350 TRANSACTIONS OF SECTION ©. 
Sir John Evans suggested that this movement of the crust was inevitable as 
a consequence of the moulding of the orographical features and consequent 
redistribution of weights; but Twisden came to the conclusion that the re- 
arrangement of the great inequalities on the Earth’s surface would be insufficient 
to produce any appreciable sliding of the order required to make material 
differences in the climate of any place. 
Oldham,'’ who was writing at the time in the field in India and thus away 
from literature, put forward the idea in 1886 as an independent thought, and 
made use of Fisher’s new theory regarding the existence of a fluid stratum be- 
tween the solid crust and the supposed solid core to account for the shifting 
of places relative to the axis of rotation from the equatorial region even to the 
polar circles. Oldham drew attention to the recorded small changes of latitude 
at certain observatories and to the probable changes of azimuth in the Pyramids 
of Egypt—evidences of a kind which have since been greatly enlarged by the 
work of Sir Norman Lockyer and others. 
The movements assumed to have taken place during the human period are 
of course small; and to project from them changes as great as the transfer of 
lands from the polar circle to the tropics has the objection that characterises a 
surveyor’s use of ‘unfavourable’ triangles in a trigonometrical survey. Before 
admitting, therefore, that these small changes of latitude and of azimuth may be 
classed with the paleo-glacialists’ evidence as data of the same kind, though 
so utterly different in magnitude, it is desirable briefly to examine the geological 
evidence regarding past ice-ages in extra-polar areas. 
From the records of ancient glaciations we might omit those of the pre- 
Cambrian rocks of North Ontario and the pre-Upper Cambrian of Norway, as 
these areas are nearer the poles than many places which were certainly covered 
with ice-sheets during the youngest, or often so-called Great, Ice Age. But 
besides these we have evidence of glaciation in the Cambrian or possibly pre- 
Cambrian rocks of South Australia at a latitude of 35° or less; in South Africa 
there were two or more distinct glacial periods before Lower Devonian times in 
slightly lower latitudes; while in*China similar records are found among rocks 
of the Lower Cambrian, or possibly of older age, at a latitude of 31° N. 
The glacial boulder-beds found at the base of our great coal-bearing system 
in India belong to the same stratigraphical horizon as the glacial beds found in 
South Africa, certain parts of Australia, and in parts of Brazil and Sao Paulo 
near or within the southern tropic. 
These glacial beds are often referred to in geological literature as Permo- 
Carboniferous in age; but Professor Koken regarded the formation in India as 
Permian. Other valuations of paleontological evidence, similar to that relied 
on by Professor Koken, place these beds at a distinctly lower horizon in the 
European stratigraphical scale, and recent work by officers of the Geological 
Survey of India in Kashmir tends to confirm this latter view; we now regard the 
base of our great coal-bearing system in India—the horizon of the glacial-boulder- 
beds—as not much, if at all, younger than the Upper Coal Measures of Britain.” 
The precise age of the horizon is not very important for our present considera- 
tion: the important point is that in or near Upper Carboniferous times a wide- 
spread glaciation occurred throughout the area now occupied by India, Australia, 
and South Africa. The records of this great glaciation are thus found stretch- 
ing northwards beyond the northern as well as southwards beyond the southern 
tropic. 
oe on the assumption that the cold climate in this region was due to a 
movement of the crust over the nucleus, Professor Koken has produced an 
elaborate map of the World, showing the distribution of land and sea during 
the period, with the directions of ocean-currents and of ice-sheets. The 
Permian South Pole he places at the point of intersection of the present 
20th parallel S. and 80th meridian E.—that is, at a point in the Indian Ocean 
about equidistant from the glaciated regions of India, Australia, and South 
Africa. The Permian North Pole is thus forced to take up its position in the 
centre of Mexico, while the Equator strikes through Russia, Italy, West 
Africa, down through the South Atlantic and round by Fiji to Vladivostock. 
17 Geol. Mag., 1886, 304. 
18 H. H. Hayden, Rec. Geol. Surv. Ind., vol. xxxvi. p. 23, 1907. 
