Igneous rocks choose one: a. form only at the earth's surface. b. are coarse-grained if they cool extrusively. c. form from the addition of heat and pressure to a pre-existing rock. d. were the first rocks to exist on the earth.

Early in the story when tom finds an indian skull in the woods which he kicks in temper. the devil then makes his appearance and, as tom surveys him, he notices that the devil is neither "negro" nor "indian." in fact, he has a "swarthy" complexion and is "begrimed with soot."

Geothermic gradient is the rate of increasing temperature with respect to increasing the depth in the earths interior. away from tech tonic plates boundaries, it is about 25-40 c/km (72-87 degrees f/mi) of depth near the surface in most of the world.