124 THE POTOMAC OR YOUNGER MESOZOIC FLORA. 



Gcepperti in the leathery texture of the pinnules and in other points. In 

 the cutting of some of the pinnules there is a good deal of likeness to 

 T. elegans, Kunze, the living species and the sole survivor. It may also be 

 compared with Asplenium Dickson ianum Heer.^ It resembles more than 

 any other desci-ibed fossil Thyrsopteris elongata Geyler.^ 



Thyrsopteris brevipennis, sp. nov. 



Plate XXXIV, Fig. 3 ; Pl.atc XXXVI, Fig. 2 ; Plate XXXVII, Figs. .'!, 9 ; Plate XXXVIII, Fig. 1 ; 



Plate XLI, Fig. 4. 



Frond tripinnate ; leaf- substance thin ; penultimate pinna? mostly 

 opposite, short ; rachises slender, terminated by an obtusely lobed seg- 

 ment; lower ultimate pinnae pinnate, vf'\i\\ basal pinnules three lobed, 

 passing towards their tips abruptly through entire pinnules into lobes more 

 or less united, short; towards the upper part of the frond and compound 

 pinnse the ultimate piiinse pass rapidly into pinnules and lobes that are 

 more or less united ; nerves departing in groups or nerve-bundles into 

 each lobe or tooth, flabellately diverging, and branching several times, 

 slender but rather distinct. 



Localities: Red clay ball in banlcs of Dutch Gap Canal; fishing hut 

 above Dutch Gap Canal ; Baltimore, collected by Meek ; Deep Bottom. 



This plant in facies is more like a Sphenoptcris than any of the species 

 united under Thyrsopteris, and tliis feature is dependent in part on the 

 shortness of tlie ultimate pinnte and the abrupt passa,gefrom lobed pinnules 

 to united lobes. It is comparatively abundant among the ])lants collected 

 by Meek at Baltimore, but is rare at the otiier localities. There are a 

 number of these species with Sphenopteris facies found in the Potomac 

 flora which differ sufficiently to forbid their union in one species. They 

 may be noted as Thyrsopterids with a Splienoptcris facies. 



Thyrsopteris alata, sp. nov. 



Plate XXXVI, Fig. 3. 



Frond unknown, probably tripinnate ; principal rachis narrowly 

 winged, very slender, somewhat flexuous ; ultimate pinnae alternate, short, 



'Flor. Foss. Are., vol. 3, No. 2, PI. I, Figs. 1-5. 



2Fos8. Ptl. Juraforui. Japans Palneoutographica, vol. 24, 15*7, PI. XXX, Fig. 5 ; PL XXXI, Figs. 4, 5. 



