A chance discovery has yielded a “treasure trove” of fossils, including specimens collected by Charles Darwin. The collection, marked “unregistered fossil plants”, has been gathering dust in a gloomy corner of the British Geological Survey for more than 150 years.
When Howard Falcon-Lang of Royal Holloway University of London happened upon the collection by accident last April, he experienced a moment of disbelief when he examined the specimens. “Almost the first one I pulled out was inscribed with a diamond cut signature of C. Darwin, Esq,” he says.
Of the 314 re-discovered specimens, 17 have been verified as Darwin’s, samples collected during his voyages on the HMS Beagle from 1831 to 1836.
Two of the slide specimens bearing Darwin’s name were gathered on the island of Chiloe in the Chilean archipelago. In his account of his travels, Darwin described the island as a “miserable hole.” However, he found fossils of 40-million-year-old trees, which he shipped back to the British Museum where they were cut and segmented using newly developed techniques.
The find of these “lost treasures” offers more than an addition to Darwin’s catalogue. The collection also contains some of the first-ever thin sections (pictured) – a slide technique of grinding rock and sheath to a microthin sliver to reveal the anatomy of its inner structure.
Falcon-Lang describes the specimens as “exquisitely beautiful,” and the historical record shows that many were in fact made as works of art. Following the invention of the thin-section and the polarizing microscope in 1829, a cadre of professional slide-makers set up new businesses to satisfy the growing demand from gentleman collectors.
The story of how the specimens came to be lost is also a story of their provenance. They originally belonged to Joseph Hooker, a renowned botanist and a close friend of Darwin. As a young man in 1846, he was briefly employed at the Geographical Survey to help produce a comprehensive geological map of Britain and its colonies.
In addition to the specimens given to him by Darwin, Hooker’s collection also includes pieces from the private cabinet of Reverend John Stevens Henslow, who had been Darwin’s mentor at Cambridge and whose daughter Hooker would later marry.
The majority of the pieces are believed to be donations from explorers, missionaries and administrators from across the British Empire, and include specimens up to 15 centimetres in length and “bizarre slides of a tree-sized mushroom from 400 million years ago”.
The Geological Survey implemented a formal registry process for acquisitions in 1848. However, by that time Hooker had left for an expedition in the Himalayas and the collection, according to Falcon-Lang, “passed out of memory.”
Image: A petrified connifer from Whitby, UK. An early example of thin section technique pioneered by William Nicol. Courtesy of the British Geological Survey.