June 12, 1896.] 



SCIENCE. 



871 



Zamia rather thau with Dioon, proposed in 1890 

 to call it Zamiophyllum. This is iu hanuouj^ 

 with Nathorst's fuudameutal principle of 

 nomenclature to make all doubtful genera 

 founded on leaves terminate iu -phyllum. Ob- 

 jectionable as this rule is in the case of dicoty- 

 ledonous leaves (see Amer. Journ. Sci. , 3dSer., 

 Vol. XXXI., May, 1886, pp. 370-375), it is 

 s'till more so for plants of lower rank, as 

 monocotyledons, while iu families in which the 

 appendicular organs are not true leaves, but 

 fronds, as in the case of cycads and ferns, this 

 practice is highly objectionable, and it is matter 

 for congratulation that Mr. Seward, in recogniz- 

 ing the same truth perceived by Nathorst, has 

 restored Schenk's name. Apropos of this form 

 it is to be noted that Mr. Seward declines to 

 recognize Prof Fontaine's two varieties from 

 the Potomac formation and Nathorst' s variety 

 from Japan, aud that he also includes in this 

 species the other Japanese form to which 

 Nathorst gave the name Zamiophyllum Nau- 

 manni. 



Passing over many other interesting features 

 of this portion of the work and also his treat- 

 ment of flowers and fruits, we come to the sec- 

 tion which, just at present, has the greatest in- 

 terest for the student of American paleobotany, 

 viz., that which treats of the cycadean trunks. 

 It is no secret that a monograph on the Cy- 

 cadean Trunks of North America is in prepara- 

 tion at the U. S. National Museum, and that a 

 large amount of material, especially from the 

 Potomac of Maryland and the Lower Cretaceous 

 of the Black Hills, has been brought together 

 as a basis for this study. Several preliminary 

 notes and papers have already appeared,* bear- 

 ing on this subject, but unavoidable delays have 

 prevented the progress of the work, and it will 

 be some time before its completion. This much 

 is said because Mr. Seward has several times 

 referred to the probable early appearance of 

 this monograph (see Pt. II., pp. 120-121 of the 

 work under review). One of the causes of 

 delay was the necessity which was felt of visit- 



*See Science, Vol. XXL, June 30, 1893, p. 355 ; 

 Proc. Biol. Soc. Washington, Vol. IX., April 9, 1894, 

 pp. 75-88 ; Journ. Geol., Vol. II., April-May, 1894, 

 pp. 250-266 ; Bull. Torr. Bot. Club, Vol. XXI., July 

 20, 1894, pp. 291-299. 



ing the European museums aud examining the 

 great collections of cycadean trunks in England, 

 France and Italy. The paper above referred 

 to* gives a somewhat full account of the in- 

 vestigation of this nature which was made iu 

 1894. 



' In restricting the Wealdeu to the beds that 

 lie between the Purbeck and the Atherfleld 

 beds (he seems to include the Lower Greensand) 

 Mr. Seward has excluded from the consideration 

 of cj'cadean trunks the oldest and best known 

 forms, viz. , those from the ' dirt beds ' (Pur- 

 beck) of the Portland quarries, first described by 

 Buokland iu 1828 under the name of Cycadeo- 

 idea. The number of distinct forms confined 

 to the true Wealden is not large and Mr. 

 Seward has treated them under the generic 

 names Bucklaudia, Fittouia, Bennettites aud 

 Yatesia. Bucklandia includes certain cylindri- 

 cal trunks of considerable height in proportion 

 to the diameter, the most important being B. 

 anomala (Stokes & Webb) Carr. , first described 

 in 1824 as Vlafhraria anomala Stokes & Webb, 

 though previously collected and subsequently 

 treated by Mantell under the name Clathraria 

 Lyellii. A large number of specimens of this 

 are in the British Museum, all of which have 

 been examined by Mr. Seward and separately 

 described. There are also some forms exhibit- 

 ing only the medulla or pith, which Mr. Seward 

 thinks may belong to Bucklandia, but which 

 come under Saporta's designation Cycadeo- 

 myelon. Two species of Yatesia, one of which 

 is the F. Morrisii of Carruthers, are also enu- 

 merated, but Mr. Seward seems to have grave 

 doubts as to whether this genus can properly 

 be separated from Bucklandia. A new species 

 of Fittouia from Mr. Euflford's collection is 

 described, but scarcely any mention is made of 

 the original species F. squamaia Carr., because 

 it is in the Geological Museum on Jermyn 

 street. It is a pity that this work should not 

 have sufficieutly expanded to include all the 

 material from the Wealden, seeiug that so 

 nearly all is actually in the British Museum. 



We come now to that form which is certainly 



of the greatest interest from whatever point of 



view, viz., the genus Bennettites of Carruthers, 



^'Sixteenth Annual Report U. S. Geol. Surv., 



1894-'95, pp. 463-542, pi. xcvii-cvii. 



