 

 veins thence free to the margin ; sori, as in the living species, linear 

 or oblong, one to each areole, becoming confluent with age; indusium 

 attached by its outer margin to the fruit-bearing veinlet. 



Type: U. S. N. M., 33992 [pi. lxiv, fig. i] ; co-types 33993 [pi. 

 LXIV, fig. 2] ; 33994 [pi. LXIII, fig. 3]. 



Locality: Southeast of Rock Springs, Wyoming. 



Geological horizon: Fort Union (Eocene). 



This splendid species is represented by a large number of well- 

 preserved specimens, but as all are in the form of detached pinnse 

 we are still in ignorance of the outline of the whole frond, though it 

 must have been of imposing size and appearance. The pinnae, as 

 stated in the diagnosis, are lanceolate in shape, and, so far as ob- 

 served, are always broadest at the base and narrowly acuminate at 

 the apex. The largest, evidently nearly perfect, pinna observed is 

 10.5 cm. in length and its width 2.75 cm. Other pinnae, especially 

 the fruiting ones, are slightly smaller, though the difference is not 

 great. In only one specimen is the extreme base of a pinna pre- 

 served, namely, that shown in figure 2. In this the basal lobes are 

 provided on the lower side with small oblong or triangular auricles, 

 and the pinna was apparently closely sessile. 



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