Additional water supplies are urgently needed in the Lake Maskinongé area, some 110 km northeast of Montreal. To hasten if possible discovery of more productive water-bearing formations, a joint investigation was undertaken by a hydrogeologist and a morpho-sedimentologist, both scientists with the Départment des Richesses naturelles du Québec.The area is in the boundary zone between the Canadian Shield and the St. Lawrence Lowlands. It is also a limit zone for Quaternary deposits, for here are, interstratified one with the other, drift deposits of St. Narcisse terminal moraine of Wisconsin age (10 500 yrs B.P.), stratified drift, sediments deposited in the Champlain Sea, and fluviatile deposits.The mean values of the porosity and the permeability coefficients of these surficial formations is about 39%, and 165 × 10−4 cm/s respectively. Because of these properties, and because of their volume and widespread distribution, the glacio-fluvial and the shore deposits have the greatest potential as aquifers.