Professor A. C. Seward — Floras of the Past. 511 



the great majority of the northern types. Until a few years ago the 

 genus Glossopteris had not been discovered in Europe, but in 1897 

 Professor Amalitzky recorded the occurrence of this genus in 

 association with Gangamopteris in Pernaian strata in northern Kaesia. 



We see, then, that in Brazil and South Africa the Glossopteris 

 flora and the northern flora overlapped, but the former was the 

 dominant partner. On the other hand, in rocks belonging to 

 a somewhat higher horizon in Russia, we meet with a northern 

 extension of the Glossopteris flora. 



There seems good reason for assuming that the Glossopteris flora 

 originated in the South, and before the close of the Permian period, 

 as well as in the succeeding Triassic era, pushed northward over 

 a portion of the area previously occupied by the northern flora. 

 This northward extension is shown by the existence of Glossopteris 

 in Upper Permian rocks of Russia, by the occurrence of several 

 southern types in plant-bearing beds of the Altai Mountains, and by 

 the existence in Western Europe during the early stages of the 

 Triassic era of such southern genera as Neuropteridium and 

 ScMzoneura. 



Triassic, Jurassic, and Wealden Floras. — It is unfortunate 

 that the records of plant-life towards the close of the Palaeozoic and 

 during the succeeding Triassic period are very fragmentary; the 

 documents are few in number, and instead of the fairly continuous 

 chapters in which the records of the Goal age have been preserved, 

 we have to be content with a few blurred pages. During the 

 Triassic period the vegetation of the world gradually changed its 

 character ; the balance of power was shifted from the Vascular 

 Cryptogams, the dominant group of the Palajozoic era, to the 

 Gymnosperms. 



One of the few floras of early Triassic age of which satisfactory 

 relics have been preserved is that described in 1844 by Schimper and 

 Mougeot from the Bunter Sandstones of the Vosges. The genus 

 Neuropteridium, a plant which may be a true fern, or possibly 

 a surviving member of the Cycadofilices, is represented by a species 

 which can hardly be distinguished fi'om that which flourished in 

 South America, South Africa, and India in the Permo-Carboniferous 

 period. This genus and another southern type, Sch'zoneura, both of 

 which are met with in the Triassic rocks of the Vosges, would seem 

 to point to a northern migration of certain members of the 

 Glossopteris flora, which took place at the close of the Palaeozoic era. 

 In the Lower Triassic flora Conifers are relatively more abundant 

 than in the earlier periods ; such genera as Alhertia (resembling in 

 its vegetative features some recent species of Arancaria), Voltzia 

 (with cones that cannot be closely matched with those of any 

 existing members of the Conifera)), and other representatives of this 

 class are common fossils. Lepidodendra have apparently ceased to 

 exist; Sigillaria may be said to survive in one somewhat doubtful 

 form, Sigillaria oculina. The genus Pleuromeia, which makes its 

 appearance in Triassic rocks, is perhaps more akin to Isoetes than to 

 any other existing plant. The Calamites are now replaced by large 



