Geologizing, with some friends, on the south coast of the Isle of Wight, a few summers since (1859), we noticed some puddles of rain-water in the clay talus of the Wealden Cliffs near Brook Point, and observed that, like other such surfaces, the partially dried clay beds of the diminished pools showed rain-prints, foot-tracks, trails, and the rings of broken bubbles. Amongst these various markings are convex trail-like lines (fig. 1), which at first appeared difficult to account for; but, recollecting Mr. A. Hancock's remarks on the so-called Annelide tracks, published in the ‘Annals of Natural History,’ 3rd series, vol. ii. p. 443, plates 14–19, I looked carefully on the wetter parts of the clay, along the edges of the puddles, and soon saw little beetle-like insects boring into the clay, and apparently traversing such galleries, just beneath the surface, as the little narrow convex sinuous markings may be due to. One of these insects I enclosed alive in its clay habitat, but I could not afterwards find it, when I had the specimen of surface-marked clay at home. The cut edges of the pieces of clay show the openings of the numerous little galleries (fig. 1b). Some of them are close to the surface; some are an eighth of an inch or more below: in the latter case, probably the roof of the gallery received coatings of mud after it was raised up, retaining its convexity.