GEOLOGY OF THE WISCONSIN STATE CAPITOL

The present Wisconsin State Capitol building is of Neoclassical design in the form of a cross with a central dome. The capitol is perched atop a drumlin on an isthmus between Lakes Mendota and Monona. The extra height from this glacial landform gives the capitol dome added visibility from the surrounding area.

Wisconsin’s capitol has not always been in Madison. The Wisconsin Territory was organized in Mineral Point; the first Legislature met in a rented wooden building in Belmont. Mineral Point and Belmont were both within the geologically and economically important lead-zinc district of the early territory. The first capitol building in Madison was constructed of sandstone quarried in the nearby village of Maple Bluff. The stone was ferried across Lake Mendota and the cornerstone was set in 1837. When state government outgrew this capitol building, construction began on a bigger building in 1857. In 1904, fire destroyed the second capitol. Construction began on the third, current capitol in 1906 and was completed in 1915.

The exterior of the capitol building is Bethel White granite from Vermont. It was chosen principally for its color, durability and low cost. Six varieties of Wisconsin granite are used as decorative accents in the interior of the building. All of the granites are Precambrian age, ranging from 1,900 million years to 1,465 million years old. The only other igneous rock in the capitol interior is a syenite from Norway. The most extensively used material inside of the building is the Kasota limestone from Minnesota. This stone covers the walls of the grand stair halls and the main corridors except for the west wing. Numerous fossils, including starfish and gastropods, are present in the walls and floors of the building. More than 30 varieties of marble (some of which are actually limestone) are also used in the capitol building. The rock came from five European countries, one African country, and seven states in the United States. In 2001 the Wisconsin State Capitol Building became a National Historic Landmark. Guided building tours and descriptive brochures add to the enjoyment of this special place.