Lannon Stone is actually dolomite. It's a type of limestone that runs through The Niagara Escarpment, which runs underneath most of the Great Lakes. In an area northwest of Milwaukee, in Waukesha County, the stone was found right on the surface. Settlers built thick-walled homes from the stone that they just lifted from the surface.
William Lannon was one of those settlers, and he recognized an opportunity to quarry and sell the stone. Quarries sprang up around an area surrounding "Lannon Springs" and the limestone that was quarried there became known as "Lannon Stone." (Today, stone homes are actually frame structures covered with a veneer of Lannon Stone.)
Many structures and bridges in Southeastern Wisconsin were built as PWA, CCC and WPA projects in the depression era and were clad with a veneer of Lannon Stone.The famous stone was also shipped to locations around the midwest.
Lannon Stone was widely used in the construction of structures in the Milwaukee County Parks. It is still widely used today, and over on the Bridge Hunter Milwaukee County bridge listings, you will find some modern bridges, as well as replacement bridges, that are clad in Lannon Stone.
Cream City Brick can also be found in many Milwaukee area structures, including bridges. The soil in southeastern Wisconsin is red lacustrine clay. When it was used in the manufacture of bricks, the clay turned a yellowish-cream color when fired. So many structures in the Milwaukee area were built using the bricks that visitors began to call Milwaukee "The Cream City." As a result, the bricks became known as "Cream City Brick."
Cream City Bricks were distributed widely. Many lighthouses around the Great Lakes and buildings in Chicago, were constructed with Cream City Bricks.
As you look at the bridges and landmarks in Southeastern Wisconsin, you will see many of them are clad with Lannon Stone and some with Cream City Brick. You might also notice many buildings and homes, in the background, that use these distinctive materials.