The following propositions respecting faults apply to strata, which are either horizontal, or which have a uniform dip. If they have a uniform dip, the country, faults and all, may be supposed turned back through the angle of dip, and the strata will become again horizontal. We need then only think of horizontal strata, if we bear in mind that “horizontal” and “vertical” really mean only, parallel and perpendicular to the bedding. This artifice will simplify the subject; but it does not imply that the faulting took place before the beds were tilted, which may, or may not, have been the case.