It was one of the settled principles of the physico-theological school, that, since the creation, the earth has undergone no important change beneath the surface, except at the deluge, because it was supposed that the Bible mentions no other event that could produce any important change. Hence all marks of changes in the rocks since their original creation must be referred to the deluge. And especially when it was found that most of the petrifactions in the rocks were of marine origin, not only were they supposed to be the result of the deluge, but a most conclusive proof of that event. And this opinion is even yet very widely received by the Christian world. The argument in its favor, when stated in a popular manner to those not familiar with geology, is indeed quite imposing. For if the land, almost every where, even to the tops of some of its highest mountains, abounds in sea shells, this is just what we should expect, if the sea flowed over those mountains at the deluge. But the moment we come to examine the details respecting marine petrifactions, we see that nothing can be more absurd than to suppose them the result of a transient deluge. Yet this view is maintained in nearly all the popular commentaries of the present day upon Genesis, and in many respectable periodicals. It is taught, therefore, in the Sabbath school and in the family; and the child, as he grows up, is shocked to find the geologist assailing it; and when he finds it false, he is in danger of becoming jealous of the other evidences of Christianity which he has been taught.