330 PROF, A. C. SEWARD AND ME. J. WALTON ON [vol. lxxix,. 



series of the Gondwana System. Excluding the possible repre- 

 sentatives of Neocalamites, the flora as a whole is indicative of a 

 position in the Lower Gondwana System, but not in the lowest 

 part thereof. This opinion is based partly upon the absence of 

 undoubted Gangamopteris leaves, and in part on the resemblance 

 of the Falkland plants to those recorded from India, South Africa, 

 and other parts of Gondwanaland. While recognizing that leaves 

 of Glossopteris, apparently indistinguishable from some of the 

 Falkland specimens, occur in the Rhsetic flora of Tongking, we 

 are inclined to regard the Falkland flora as homotaxial with the 

 Damuda and Beaufort floras of Gondwanaland and with the 

 Permian of Angaraland. 



We are influenced in our estimate of the age of the plants by 

 certain recently discovered facts, to some of which attention has 

 been drawn by Dr. A. L. Du Toit. This author considers, and (we 

 believe) rightly, that the recent tendency has been to assign the 

 Lower Gondwana strata of the Southern Hemisphere to a Carboni- 

 ferous rather than, as formerly, to a Permian horizon. If, as 

 seems likely, the tillites of South Africa, South America, India, 

 and Australia, are in the main of Upper Carboniferous age, the 

 recent discovery by Mr. T. N. Leslie 1 at Vereeniging, of Ganga- 

 mopteris leaves close to the old land-surface below the Dwyka 

 Conglomerate, brings the oldest members of the Glossopteris flora 

 within the Carboniferous Period. We have reproduced in fig. 23 

 (PI. XXII) a well-preserved impression of a small Gangamo- 

 pteris leaf which Mr. Leslie generously sent to one of us [A. C. S.]> 

 with other specimens discovered by him near the base of the 

 Dwyka tillite. It shows very clearly the typical Gangamo- 

 pteris venation : the groove near the middle of the lamina, as 

 the veins demonstrate, does not indicate the presence of a midrib, 

 but is purely accidental. 



Similarly, the identification by Mr. H. Woods 3 of a crustacean 

 from the Kimberley Shales as a species of Pygoceplialiis, a genus 

 characteristic of the Coal Measures of Britain and North America,, 

 points to the same conclusion. It may be possible, by a critical 

 review of the available data, to clarify our views on the age- 

 relation ships of the floras of the two botanical provinces : the- 

 southern province with its northward extension into Europe and 

 Siberia, and the northern province occupied by the Permo-Car- 

 boniferous plants of Western Europe and North America. The 

 analysis and correlation of- these floras are reserved for separate 

 treatment elsewhere. Dr. T. G. Halle draws attention to the 

 uniformity in general character of the Permo-Carboniferous flora 

 of the Falkland Islands, a feature borne out by the additional 

 material obtained by Dr. Baker. Halle's conclusion, that the 

 discovery at Dos Lomas of the leaf assigned \>j him to Ganga- 

 mopteris is evidence of a geological horizon lower than that of 

 the beds at other localities where similar leaves Avere not discovered,. 



1 Leslie (21). 2 Woods (22). 



