Gilbert and Ellice Islands 12 January 1916 by the Gilbert and Ellice Islands Order in Council, 1915. Fanning Island and Washington Island also became included in the colony together with the islands of the Union Islands (now known as Tokelau); Christmas Island was included in 1919 but was contested by the U.S. under its Guano Islands Act of 1856. The Union Islands were transferred to New Zealand in 1926. The Gilbert and Ellice Islands colony continued to be administered by a Resident Commissioner. In 1930 the Resident Commissioner, Arthur Grimble, issued revised laws, "Regulations for the good Order and Cleanliness of the Gilbert and
Geology of the Pacific Ocean . The Pacific Ocean developed from the Panthalassa, a vast global ocean, following the breakup of the supercontinent Pangaea in the Mesozoic Era, gradually forming Gondwana and Laurasia, which in turn divided. There is no firm date for when the changeover occurred, as the replacement of the sea bed is a continuous process, though reconstruction maps often change the name from Panthalassic to Pacific around the time the Atlantic Ocean began to open. The Panthalassic Ocean first opened around 750 million years ago at the breakup of Rodinia, but the oldest Pacific Ocean floor is only around 180 Ma old.