GREAT LAKES OF NORTH AMER

ICA, the collective name for six freshwater lakes—Superior, Michigan; Huron, St. Clair, Erie, and Ontario—situated between Canada on N. and U.S. on 8S. upper waters of St. Lawrence R. Superior, largest lake, is connected with Huron by St. Mary R.; Michigan (ying wholly in U.S.) joins Huron at Straits of Mackinac: Huron empties itself into Erie by St. Clair R., and lake, and Detroit R.; between Erie and Ontario are Niagara R. and Falls. Lakes opened up to navigation, and differences of levels overcome by system of canals with numerous locks. The lakes are frozen for four or five months in winter. Some of the largest and most important towns in N. America situated on shores of lakes. Chicago, on Michigan, and Buffalo, on Hrie, share greater part of lake traffic. Around lakes are extensive coal-fields, iron mines, fruit and grain-growing regions. Area exceeds