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Chalk is so common in Cretaceous marine beds that the Cretaceous Period was named for these deposits. The name Cretaceous was derived from Latin creta, meaning chalk. [10] Some deposits of chalk were formed after the Cretaceous. [11] The Chalk Group is a European stratigraphic unit deposited during the late Cretaceous Period.
Alaska: An American Colony. University of Washington Press, Seattle, WA. ISBN 0-295-98249-7. Henning, Robert, ed. (1981). Bits and Pieces of Alaskan History: Published over the years in From Ketchikan to Barrow, a department in the Alaska Sportsman and Alaska magazine – v.1. 1935-1959 / v.2. 1960-1974. Anchorage: Alaska Northwest Publishing ...
The Demopolis Chalk is a geological formation in North America, within the U.S. states of Alabama, Mississippi, and Tennessee. The chalk was formed by pelagic sediments deposited along the eastern edge of the Mississippi embayment during the middle Campanian age of the Late Cretaceous . [ 1 ]
As a teenager in the 1960s, Lewis Bratcher would devour stories in Life magazine about Alaska and dream of visiting America's last frontier. By the time he graduated from the University of ...
The Alaska Purchase was the purchase of Alaska from the Russian Empire by the United States for a sum of $7.2 million in 1867 (equivalent to $129 million in 2023) [1].On May 15 of that year, the United States Senate ratified a bilateral treaty that had been signed on March 30, and American sovereignty became legally effective across the territory on October 18.
The United States bought Alaska in 1867 from Russia in the Alaska Purchase, but the boundary terms were ambiguous. In 1871, British Columbia united with the new Dominion of Canada . The Canadian government requested a survey of the boundary, but the United States rejected it as too costly; the border area was very remote and sparsely settled ...
Niobrara Chalk was weathered and opalized in the Valentine phase of the Ogallala Formation. The Niobrara Formation / ˌ n aɪ. ə ˈ b r ær ə /, also called the Niobrara Chalk, is a geologic formation in North America that was deposited between 87 and 82 million years ago during the Coniacian, Santonian, and Campanian stages of the Late ...
Chalk mining is the extraction of chalk from underground and above ground deposits by mining. [1] Mined chalk is used mostly to make cement and bricks . Chalk mining was widespread in Britain in the 19th century because of the large amount of construction underway (and the Industrial Revolution ). [ 2 ]