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
Lake Champlain to take some of the traffic burden. On December 28, 2009, the bridge was destroyed by a controlled demolition. A new bridge was rapidly constructed by a joint state commitment, opening on November 7, 2011. North of Ticonderoga, New York, the lake widens appreciably; ferry service is operated by the Lake Champlain Transportation Company at: While the old bridge was being demolished and the new one constructed, Lake Champlain Transportation Company operated a free, 24-hour ferry from just south of the bridge to Chimney Point in Vermont at the expense of the states of New York and Vermont at a