THE PRESIDENTIAL ADDRESS 13 
vincing than that displayed at Nooitgedacht, near Kimberley ; while 
the illustrations and other evidence published by David and Howchin 
from Australia are equally striking. 
Du Toit’s work on these glacial deposits brings out two remarkable 
facts ; first, that the movement of the ice was southerly, pole-ward 
and away from the equator, the opposite to what would be expected, 
and to the direction of the Pleistocene ice-movement ; secondly, 
that the ice in Natal invaded the land from what is now sea to the 
north-east. 
When it is realised that at this period there is no evidence of glacial 
action in northern Europe or America, but a climate in which grew 
the vegetation that formed the coal seams of our Coal Measures, 
it is clear that we are not dealing with any general refrigeration of 
the globe, even if that would produce such widespread glaciation : 
we are face to face with a special glaciation of Gondwanaland. 
On both sides of the Atlantic these glacial episodes in Carboniferous 
times were followed by dry and desert climates in Triassic time, 
and these by violent volcanic outbursts. Nor are the rocks alike 
only in mode of formation, the structures by which they are traversed 
correspond ; while even in details there is remarkable agreement, as 
in the peculiar manganese deposits, and the occurrence of diamonds 
in ‘ pipes ’ of igneous rock, both east and west of the Ocean. 
Rather than face the difficulties presented by the subsidence of 
lands connecting the severed portions of Gondwanaland, as pictured 
by Suess, Wegener has preferred, and in this he is supported by 
Du Toit and many other geologists, to bring into contact these 
severed parts, which could be fitted together as nearly as might be 
expected, considering the dates of severance. Du Toit’s map of the 
period places South America to the west and south of South Africa, 
Madagascar and India to the east, Antarctica to the south, and 
Australia farther to the south-east. Such a grouping would form 
a continent much less wide in extent than that envisaged by Suess, 
and would offer some explanation of the more remarkable features 
of the glaciation in the several areas, as well as the problems of the 
rocks, fossils, and structures involved. 
In its application to the geology of Gondwanaland the modified 
hypothesis of Wegener cuts a Gordian knot; but it still leaves a 
great climatal difficulty, unless we take his further step and conceive 
that at this date the terrestrial south pole was situated within 
Gondwanaland. No shift in the axis on which the earth rotates 
would, of course, be possible, nor is it postulated: only a drifting 
at that date of continental land across the pole. 
If a hypothesis of drift be admitted for Gondwanaland, it would 
be illogical to deny its application to other regions, including the 
north Atlantic. I have already mentioned some facts in its favour. 
