An almost vertical ascent amongst treacherous boulders, however, seems an indication of a possible route onwards, which may, I trust, with care be yet explored. The last 50 yards of the cave run to the south-east--that is, away from the direction of St. Dunstan's Well--a beautiful spring rising from the Carboniferous Limestone hard by; yet I feel sure that it must of necessity be a part of the same waterway. Either it was an inlet which received the waters of some vanished Old Red Sandstone spring, or it was a former outlet for the waters of that well. I am inclined to favour the former theory. As to the present source of the waters of St. Dunstan's Well there can be no doubt whatever. In the valley below Stoke Lane, and three-quarters of a mile distant from the well and from Cox's Hole, there is a most interesting swallet, of comparatively recent age. It is obviously certain that, not so long ago, the stream which courses down the valley flowed unchecked down its whole length, and so reached the larger stream below. Slightly retarded, in all probability, by some flood-borne silt, the water found a little joint in the western bank of the valley, and by slow degrees so enlarged it that it at last became capable of swallowing the whole. Even now a few hours' work would divert the water and cause it to resume its former course. Upstream is a mill, the owner of which has courteously given every facility for testing and for exploration. It was found that the effect of damming the mill stream entirely was to reduce the flow at St. Dunstan's Well enormously, and to render the entrance of the swallet passable. Mr. Marshall of Stratton-on-the-Fosse with his party made a successful descent, and travelled a considerable distance, mainly parallel with the valley without and to a great extent horizontally, through water-tunnels of small size. As no measurements were taken one cannot say yet how far it is passable, but he says that they did not get to the limits of possible exploration, as the time which they spent there was getting dangerously near the hour up to which it is possible to dam the water, and they most wisely beat a hasty retreat. The first opportunity will be taken by us to make use of a spell of fine weather to carry this exploration to a successful issue. Not far distant, too, is another swallet, from which the water has been diverted to be used for water-supply. This is in the vicinity of a ruined hunting lodge, and is said to lead in the same direction as the Stoke Lane Swallet. The whole of this district is likely to be very interesting, there being a series of remarkable rifts or fissures in the Dolomitic Conglomerate which deserve attention. One of these, called Fairy Slats, has been known for many years, and is indeed shown on the Ordnance map; and the fact that such fissures abound has been forcibly brought home by a disaster to a new reservoir, only recently completed by the