390 Professor A. C. Seward — 



vegetative shoots resembling some of those collected by Dr. Teale. 

 Potonie instituted a new generic name Voltziopsis for the fragments 

 submitted to him, but in a recent edition of his textbook, edited 

 by Dr. Grothan,^ he wisely abandoned a designation which was 

 unnecessary and simply described the fossils as agreeing generally 

 with Jurassic species named by Heer Leptostrohus. There is, however, 

 no proof that the African specimens conform to the characters of 

 Heer's genus. Scales similar to the Tanganyika impressions have 

 been described by Nathorst from Rhsetic strata in Scania as 

 Swedenhorgia cryptomerides.^ It is with scales usually included in 

 Voltzia that the specimens agree most closely, at least in form, 

 though they are smaller than most of the European examples from 

 Bunter and Zechstein beds. 



Conclusion. 



The fossil plants described by the late Dr. Potonie from the 

 Tanganyika territory in 1900 ^ consist of small pieces of vegetative 

 shoots and lobed scales generically identical with Dr. Teale's 

 specimens referred to UUmannia and Voltzia. The more recently 

 acquired material includes coniferous branches which exhibit a 

 greater range in habit than those figured by Potonie, and the scales 

 are rather smaller than those he recorded ; the differences are un- 

 important. The single leaf (specimen 175) and the specimens 

 which I am inclined to regard as inorganic are unrepresented in the 

 German collection. The evidence furnished by the Ullmannia-like 

 fragments and the Voltzia scales would seem to favour comparison 

 of the plant beds with Permian and Triassic strata in Europe. It 

 is probable that both shoots and scales belong to the same genus ; 

 but though it may seem illogical to employ distinct generic names 

 for fossils which may be parts of the same plant, I adopt the 

 designations UUmannia and Voltzia on the ground that they best 

 describe the features of the two kinds of specimens. 



Coniferous branches agreeing closely in habit with some of those 

 from the Tanga Hinterland occur also in Rhaetic and Jurassic 

 rocks, but the association of the Voltzia-like scales is a point in favour 

 of a somewhat lower horizon . The leaf compared with Eretmophyllum, 

 though too imperfect to be identified with precision, accords more 

 with a Rhaetic or Jurassic age. 



It is noteworthy that the Tanga collection does not include any 

 examples of the genus Glossopteris, and while it is often unsafe to 

 attach much importance to negative evidence, especially when the 

 data are few, the presumption is that the flora is distinct in facies 

 from Upper Palaeozoic and Lower Mesozoic floras obtained from other 

 parts of Africa. The Tanga flora is rather European than African 

 in type. Glossopteris is recorded from several regions in the 



^ H. Potonie, Lehrbuch der Palaeobotanik, 2nd. ed., 1921, p. 322. 

 ^ A. C. Seward, Fossil Plants, vol. iv, 1919, pp. 296 et sej. 

 ' H. Potonie, loc. cit. 



