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ferns, gigantic club mosses, horse tails, and other plants which 
show a much warmer climate. Some people explain this by 
supposing that the earth’s axis has changed, some by the change 
in distribution of sea and land, others by the change in eccen- 
tricity of the earth’s orbit and the precession of the equinoxes. 
Others again say that the sun is a variable star, like many other 
stars in the heavens. I know of no explanation which is not 
surrounded with apparently insuperable difficulties. The activity 
of the volcanoes was on the increase. We find them in Cornwall 
and South Devon. In Derbyshire three beds of toadstone, form- 
ing an average thickness of 60 to 70 feet, tell the tale of fire and 
devastation at that time. But when we come to Scotland we 
might imagine ourselves in the Lipari Isles, or in Ischia, or on 
the slopes of Etna, where in one small island—the island of 
Ischia—is no less than 20 small craters, and in the Liparis over 
that number, whilst on the sides of Ktna are altogether 200 of 
these secondary cones. Take your stand on Arthur's seat, 
examine it, and you will find that it is the stem of a volcano 
or consolidated rock, which once bubbled and boiled at an intense 
white heat. Around you are other minor stumps. In Fife and 
Lothian are innumerable little rents whose lava flows thinned out 
from 100 feet to nothing in the distance of one mile. The great 
mountain has been washed away and only the centre rock left, 
but around this are the little side cones which have escaped the 
action of the water. In North Ayrshire the same kind of thing 
occurs and in Ireland. If we measure the distance, we shall find 
Naples to Lipari about 100 miles, Lipari to Etna 25 miles, 
almost in a line. In Scotland, we find the distances not very 
unlike, west to east about 50, and into Ireland 150, almost in a 
line, and to increase the similarity, the district was a shallow 
inland sea. To reproduce the scene we have but to read a 
description of the eruptions of modern Stromboli and its fellows, 
and imagine that the writer, instead of being on the mainland of 
Italy, was standing on the land formed by the Grampians during 
the coal period. In the Permean period considerable changes of 
surface took place, but the only points that I wish to mention 
are the rise of the Mendip Hills, and a ridge stretching across 
Yorkshire, east to west, probably including Ingleborough, Whern- 
‘side, and Penyghent, and probably Pendle Hill, during the first 
stage of their development. The next point was the rise of the 
Pennine range by a great anticlinal bend running north and 
south. During the whole secondary period the volcanoes were 
at rest, and few mountains were formed at any part of the 
earth’s surface. The Yorkshire Wolds were formed during this 
age. The Tertiary period requires a little notice before closing. 
During this most recent period of geology nearly all the cele- 
brated mountains of the earth have been raised—Alps, Himalaya, 
