Paleobotany Collection The paleobotany collections at Field Museum rank fourth or fifth in size nationally with about 77,800 curated specimens that range in geologic age from Precambrian to Pleistocene. The paleobotanical collections at The Field Museum are an important national and international resource for systematic and evolutionary plant biology. In the past five years these collections have grown by over 10% (ca. 7,800 specimens). Of the recent acquisitions, ca. 41% were added through the activities of Field Museum staff and associates, and ca. 59% were added through the acquisition of scientifically important donated collections. Active field work by Field Museum staff, associates and students during this period has resulted in steady growth of the paleobotanical collection. Systematic Coverage-Most groups of plants are wellrepresented in the paleobotanical collections. Particular strengths include a wide array of Carboniferous taxa, and Cretaceous and Paleogene angiosperms. Geographic Strengths-The paleobotanical collections possess nearly worldwide coverage, but are strongest for North American localities. Within North America the collections are especially strong in Paleozoic material from Illinois, Indiana, Iowa, Michigan, Ohio and West Virginia, Mesozoic material from Alaska, Utah, Virginia, Maryland, Georgia and Tennessee, and Cenozoic material from Mississippi, Tennessee, North Dakota, Wyoming, Montana and Colorado. Especially significant localities are described below. Type Specimens-Approximately 1,200 specimens of fossil plants have been designated as types, or figured in publications by scientists from The Field Museum and other institutions. Type and figured paleobotanical specimens are housed separately from the general collection and are organized by publication. Mazon Creek Flora-One of the greatest strengths of the paleobotanical collection is the Pennsylvanian Mazon Creek flora, a collection of 23,907 fossil plant specimens. The Mazon Creek assemblage was the subject of an NSF facilities grant that supported curatorial improvements to this unique collection. One important result of these activities is that 455 type and figured fossil plant specimens from Mazon Creek have been identified and removed to the type and figured collection. Paleocene of the Rocky Mountain and Great Plains-The paleobotany holdings at Field Museum are also particularly strong in the Paleocene of the Rocky Mountain and Great Plains area. The bulk of this collection derives from field activities by Crane, Herendeen and others in North Dakota, Montana, and Wyoming, where in the past ten years approximately 5,350 fossil plant specimens have been collected, primarily from two localities, Almont and Melville. The most significant of these localities is that near Almont, North Dakota, where a laterally restricted outcrop of shale belonging to the upper Paleocene Sentinel Butte Formation has yielded approximately 3,500 specimens, from which 65 types of fossil leaves, fruits, seeds and stems belonging to 3045 species have been identified (Crane et al., 1990). This Paleocene flora is particularly significant both because it is diverse (as compared to other assemblages of similar age) and because many specimens are silicified and anatomically wellpreserved (e.g., Crane et al., 1990, 1991). Mid and Late Cretaceous of Eastern North America-Recent field work by Crane and Herendeen and colleagues in the midCretaceous Potomac Group and Late Cretaceous of the southern Atlantic Coastal Plain of eastern North America has generated a large collection of fossil angiosperm, gymnosperm and pteridophyte material. Fossil plant materials from the Atlantic Coastal Plain are isolated from unconsolidated sediments by sieving and are exceptionally well preserved. Specimens are mummified and fusainized and are providing a wealth of information about the morphology and anatomy of Cretaceous plants (e.g., Crane and Upchurch, 1987; Crane et al., 1989, 1993, 1994; Srinivasan and Friis, 1989; Drinnan et al., 1990, 1991; Herendeen, 1991a,b; Pedersen et al., 1991, 1994; Herendeen et al., 1993, 1994, 1995; Srinivasan, 1992). Although the fossil angiosperms remain the focus of active ongoing research and are being actively curated in concert with the research effort, the abundant gymnosperm, pteridophyte and bryophyte material is equally significant (e.g., Srinivasan and Friis, 1989; Srinivasan, 1992). Recent Acquisitions-Two large paleobotanical collections have recently been added to The Field Museum holdings. The larger of these collections, which numbers approximately 4,600 specimens, was given by Prof. A. T. Cross (Michigan State University). The Cross collection, which is extensively documented by field notes with precise locality and stratigraphic data, includes material from numerous North American and foreign localities from the Silurian through the Paleogene (Neogene collections were retained at Michigan State University). Of these localities several are particularly significant. A Middle Pennsylvanian locality from near Grand Ledge, Michigan, is a deltaic siltstone deposit in which fossil plants are abundant. The Grand Ledge collection comprises approximately 850 specimens of taxa such as Megalopteris, Ginkgophyllum, cordaite stems, leaves and seeds of several types, and other reproductive structures (Cross et al., 1981). Another extensive collection made by A. T. Cross and colleagues is that from the Early Permian (Dunkard) of the Appalachian Plateau (Cross, 1984). The Dunkard flora, which comprises over 1,000 specimens of compression fossils in siltstones and shales, was extensively collected from numerous localities in West Virginia, southeastern Ohio and western Pennsylvania. The Dunkard florules are generally dominated by Late Pennsylvanian species with Early Permian plants represented in lesser numbers. Other significant floras in the Cross collection include the Paleocene and Eocene of Alaska (ca. 360 specimens) and the Cretaceous of Wyoming and Utah (ca. 1,500 specimens). While the Cross collection is extensively documented by field notes, considerable curatorial work is required to improve the availability of these materials and to maximize their utility to the scientific community. Other Geology Department Collections: Paleontology | Fossil Amphibians and Reptiles |Fossil Fishes | Fossil Invertebrates |Fossil Mammals | Fossil Plants | Physical Geology