In New England, the ground-water geochemistry results mainly from the reaction of CO2-charged water with feldspar and other primary silicates. Water in the New England bedrock is more highly evolved geochemically than water in the drift, presumably as a result of its longer residence time. In the New York area, the geochemistry of water in both types of aquifers results mainly from carbonate-mineral dissolution. Water in most glacial drift and bedrock is saturated with respect to calcite. In some parts of New York, the dissolution of evaporite minerals has a marked effect on the water chemistry of the bedrock. In most of the Pennsylvania area, the geochemistry of water in both types of aquifers indicates that, although carbonate minerals are the principal reactants, their influence on water chemistry is less than in New York. In parts of Pennsylvania, chemical differences between ground water from drift and ground water from bedrock are attributed to a higher proportion of reactive minerals in the drift than in the local bedrock as a result of glacial transport. -from Author