There are many parts of our coastline where changes, due to erosion or deposition, are rapid and obvious; these are often matters of some concern to the local inhabitants, and are well known to those who study the coastline. Usually, however, the knowledge of the local inhabitants is vague and exaggerated, for the simple reason that it is not based on any proper measurements of what has taken place. More often than not the only reliable measurements available are the widely spaced (in time) surveys of the Ordnance Survey or of the Hydrographic Department of the Admiralty.l While these surveys are of the greatest value they are, for obvious reasons, insufficient for complete understanding. They occur too rarely; the scale, especially of the hydrographic surveys, is often too small, and the practical diffi? culties of making precise surveys are considerable where the foreshore is regularly covered by the advance of the tide. These surveys are to be regarded, therefore, as occasional (though authoritative) glimpses in a long story. They make no attempt to explain how the changes came about, whether as a result of one or more catastropic events, or by slow but progressive stages. This cannot be known unless attention is focussed more closely, and observations are made more often. There is, therefore, a large and fascinating field of research open to those who can make these more detailed and more frequent surveys, and, at the same time examine the hydrodynamic processes which must be responsible for what has occurred. Between Covehithe and Kessingland, in Suffolk, erosion is taking place at one point at an alarming rate, while, less than a mile away, the coast is building up. In the vicinity there are features above and below mean sea level which, instead of going in the direction common to east coast features, are moving in exactly the opposite direction. These circumstances came to my notice in 1950, when I had completed a series of observations in the laboratory, and on tideless beaches of the Mediterranean, and had come to some general conclusions about wave action.2 I was then looking for a suitable place to continue my researches on a coast in tidal waters, and was therefore most interested and grateful when Professor Steers directed my attention to this particular place. In 1951 I began the series of observations which are briefly described in this paper. The object of the research has been to record the rates of erosion and deposition systematically, and to discover as far as possible the agencies which are causing the changes. It is tempting to go further, and to predict what will happen, and one is frequently asked what can be done to prevent the erosion that is so obvious, and so serious to the landowners. In this case prediction is not difficult; but the remedies, sea defences, are the province of the engineer. It is thought, however, that systematic surveys of coastal changes are of great importance. Few such observations are known to exist, and I am sure that there is a great need for other surveys of this kind to be made round our coasts. If we in our generation