7$ ]}arwin- Wallace Celebration. 



In the MEETING ROOM, on the ground floor, two short Lantern 

 Demonstrations were given during the evening. 



At 9.30. Prof. A. C. SEWARD, F.R.S., F.L.S. 



"THE JURASSIC VEGETATION OF THE WORLD: 

 A STUDY IN PLANT-MIGRATION." 



THE Lecturer dealt with the geographical distribution of Jurassic 

 plants, calling special attention to the general uniformity in the 

 floras which occur in almost all parts of the world. 



He emphasised the importance of bearing in mind the opinions 

 expressed by Darwin and by Hooker in regard to the Imperfection 

 of the Geological Record and quoted Huxley's words on the impossi- 

 bility of demonstrating absolute synchronism of strata. 



A brief account was given of the Jurassic vegetation as represented 

 by specimens obtained from the Inferior Oolite rocks of the Yorkshire 

 coast, attention being called to the apparent absence of Flowering 

 plants. The wide distribution of floras classed as Jurassic was 

 illustrated by maps and by drawings of specimens collected in widely 

 separated regions. Araucarites, some genera of Cycads, the Maiden- 

 hair tree, Matonidium, Clad&phlebis, and other Jurassic types were 

 described. Special attention was called to the important discovery 

 made a few years ago by Prof. Andersson, of the Swedish Antarctic 

 expedition, of Jurassic plants in Louis Philippe Land (lat. 63 15' S.) : 

 through the kindness of Prof. Kathorst and Prof. Andersson the 

 Lecturer was able to show some illustrations, not yet published, of 

 these Antarctic plants which are now being described by Prof. 

 Nathorst. 



In conclusion reference was made to the question of means of 

 dispersal possessed by members of the Jurassic Floras. 



