Champlain Valley southward into the Valley of Vermont. The Vermont Lowlands are primarily underlain by sedimentary rocks, especially limestone and shale, though metamorphic rocks such as marble and slate are also present. Lake Champlain is situated in the Champlain Valley between the Green Mountains of Vermont and the Adirondack Mountains of New York, drained northward by the Richelieu River into the St. Lawrence River at Sorel-Tracy, Quebec (northeast of Montreal). Major tributaries of Lake Champlain include Otter Creek and the Winooski, Missisquoi, and Lamoille rivers in Vermont, and the Ausable, Chazy, Boquet, and Saranac rivers in New York. Lake Champlain also receives
New York (state) that includes within its borders parts of the Great Lakes and the Atlantic Ocean. The Hudson River begins near Lake Tear of the Clouds and flows south through the eastern part of the state, without draining Lakes George or Champlain. Lake George empties at its north end into Lake Champlain, whose northern end extends into Canada, where it drains into the Richelieu River and then ultimately the Saint Lawrence River. The western section of the state is drained by the Allegheny River and rivers of the Susquehanna and Delaware River systems. Niagara Falls is shared between New York and Ontario