If the deformation of the earth’s crust, to which the face of the earth owes its salient features, had been one dynamic event, a careful analysis of the pattern produced would yield sufficient clues to lead directly by inductive reasoning to an understanding of the forces that produced it. But the features that we see are the result of innumerable acts of deformation, each later one more or less superimposed upon and partly obliterating the patterns produced by the earlier ones. The unraveling of the super-imposed patterns would be a baffling task even if the whole face of the earth were exposed to view and if our knowledge of it were complete. With less than one-third of the face of the earth accessible to view and so very little of that known accurately, we can only base our reasoning on generalizations we believe to be fact, giving weight to . . .