Whilst staying at Sidmouth, in 1877, I discovered the occurrence of Celestine, Sulphate of Strontian, in cavities of Red Marl lined with crystals of Calcite, occurring in masses which had fallen from the cliff on to the shore, under the summit of Peak Hill. It appears in the form of crystals, occasionally one inch in length, which occur singly or in groups, presenting a tabular, prismato-tabular, or prismatic form,—in the latter case resembling the Barytes Crystals of Alston Moor,—and are either simple, or form compound aggregations of considerable size. In colour they are blue, wine-yellow, or of an olive-yellow hue, and as regards form, brilliancy, and transparency, surpass in beauty any examples of this mineral that I have hitherto seen. A series of the choicest specimens collected by me are exhibited in the Museum of Practical Geology, Jermyn Street.