local. (s.w.) [Obscure formation on SWALLOW v., ? after gullet.] An underground stream of water such as breaks in upon miners at work. Also (in full, swallet hole), the opening through which a stream disappears underground. Cf. SWALLOW sb.2 1 b.
1668. Phil. Trans., III. 769. If they find a Swallet, they drive an Adit upon Levell, till ’tis dry.
1761. A. Catcott, Treat. Deluge, III. (1768), 356. The collateral conduits of the swallet-holes, leading down into one great unfathomable cavity in the bowels of the earth.
1778. Pryce, Min. Cornub., 84. The larger submarine gulphs or swallets.
1856. S. Hughes, Waterworks, 133. Swallet holes and subterranean rivers in the district of Gower and in the Mendip hills.
1865. Reader, Jan. 7. This stream is known to commence its subterranean journey about two miles off, where it enters a ‘swallet.’
1910. Spectator, 8 Jan., 47/1. Mendip [has] … underground springs and rivers … faintly indicated by the countless swallets that pit the surface of the hills.
