Vác vs Boulder

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This is a list of auxiliaries of the United States Navy. It covers the various types of ships that support the frontline combat vessels of the United States Navy. Auxiliary ships which function as hospital ships and as oilers are to be found in their own articles: List of United States Navy hospital ships and List of United States Navy oilers. Escort carriers, amphibious warfare vessels, and some mine warfare vessels were also originally classed as auxiliaries but were later given their own hull classification symbols outside the auxiliary series (which all begin with an 'A'). Links to these and other list articles of similar ships can be found throughout this article. Yard and district craft also function as auxiliaries but generally are smaller and less capable than their ocean-going counterparts, and so they generally remain in harbors and coastal areas.

Their hull classification symbols begin with a 'Y'. Ship status is indicated as either currently active [A], ready reserve [R], inactive [I], or precommissioning [P]. Ships in the inactive category include only ships in the inactive reserve, ships which have been disposed from US service have no listed status. Ships in the precommissioning category include ships under construction or on order. Listed ship classes will often state 'MA type' or 'MC type'. The difference is that 'MC Type' refers to ships designed by the United States Maritime Commission aka MarCom, while 'MA Type' refers to ships designed or converted under MarCom's successor agency, the United States Maritime Administration or MarAd. They are in fact the same designs, and the year 1950 is the date at which MarAd succeeded MarCom.

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