NO. 1994. A NEW FOSSIL FERN FROM WYOMING— KNOWLTON. 557 



United States remains so described are known from the Kootenai, 

 Dakota, Raritan, and in the Montana. From the Kome (Urogonian) 

 of Greenland Heer has described many beautifully preserved exam- 

 ples, a few of which show the characteristic sporangia. 



In the course of investigations by the United States Geological Sur- 

 vey into the coal resources of the West that have been going on for the 

 past six or eight years, many beautifully preserved ferns have been 

 found, among them a considerable number that clearly belong to 

 Gleichenia} The specimens here considered may be known as : 



GLEICHENIA PULCHELLA, new species. 

 Plate 44, figs. 1, 2. 



Frond probably of large size, distinctly xerophilous in habit; 

 primary leaf axis unknown; secondary axis stiff, naked, terete and 

 smooth, dichotomous, or pseudo-dichotomous, the included bud large, 

 always ( ?) undeveloped ; internodes apparently equal, each with about 

 three or four pairs of alternate, scattered pinnules ; terminal branches 

 (pinnae) apparently equal, erect, stiff, each with numerous pairs of 

 mainly alternate, rather remote, sessile, linear-lanceolate pinnules; 

 pinnules with a larger basal segment, thence cut nearly to the midrib 

 into nmnerous round moniliform lobes, these being reduced until near 

 the tip they are merely undulations; margins clearly revolute; midrib 

 relatively thick, 3-striate; nervation of segments obscure but appar- 

 ently not forked, deHcate; fruit-dots (?) immature, minute, usually 

 about two to each segment. 



Type.— Csit. No. 34,446, U.S.N.M. (pi. 44, fig. 2); faror-type, Cat. No. 

 34447, U.S.N.M. (pi. 44, fig. 1). 



Locality. — One-half mile north of mine D, Superior, Wyoming (sec. 

 17, T. 21 N., R. 102 W.). 



Geological horizon. — Cretaceous (Montana). Rock Springs coal 

 group, Mesaverde formation. 



This species is represented by a large number of examples, the two 

 figured being in some respects perhaps the best. Judging by analogy 

 with Hving species, it probably bore fronds of large size, for which 

 supposition there is some warrant in larger fragments of what appear 

 to have been axes lower than the ones shown in the figures. The low- 

 est segment of the axis, or internode, figured is nearly 2 mm. thick and 

 is preserved for a length of 2.5 cm. The internodes are 3 to 4 cm. long, 

 apparently nearly or quite equal, and, as stated above, bear 3 or 4 



1 The generic name Gleichenites, establisliecl by Goppert in 1836 for certain Paleozoic forns, is not tenable 

 for Mesozoic or later fossil forms. The tj'pe species of Olcichcnltcs is O. linliii, but this, according to the 

 opinion of David White, is a Sphenopteris of the group represented by S. hoeninghausi Brongniart, 182S, 

 which is the frond of the best known of the Pteridosperms, Lyginodciidron (Lygenopteris). The other four 

 species originally placed in the genus by Goppert are now distributed among Sphenopteris, Neuropteris, 

 and Ercmopteris, and the name Gleichenites is abandoned for Paleozoic ferns. On the principle of "once a 

 synonym always a synonym," it can not be resurrected for subsequent use. 



