I - THE EVIDENCE DERIVED FROM GEOLOGY

Summary

Sources of information

Fossil remains

In any question as to the origin of the world pursued on scientific grounds, the sources to which we can look for any positive or substantial information, must, in an especial degree, be those opened to us by geology and palæontology; and of some of the most material facts and admitted theoretical opinions in these departments, bearing on the question, it will be necessary to take a cursory review.

Theories of progression and non-progression

When we trace backward, by the light of fossil remains, the succession of varied forms of organised existence which have tenanted the surface of our globe during the incalculably vast periods of past time, the fact of their presenting apparently very different characters in different epochs naturally led geologists and naturalists to speculate on the question, whether those variations could be reduced to anything like a determinate order or law of succession; and probably the most prevalent opinion has been that, at least in a general sense, there has been a succession in the order of progress or advance from lower and more simple, towards higher and more complex forms of structure and function.

More recently, however, this has been much disputed. Not only have particular instances, supposed to invalidate this law, been brought forward as demanding certain modifications in the statement of it, but the entire principle has been contested and positively denied.