My friend and colleague, Mr. H. B. Medlicott, published, in the August (1869) number of the GeologicalMagazine, a paper “On Faults in Strata,” in which he endeavoured to show that the evidence usually accepted for faults, in the true geological acceptation of the term, is insufficient; that a large number of the lines of junction between rocks of dissimilar age, usually mapped by the Survey of Great Britain and other Surveys as “faults,” are, in truth, natural junctions, due to deposition against cliffs or other steep surfaces; and that direct evidence of friction is necessary to establish the existence of a fault. The latter is rather left to be inferred than positively asserted; nevertheless it is very clearly intimated that it is the writer's opinion.