FOSSIL PLANTS. 439 



broad, ascending to at least three-fourths of the leaflets; ner- 

 vules oblique, deeply marked, all forking twice. 



This species appears distinct from all the others of this 

 genus. It has some relation to the former and also to Aletliop- 

 teris Dournardii, Brgt., especially by its pointed terminal leaf- 

 let, but it is different from both by the nervation, the size and 

 the form of this terminal leaflet. As in Pteris aquilina of our 

 time, part of the pinnae, probably the lower ones, have a 

 winged rachis, and the tertiary divisions become insensibly 

 shorter in ascending to the point of the pinna, which is thus 

 only pinnately divided near the top. 



The species is abundantly found at Massillon, Ohio, in the 

 shales of No. 1 B coal. I have never seen it elsewhere, except 

 once among the specimens sent by Mr. Even from Mazon creek. 

 Though this last specimen has its nervation somewhat obsolete, 

 it evidently belongs to this species. It is copied fig. 4. A large 

 specimen, showing the common broad rachis and horizontal 

 branches, as described above, is not figured here. 



Aleilwpteris Owenii, Lsqx. Geol. Rep. of Arkansas, vol. 2, p. 

 309, pi. 2, fig. 1 and la. A small indistinct fragment from 

 Mazon creek, is referred with doubt to this species. 



AletJiopteris Serlii, Brgt. Hist, des Veg. Foss., 1, p. 292, tab. 

 85. Abounds at Murphysboro, Jackson county, Illinois. 



AletJiopteris crenulata, Gopp. 



Pecopteris crenulata, Brgt. Hist, des Veg. Foss., 1, p. 300, tab. 

 87, fig. 1. This species is extremely rare. M. Brongniart saw 

 and figured only a small branch of it, resembling that of our 

 fig. 4. Though still incomplete, the specimens figured on our 

 plate 39, fig. 2, 3 and 4, evidently show that this species is a 

 true AletJiopteris, of large size, at least bipinnately, but more 

 probably tripinnately divided, with a punctulate and irregu- 

 larly striated rachis. In all our specimens the pinnules are 

 ovate, obtuse, regularly divided to near the rachis, separated 

 by a flat sinus, and thus leaving a narrow margin along the 



