l.-.-l 



(1. /,'. 117- land— WiHiarnxonhtn Tribe. 



to better understand the outer apical features of some of the 

 silicified Btrobili. [t shows, especially, how in the bisporan- 

 giate strobilus of Oycadeoidea-dacotensis the prolongation of 

 the apical region of the young ovulate cone must have filled 

 out the inverted conical space formed by the incurving of the 

 microsporpphylls beneath the enveloping bracts, so as to form 

 a solid bud. [Etching experiments with hydrofluoric acid or 



Fig. 11. 



Fig. 11. Wiiliamsonia fructifications of the James Yates collections 

 from Cliffs of Hawkser and Kunswick (1843 or before), x 1/3. 



(.4) Wiiliamsonia (species). Probably not W. gigas, the bracts being 

 very large. This specimen is in the collections of the Jardin des Plantes, 

 Paris. It is figured by Saporta in Plantes Jurassiques. The present figure 

 results from developing the specimen slightly. Two views of the terminal 

 bud are given. Might pertain to the stem shown in fig. 3. 



(B) Wiiliamsonia gigas fruits and foliage accompanied by large and broad 

 leaf of Yuccites (= Cordaites?). Compare the young fruit below with (A) 

 illustrating distinct variation in bract husk. (Yale — James Yates Collection.) 



alkalies producing erosion effects in Wiiliamsonia fruits yet 

 remain to be tried.] 



Throughout the entire fruit, therefore, the manner of pres- 

 ervation is found most instructive in its bearing on both fossil- 

 ization and features, it being altogether clear how preservation 

 of the sterile apical region with either dehiscence of the lateral 

 mass of seed stems and interseminal scales, or its nonpreser- 



