40 



species ; nor have I been able to discover any trace of those 

 radiating plates, which both in the recent Cycadeee and in the 

 Portland specimens are perfectly manifest to the naked eye. 



But a still greater difficulty presents itself, to which I beg to 

 direct the attention of any geologists or botanists, who may have 

 the opportunity of aiding in the study of this fossil. My re- 

 construction of the plant is founded upon the examination of 

 about 300 specimens, some of them found by me at Runswick, 

 others preserved in various Museums, both public and private. 

 I think there can be no doubt, that the appearance, both of the 

 lower plant, consisting of the stem with the leaves proceeding 

 from it, and of the upper part, consisting of a branched fruit- 

 stalk with its inflorescence, was such as I now exhibit in the 

 drawing. But the evidence, though very considerable and 

 sufficient to produce conviction in ordinary cases, is not so com- 

 plete as might be desired in reference to the question whether 

 the upper and the lower part belonged to the same plant. The 

 heads or flowers of the upper part do not at all resemble the 

 flowers of Cycadea?, either in their external form or in their 

 internal structure. M. Brongniart long ago pronounced the 

 opinion, that notwithstanding the exact resemblance of the 

 fossil leaves to those of the recent Zamia, the fructification may 

 have been difierent. * Nevertheless, judging, as we must do in 

 the absence of other evidence, from the analogy of the living 

 plant, these fossil leaves would have induced us to expect a 

 flower in the form of a cone or a catkin. But we perceive 

 nothing of the kind. The head of the Zamia Gigas, found at 

 Runs wick, consists of a considerable number of scales, resembling 

 sepals, petals, or perhaps dilated stamens, all growing from the 

 top of the fruit-stalk, and overlapping one another. They sur- 

 round an oval or pyriform cavity, which is dilated at the top, and 

 which appears to have contained the germen. This, so far as I 



• Comparing the leaves of Z. Mantellii to those of the recent Zamia, he says 

 (^Prodrome dune Histoire, dtc.) "Cette identite est telle que nous ne pouvons pas 

 nous empecher de placer ces plantes dans le genre Zamia, tout en etablissant qu'il 

 etoit possible, que ces plantes, tout-a-fait semblables par leurs feuilles, fussent 

 differentes par leur fructification." 



