[Rockhounds] Rare chunks of Earth’s mantle found exposed in Maryland

[Kreigh Tomaszewski]

Standing among patches of muddy snow on the outskirts of Baltimore,
Maryland, I bent down to pick up a piece of the planet that should have
been hidden miles below my feet.

On that chilly February day, I was out with a pair of geologists to see an
exposed section of Earth's mantle. While this layer of rock is usually
found between the planet's crust and core, a segment peeks out of the
scrubby Maryland forest, offering scientists a rare chance to study Earth's
innards up close.

https://www.nationalgeographic.com/science/article/rare-chunks-of-earths-mantle-found-exposed-in-maryland