NILSSONIA. 53 



of the genus himself. An inspection of Nathorst's figures of 

 Anomozamites and Ptilozamites species suggests a difficulty in 

 certain cases in deciding between the two genera. In such a form 

 as Anomozamites gracilis, Nath., 1 we have well-marked branching 

 in some of the veins, and a close approximation in general 

 appearance to other species included in Ptilozamites, cf. e.g. 

 P. Heeri, Nath., 2 and A. minor * (Brong.). 



Fontaine 4 figures a few small fragments of leaves from the 

 Potomac flora under the name Anomozamites, but there is hardly 

 enough material to justify even a generic determination, and still 

 less to warrant the institution of two new species. 



Nilssonia Schaumburgensis (Dunk.). 



[Figs. 3, b, and c.] 



1843. Pterophyllum Schatimburgense, Dunker, Progr. p. 6. 



1844. Pterophyllum Schaumburgense, Gb'ppert, Foss. Cycad. p. 54. 



1846. Pterophyllum Schaumburgense, Dunker, Wealdenbildung, p. 15, pi. i. 

 fig. 7 ; pi. ii. fig. 1 ; pi. vi. figs. 5-10. 



1848. Pterophyllum Schaumburgense, Bronn, Index pal. nomencl. p. 1056. 



1849. Pterophyllum Schaumburgense, Brongniart, Tableau, p. 107- 



1850. Pterophyllum Schaumburgense, linger, Gen. spec, plant, foss. p. 292. 



1851. Pterophyllum Schaumburgense, Miquel, Rangscbik. foss. Cycad. p. 213. 



1852. Pterophyllum Schaumburgense, Ettingshausen, Abh. k.-k. geol. Reichs. 



vol. i. Abth. iii. No. 2, p. 22. 

 1856. Pterophyllum Schaumburgense, Bornemann, Organ. Rest. Lettenkobl. 



p. 58. 



1869. Anomozamites Schaumburgensis, Schirnper, Trait, pal. veg. vol. ii. p. 141. 

 1871. Anomozamites Schaumburgensis, Schenk, Palseontograpbica, vol. xix. 



p. 231, pi. xxxiii. 

 1883. Pterophyllum Schaumburgense, Peyton, Quart. Journ. Geol. Soc. vol. 



xxxix. Proc. p. 3. 

 1890. Nilssonia cf. Schaumburgensis, Nathorst, Denkschr. k. Ak. Wiss. 



math.-nat. Cl. vol. Ivii. pp. 45, 49, and 53, pi. i. figs. 6-9. 

 1894. Nilssonia Schaumburgensis, Yokoyama, Journ. Coll. Sci. Japan, vol. vii. 



pt. iii. p. 227, pi. xx. figs. 12 and 14 ; pi. xxi. fig. 14 ; pi. xxii. 



figs. 5-7. 



1 ( 



A. 1), Flor. Bjuf. p. 65, pi. xv. fig. 15. 



2 Ibid. p. 60, pi. xii. figs. 1 and 7. 



3 Ibid. p. 66, pi. xiv. figs. 5-7, and pi. xviii. fig. 4. 



4 (A. 2), Potomac Flora, p. 167, pi. xxx. 



