A collection of long lost slides were rediscovered in a dusty cabinet after more than 165 years. The 314 slides feature fossil evidence collected by Charles Darwin and Joseph Hooker from research voyages taken in the early 19th century. The treasure trove of fossils, rediscovered in a chance encounter, sheds light on the early work of Charles Darwin that influenced the development of his theory of evolution and natural selection.

The fossils were found in the vaults of the British Geological Survey headquarters in the UK. Dr. Howard Falcon-Lang, a paleontologist at Royal Holloway, University of London, told the Associated Press that he found the labeled unregistered fossil plants in a drawer of an old wooden cabinet.

I can't resist a mystery so I pulled one open, Falcon-Lang told the Daily Mail. What I found inside made my jaw drop! Inside were hundreds of beautiful glass slides. Almost the first I picked up was labeled 'C. Darwin Esq.'

It took me a while just to convince myself that it was Darwin's signature on the slide, the paleontologist told the Guardian, realizing quickly that he had found important and overlooked specimens.

This is an amazing snapshot into Darwin's working life. This was one of the most exciting periods in the history of science, forming the mind of the man who would develop the theory of evolution, which would change the world, he continued, reports the Daily Mail.

The hundreds of rediscovered slides reveal beautiful thin sections of fossil wood found in the early nineteenth century. The collection was put together by Joseph Hooker, a close friend of Charles Darwin, while he was employed by the Survey in 1846.

It is unclear why the unregistered collection was ever lost in the first place. The Geological Survey started a formal register of acquisitions in 1848, two years after Hooker had put together the slides. At the time, he was in the Himalayas and was not available to assist with the arrangement. When he returned in 1851, the slides had been moved. It may be that in Hooker's haste he failed to adequately catalogue the slides leading to their misplacement.

The collection includes early specimens taken by William Nicol, the pioneer of petrography, in the late 1920s and pieces from Darwin and Hooker from their adventures around the world in the 1830s and 40s. The collection includes pieces of fossil wood collected during Darwin's most famous Voyage of the Beagle in 1832 in South America. His trip marked the first developments of his theory of evolution.

The slides are available Tuesday in a new online museum exhibit. Take a look at the unregistered slides on the British Geological Survey's website.