AT many points in the foregoing discussions concerning the relation of man to the continent of North America it has been necessary to refer to the work which, during the olden days, the natural forces have done upon this land. It is a peculiar feature of our modern science that it becomes ever more and more necessary in the advance of learning to explain the living moment by the dead past. This method of consideration, which is peculiarly characteristic of our own time, has not only an intellectual but an economic importance. From the point of view of learning men may profit greatly from the study of the past, for such inquiry vastly extends their understanding of their place in the world, and by enlarging the perspectives of thought gives a dignity and beauty to the history of man and the fields he inhabits which can be attained in no other way. On the other hand, through a comprehension of the events which have taken place in the development of any land, the men who dwell in it are able, in a systematic way, to avail themselves of the economic resources which are stored in the depths of its earth, or which are contained in the soil.
The fitness of the earth to produce crops depends upon the character of the rocks which have afforded the mineral matter of the soil, or upon the nature of the forces which have acted to bring these materials into the position where they may be taken into the bodies of plants. The coal which is won from the depths of the earth owes its development and preservation to events which took place in remote ages. The plants which formed it were fostered by the ancient sunshine; the swamps in which the peaty matter was preserved were due to the conditions of the geography and the climate of those vanished days. The burial and preservation of the peat were brought about through the deposition of strata upon the old morasses. When we burn the fuel we avail ourselves of energy which has been husbanded through age-long actions. Thus the power of our engines, the