The Tilestone passage-beds between the Upper Ludlow rocks and those cornstones, now established as the natural base of the Old Red Sandstone, are, from the interesting character of their animal contents, attracting the greatest interest. I think it would be of value if the pages of the Geologist were open to detailed descriptions of the lithological character and fossils of these “Tilestones,” as exposed in different parts of Shropshire, Worcestershire, and Herefordshire. A comparison may thus be instituted which would greatly aid our comprehension of them.