204 SECTIONAL ADDRESSES. 



seed-bearing, Fern-like plants, the Pteridosperms, is one of the more 

 arresting features of the later Palaeozoic floras. During the latter part of 

 the Carboniferous period and the first half of the Permian period the vegeta- 

 tion of North America and Europe was more uniform in composition than 

 the floras of the old and new world to-day. Far-travelled members of this 

 northern vegetation were discovered a short time ago in Sumatra and the 

 Malay Peninsula : their geological age is either uppermost Carboniferous 

 or Lower Permian. Prof. Halle, of Stockholm, in his scholarly volume on 

 the late Palaeozoic floras of Central Shansi, in China, has shown that some 

 of the vegetation of the Far East agreed closely with that of North America 

 and Europe. The coal seams of China, though probably rather younger 

 in age than the richest seams of Europe and America, consist of the altered 

 debris of forests which had spread across the world. 



Before leaving the northern hemisphere attention must be called to the 

 records of a late Palaeozoic flora scattered over a broad region stretching 

 from Northern Russia to the Pacific Coast : this flora consists in part of 

 plants generically identical with European and American Permian types 

 associated with Glossopteris and other genera characteristic of India and 

 the southern hemisphere. For convenience we may speak of this vegeta- 

 tion as the Kusnezk Flora, from a Siberian locality where many of the plants 

 were found : its age is Permian, possibly Upper Permian. Though 

 occupying a territory separated only by a short distance from the Shansi 

 region, the Kusnezk flora has little in common with those to the South and 

 West : its most striking peculiarity is the presence of Gangamopteris and 

 some other types characteristic of the Glossopteris Flora, which presumably, 

 as immigrants from the Southern Continent, had found a passage across 

 the Tethys Sea. 



The Glossopteris Flora and the Late Paleozoic Ice Age. 



At the stage of geological history we are considering a broad expanse 

 of water — the Tethys sea— formed a west and east boundary between the 

 northern continent and Gondwanaland. Let us now pass across the Tethys 

 and take note of the conditions farther south. In that part of Gondwana- 

 land that is now South Africa no undoubted examples of Lower Carboni- 

 ferous plants have been found : the lowest beds of the Karroo system, 

 which rest on Devonian or Pre-Devonian rocks, consist of glacial deposits 

 similar to those which are spread over a wide area in South America, the 

 Falkland Islands, India, and Australia. There is proof of a long-continued 

 reign of ice-sheets and glaciers. The occurrence of well-preserved im- 

 pressions of plants at the base of the old boulder beds at Vereeniging shows 

 that some members of the Glossopteris Flora coexisted with the ice. The 

 problem which I now propose to discuss is this : at what period did the 

 Ice Age begin, and what is the geological age of the first phase of the 

 Glossopteris Flora ? As Prof. Suess said : following the events 

 chronicled in the Coal Measures of the northern hemisphere, in the south, 

 ' the outlines of a great continent become disclosed to us, and from the 

 closing days of the Carboniferous this remains for a long period one of the 

 most prominent features of the earth, Gondwanaland. ' The most important 

 of recent contributions to the vexed question of the date of the Gondwana- 

 land Ice Age and of the initial stages of the Glossopteris Flora is from 



