similar mutations, caused, for instance, by the advent of a conquering race or a new religion. The fresh factor may produce either an exaltation or a retrogression, nevertheless, the general external and internal aspects of folk-custom will, for a long time afterwards, suffer little alteration, and the movement which is visible at the surface will not influence the undercurrents of belief to a corresponding extent. If the modification of the outward signs may be incautiously exaggerated, the strength of the unseen movements of belief may be carelessly deemed exhausted, when, in truth, it has scarcely waned at all. The hidden pagan forces which exist in England to-day, though they are normally kept in check by conventional habits and national religion, are well known to the professed student of survivals, while they are largely ignored by the orthodox historian. On the whole, then, experience teaches that the introduction of an alien religion does not interpose an impassable gulf between the old and the new, but that there will follow gentle transitions in custom, probably masked, for the time, by local outbursts of fanaticism or by the apparent sudden conversion, in certain districts, of large masses of the people. Beneath these disquieting superficial symptoms, there runs, in the main, an unbroken sequence of life and custom. The present place seems convenient for expressing a warning against certain false appearances which an old graveyard may present. Often the area has been girdled with a trench, several feet in depth, in order to afford greater protection against the intrusion of cattle than could be provided by a railing or a stone wall alone. By this means, too, the animals are prevented from browsing upon evergreen hedges where these are planted. This double barrier is especially necessary when the church is in the neighbourhood of a park, in which deer are kept. The wall-and-ditch arrangement, or even the ditch only, is common in the West country, though it is not infrequent in other districts. To allow the entrance of worshippers to the churchyard, and at the same time to baulk the efforts of cattle, a single block of stone, or a “grid” composed of two or three narrow slabs, set edgeways, is placed across the trench to form a bridge. A subsidiary purpose of the ditch is that of drainage. Or again, where the ditch is absent, rude stone pillars, sloping outwards from the base, serve as a strait gateway. All these features may suggest to the unwary a simple system of fortification. Moreover, one may often trace, in the vicinity of the church, vestiges of earthen banks, the remains of the boundaries of a Mediaeval village (cf. p. 16 _supra_). Thus there is a double possibility of deception. A dry ditch does not necessarily denote antiquity. A favourite method of setting about the enclosure of an estate or the establishment of a coppice was to construct a trench along the proposed limits, and this