OF ARKANSAS. 313 



resembles Neuropteris flexuoso, Brgt., it is easily distinguished by the more 

 generally rounded base of the leaflets. It is very variable in size, and 

 sometimes the leaflets are expanded on one side and somewhat auriculated. 

 The veinlets, though thin and generally divided two or three times, are 

 more distinct than in Neuropteris flexuosa. The species is interesting with 

 regard to its distribution, and it was worth figuring it here because the 

 Arkansas specimens show for the first time two extreme sizes of the leaflets 

 of that fern. Fig. 2 is a very large, and fig. 6 a very small form, which 

 have not been published before. Moreover, at least in America, the 

 species looks peculiar to the lowest coal. It was found in abundance at 

 Shamokin, Pennsylvania, in connection with the lowest bed of coal, either 

 just above the Conglomerate, or between two strata of that formation. 

 In Europe, if there is identity in the species, it has been found as high as 

 the New Eecl Sandstone. It was seen at all the openings of the coal of 

 Arkansas. 



19. Odontopteris intermedia, Sp. nov. (PL 5, Sig. 7.) This species appears 

 to be intermediate between Odontopteris Brardii, Brgt., and Odontopteris 

 crenulata of the same author. It differs from the former by shorter leaflets 

 united to the middle, and by the basilar inferior leaflet which does not 

 differ in form from the other, and is separated from the last species by 

 entire leaflets and a more straight nervation. In our species, the leaflets 

 are somewhat obtuse ; the medial nerve is marked sometimes, or entirely 

 obsolete; the nervules are very thin and obsolete. Both primary and 

 secondary rachis are broad and flat. Better specimens will be needed to 

 Hx the validity of this species which, in any case, has not been found till 

 now in America, but at Jenny Lind prairie coal-bank. 



20. Rhabdocarpus minutus, Sp. nov. (PL 5, fig. 8 .and 8 a). A small 

 fruit, of w T hich the natural size, fig. 8, is enlarged, fig. 8 a. It is oval in 

 outline, marked with a small notch at the base, and regularly and minutely 

 ribbed. Found at James' fork of Poteau, and at Male's coal-bank. 



21. Ehizolithes palmatifidus, Sp. nov. (PL 5, fig. 9). Evidently a root, 

 perhaps the root of Cordaites Borassifolia, Ung. ; this last species being 

 found in great abundance in connection with this root at Erog bayou coal- 

 bank. "With this root there w T as at the same place a fine branch of a 

 Stig?naria, with distant leaves, scars very small, irregularly placed, and 

 more distant than in any other species of this genus. It might perhaps 

 be referred to Stigmaria irregularis, Lesq., of the Pennsylvania Geological 

 Report. Want of room prevents its being figured. 



22. Dyctiopteris obliqua? Bunb. (Plate 5, fig. 10 and 10 6). This small 

 leaflet, fig. 10, enlarged fig. 10 b, is referred with doubt to this species. It 

 belongs evidently to a species of the genus Dyctiopteris. But the leaflet 

 is too small and too regular to agree w T ith the species. Nevertheless, as 

 nothing more was found of this plant but the small leaflet, it is not suffi- 

 cient to give characters to a new species. Found at James' Fork of Poteau. 



