90 Reports & Proceedings — Geological Society of London. 



Foliage. 

 Zamites spp. 

 Zamites gigas. 



Otozamites sp. 

 Ptilophyllum pectinoides. 

 Anomozamites minor. 



Trunk. 

 Bennettites spp. 

 Attached, no separate 

 name. 



Fructifications. 

 Bennettites spp. 

 Williamsonia gigas. 



— Williamsonia spectabilis. 



— Williamsonia whitbiensis. 

 (Only slender branches Wielandiella angustifolia. 



known, no name.) 

 Tceniopteris vittata. — Williamsoniella coronata. 



Dr. Stopes exhibited slides of uiicrophotographs of the stem and 

 leaf-base anatomy of the group, including some unpublished details 

 of Bennettites maximus. The roots of the group have hitherto been 

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

 rootlets penetrating tbe 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. saxlyanus : 

 they are covered with wonderfully petrified root-hairs, ■ running 

 uncollapsed through the silica matrix. They raise interesting 

 questions concerning the possible chemical conditions of the infiltra- 

 tion 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 of the seed-cone of an interesting unpublished new species from the 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 know- 

 ledge of the finer anatomy of the seeds and associated structures. It 

 is also the largest cone of the Bennettitales yet known, though it 

 occurs 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 Bennettitales (including tbe cohorts 

 Bennettitese and Williamsonese) : — 

 Upper Cretaceous. 



Middle Cretaceous 



Gault. 

 Lower Cretaceous : 



Lower Greensand. 



Potton Sands. 

 Wealden . 



Jurassic : Purbeck. 



Oolites. 



Lias. 



Bhretic. 



Very fragmentary and uncertain records ; apparently 



the group is nearly or quite extinct. 

 The new large-sized seed-cone. 



B.morierei ? (? described originally from the Jurassic). 

 Well-petrified trunks with fructifications. 

 B. gibsonianus (type-species of the Bennettitese). 

 B. maximus. \ Throughout tbese 



Trunks, e.g. Colymbetes edwardsi. periods in 

 Trunks (casts and petrifactions), America, trunk- 

 foliage, remains very 



B. saxbyanus. abundant, often 

 Trunks (casts and semi-petrifac- petrified and with 



tions). [fructifications, 



Buckland's original Cycadeoidea [particularly from 



spp. the Black Hills, 



C. gigantea. South Dakota, 

 Trunks, pith-casts, etc. Much and Maryland. 



foliage of various types. Wil- C. jenneyana, 



liamsonia gigas and other fruit- C. ingens, C. 



impressions. J wielandi, etc. 



W. scotica. 



Williamsoniella coronata. \ Bich impressions in Mexico 

 Foliage and Williamsonia J-of Williamsonia and many 



fruits (India). J foliage genera. 



Wielandiella angustifolia and foliage. 



