30 NATURE 


[JANUARY 6, 1923 
The Wegener Hypothesis. ' 
Discussion AT THE BriTisH ASSOCIATION, HULL. 
Cs Monday, September 11, the meeting room of 
the Geological Section of the British Associa- 
tion was the theatre of a lively but inconclusive 
discussion on the Wegener hypothesis of the origin 
of the continents. This hypothesis, which is a 
development of the well-established theory of isostasy, 
regards the continental masses as cakes of light 


Pic. 1.—The world in the Carboniferous and Eocene periods and Old Quaternary 
era according to the displacement theory. White denotes land, dots shallow 
From Discovery, May 1922, p. 116, by 
water, cross-hatching deep sea. 
the courtesy of the publishers. 
siliceous material floating on a heavier basaltic, 
fluid or viscid, substratum, which in its turn reaches 
the surface in a solidified form on the floors of the 
"oceans. The continents, which are thus movable, 
are supposed in Carboniferous times to have formed 
a single mass, and to have split up by rift-valley 
formation and started floating apart in late Cretaceous 
or early Tertiary times. The mountain ranges 
fringing the Pacific are supposed to have been pro- 
duced along those margins of the continents which 
are or have been, in virtue of their motion, impinging 
on the hard oceanic crust, the belts of thick sedi- 
NO, 2775, VOL, 117] 

— 
mentation along the continental shelves localising 
the folding. 
The union of the continental masses in former 
geological times explains many peculiarities in the 
distribution of life both past and present. It also 
affords an easy explanation of the hitherto unsolved 
problem of the Permo-Carboniferous glaciation, by 
supposing the pole to have been located in South 
Africa and the other glaciated parts of Gondwana- 
land to have been grouped around. When a 
reconstruction of this sort is made it is found that 
the main Carboniferous coalfields of the world lay, 
at the time of their formation, within the tropics. 
The discussion brought forth a great diversity 
of opinion regarding the validity of the hypo- 
thesis, almost the only point on which there seemed 
ness to admit that the birth of the North Atlantic 
could have occurred at so late a date as the 
Quaternary. Proceedings were opened by the 
reading of a discourse by Dr. J. W. Evans, who 
was unfortunately unable to be present. Dr. 
Evans gave an outline of some of the leading 
features of the theory and emphasised the well- 
known similarity of the geological formations on 
opposite sides of the oceans. He, however, 
questioned Dr. Wegener’s estimates of the thick- 
ness of the crust whether continental or oceanic, 
and considered that the latter, being probably as 
strong as the continental crust, would inhibit the 
continental drift. He dealt more particularly with 
the supposed recent variations of relative longi- 
tude and with the precautions which would have 
to be taken in the case of an attempt to repeat 
the observations. 
Prof. H. H. Turner stated that the only piece of 
astronomical evidence supporting Wegener’s hypo- 
thesis, and worthy of serious consideration, was the 
apparent westerly drift of Greenland. He was 
inclined to regard the longitude observations made 
up to the present as so much waste paper, but 
considered that the magnitude of the discrepancies 
between the Greenland observations of the years 
1870 and 1907, which indicated a westerly drift 
relatively to Europe of 1200 metres, made a good 
case for repeating the observations to-day. 
Mr. W. B. Wright pointed out that a critical 
comparison of the geological formations on the two 
sides of the North Atlantic shows on the whole 
a very remarkable correspondence, both strati- 
graphical and paleontological, from the Archean 
to the Cretaceous, and in particular brings to 
light certain facts even more strikingly indicative 
of a former vapprochement between the two con- 
tinents than any pointed out by Wegener. 
The recurrence in America on opposite sides of 
the old Appalachia of the two facies of the European 
Cambrian and early Ordovician, which are here 
separated by the Caledonian chain, is perhaps the 
most striking, the lithological and faunal characters 
and the sequence of transgression and recession, 
different on either side of the chain, being reproduced 
with remarkable precision. Again, the continental 
and marine facies of the Devonian are separated in 
both countries by boundaries which become conter- 
minous on the Wegener reconstruction. 
Prof. Coleman, of Toronto, considered that the 
similarity in the Archean formations on the two 
sides of the Atlantic, cited by Mr. Wright, meant 
very little, as the Archzean was a universal formation. 
He also raised the question of the meteorological 
to be any general agreement being an unwilling-— 
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