[Appendix to Volume XV of The Essex Naturalist. RED-HILLS EXPLORATION COMMITTEE. I. CHALKLEY GOULD, F.S.A., Chairman. F. CHANCELLOR, J.P. Dr. PHILIP LAVER. MILLER CHRISTY, F.L.S. Prof. R. MELDOLA, F.R.S. WILLIAM COLE, F.L.S. CHAS. H. READ, F.S.A. Rev. T. H. CURLING, E.A. FRANCIS W. READER. W. H. DALTON, F.G.S. Col. O. E. RUCK, R.E. T. V. HOLMES, F.G.S. F. W. RUDLER, I.S.O., F.G.S. Dr. H. LAVER, F.S.A. H. WILMER, C.E., Hon. Sec. and Treasurer, St. Alban's Crescent, Woodford Green, Essex. INTERIM REPORT FOR 1906. SCATTERED along the margins of the estuaries and tidal rivers of Essex (and, probably, of other counties on the East Coast of England) are many curious deposits of red burnt clay, intermingled with fragments of rude pottery, to which the name of "Red-hills" has been given. These Red-hills, of which there are probably several hundreds on the coast of Essex alone, vary in size from a few rods to several acres. They are now given over, in many cases, to cultivation, as the soil of which they are composed appears to be singularly productive. That they date from a remote period, and that some at least are Pre-historic, is proved by the nature of the pottery contained in them. The origin of the Red-hills and the purpose or purposes which they served have been for long a matter of speculation. The number of theories advanced to account for their existence well shows the mystery surrounding them. By some, they have been regarded as salt-works : by others, as cattle shelters, human habitations, potteries, or glass-factories. Observations in regard to the characteristics of the Red-hills have been made from time to time—notably by Messrs. Stopes, Atkinson, Dalton, Laver, and Gould. Several of the hills have been examined and recently reported upon (see Essex Naturalist, vol. XIV, pp. 170-183, 1906) by Mr. William Cole, F.L.S., the Hon. Secretary of the Essex Field Club and a member of your Committee.