DESCRIPTION' OF SPECIES. PP. 47 



mopolitan forms N. liirsiita and N. fiexuosa. These range 

 nearly tlirough the entire carboniferous formation. They 

 extend to the highest portions of the Upper Barren Meas- 

 ures where plants are found, forming by far the larger 

 part and sometimes nearly all of the flora of the highest 

 horizons. 



Neuropteris hirsuta, Lesqx., Figs. 7 and 8, PI. VIII. 



This species is one of the most abundant plants at all 

 horizons and at all localities in the Upper Barrens. It is a 

 noteworthy fact, that where it and N. flexuosa abound, 

 we rarely And many other species, these two plants seem- 

 ing to exclude the small foliage ferns, such as Sphcnop- 

 teris, Precopteris, &c. This peculiarity is so marked that, 

 Avhile in the particular part of the stratum holding the 

 neuroi3terids in question we find no other ferns, yet in a 

 layer above or below, deposited under different conditions, 

 and separated by but a few inches of space from the first 

 named, we often find great numbers of Pecopterids &c. 

 but no Neuropteris hirsuta and N. flexuosa. Their mode 

 of growth and exposure to transj)ort l)y water must have 

 been totally different from those of most other genera of 

 ferns. 



The hirsute character of iV. liirsuta is almost never seen 

 in the upper beds ; but the form, nervation &c. are identi- 

 cal with those of the plant which shows this featu]-e when 

 found at lower horizons. 



During our researches into the flora of the various beds 

 of this and adjoining States we were so fortunate as to find 

 undoubted fruiting forms of N. Mrstita, and are thus able 

 to throw some light on the character of the fructification of 

 this important genus, a point which has long remained in 

 obscurity. 



This fructification, as shown in Figs. 7 and 8, PL VIII, con- 

 sists of linear-elliptical sori, 4^ mms. long and 1 mm. wide 

 at the middle. They are normally placed in groups of four, 

 the sorus nearest the base of the pinnule being situated 

 near the middle of the lamina of the pinnule, while each suc- 

 ceeding sorus of the group approaches nearer to the mid- 



