The paleobotanical collections at the University of Michigan contain approximately 20,000 individually catalogued specimens. The collections are strong in Paleozoic vascular plants, especially progymnosperms, pteridophytes,and gymnosperms. Early Cretaceous angiosperms, the earliest flowering plants, are also well represented, many of these representing isolated leaves and dispersed curicle remains recovered from sediments, well before the time when larger portions of these plants are preserved intact. The invertebrate collections contain over 2,000,000 specimens. There is special strength in Paleozoic faunas, especially corals, trilobites, ostracods, and echinoderms of the Michigan Basin and surrounding areas.
Mesozoic invertebrates are also well represented from Central America, North America, and Europe.
There are about 30,000 catalogued lots of vertebrate fossil specimens, each containing from one to several hundred specimens, totaling perhaps 200,000 specimens. They include late Paleozoic and early Mesozoic reptiles and amphibians, representing some of the earliest, fully terrestrial vertebrate communities, and the early Cenozoic mammal collections from the Bighorn Basin of Wyoming that Dr. Philip Gingerich has used to document some of the best known cases of gradual evolutionary change over geological time. Late Cenozoic fishes demonstrate long records of diversification within major lacustrine systems, and our late Cenozoic mammal collection includes the best record of human association with extinct Ice Age mastodons found anywhere on this continient.