28 
A. GIBB MAITLAND, F G.S. : 
If the position of the earth’s axis of rotation were 
shifted to about the middle of the Indian Ocean, or of a 
Gondwanaland occupying its present position, the north 
pole would be somewhere in New Mexico, near the boundary 
of Texas. It may be mentioned in favour of the hypothesis 
of migration of the poles in Permo-Carboniferous times to 
the positions indicated, that the movement of the Talchir 
or Indian ice sheet and that of the Dwyka in South Africa 
are away from the equator (Fig. 15, Plate XI). 
At the same time, if evidence of a Permo-Carboni- 
ferous : — 
" warm climate were to be found anywhere in a zone that 
would bo equatorial to an Indian Ocean polar area, or if another 
Permo-Carboniferous glacial area were to be found in the regions 
antipodal to the Indian Ocean, this shifting of the poles would have 
to be very seriously taken into account.” 
It may in this connection be interesting to recall the fact 
that a conglomerate ol Permo-Carboniferous Age, the 
characteristics of which are of such a nature as to suggest 
its origin being due to ice action, has recently been described 
as occurring in Colorado. The remarkable focussing of 
glacial deposits about the Indian Ocean in Permo-Carboni- 
ferous times may in a certain sense be paralleled with that 
about the North Atlantic Ocean in Pleistocene times. 
On the other hand astronomers seem all to agree that 
a migration of the pole as would bring it into such a position 
in the Indian Ocean as has been indicated (involving, as 
such would do, a change of about 66°) is an impossibility, 
at any rate since the birth of the moon, which took place 
in those “ Dark Ages ” of the earth’s history long prior to 
Permo-Carboniferous times. The objection, however, to 
the hypothesis of the migration of the poles is not based 
upon the results of direct observation, but rather upon 
mathematical reasoning. 
It would make too large a draft upon your time to 
attempt even a cursory examination as to whether this 
Permo-Carboniferous glaciation was brought about by local 
elevation of the land masses through thousands of feet ; by 
the high phase of the eccentricity of the earth’s orbit in 
combination with winter in aphelion ; by variations in the 
amount of aqueous vapour ; by the ionization of the at- 
mosphere ; by variations in the amount of carbon dioxide 
in the atmosphere ; by the ocean currents resulting from 
the contemporaneous relations of land and sea ; or by avaria- 
tion in the amount of the sun’s heat ; as these are somewhat 
outside the scope of this address. 
The exact cause of this Palaeozoic glaciation of Western 
Australia would seem to me to remain as yet an unsolved 
problem, though it may be that as the question of past 
