River Valley has a soft surface. It is also high in nutrients and host the majority of Connecticut's farmland soils. The land on either side of the Connecticut River Valley is less suitable for farmlands. The eastern section holds the shallow Proto-North American Terrane while the western section contains the Iapetos and Avalonian Terranes. These places still holds remnants of glacial till and lack the soft fluvial sediments so prominent in the Connecticut River Valley region.