A very rare signed scrimshawed whale's tooth from Charles Darwin's voyage on HMS Beagle, 1832-36, (£30,000-50,000) is one of the most intriguing items in the forthcoming Travel and Exploration sale at Bonhams on 15 September.

It belonged to Private Thomas Burgess, a Royal Marine on board HMS Beagle for the entirety of its four year voyage and has come down through the family.

The tooth is the work of a fellow Marine on board HMS Beagle, James Adolphus Bute, who is known to have produced several examples during the epic voyage.

The silver mounted tooth depicts on one side a group of Fuegan natives in a canoe in the Beagle Channel, and on the other a settlement on Queen's Island, Tahiti.

On his return to England, Burgess made his way back to his home town of Stockport. He bought himself out of the service and, with the help of Admiral Sir Salisbury Davenport, secured an appointment in the Cheshire Constabulary where he served for 32 years until his retirement.

In the 1870s he corresponded with Charles Darwin, reminding him of their time together on the ship and received a signed photograph and a copy of Darwin's book in return.

Scrimshaw engraving on the teeth and bone of whales flourished from the first half of the 19th century, but few signed, or attributable examples are known to exist.

The Managing Director of Bonhams Knightsbridge branch, Jon Baddeley said, "The voyage of the Beagle is such an important journey in the history of mankind that anything associated with it takes on a special quality. This scrimshawed whale tooth is not only historically important it is also a beautiful object in its own right and has an impeccable provenance."

For further sale information please go to www.bonhams.com/travel