I. Introductory. Until the summer of 1895 I spent at least a month in every year in the immediate neighbourhood of the northern end of Cannock Chase. In 1880 I published 1 a short note on the pebbles in the Bunter Conglomerate, so largely developed on that moorland. A second appeared in 1883, 2 and the subject was mentioned in my address to Section C at the meeting of the British Association in Birmingham in 1886. 3 In 1890 4 I replied briefly to certain criticisms on the hypothesis which I had adopted in regard to the origin and history of these pebbles. Besides this, I published in 1888 some observations on the action of rivers in forming pebbles, the results of a journey planned with a view of obtaining the necessary facts, and in 1895 a note on the Budleigh Salterton pebbles which I had examined for comparative purposes. Since that year, when my close connexion with Staffordshire was broken, the pressure of other work has kept me from putting together information acquired after 1886, drawing up a summary of the whole evidence, and pointing out its bearing on the hypotheses which have been advanced as to the origin of the pebbles. Throughout my work, though it was rather desultory, I have gathered facts for myself, and so shall not attempt to burden these pages with an elaborate list of the ‘literature of the subject.’ That prior to 1869 is enumerated in the memoir of the Geological Survey on the Coal Measures, Permian,