James Clark Ross, exploring the Arctic with his uncle Sir John Ross and rear admiral William Parry, locates the position of the North Magnetic Pole on a northern extension of the Canadian Shield and the North American mainland located in the Arctic portion of the Northwest Territories, Canada.

Ross names the peninsula for his patron, Sir Felix Booth. (Boothia Peninsula is the former location of the North Magnetic Pole; by 1970, the pole will have migrated northward, to Bathurst Island).

British Royal Navy officer James Clark Ross locates the position of the North Magnetic Pole on the Boothia Peninsula on June 1, 1831.

British naval officer James Clark Ross commands the first scientific expedition to survey Antarctica, comprising the vessels HMS Erebus and HMS Terror.

Departing from Britain in 1839, the four-year voyage will chart much of the coastline of the Antarctic continent.

James Clark Ross commands HMS Erebus on his own Antarctic expedition and charts much of the continent's coastline between 1839 and 1843.

Captain Francis Crozier is second-in-command of the expedition, commanding HMS Terror.

Support for the expedition had been arranged by Francis Beaufort, hydrographer of the Navy and a member of several scientific societies.

On the expedition is Joseph Dalton Hooker, who had been invited along as assistant ship's surgeon.

Erebus and Terror are bomb vessels—an unusual type of warship named after the mortar bombs they are designed to fire and constructed with extremely strong hulls, to withstand the recoil of the mortars, which are to prove of great value in thick ice.

In 1841, James Ross discovers the Ross Sea, Victoria Land, and the volcanoes Mount Erebus and Mount Terror, which are named for the expedition's vessels.

They sail for two hundred and fifty nautical miles (four hundred and sixty kilometers) along the edge of the low, flat-topped ice shelf they call variously the Barrier or the Great Ice Barrier, later named the Ross Ice Shelf in his honor.

Antarctic explorer James Clark Ross discovers Snow Hill Island on January 6, 1843.

Uncertain of its connection with the mainland, Ross names it Snow Hill because its snow cover stands out in contrast to the bare ground of nearby Seymour island.