Distinguished Wisconsin naturalist Increase Lapham examines a Wisconsin meteorite.


Mifflin L5 chondrite meteorite fragment showing internal brecciation. (Image courtesy John Valley; unauthorized reproduction is prohibited.)

CLARK COUNTY: Two stony meteorites with a combined weight of over 200 pounds fell at 6:15 P.M. on July 4, 1917 near Colby (Read, 1962). Samples of the Colby meteorite are in the Geology Museum at UW Madison.

COLUMBIA COUNTY: A 772-gram stony meteorite fell through a barn roof near Kilbourn at 5:00 P.M. June 16, 1911 (Read, 1962). Specimens and a replica of this meteorite are in the Geology Museum at UW Madison.

IOWA COUNTY:  The Mifflin Meteor made a spectacular fireball over parts of Wisconsin, Iowa, and Illinois as it fell on April 14, 2010. Over 3.5 kg of fragments have been found so far in a meteorite-strewn field centered at Mifflin, but extending from Livingston to Mineral Point. The meteorite is classified as a L5 chondrite, and has a beautiful internally brecciated texture.  UW–Madison is the designated repository for reference materials of this meteorite (2011, Meteoritical Bulletin database, Meteoritical Society; Kita and others, 2013). For a catalog of fragments found, visit the UW–Madison’s Department of Geoscience page on the Mifflin Meteorite (

KEWAUNEE COUNTY: A meteorite massing nearly 4 kg was found during plowing on a farm about 4 miles west of Algoma. It contained 88.6% Fe and 10.6% Ni. It was described as an “octahedral siderite rich in kamacite and taenite and relatively poor in plessite” with internal schreibersite bands, Widmannstatten figures, Neumann lines and Reichenbach’s lamellae (Hobbs, 1903). This meteorite is now in the Geology Museum at UW Madison.

LAFAYETTE COUNTY: A stony meteorite weighing 58.28 pounds was found in 1958 near Belmont. It contained mostly bronzite and olivine, but also contained about 23% Fe-Ni alloys (Broughton and LaPaz, 1962). The Belmont meteorite is currently in the Geology Museum at UW Madison.

SHAWANO COUNTY: A 33-pound iron meteorite was found in 1916 during plowing on a farm approximately 3 miles north of Angelica (Read, 1962a).

ST. CROIX COUNTY: An iron meteorite massing 24,000 grams (52.91 pounds) was recovered from a plowed field (N1/2 SW Sec. 31 T.29N R.17W) near Hammond in 1884. Troilite was present in nodules and as fracture fillings. Chemical analysis gave 89.78% iron and 7.6% nickel with trace amounts of cobalt, phosphorous, silicon, carbon, copper and tin (Fisher, 1887).

VERNON COUNTY: The “Claywater Meteorite” was observed to fall at 9 A.M. on March 25, 1865. It came in as a rotating fireball and exploded near ground level. Two fragments with a combined mass of 1500 grams were recovered. The meteorite was mostly stony, containing olivine and enstatite. It also contained about 17% Fe-Ni alloys (Smith, 1876).

WALWORTH COUNTY: The “Zenda Meteorite” was found in 1955, about a half mile west of Zenda. It massed 3.7 kg and was deeply oxidized. It was an iron meteorite containing kamacite, schreibersite patches, troilite, taenite and lawrencite. It also contained minor graphite, olivine and pyroxene (Read, 1963).

WASHINGTON COUNTY: A number of large fragments of an iron meteorite have been found in Trenton township, east of West Bend. Fragments were originally found in 1858. More fragments turned up in 1873. A detailed search of the area with a metal detector turned up more fragments in 1952 and 1964. At least 13 fragments had been found so far. The largest chunks weighed 527 and 413 pounds. The most recent finds were made in the NE Sec. 33 T.11N R.20E. Sawn and treated fragments show troilite nodules and lenses (Irving, 1882; Lapham, 1877; Smith, 1869; Read and Stockwell, 1966). Specimens from this meteorite are in the Geology Museum at UW Madison.

WAUSHARA COUNTY: An iron meteorite with stony inclusions was found in 1894 near Saxeville, Sec. 8 T.20N R.2E. Its mass is 3,600 grams (7.94 pounds) (Perry, 1944; Read, 1962). This proved to be an unusual meteorite that was named the “Pine River Meteorite.” It is an octahedrite with many silicate inclusions and an “anomalous member of chemical group IA.” The silicate inclusions consist of “granular crystalline intergrowths of orthpyroxene, olivine, plagioclase feldspar, troilite and iron nickel metal with accessory chromite, diopside and schreibersite” (Beavar and Grady, 1988).

— A stony meteorite massing 676 grams (1.49 pounds) was found near Mt. Morris at 44° N 89°15’W (Buckstaff, 1962). The Mt. Morris Stone is a coarsely crystalline sulfide rich stone with forsterite, enstatite, kamacite, schreibersite, troilite, graphite, chromite, daubreelite and chalcopyrite (Bild, 1977). Later detailed geochemical suggests that the Mt. Morris meteorite is a fragment from the Pine River Meteorite (Beavan and Grady, 1988).

WINNEBAGO COUNTY: A 1/4 lb. fragment of stony meteorite was found on gravel approximately 2 miles northwest of Oshkosh (Read, 1962).