Crust (geology) formed almost immediately after formation of the Moon. Magmatism continued after the period of intense meteorite impacts ended about 3.9 billion years ago, but igneous rocks younger than 3.9 billion years make up only a minor part of the crust. Crust (geology) In geology, the crust is the outermost solid shell of a rocky planet, dwarf planet, or natural satellite. It is usually distinguished from the underlying mantle by its chemical makeup; however, in the case of icy satellites, it may be distinguished based on its phase (solid crust vs. liquid mantle). The crusts of Earth, Moon, Mercury, Venus, Mars,
The Dog and Its Reflection down as it is crossing a stream and sees its own reflection in the water. Taking it for another dog carrying something better, it opens its mouth to bark at the "other" and in doing so drops what it was carrying. The story became incorporated into mediaeval animal lore. The Aberdeen Bestiary, written and illuminated in England around 1200, asserts that 'If a dog swims across a river carrying a piece of meat or anything of that sort in its mouth, and sees its shadow, it opens its mouth and in hastening to seize the other piece of meat, it