They sailed for 250 nautical miles (460 km) along the edge of the low, flat-topped ice shelf they called variously the Barrier or the Great Ice Barrier, later named the Ross Ice Shelf in his honour. In the following year, he attempted to penetrate south at about 55°W, and explored the eastern side of what is now known as James Ross Island, discovering and naming Snow Hill Island and Seymour Island. Ross reported that Admiralty Sound (which he named Admiralty Inlet) appeared to Ross to have been blocked by glaciers at its southern end.[4] He was awarded the Gold Medal of the Société de Géographie in 1843, elected to the Royal Society in 1848 and knighted in 1844.[5]