Supplement 2, corrections and additions to Bulletins 11a-11e, Lake Superior and St. Marys River; Lake Michigan, and Green Bay; Lake Huron, St. Clair River, Lake St. Clair, Detroit River; Lake Erie and Niagara River to Niagara Falls; Niagara River below Niagara Falls, Lake Ontario, St. Lawrence River: to supplement information given upon charts of Great Lakes.