The grassy mountain valley just south of Florissant held treasures past and present. Summer wildflowers, a petrified forest, and shale containing fossil leaves and insects attracted the attention of both tourists and scientists. Scientific interest in Florissant blossomed early.

Scientific Pioneers of Florissant

For nearly 140 years scientists have been studying Florissant. If, on average, a career spans 30 years, then over 4 “generations” of scientists have worked at this fossil site. This scientific work, accumulated over lifetimes, has illuminated the changing geology and ecology of Florissant during the late Eocene, approximately 36-34 Ma. The rich fossil assemblage allows scientists to estimate the paleoclimate and paleoelevation at the time of deposition. Studies on the microscopic structure of Florissant lake shales have revealed the possible role of biofilms in fossil preservation. Volcanic sediments and key mammalian fossils allow scientists to test and corroborate multiple techniques for determining the age of the Florissant Formation. Comparisons between younger and older fossil deposits provide insights into paleoclimates, biogeography, and the evolution of plants and animals during the Paleogene.

This summary will highlight the work of key individuals to gain an appreciation for the important work accomplished by people past and present. A more complete and in-depth history of the scientific work at Florissant can be found in The Fossils of Florissant (Meyer 2003) and History of paleontology at the Florissant fossil beds, Colorado (Veatch and Meyer, 2008). Saved in Time: The Fight to Establish Florissant Fossil Beds National Monument (Leopold and Meyer, 2012) and A History of Florissant Fossil Beds National Monument: In Celebration of Preservation (McChristal, 1994) also provide some interesting perspectives on the history of Florissant.

Albert Charles Peale (1849-1913), a geologist working with the Hayden Survey, explored the Florissant Valley in 1873. Peale mentions the fossil lake deposits and notes the existence of 20 to 30 stumps of silicified wood, known to the locals as “Petrified Stumps.” Members of the Hayden Survey collected vertebrate, insect, and plant fossils that would later be described by other scientists.

Three students from the College of New Jersey organized what is now known as the Princeton Scientific Expedition of 1877. The goal of the expedition was to collect vertebrate fossils in Colorado, Wyoming, and Utah. In 1877, the three students, William Berryman Scott (1858-1947), Henry Fairfield Osborn (1857-1935), and Frank Speir Jr. (?) spent two days in July collecting fossils at Florissant. These two days would prove to be very fruitful. At least 180 of the expedition’s plant and insect fossils became type specimens. A new species of fish was also discovered. Charlotte Hill (1849-1930) and Adam Hill (1834-?), homesteaders who lived near the Big Stump, shared some of their fossil finds with the three students. The Princeton Scientific Expedition of 1877 marked the start of an important relationship with the Hills and scientific investigators. Charlotte Hill was the first person to find a fossil butterfly at Florissant--the first of its kind to be found in America. This butterfly would latter be described by Samuel H. Scudder.

Leo Lesquereux (1806-1889) was a watchmaker, bryologist and paleobotanist. Lesquereux initially pursued a teaching career, which was cut short after suffering hearing loss. Lesquereux’s hearing loss was the result of an illness during the 1830s, just two years after getting married. Treatments for the hearing loss left him deaf. Lesquereux gave up teaching and joined his father as a watchmaker. In his spare time he collected mosses, which would eventually lead to a scientific career. To read a more detailed account of Lesquereux’s life, visit the Leo Lesquereux Autobiography on the American Philosophical Society website.

Lesquereux is best known for his work on the origin of peat, the study of living mosses, and Carboniferous fossil flora. Lesquereux was the first to describe fossil plants from Florissant, naming over 100 new species sampled from the Hayden Survey, the Princeton Scientific Expedition of 1877, and fossils purchased by Scudder from Charolette Hill. Lesquereux described a rose plant found by Mrs. Hill, naming it Rosa hilliae (Lesquereux 1883) in her honor. Lesquereux was the first person to write a scientific paper on Florissant and in 1883 he published Contribution to the fossil flora of the Western Territories, which included his work from Florissant.

Samuel Hubbard Scudder (1837-1911), F.C. Bowditch (?-1927) and Arthur Lakes (1844-1917) arrived in Florissant in August of 1877, just weeks after the Princeton Scientific Expedition. The trio collected for 5 days. Scudder, an American entomologist and paleontologist, made the first measurements of Florissant lake deposits near the Big Stump. Arthur Lakes, a geologist, often captured his fieldwork with sketches and watercolors. Lakes made the first sketch depicting the geology of Florissant during this trip. He later made a watercolor of his sketch entitled “Map of Sedimentary Lacustrine basin at Florissant near South Park, Supposed to be Upper Miocene, drawn by A. Lakes, Colorado, Feb 20, 1878” (Meyer, 2003, p. 9). Scudder acquired many excellent specimens from the Hills and would later visit the area two more times.

Scudder became very familiar with the insects of Florissant, working with specimens collected as part of the Hayden Survey. During his career, Scudder described roughly 600 species and produced 23 papers on Florissant. Much of Scudder’s early work on Florissant was included in his 1890 monograph The Tertiary Insects of North America. Scudder was the first person to use the insect fauna to interpret a warmer paleoclimate for Florissant.

Scudder described and named possibly the finest butterfly compression fossil known to exist, which was found by Charlotte Hill. The butterfly, Prodryas persephone (Scudder 1878), is now housed at the Museum of Comparative Zoology at Harvard University (Pick & Sloan, 2004, pp. 64 & 65). The name persephone alludes to Persephone, the daughter of Zeus. As a ninth grader, Frank M. Carpenter, saw a picture of P. persephone in Scudder’s book Frail Children of the Air, which inspired his career studying insect fossils (Brosius, 1994, p. 120). Frank Morton Carpenter (1902-1994) became one of the most influential paleoentomologists of his time, working as the curator of fossil insects at the Harvard Museum of Comparative Zoology for over 60 years.

T.D.A. Cockerell (1866-1948) of the University of Colorado organized expeditions to Florissant from 1906 to 1908. Cockerell studied both plants and animals and published more articles on Florissant than any other paleontologist. Cockerell was the first to document the different collecting sites at Florissant. He was also the first person to describe tsetse fly specimens from Florissant, the discovery of which was a great surprise as living species are restricted to sub-Saharan Africa. S.H. Scudder described Palaestrus oligocenus in 1892 believing it was in the family Oestridae. Flies in this family are commonly known as botflies, warbler flies, heel flies and gadflies. The larvae of all of these flies are internal parasites to mammals. At the turn of the century better preserved specimens showing a clear proboscis were discovered. Cockerell recognized the new fossils and Sudder’s earlier specimen as belonging to the genus of tsetse flies Glossina. Tsetse flies are sanguivores, feeding on the blood of vertebrates. Glossina oligocena (Cockerell in 1908) is twice the size of living species (Gimaldi and Engel, 2006, p. 545).

Harry D. MacGinitie (1896-1987) was a paleobotanist who spent most of his career teaching at Humbolt State College in northern California. Early in his career MacGinitie worked for the University of Colorado where he was encouraged by Cockerell and Childs Frick (1883-1965), an American vertebrate paleontologist, to revise earlier work on the fossil plants of Florissant. MacGinitie excavated new sites at Florissant in 1936 and 1937 to collect additional specimens. In 1953 MacGinitie published the culmination of this work in his classic monograph Fossil Plants of the Florissant Beds, Colorado. MacGinitie revised the work of earlier paleontologists and was the first to consider Florissant fossil plants as a community, comparing them with modern vegetation. MacGinitie also used the fossil plant community to make inferences about the ancient ecology, climate, and elevation of Florissant.

The development of new technologies and techniques allow scientists to collect empirical data not accessible to explorers of the past. Thus, Florissant is a frontier that still has its modern day pioneers. A few examples are in order. Fossil Flora and Stratigraphy of the Florissant Formation, Colorado (Evanoff, Gregory-Wodzicki, and Johnson, 2001) includes papers exploring the stratigraphy, geochronology, paleoclimatic implications of the leaf and pollen floras, updates on megafossil flora, climatic implications from tree ring analysis of permineralized Sequoioxylon pearsallii specimens, identification of fossil dicots, and a review of paleoelevation estimates. This volume extends the work of MacGinitie.

Papers exploring the history of scientific work on Florissant, the role of biofilms in fossil preservation, paleoclimate, biogeography, spider identification, mammal fauna, preservation and conservation of fossil wood, as well as the development of a web-based paleontological database, were published together in Paleontology of the Upper Eocene Florissant Formation, Colorado (Meyer and Smith, 2008).

Herbert W. Meyer is a paleontologist with the U.S. National Park Service. In addition to his scientific papers, he is also author of The Fossils of Florissant (Meyer, 2003), the most important and detailed book on Florissant. The book is a true gem. Meyer has a gift for making scientific work public. Over a period of 130 years more than 1,700 fossil species have been described in more than 300 publications and dispersed to roughly 15 museums. Meyer has been instrumental in developing an on-line database, which digitally updates and archives this previously dispersed work (Meyer, Wasson, and Frakes, 2008, pp. 159-177).