A 26 ft. high approach fill was constructed in November 1959 for a bridge over the Rideau river near Kars, Ontario. The fill was placed over 50 ft. of Leda clay, the lower 30 ft. of which was extremely sensitive and compressible. Prior testing indicated that the preconsolidation pressure of the clay would be exceeded.Settlement gauges and piezometers under the fill have been observed since the start of construction. After 7½ years, 20 in. of settlement has occurred under the centre of the fill. Settlements are continuing at an appreciable rate although the excess pore water pressure has dissipated to a low level and is nearly constant through the clay layer.The field observations of settlement and pore water pressure are compared with values calculated and a closed form solution to the process of consolidation obtained by a heat balance integral technique and by considering the clay layer to be a rigid plastic.