Robert Logan Jack was appointed geologist for northern Queensland in March 1876, arrived in the colony in April 1877, and soon afterwards was made geologist for the whole colony, succeeding Richard Daintree. Wikipedia entry Australian Dictionary of Biography Notebooks (1882-1890) Northmost Australia
Captain Willem Jansz (Willem Janszoon) commanded the Duyfken, which sailed south-east from the coast of New Guinea and coasted down the western shore of Cape York Peninsula in 1606. Wikipedia entry Australian Dictionary of Biography The First Discovery of Australia With an account of the Voyage of the "Duyfken" and the Career of Captain Willem Jansz
Frank Jardine, with his younger brother Alexander Jardine,set out from Rockhampton with 42 horses and 250 head of cattle, bound for Somerset at the tip of Cape York Peninsula where his father John was setting up a cattle station. The pair reached Somerset on 2 March 1865 with 12 horses and 50 cattle, having dealt with constant harassment along the way as they forced their way through scrub and swamps and crossed at least six large rivers. Jardine claimed to have personally killed 47 people, with a total death toll for the trip of over 200. Both brothers were elected Fellows of the Royal Geographical Society and received the Murchison Award. In 1866 Frank settled on a station near Somerset and was appointed police magistrate in 1868. He died in 1919 of leprosy and is buried at Somerset with his Samoan Princess bride Sana Solia Expedition from Rockhampton to Cape York. Wikipedia entry Australian Dictionary of Biography Obituary Narrative of the Overland Expedition of the Messrs Jardine, from Rockhampton to Cape York, Northern Queensland.
Lieutenant Charles Jeffreys, naval officer who named islands in the Whitsundays Australian Dictionary of Biography Lieut. Charles Jeffreys, R.N. The Last Buccaneer?
Inspector Robert Arthur Johnstone entered the police service in September 1871, was appointed police magistrate at Winton in February, 1881 and closed his active connection with the public service in 1891 after occupying magisterial positions in various districts. His memoirs were first published in the Queenslander newspaper and subsequently republished under the title Spinifex and Wattle. Australian Dictionary of Biography Death notice (Brisbane Courier)