Thomas Lempriere and James Clark Ross carve a marker on the Isle of the Dead in Van Diemen's Land to measure tidal variations, one of the earliest surviving benchmarks for sea level rise.

Thomas James Lempriere was a British colonial administrator in the Australian colony of Van Diemen's Land. He is known for his diaries depicting the convict period in Van Diemen's Land, his work as a portrait and landscape painter, and his work as a pioneering naturalist.

Rear-Admiral of the Red Sir James Clark Ross was a Royal Navy officer and explorer who explored both the North and South Poles. In the Arctic, he participated in two expeditions led by his uncle, John Ross, and in four led by William Edward Parry: in the Antarctic, he led his own expedition from 1839 to 1843.

Isle of the Dead is an island, about 1 hectare in area, adjacent to Port Arthur, Tasmania, Australia. It is historically significant since it retains an Aboriginal coastal shell midden, one of the first recorded sea-level benchmarks, and one of the few preserved Australian convict-period burial grounds. The Isle of the Dead occupies part of the Port Arthur Historic Site, is part of Australian Convict Sites and is listed as a World Heritage Property because it represents convictism in the era of British colonisation.

Van Diemen's Land was the colonial name of the island of Tasmania during the European exploration and colonisation of Australia in the 19th century. The Aboriginal-inhabited island was first visited by the Dutch ship captained by Abel Tasman in 1642, working under the sponsorship of Anthony van Diemen, the Governor-General of the Dutch East Indies. The British retained the name when they established a settlement in 1803 before it became a separate colony in 1825. Its penal colonies became notorious destinations for the transportation of convicts due to the harsh environment, isolation and reputation for being escape-proof.