438 PALAEONTOLOGY OF ILLINOIS. 



Hyinenophyttites Clarl-ii, Sp. nov. PI. 39, fig. 7. Frond ap- 

 parently large, irregularly divided ; primary divisions oblique, 

 decurrent, obovate, irregularly subpinnately cut in obtuse, ob- 

 lanceolate, short, subreflexed lobes; veins fasciculate at the 

 base and along the common inflated rachis, simple in ascending 

 into the secondary or tertiary divisions, or irregularly dichoto- 

 mous, thin, ascending to the sinuses of each lobe. It is dis- 

 tantly related to Hymenophyllites Gutbierianus, Ung. We 

 know it only from small specimens. The first one sent to me 

 was found by Mr. James H. Clark, of Newport, R. I. The 

 one figured here is from Mazon creek, Grundy county, Illinois. 

 Genus Alethopteris, Sternb. and Gopp. Frond bitripinnate 

 or tripinnatifid ; secondary nerves perpendicular or nearly ob- 

 lique to the medial nerve, simple, once or twice forking ; mar- 

 gins of the pinnules often re volute. 



Alethopteris aquilina, Brgt. Hist, des Veg. Foss., 1, p. 248, 

 tab. 90. Our American form does not agree perfectly with the 

 descriptions and figures of the European species. The leaflets 

 are narrower, the margins more reflexed, the nervation less 

 distinct, sometimes obsolete. Locality: St. John, Perry county, 

 Illinois. 



Alethopteris Massillonis, Sp. nov. PI. 40, fig. 1-4. Frond 

 tripinnately divided ; primary rachis about one inch thick, 

 irregularly grooved and striated, smooth, with horizontal, alter- 

 nate branches ; pinna diversely divided. In the superior one? 

 the naked rachis bears alternate long, linear, pointed pinnse, 

 deeply pinnately lobed, with alternate, oval-lanceolate or oblong 

 obtuse pinnules, irregularly undulate on the margins, and sep- 

 arated to near the base, by a broad, flat or acute sinus. In the 

 inferior? primary pinnse, the narrow rachis is winged, or the 

 shorter secondary pinnae are pinnately divided into regular, 

 proportionally broader pinnules, becoming shorter in ascend- 

 ing, and forming only regular, broad, alternate undulations 

 near the top of the pinnae — fig. 3. The terminal pinnule is 

 lanceolate, acute, undulate, lobed at the base. Medial nerve 



