198 J. S. Newberry— Flora of the Great Falls Coal Field. 



Since the above notes were written I have received, through 

 the kindness of Mr. Williams, another collection of fossil plants 

 from Great Falls. With several species before mentioned, it 

 includes some which seem to be new, and of which brief de- 

 scriptions are given below. 



Chiropleris Williamsii, n. sp. 

 PL XIY, fig. 10, 11. 



Fronds orbicular, oblong or lobed, two to four inches in diam- 

 eter; petiolate, margins entire, nervation radiate, dickotomously 

 forked and somewhat reticulated. 



Of this remarkable fern I have many specimens, but none quite 

 complete. At first sight they suggest the fronds of Doleropteris 

 of the Coal Measures, but in that genus the nerves are fasciculate 

 and divide by separation of the bundles and not by forking, and 

 they never anastomose. In some specimens of the plant before 

 us the nerves are buried in the parenchyma, showing that the con- 

 sistence was thick and leathery ; in others, perhaps more macer- 

 ated, the nerves appear very distinct and rather coarse. A single 

 small specimen shows a distinct stipe at the base. 



This plant I have included in the genus Chiropteris with much 

 hesitation, for it differs from the type species in having an orbicu- 

 lar or elliptical frond which is generally simple, though some- 

 times lobed, while in C. Kurriana, the type, the frond is flabel- 

 late and deeply lobed, almost palmate, thus approaching Sagenop- 

 teris, but in that genus the frond is distinctly palmate, the divis- 

 ions being lanceolate, though springing from a common base. 

 The nervation too of Sagenopteris is much more closely reticu- 

 lated. In these respects the two genera would seem to be distinct. 

 The nervation of our plant is essentially that of Chiropteris, the 

 nerve branches anastomosing only at rare intervals, the meshes 

 being many times longer than broad. 



In the original notice of Chiropteris, by Dr. H. G. Bronn (Jahr- 

 buch fur Mineralogie, 1858), the fronds are represented as radiat- 

 ing in a whorl from a common base, and the nerves are neither 

 figured nor described as inosculating, but Schimper in his Palae- 

 ontologie Vegetale, (Yol. I, p. 643, PI. XLIII) describes and fig- 

 ures the frond of C. Kurriana, as flabellate, digitately-incised, 

 the nerves frequently forked and anastomosing to form narrow 

 meshes. This description corresponds closely with some speci- 

 mens of our plant, and while it is specifically distinct I do not feel 

 justified, without more material, in separating it from the genus 

 Chiropteris. Possibly facts will hereafter come to light which 

 will require this to be set apart a* the type of a new genus. 



The horizon of the type specimen of Chiropteris is the upper 

 Trias or Rhaetic. In the Jurassic rocks the genus has not been 

 recognized, but its place has been taken by the allied Sagenopteris. 

 Prof. Fontaine, in Monograph XV, U. S. Geological Survey, de- 

 scribes several species of Sagenopteris, but in these the form was 

 very different and the nervation much more closely reticulated. 



