JURASSIC CYCADS FROM WYOMING. 199 



in organic connection with the trunks to which they belong. And even 

 in this case the evidence upon which Wilhamson based his original 

 restoration" was for many years called in question by most working 

 paleobotanists. 



Count Solms-Laubach (1887)" states that the only instance known 

 to him of a cycad with attached leaves that could be identified with 

 certainty was to be seen in a specimen of Williamsonia (Zamites) gigas 

 from the Upper Jurassic sandstone of Yorkshire, England. This specimen 

 was originally figured by Saporta." 



Still further examples of more or less full-grown fronds of the Wil- 

 liamsonia type, whose organic connection with stems may be proved, 

 were given by Seward in 1897,'' together with quite conclusive evidence 

 in favor of the identity of Williamsonia and the cycadean trunks referred 

 to the genus Bennettites of English and Continental paleobotanists. 



Here the subject rested until I announced the discovery of the 

 crown of young leaves with structure preserved in the type of Cycadeoidea 

 ingens Ward." This was one of the earliest results of the microscopic 

 examination of our superb series of American fossil cycads undertaken 

 by me, an examination which Professor Ward has done so much to 

 encourage. 



Since then many additional facts have been discovered concerning 

 the leaves of the Bennettitacese, and the forms in various other species 

 determined, but an account of these is reserved for a future extended 

 publication on the entire subject. It is only intended here to describe 

 more briefly the discovery of the leaves in a typical form of Cycadella, 

 this making the third Bennettitean genus in which they have been 

 positively determined, and the second in which both structure and 

 prefoliation are known — that is, if we regard Bennettites and Cycadeoidea 

 as including forms generically distinct. Evidence is accumulating that 

 such is the fact. 



« Contributions towards the History of Zamia gigas Lindl. & Hutt., by W. C. Williamson. Trans. Linn. 

 Soc. London, Vol. XXVI, London, 1870, pp. 663-674, pi. lii, liii. 



6 Einleitung in die Paliiophytologie, Leipzig, 1887, p. 96: Introduction to Fossil Botany, English trans- 

 lation, 1891, p. 94. 



c Paleontologie fran(;'aise, Plantes Jurassiques, Vol. II, Paris, 1873, p. 56, pi. Ixxxi, fig. 1. 



d On the leaves of Bennettites: Proc. Cambridge Phil. Soc., Vol. IX, Pt. V, March 8, 1897, pp. 273-277. 



« A study of some American fossil cycads; Part II, The leaf structure of cycadeoidea: Am. Journ. Sci., 

 4th ser., Vol. VII, April, 1899, pp. 305-308, pi. vii. 



