346 E. A. Neicell Arber — The Glossopteris Flora. 



examples which are referred to this species. I is the type- specimen 

 from [the Middle Lias] Les Moutiers, Normandy [B.M. no. 37,010] ; 



II, the specimen from the [Middle] Lias, Curcy [B.M. no. 37,005] ; 



III, the example from the Marlstone, Alderton Hill ? [Cheltenham 

 College Museum, no. 900] ; IV, the specimen from the Marlstone, 

 Gretton [Cheltenham College Museum, no. 901]. (For comparison 

 with the other examples the measurements of the French specimens 

 are given both at their greatest diameter and also at a diameter of 

 160 mm. and of 128 mm. respectively.) 



I . II. III. IV. 



Ratio to Eatio to Eatio to Eatio to Eatio to Eatio to 

 mm. diam. mm. diam. mm. diam. mm. diam. mm. diam. mm. diam. 

 Diameter ...204 + (100) 160 (100) 166 + (100) 128 (100) 220 + (100) 165 + (100) 

 Thickness ...136+ (66-6) ll7 + (73-l) 116 + (69-8) 87 + (68) 153 + (69-5) 119 + (72-l) 



^imbi]icus}33 (16-1) 26 (16-2) 25 (15) 20 (15-6) 33-(15) 26-(15-7) 



I think it highly probable that to this species belongs also 

 a specimen in the National Collection [No. C. 4,487] from the 

 Middle Lias of South Petherton, Somerset. It is entirely septate, 

 and has the following dimensions : diameter of shell (wanting test 

 near aperture), 130 mm.; thickness of outer whorl (wanting test 

 on one side), 78 mm. ; width of umbilicus (test present on each • 

 side), 21 mm. 



Ill- — On the Distribution of the Glossoptesis Flora. 



By E. A. Kewell Aeber, M.A., F.G.S., Trinity College, Cambridge; University 

 Demonstrator in Paleobotany. 



AMONG extra -European fossil floras, none is perhaps better 

 known than that of the Permo-Carboniferous rocks of the 

 Southern Hemisphere. These rocks are extensively developed in 

 Southern India, Australia, South Africa, and South America,^ and 

 there can be little doubt that these regions once formed part of 

 a great continent, to which the name Gondwana-land has been 

 appropriately applied. 



The flora of Gondwana-land diifers in a remarkable degree from 

 the contemporaneous flora of Europe and North America. The 

 characteristic and predominant plant types in Europe in the Permo- 

 Carboniferous period were Calamites among Equisetales, Lepidodendron 

 and Sigillaria among Lycopodiales, with numerous representatives of 

 the Filicales, and of three groups, now long extinct, the synthetic 

 types Cycadofilices and Cordaitales,- and the isolated phylum 

 Sphenophyllales. These compose what we may term the northern 

 type of Permo-Carboniferous flora. 



The Glossopteris, or southern Permo-Carboniferous flora, consists 

 essentially of four types, Phyllotheca and Scliizoneura among 

 Equisetales, the fern-like plant Glossopteris, including Gangamopteris,^ 



^ Seward: Science Progress, 1897, vol. ni, p. 198. 



2 Scott: Trans. E. Soc. Edinb., 1902, vol. xi, pt. 2, p. 331. 



2 Etheiidge : Proc. Linn. Soc. N.S. Wales, 1894, ser. ii, vol. ix, p. 228. 



