FLORA OF THE SHASTA FOKMATION. 245 



1870. Dioonites Buchianus (Ett.) Born. Schimper: Pal. Veg., Vol. II, p. 149. 



1889. Dioonites Buchianus (Ett.) Born. Fontaine: Potomac Flora (Monogr. U. S. 



Geol. Surv., Vol. XV), p. 182, pi. Ixviii, fig. 1; pi. Ixix, figs. 1, .3; pi. Ixx, 

 "figs. 2, 3; pi. Ixxi, fig. 1 ; pi. Ixxii, figs. 1, la, 2, 2a; pi. Ixxni, figs. 1-3, 3a, 3b; 

 pi. Ixxiv. 



1890. Zamiofhxjllum Buchianum (Ett.) Nath.: Denkschr. Wien Akad., Vol. LVII, 



p. 46 [6], pi. ii, figs. 1, 2; pi. iii; pi. v, fig. 2. 

 1896. Zamites Buchianus (Ett.) Sew.: Wealden Flora, Pt. II, p. 79, pi. iii, figs. 1-5; 

 pi. iv; pi. viii, fig. 1. 



Specimens of probable Dioonites Buchianus, of rather doubtful 

 character, occur at localities Nos. I, 15, 20, and 22. They are doubtful 

 because they are composed of fragments of detached leaflets. But at 

 locality No. 17, in the lower part of the Horsetown beds, Messrs. Ward 

 and Storrs found seven specimens of this plant which admit of no doubt. 

 They show portions of the midrib with leaflets attached. These have 

 all the characteristic features of Dioonites , Buchianus. Man}'- of these 

 features are so well marked and characteristic of this plant that there is 

 no occasion for confounding it with any other, provided they are dis- 

 tinctly displayed. This makes the plant especially valuable in the 

 comparison of the geological age of strata. It is to be noted that it 

 occurs here in the Horsetown beds, whose age has been determined 

 from the marine invertebrates which they contain to be Lower Cretaceous. 



Figs. 16 and 17 give representations of two of these specimens. 



Dioonites. Buchianus seems to have had a world-wide distribution, 

 and it has always been found onl^^ in Lower Cretaceous strata. It was 

 first found in the Urgonian beds of Grodischt. Later the writer discov- 



hausen's plant to Dioonites with doubt and in an obscure manner, but Schimper (Pal. V^g., Vol. II, p. 149) 

 did the same thing independently, and evidently without any knowledge that Bornemann had already done so. 

 Mr. Seward includes in this species the Cenonianian Pterophyllum saxonicum Reich , so named by Reich in the 

 Freiberg Museum, apparently only an the label, first mentioned in print by Geinitz in Gaea vonSachsen (1843), 

 p. 134, without description, and first described and figured by Goppert in 1848 (Nov. Act. Acad. Caes. Leop. 

 Carol. Nat. Cur., Vol. XXII, p. 362, pi. xxxviii, fig. 13) from specimens sent to him by Reich. Schimper 

 referred this also to Dioonites (Pal. Veg., Vol. II, p. 211), but did not identify it with Ettingshausen's plant- 

 Professor Fontaine in his Potomac Flora, pp. 182, 184, also puts the Dioonites saxonicus (Reich) Schimp. in 

 the synonymy of this species, but apparentlj' on the strength of two figures of Ettingshausen (Sitzb. Wien. 

 Akad., Vol. LV, Abth. I, pi. i, figs. 11, 12, p. 245) and the very imperfect fragment figured by Hosiusand von 

 der Marck from the Neocomian of Westphalia (Palaeontographica, Vol. XXVI, pi. xhv, fig. 198). He does not 

 seem to have seen Goppert's figures of Reich's Cenomanian plant. There is no certainty that the Westphalian 

 fragment belongs to that species. In view of this uncertainty and of the general improbability that the 

 species persisted into the Cenomanian, I shall not follow this course. IT future investigation ever makes it 

 necessary the species must of course bear Reich's name, which has priority over that of Ettingshausen by nine 

 years. — L. F. W. 



