This is not your typical geocache, it is an EarthCache, you will not be looking for a "cache container" rather, an EarthCache is designed to bring you to a geological feature. See http://www.earthcache.org/ for further details.
BUILDING STONES OF DOWNTOWN MILWAUKEE
Our civilization is heavily dependent on geologic materials for constructing roads, bridges, buildings, and monuments. Three downtown Milwaukee buildings that used stone as a building material have been selected to illustrate two interesting geological rock types that are visible in the downtown area as well as the architectural history of the city.
Wauwatosa Limestone: This dolomitic rock is most frequently referred to as limestone, in spite of its composition of calcium and magnesium carbonate. It is also known as Niagarian Dolomite, because it is the same rock unit that caps Niagara Falls in Western New York. It is used throughout eastern Wisconsin for buildings and roadwork because it is close to the surface and easy to quarry. It forms the prominent ridge that runs form Door County through Milwaukee and Waukesha and continues just below the surface though Racine and Chicago. It is middle Silurian age (450 million years old) and noted for the ancient coral reefs that are found in it. The reef structures provide clues to Wisconsin's past environment, suggesting that Wisconsin was once part of a shallow tropical ocean. The Milwaukee Public Museum has an exquisite diorama showing life on a Silurian reef. Fossils form quarries in S.E. Wisconsin can be viewed in the Greene Gallery on the UWM campus.
The rock tends to be light tan to gray in color and fairly compact or dense. This makes for an ideal building stone, especially since it is close to home. An example of this building material follows.
Immanuel Presbyterian Church
1100 North Astor Street
Architects: Edward Townsend Mix 1873
The Victorian Gothic church, designed by the Milwaukee architect Edward Townsend Mix, has a combination of different building stones. The cream-gray Wauwatosa Limestone was used for the walls. Alternating red and gray sandstones were used for trim on the arched openings. Polished red granite columns at the entrance and the blue-gray slate roof completed the polychromy of the building.
Mix used sandstone frequently in his designs. In 1869, he used Lake Superior Sandstone in the design of the former Milwaukee County and City Courthouse.
Lake Superior Sandstone: This sandstone that is mostly red or brown in color comes primarily form the Bayfield Group of sedimentary rocks that are found near Bayfield, Wisconsin and on the Apostle Islands in Lake Superior. The bass Island Sandstone is one example. the sandstone of choice in this group is mostly a red feldspathic (has feldspar as a dominant mineral) sandstone deposited as the final stage of the infilling if the Keweenaw Rift. It is presently considered to be the last Precambrian event in Wisconsin which makes it about 1040 million years old.
This reddish sandstone looks similar to the popular "brownstone" used in many east coast row-houses, churches and government buildings, which made it popular as a building stone in the Midwest. It is not always the hardest or well-cemented rock, so it is susceptible to weathering.
St. Paul's Episcopal Church
914 East Knapp
Architects: Edward Townsend Mix 1883
St. Paul's Episcopal Church is an outstanding example of the Richardsonian Romanesque style. It was constructed of Lake Superior Red Sandstone from the Bass Island Quarry, located on the south end of Bass Island, one of Apostle Islands in Chequamegon Bay of Lake Superior, to the northeast of Bayfield, Wisconsin.
To log the Earthcache please visit each of the buildings, which can be viewed from public sidewalks. Please email your answers to the following questions.
1. At the cache coordinates look for the remains of the grist mill by the Historical Marker Sign on the building. Based on your observations at the listed coordinates which type of stone do you think the grist mill was made of?
2. At the Immanuel Presbyterian Church examine the columns by the front entrance. How do the front of the columns feel? How do the back of the columns feel? What might have caused the difference?
3. After looking at the two churches which stone do you think is holding up better against the affect of erosion? What evidence did you observe to support your conclusion?
Photographs at the sites are not required but welcome as long as they do not reveal the answers to the questions. Feel free to offer your theory on what happened to the grist mill near here in your online log.