198 MESOZOIC FLORAS OF UNITED STATES. 



of the less perfect specimen, No. 500.38. It is 30 cm. high, 23 cm. in 

 longer and 14 cm. in shorter diameter, and has a girth of 58 cm. It 

 weighs 11.34 kg. 



PL LXI is a view of the best side (that not distorted by pressure). 



INTERNAL STRUCTURE OF CYCADELLA. 



In the spring of 1901 Mr. George R. Wieland, after some corre- 

 spondence with Professor Knight, in which the latter authorized him to 

 cut sections of the cycads from the Freezeout Hills, came to Washington 

 and selected material for the purpose, which was sent to New Haven. 

 Mr. Wieland has found time to make a somewhat careful studj^ of some 

 of the specimens, especiallj' of certain ones belonging to the species 

 Cycadellaramantosa, the structure of which was also studied b}^ Doctor 

 Knowlton and myself. The results thus far obtained are important, 

 and at my request Mr. Wieland has kindly furnished some notes describ- 

 ing them and figures of the leaves detected in these fossils. I am very 

 glad of the opportunity to introduce his notes in full in this place and 

 also his figures. 



ON TEE FOLIAGE OF TEE JURASSIC CYCADS OF TEE GENUS CYCADELLA. 

 By G. R. Wieland. 



One of the most gratifying results of the structural study of the fine 

 series of silicified cycadean trunks from the Freezeout Hills of Carbon 

 Count}', Wyo., constituting the genus Cj'cadella of Ward, has been the 

 discovery of their young fronds. These have their structure presented, 

 and also exhibit their prefoliation. Although minute and yet enveloped 

 by the surrounding armor of leaf bases and ramentum, a fact to which 

 we are chiefly indebted for their preservation, the various tissues are 

 already well developed, and one may. surmise with no small degree of 

 confidence what must have been the character of the fully expanded 

 adult frond. 



This is of importance because the occurrence in the fossil condition 

 of foliage with structure preserved in connection with the trunks is rare. 

 Of the vast numbers of isolated cycadaceous fronds with which the plant- 

 bearing strata of Mesozoic age usually teem, wherever found upon the 

 globe, only those of Williamsonia gigas (L. & H.) Carr. have been found 



