knowlton] kootanil plants from great falls, Montana 125 



Certain of the specimens from Montana agree also with some of 

 the forms that have been referred to Ginkgo digitata (Brongn.) Heer, 

 and with fewer specimens there would probably be no hesitation in 

 so referring them, but they grade one into the other to such an ex- 

 tent as to make any line unsatisfactory. 



There are a number of small specimens (cf. plate xiv, figs. 1,2) 

 that are absolutely indistinguishable from Ginkgo polaris Nathorst 1 

 except in possessing a long, strong petiole. As Nathorst has sug- 

 gested, his species can be especially compared with G. sibirica Heer 

 and G. Habcllata Heer; so that, as he naively adds, "there is the 

 temptation of classing some fragments with one species, some with 

 the other." As the more perfect examples appeared to differ from 

 either in the petiole being neither so long nor strong, he decided to 

 give it a separate name. As the specimens under consideration are 

 otherwise indistinguishable, their having a relatively long and very 

 strong petiole may properly exclude them from G. polaris. 



In his first paper on the Great Falls coal field, Newberry described 

 a deeply lobed leaf as Baicra brcvifolia, comparing it especially with 

 B. pluri partita Schimper, from the Wealden of North Germany. I 

 have not seen this specimen, and the figure of it is so poor that noth- 

 ing of the nervation can be made out, but I can see no reason to 

 suppose it is other than a small leaf of Ginkgo, especially as it can 

 be matched satisfactorily by specimens before me. I have therefore 

 referred it tentatively to G. sibirica. 



Finally, I may add that I have given on the plate a number of 

 figures showing the normal and extremes exhibited, and while it 

 must be confessed some of them are very unlike what has usually 

 been referred to Ginkgo sibirica, there are so many intermediate 

 forms that it is quite impossible to draw any satisfactory line between 

 them. They must either be regarded as belonging to one poly- 

 morphous species or to half a dozen poorly defined forms. 



Locality. — Shale below main coal seam, 3 miles southeast of 

 Xollar's ranch, at Meridith mine, and about 6 miles southwest of 

 Geyser, Cascade County, Montana. Mr. Fisher also noted, but did 

 not collect, this species opposite the smelter, on the south bank of 

 the Missouri River at Great Falls. 



1 Norwegian North Polar Exped., 1893-1896, Foss. PI. from Franz Josef 

 Land, p. 4, pi. 1, fig. 8. 



