One of the ancient volcanoes is even famous in geological circles: the Ossipee Ring Dike. Its eroded mountains formed the cone of a volcano believed to have been about 10,000 feet tall.

The Ossipee ring dike formed around 90 million years ago, during the second of three major eruptions throughout the active period of the volcano that created the structure.

The Ossipee Mountains are an example of a “ring dike complex,” which forms when a magma chamber collapses. There was once a two-mile-tall volcano on Mount Desert Island, according to the ...

The Ossipee Mountains are an example of a “ ring dike complex,” which forms when a magma chamber collapses. Molten rock flows up to the surface and then cools, forming an outer ring of ...

The Ossipee Mountains are considered by many geologists to be a good example of a ring dike formation. These structures are created when an underground bubble of magma collapses, leaving a ...

The Ossipee ring dike formed around 90 million years ago, during the second of three major eruptions throughout the active period of the volcano that created the structure.