Reports & Proceedings — Geological Society of London. 89 



information of the output of minerals in the country and of the 

 imports from outside. As usual this report is divided into two main 

 parts, of which the first deals with metallic and the second with 

 non-metallic, substances, the latter including fuels, structural 

 materials (other than metals), chemical minerals, and precious 

 stones. Each chapter is entrusted to a different writer, and each 

 is issued separately as soon as it is ready. The date of publication 

 of the several chapters is given on the wrappers, but disappears in 

 the bound-up volume ; the pagination is continuous, but separate 

 throughout each part of the report, including the summary. The 

 series is so well known that detailed criticism is uncalled for; it is 

 sufficient to say that the present report is well up to the high 

 standard of its predecessors. 



EEPOETS ^.ISTID IFIROOIEIEIDIISJ-GrS- 



I. — Geological Society of London. 



1. December 20, 1916.— Dr. Alfred Harker, F.K.S., President, 

 in the Chair. 



Marie C. Stopes, D.Sc, Ph.D., gave an account of some recent 

 researches on Mesozoic 'Cycads' (liennettitales), dealing particularly 

 with recently discovered petrified remains which reveal their cellular 

 tissues in microscopic preparations. To make the significance of the 

 various fossil forms clear, Dr. Stopes first showed some lantern-slides 

 of living Cycads, and then pointed out that it was in their external 

 features and in their vegetative anatomy only that the fossil 'Cycads' 

 ■were like the living forms ; the most important features, the repro- 

 ductive organs, differ profoundly in the two groups, and the fossils 

 were fundamentally distinct, not only from the living Cycads, but 

 from all other living or fossil families. 



The fossils representing the group that are most frequently found 

 are (a) trunks, generally more or less imperfect casts or partial 

 petrifactions, and sometimes excellent petrifactions preserving 

 anatomical details and cell-tissues; (b) impressions of the foliage. 

 Not infrequent are the detached impressions of incomplete ' flowers ' 

 or cones, of one cohort (the Williamsonese), while petrified fructi- 

 fications are numerous in some of the well-petrified trunks of the 

 Bennettitese. The described species of the group run into hundreds, 

 but probably many of these duplicate real species, because the foliage, 

 trunks, pith-casts, various portions of the fructifications, etc., have 

 often been separately found and named. In very few cases have the 

 different parts been correlated. The species of the foliage are the 

 most generally known, as they are the most readily recognized with 

 the naked eye ; they have been described under a variety of generic 

 names, 



The following table gives the proved, or probable, associated parts 

 of some members of the group : — 



