FORM OF THE CONTINENTS— WATTS 197 



On both sides of the Atlantic these glacial episodes in Carbonifer- 

 ous 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. 



Kather 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 

 De 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 southeast. 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 Avould 

 be illogical to deny its application to other regions, including the 

 North Atlantic. I have already mentioned some facts in its favor. 

 Others are the resemblances of all sedimentary rocks on the two 

 sides from the Cambrian to the Ordovician, and from the Devonian 

 to the Trias; the links between the structures of the land, as, for 

 instance, between Ireland and Newfoundland; and the instance 

 given by Professor Bailey in his address to Section C in 1928. As 

 Bailey then pointed out, the great Caledonian range which crosses 

 Scotland, northern England, and Wales from northeast to south- 

 west on its course from Scandinavia is affected and displaced by the 

 east to west Armorican (Hercynian) chain extending across from 

 Brittany to South Wales. "The crossing of the chains, begun in 

 the British Isles, is completed in New England" ; and from here the 

 Armorican structure continues its westerly course. This is wliere it 

 should cross if the continent of North America were brought back 



