Geology of the Rocky Mountains Japan, Indonesia and the Aleutians; others are fragments of oceanic crust obducted onto the continental margin while others represent small isolated mid-oceanic islands. Magma generated above the subducting slab rose into the North American continental crust about inland. Great arc-shaped volcanic mountain ranges, known as the Sierran Arc, grew as lava and ash spewed out of dozens of individual volcanoes. Beneath the surface, great masses of molten rock were injected and hardened in place. For 270 million years, the effects of plate collisions were focused very near the edge of the North American plate boundary, far to the west of
Land Beneath the Ground! Volume 1. There is a "DuckTales" episode called "Earth Quack" which is basically a retelling of the same story. The difference is that Donald is not in the cartoon episode and Gyro Gearloose, Mrs. Beakley, Webby Vanderquack, and Duckworth were added. The Terries and Fermies have since reappeared in the "DuckTales" reboot, in the episode "Terror of the Terra-firmians". Land Beneath the Ground! "Land Beneath the Ground!" is a Scrooge McDuck comic strip story that appeared in 1956 in the comic book Uncle Scrooge, written by Carl Barks. Scrooge is worried about earthquakes damaging his money bin and is determined