Maine is a small state in the far northeast of the United States, one of the New England States. It is part of the eastern mountain range, the Appalachians, and consists of various intensively folded rocks. Unfortunate for the existence of caves, they are predominantly crystalline rocks. Today's irregular coastline is a result of the last ice age, as the coastal area with its valleys was flooded by the rising sea. The typical caves are small but interesting, talus caves and fissure caves formed by tectonic movements, and all forms of erosional caves, especially sea caves along the 6,000 kilometers of coastline.