This is not a level, stable, protected kind of beach. It is steep, full of long shoulders and curves, and fluctuates in outline not only as a result of storms but with each tide and even with every wave, making new bays, curves, shallow hills, and hollows; but the beach is an interbalanced system. All its materials come from offshore or the erosion of the cliffs. Wave action removes the cliff material, and currents moving parallel to the shore take it both north and south: there being a neutral point around Cahoon’s Hollow, halfway between Highland Light and South Wellfleet, although its location is dependent on the angle at which the waves come in along the shore. Half the cliff material moves north to build up the hood at Provincetown, and half moves south to be deposited along the sandspits from Nauset to Monomoy. A study made by the Woods Hole Oceanographic Institution, under the direction of John M. Zeigler, points out that the north and south ends of the Cape terminate in fairly deep water, 205 feet off Race Point and about fifty feet off Monomoy, and that: “It seems unlikely that material is moved to the Outer Cape from deep water, either from north and south, or by littoral drifting from any other part of the New England coast. Drifted detritus would be trapped or obstructed many times before it could reach the beaches of the Outer Cape.” During the course of the same study beach profiles were measured for several years and it was found that the sands were constantly changing in elevation, all the way from several tenths of a foot in one place during a mere ten minutes to a ten-foot loss in another during a period of two days. The average change per tide was about four tenths of a foot and sometimes went up to a foot. The beach has a kind of rhythmic beat, up and down. If its changes were translated into visual, continuous motion on a screen you might see it dipping, rising, and undulating like the waves at sea. Turbulence and change are not outside a frame of order. Loss is balanced by gain, so that the sand which is taken from one part is added to another, and though the relative volume of the beach is greatly reduced it may be restored in a year or so to more or less its original size.