THE RECORD OF THE ROCKS
as they have been traced their succession is the same. When we come to a gap (say the English Channel) and when we find that the succession of fossils on the other side is the same, must we not suppose that the succession of the rocks (say in France) is the same as in England?
In this way, step by step, it has been possible to pass from one country to another, until the stratified rocks of the whole world have been correlated or linked up just as the succession of Emperors in China can be correlated with the Kings of England. There are difficulties, no doubt, owing to large gaps like the Pacific Ocean, or to the readily intelligible fact that some animals live in the sea and others on land or in fresh water; also to the fact that there are differences between the inhabitants of arctic and tropical climates. But, so long as attention is limited to fossils of similar nature, these difficulties rarely obtrude. One finds, for example, in the State of New York and in Quebec a clear succession of fossils precisely comparable to the succession in Great Britain.
It is perfectly true that there are places where a rock (A) overlying another (B) contains fossils that elsewhere are found to lie below B. But we shall generally find that such places show signs of disturbance of the rocks. If we admit (as everyone does) that the fossils found in the Alps, the Rockies, and the Himalayas are the remains of sea-animals, then we recognize that these mountain chains must have been raised from the sea-floor by forces so enormous that they could not help crushing, crumpling, and overturning the rocks. There are plenty of obvious evidences that this has happened, and it may well have happened in places where the signs are not so obvious. Tremendous though these movements seem by our pygmy human standards of comparison, it is well to remember that the greatest ups and
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