The Madison Boulder is one of the largest known

glacial erratic A glacial erratic is glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by glacial ice, often over distances of hundred ...

s in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

and among the largest in the world; it is preserved in the Madison Boulder Natural Area in Madison, New Hampshire. The boulder is a huge

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

rock measuring in length, in height above the ground, and in width. It weighs upwards of . A part of the block is buried, probably to a depth of . It was acquired by the state from the Kennett family in 1946. In 1970, Madison Boulder was designated as a National Natural Landmark by the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propertie ...

References

External links

Madison Boulder Natural Area
New Hampshire Department of Natural and Cultural Resources Glacial erratics of the United States Landforms of Carroll County, New Hampshire Rock formations of New Hampshire National Natural Landmarks in New Hampshire State parks of New Hampshire Parks in Carroll County, New Hampshire Protected areas established in 1946 1946 establishments in New Hampshire {{NewHampshire-geologic-formation-stub