148 BENNETTITES. 



in 1867, refers to the opinions of Yates and Williamson, and 

 adds : "I have examined numerous specimens of this fossil 

 ( Williamsonia gigas] in the British Museum, but have been 

 unable to determine anything satisfactorily in regard to the 

 precise structure of this anomalous fruit. It presents so many 

 peculiarities unknown in the fruit of any modern cycad, that 

 for the present at least, and notwithstanding its Zamia-like leaves, 

 I must consider it a doubtful cycad." 



In the volume of the Linnean Society's Transactions for 1870 

 we have the first exhaustive treatment of this Oolitic fossil. 1 

 From his intimate knowledge, both of the fossils and their 

 manner of occurrence in the rocks of the Yorkshire coast, 

 "Williamson was peculiarly fitted to attack this difficult problem. 

 Williamson describes and figures what he regards as the stem of 

 Zamites gigas, L. and H. ; the surface is made up of broad 

 lozenge-shaped areas, and is compared with the trunk of a recent 

 Ci/cas. One example is referred to as " obviously the apex 

 of a stem with portions of seven or eight diverging fronds." 

 The fronds are next described, also certain structures spoken 

 of as the " squamous peduncles" of the fructification. The 

 greater part of the paper is, however, devoted to a detailed 

 examination of the "organs of fructification." Surrounding the 

 ovoid inflorescence we have a number of linear bracts constituting 

 an involucrum ; usually these involucral leaves have been broken 

 off towards the base, and immediately below the broken ends 

 there is exposed an annular area of "radiating cells." In 

 pi. Hi. fig. 7, Williamson represents a specimen in which the 

 bracts have been completely preserved and are continued to the 

 base of the fructification. The central part of the whole structure 

 is occupied by a pyriform cavity which contracts apically, and 

 then expands into a funnel-shaped appendage. In one of the 

 figured specimens the form of this central cavity is clearly seen, 

 and from its being filled with carbonaceous matter, it is assumed 

 that the axis was originally a solid structure. A very similar 

 appearance is presented by one of llutrord's recently discovered 

 specimens. 2 The ring of radiating cells seen at the base of most 

 of the examples is considered to be the lowest margin of a layer 



1 Williamson (3). 



2 Fig. 8, p. 16. 



