294 



Otiological Society. 



The following table gives the jjroved, or probable, assoeiated 

 parts of some members of the group : — 



Foliage. 



Trunk. 



Fructifications. 

 Bennettites spp. 

 Williamsonia gigas. 



Williamsonia spectabilis. 

 Williamsonia tvhitbiensis. 

 Wielandiella angnstifolia. 



Zainites spp. Bennettites spp. 



Zamites gigas. Attached, no separate 



name. 



Otozamites sp. 



Ptilopliyllum pectinoides, 



Anomosamites minor, (Only slender branches 



known, no name.) 

 Tseniopteris vittata. Williamsoniella coronata. 



Dr. Stopes exhibited slides of microphotographs of the stem 

 and leaf -base anatomy of the group, including some unpublished de- 

 tails of BeiDiettltes maximus. The roots of the group have hitherto 

 been entirely unknown, and a slide was exhibited for the first time 

 showing rootlets penetrating the leaf -bases of a petrified specimen 

 (represented by a section in the Geological Department of the 

 British Museum — Natural History). These roots probably belong 

 to B. saxhyamts : they are covered with wonderfully petrified 

 root-hairs, running uncollapsed through the silica matrix. They 

 raise interesting questions concerning the possible chemical con- 

 ditions of the infiltration of the silica. Illustrations were also 

 exhibited of the famous complex ' flower ' and cone-structures, and 

 of Wieland's brilliant restorations of the same. Microphotographic 

 slides were exhibited of the seed-cone of an interesting unpublished 

 new species from the British Gault. This is beautifully petrified, 

 and adds to our knowledge of the finer anatomy of the seeds and 

 associated structures. It is also the largest cone of the Bennettitales 

 yet known, though it occm-s in the Gault, by which time the group 

 appears to have begun rapidly to die out. 



The following table indicates the distribution of a few of 

 the most interesting representatives of the Bennetti- 

 tales (including the cohorts Bennettitese and William- 

 son ese) : — 



Upper Cretaceous. Very fragmentary and uncertain records ; apparently 

 the group is nearly or quite extinct. 



Middle Cretaceous ; The new large- sized seed-cone. 



Gault. B.monerei 5 (? described originally from the Jurassic). 



Lower Cretaceous ; Well-petrified trunks with fructifications. 



Lower Greensand. B. gibsonianns (type-species of the Bennettitese). 



Throughout 

 these periods 



Potton Sands. 

 Wealden. 



Jurassic; Purbeck. 



B. maxiimis. \ 



Trunks, e.g. Colymbetes edivardsi. 



Trunks (casts and petrifactions), 



foliage. 

 B. saxbyanus. 



Trunks (casts and semi-petrifac- 

 tions). 



Buckland's original Cycadeoidea 

 spp. 



C. gigantea. 



in America, 

 trunk-remains 

 very abun- 

 dant, often 

 petrified and 

 with fructifica- 

 tions, parti- 

 cularly from the 



Black Hills, 

 South Dakota. 



