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c.34 million years old

Collection of Fossils

from Florissant, Colorado, USA

An example of early twentieth century collecting practices.

By Joanne O Meadhra-Elder


In the National Museum of Ireland’s Natural History acquisition register (dated November 2nd, 1909), the entry for  NH:1909:326, reads: “Collection of Florissant fossils (chiefly plants) bought from T.D.A. Cockerell; Florissant, Colorado; Received March and April 1909”.

The Collection

Consisting of 74 individual palaeobotanical hand specimens, from an area known as Florissant in Colorado, USA, the Florissant Collection contains 41 species of fossilised plants from the Florissant Formation (c.34 million years old) which belongs to the Eocene period. The collection was compiled from material collected by T.D.A. Cockerell during 1906-1908. Within the collection are three specimens which were published by Cockerell prior to their acquisition by the Museum in 1909. The specimen figured below, labelled Ailanthus americana by Cockerell, was one of these specimens.

Who was T.D.A. Cockerell?

Theodore Dru Alison Cockerell (1866-1948) was a British-born Victorian naturalist who despite never attaining a degree became Professor of Systemic Zoology at the University of Colorado in 1906. That same year his connection with Florissant began when he carried out excavations at the fossil beds there. The following year he was supported in his expeditions to Florissant by Yale University, University Colorado, The British Museum and The American Museum of Natural History.

Although best remembered for his work as an entomologist, he published in the region of 4000 papers covering a variety of scientific topics that interested him, including 140 papers on the fossilised flora and fauna of Florissant. His personal philosophy that learning should be done through action rather than books alone is evident in his numerous fossil hunting expeditions.

Collecting Practices and their Legacy

The early collectors of fossils from Florissant were primarily focused on the description of taxa to the detriment of other important scientific data. Unlike his predecessors, Cockerell’s approach was different. He was a pioneer in developing and advancing the traditional approach to the science of Palaeontology, and was the first scientist at Florissant to record localities and collecting sites during the course of his excavations. As a result of his prolific specimen recovery at Florissant between 1906 and 1908, a very large body of material became available for scientific scrutiny for the first time. Subsequent discreet collections of material compiled by Cockerell were acquired by museums and institutions across the globe, and it is within this context that the Florissant Collection found its way into the collections of the National Museum of Ireland.

A common issue encountered when documenting historic collections is the presence of extraneous data on a specimen, the meaning of which may have been known to the collector but which has subsequently been lost to memory. Whilst the Florissant fossils in the Museum’s collection were labelled to a high standard, several of them also had numbers written directly onto the specimen. No record had been included with the purchase of the specimens in 1909 as to the meaning of these numbers, however thanks to the high standards of data recording that Cockerell employed during his field excavations, and through liaison with present day scholars from the National Parks Service at Florissant Fossil Beds National Monument, it was possible to find out that these numbers related to not only the localities of the specimens within Florissant, but also the exact team member who collected the specimen. This exchange of information was made possible as a direct result of the high standard of collecting techniques and recording pioneered and employed by Cockerell.

Learn More

This collection of specimens is part of the museum’s research collection and is not on public display; however there are displays of other palaeobotanical fossils on the ground floor of the Natural History Museum.


I am very grateful to Stephen Callaghan for his work producing the photographs for this article.


Meyer, H.W. & Smith, D.H. (Eds). (2008) Palaeontology of the Upper Eocene Florissant Formation, Colorado, [Special Series] The Geological Society of America, 435.


Collection of Fossils is located at:
In Storage

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Canadian Pseudo-fossil

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A Consequential Cache

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