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travel across, and how did tbey get up the hill ? Sometimes these 

 erratics are curiously marked with parallel scratches, sometimes 

 with two or three sets of them crossing each other. Similar mark- 

 ings can also be seen on the rocks in situ on each side of the valley 

 and in the bed of the valley. Frequently the faces of these rocks 

 are polished quite smooth, as if an enormous weight had been 

 slowly moving for them for long ages. You may see all these as 

 you wander about in the Alps or in the Scottish Highlands ; the 

 valleys radiating from Snowdon abound with deeply scored masses, 

 the marks as a rule all tending down the valleys. What are these 

 marks ? How were they made ? What were the graving tools ? 



As men travelled about more and studied more deeply what they 

 saw, another phenomenon was noticed, viz., the occurrence of 

 numerous lakes, where the marks and signs already noticed were 

 found — long narrow lakes lying in the valleys, bordered by the 

 scratched rocks, and at the lower ends of these lakes huge mounds 

 of debris, composed of materials found in the valleys themselves, 

 and containmg pebbles and blocks of all sizes, some smooth and 

 rounded, others with the hieroglyphic scratches. The presence of 

 these lakes and mounds must then be taken into account in any 

 explanation that may be given. We may instance such localities 

 as the Highlands of Scotland, the Lake District ofEnglanrl, and 

 especially the north of Europe and of North America. 



I have put before you the problem, — What have we to say in 

 explanation of it ? 



It is the general practice now among all students of nature, 

 geologists especially, to try to explain all phenomena by the action of 

 known causes. In the early part of the century it was not so, and 

 the phenomena I have so briefly described, so extensive in their 

 results and betokening apparently such huge and unfamiliar 

 agency, seemed above all others incapable of explanation in such 

 fashion — all spoke of irregularity and confusion. And so men fell 

 back on hypotheses, on invented, not discovered, explanations, as 

 man is so prone to do. There is no harm in the thing itself, so long 

 as you have sufficient ground to go upon, but to invent out of one's 

 inner consciousness a wild baseless explanation is not scientific, 

 though it may sometimes be easy — easier than searching for facts. 

 A friend of mine, who is always trymg to explain the unexplainable, 

 whenever he is non-plussed, says it must be electricity, of which 

 agent he has invented several varieties unknown to the scientific 

 world, just as in mediaeval times all mysteries were referred to the 

 agency of the great magieian, Michael Scott, 



A wizard of such dreaded fame, 

 That when, in Salamanca's cave, 

 Him listed his magic wand to wave, 



The bells would ring la NotreiDame? 



