I want you to bear in mind the trend of the ground, for some time, sooner or later, we shall do well to have it in our mind's eye when we are considering the ancient traditions and superstitions, and are trying to find the _rationale_ of them.

Each legend, each superstition which we receive, will help in the understanding and possible elucidation of the others.

And as all such have a local basis, we can come closer to the truth--or the probability--by knowing the local conditions as we go along.

It will help us to bring to our aid such geological truth as we may have between us.

For instance, the building materials used in various ages can afford their own lessons to understanding eyes.