Pumping operations conducted by the Associated Portland Cement Manufacturers Co., Ltd., in the large chalk quarry situated between Brook Vale and the Southern Railway track to the east resulted in the normal water-level for the immediate vicinity being lowered by approximately 50 ft. This volume of pumping, however, had the effect of filling to capacity all streams and conduits connected with the outflow, so that archaeological investigation of the low-lying deposits of the neighbourhood was rendered impossible.

In the summer of 1938 operations in the quarry were abandoned, and the pumps were withdrawn for installation in Baker's Hole, half a mile to the west.

Upon the cessation of pumping the water-level immediately began to return to normal at the rate of about 9 in. every twenty-four hours, whilst the beds of the streams and conduits promptly dried up.

Such a state of affairs rarely presents itself to the archaeologist, and I forthwith decided to make two excavations at what I considered were likely to prove ‘key’ sites in the bed of the Ebbsfleet. The first spot chosen lay at the junction of Brook Vale and the Ebbsfleet, and the second was at a point a quarter of a mile farther upstream.