A few months ago I sent to the British Museum a block of mountain limestone, perforated into deep cells by mollusks. It was met with on a limestone ridge three miles south-west of Ulverston, and first attracted notice by being brought to town to be employed for building purposes.

The perforations were found to be on the under-side of a projecting ledge, and were large enough for the fingers to be introduced upwards to the depth, in some, of three inches, the diameter being about seven-eighths of an inch. They were inhabited, at the time of the discovery (August), by the land-snails Helix nemoralis and Helix concinna.

Mr. Woodward, on receiving the stone, very kindly sent for my perusal a ‘Memoir on Perforations by Helices in the Calcareous Rocks of the Boulonnais,’ by M. Bouchard-Chantereaux. In this memoir the author states his belief that the cells are the work of Helices, and that the eroding action is performed by the foot, with the aid of an acid secretion.

Ever since I became familiar with the microscopic structure of the tongue of Helix, etc., I have always believed that it was so constructed for purposes of abrasion, either of stone or other hard substances; but I was not previously aware that the land-snails were, any of them, supposed to form for themselves hollowed, hybernating chambers in rocks.