CHAPTER XXIII.
EXPLANATION OF THE GEOLOGICAL MAP.
Since this volume contains a Geological Map, it may be expected that I should offer some explanatory observations upon it.
Every good Geological Map ought to explain itself. It ought, in fact, to tell its own story regarding the features of the country it represents, and the rocks and formations of which the region is constructed; and if every person was acquainted with the principles of geology, and had been properly instructed in the plan according to which Geological Maps are prepared, no explanation would be required. With a Geological Map of any district before him, and one also showing the features of hill and dale, mountain and valley, an observer would receive a correct idea of the physical structure of the whole region. He would be able for himself to determine what were the older, or newer, formations: in what way they were disposed one to the other; and, also, be able to form some idea regarding the distribution of land and sea at past periods. Such a map would speak to his mind regarding past physical events as distinctly as a piece of written music, when placed before a musician, conveys to his mind what would be the character of the composition if reproduced on an instrument.
Unfortunately the sublime science of geology has only as yet a limited number of cultivators. Its truths have as yet only been revealed to the favoured few; but the day will doubtless come when the study of geology will be considered as essential to a good education as is the study of geography or history. It is now admitted that geology is the basis of geography; and it cannot be questioned that the physical history of any country has had an important bearing on the history and character of its inhabitants; so that, in order properly to understand the latter, we ought not to neglect the investigation of the former.
