District of Revúca vs Boulder

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Philip Heath Mendelson (born November 8, 1952) is an American politician from Washington, D.C. He is currently Chairman of the Council of the District of Columbia, elected by the Council on June 13, 2012, following the resignation of Kwame R.

Brown. He was elected to serve the remainder of Brown's term in a citywide special election on November 6, 2012, and re-elected to a full term in 2014 and 2018.

Source: Wikipedia

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In geology, a boulder is a rock fragment with size greater than 256 millimetres (10.1 in) in diameter. Smaller pieces are called cobbles and pebbles. While a boulder may be small enough to move or roll manually, others are extremely massive. In common usage, a boulder is too large for a person to move. Smaller boulders are usually just called rocks (American English) or stones (In British English a rock is larger than a boulder). The word boulder is short for boulder stone, from Middle English bulderston or Swedish bullersten.In places covered by ice sheets during Ice Ages, such as Scandinavia, northern North America, and Siberia, glacial erratics are common. Erratics are boulders picked up by ice sheets during their advance, and deposited when they melt.

They are called "erratic" because they typically are of a different rock type than the bedrock on which they are deposited. One of them is used as the pedestal of the Bronze Horseman in Saint Petersburg, Russia. Some noted rock formations involve giant boulders exposed by erosion, such as the Devil's Marbles in Australia's Northern Territory, the Horeke basalts in New Zealand, where an entire valley contains only boulders, and The Baths on the island of Virgin Gorda in the British Virgin Islands. Boulder-sized clasts are found in some sedimentary rocks, such as coarse conglomerate and boulder clay. The climbing of large boulders is called bouldering.

Source: Wikipedia