The three lakes of the middle group stand at practically the same level: Michigan and Huron are connected by the Strait of Mackinac (pronounced Mackinaw); Huron and Erie by the St Clair and Detroit rivers, with the small Lake St Clair between them.
The soil of south-west and south-east Michigan is for the most part a dark clay loam or muck; in the north central part of the lower peninsula it is a light sandy loam, along the Huron shore it is heavy with blue clay, in the mining districts of the north-west the rocks are usually either barren or very thinly covered; and elsewhere in the state the soil is generally rich in a variety of mineral elements, and varies chiefly in the proportions of vegetable loam, sand or gravel, and clay.
Corresponding outlets are known for the glacial lakes Erie, Huron and Superior, and for a very large sheet of water, named Lake Agassiz, which once overspread a broad till plain in northern Minnesota and North Dakota.
Here he worked at Sault Ste Marie, St Esprit (near the western extremity of Lake Superior) and St Ignace (near Michilimackinac or Mackinaw, on the strait between Huron and Michigan).
Gypsum is obtained from deposits along the banks of the Grand river in Kent county and in the vicinity of Alabaster along the shore of Lake Huron in Iosco county.
South and south-east of Keweenaw Bay, in the Marquette iron district, is an irregular area of mountains, hills, swamps and lakes, some of the mountain peaks of the Huron Mountains (in Marquette county) rising to an elevation of 1400 ft.
Lakes Superior and Huron both reach depths hundreds of feet below sea-level, but the next lake in the series, St Clair, towards which Lake Huron drains southward through St Clair river, is very shallow and marshy.
In the second half of 1812 the British general, Sir Isaac Brock, lieutenantgovernor of Upper Canada, adopted measures for opposing the Americans on the frontier line, between Huron and Erie.
From Lake Huron to the south-east shore of Saginaw Bay a wide sandy beach is followed northward by precipitous shores abounding in rocks and bluffs.
The north-east shores of Lake Huron and its large expansion Georgian Bay are fringed with thousands of islands, mostly small, but one of them, Manitoulin Island, is 80 m.