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
Champlain Canal Lake Champlain, between above sea level, at Whitehall. By traveling the length of Lake Champlain, boaters can access the Chambly Canal, which connects Lake Champlain to the Saint Lawrence River. The following list of locks is provided for the current canal, from south to north. There are a total of 11 locks on the Champlain Canal. All locks on the New York State Canal System are single-chamber; the dimensions are 328 feet (100 m) long and 45 feet (13.7 m) wide with a minimum 12-foot (3.7 m) depth of water over the miter sills at the upstream gates upon lift.