Crust (geology) Mars comprise secondary crust, as do the lunar maria. On Earth, we see secondary crust forming primarily at mid-ocean spreading centers, where the adiabatic rise of mantle causes partial melting. Tertiary crust is more chemically-modified than either primary or secondary. It can form in several ways: The only known example of tertiary crust is the continental crust of the Earth. It is unknown whether other terrestrial planets can be said to have tertiary crust, though the evidence so far suggests that they do not. This is likely because plate tectonics is needed to create tertiary crust, and Earth is the
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