The more we learn about volcanos, the more obvious it becomes that they had a big hand in shaping the world as it is. They build mountains, they form rock, and they even preserve some of the wildlife they kill. Volcanic ash can bury and preserve animals hundreds of miles away from an eruption! Even those who survived the ash later had their footprints preserved as the ash hardened, and that gives us clues about those creatures' movements in life.
Closer to the volcano, pyroclastic flow, in addition to ash, can kill and create negative images of whatever it buried. The case of the Blue Lake Rhino is a further method of preservation, when a strange confluence of conditions left a rhino-shaped cave. Even stranger are dinosaur footprints that formed in magma underground! How did that happen? The story is a little complicated, but SciShow explains it in simple terms. Volcanos are crazy. -via Damn Interesting