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Part of Hall of Planet Earth.
AMNH/R.Mickens
Tightly folded rocks like the ones in this outcrop illustrate how rocks can be deformed at high temperatures and pressures. The rocks were once siltstones and limestones. They were buried, folded, and transformed into slate and marble during the uplift of the huge mass of molten granite, known as a batholith, that now makes up the Sierra Nevada mountain range.