Thomas Greene was a methodical scientist and committed to assembling a comprehensive collection of Silurian and Devonian fossils. He made great efforts towards these ends—vigorously collecting, purchasing, and trading specimens across the country, especially Wisconsin, Illinois, and Indiana. In this way he assembled a collection of approximately 60,000 primarily Paleozoic marine fossils. This number is approximate because a portion of the collection remains uncatalogued. However, Thomas Greene was meticulous, and most specimens have robust associated stratigraphic and provenance data. Many still have their original hand-written labels, and the original catalog series survives to this day. The collection was, at the time of Thomas Greene’s death, considered the most valuable private collection west of Philadelphia. Today, it is the single greatest collection of Silurian reef fossils in North America and, possibly, the world. It certainly maintains the most thorough accounting of marine Paleozoic fossils from the Milwaukee and Chicagoland areas. Due to urbanization and changes in quarrying techniques many of the original localities are now closed or destroyed, making this collection truly irreplaceable.
Many historically relevant geologists graced the collection at various times, and in various ways. James Hall, the father of North American paleontology, was among Greene’s collaborators and helped describe the geology of the Milwaukee area in his Report on the Geological Survey of the State of Wisconsin (1862). Several original copies still survive in the Thomas A. Greene library collection. Hall also referenced the value of Greene’s endeavors in the Paleontology of New York, vol. VIII, wherein he described three new species of gastropods from the collection. One of these, Parastrophia greenii, was named in Thomas Greene’s honor. This and several other holotypes are currently stored in the Museum collections. Other notable scientific contemporaries of Thomas Greene included Increase Lapham, (namesake of Lapham Hall and considered Wisconsin’s first great scientist), Fisk Holbrook Day, and Rollin Salisbury. Much of the work in cataloging, preserving, and showcasing the collection since the 1970’s was performed by the late Joanne Kluessendorf—founding director of the Weiss Earth Science Museum (WESM) in Menasha, WI—and Don Mikulic, who is associated with the Greene collection to this day.
Today, the bulk of the collection is stored among wooden drawers in climate-controlled compactor storage in the basement of Lapham Hall at UWM. Some mineral specimens are alternatively stored in gasketed metal cabinets. Approximately 5,000 of the 65,000 total specimens are exhibited on the first floor in the gallery space (Lapham 168), of which half is devoted to fossils. Both the original Thomas A. Greene Memorial Museum building and the Schoonmaker Reef (from which a portion of the collection is derived) are registered as National Historic Landmarks, thanks in large part to the efforts of Don Mikulic and Joanne Kluessendorf. Currently, only 2,633 such designations exist, forty-five of which are in Wisconsin. In 2024, the Greene collection further earned an IUGS designation as an internationally recognized Geo-Heritage Geocollection. It was among the first eleven collections to be granted this prestigious honor and recognized for their monumental historical value. The Greene collection currently stands as the only internationally recognized Geo-Heritage collection in the United States.
The Museum is free and open to the public and serves as an educational resource for the Department and its students. It is staffed by geoscience undergraduates approximately twenty hours weekly, and tours are occasionally provided to local schools and other groups, free of charge. Uniquely, the descendants of Thomas A. Greene have been intermittently involved with the collection. This interaction with the family, and their role as stewards of their ancestor’s collection, has increased significantly in the past four years as interest in the Museum has been reinvigorated. These factors make the Thomas A. Greene Museum a true local treasure, and a critical repository of Milwaukee’s natural heritage.