Medical Definition of amnesia. 1: loss of memory sometimes including the memory of personal identity due to brain injury, shock, fatigue, repression, or illness or sometimes induced by anesthesia a period of amnesia after the wreck.
Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call mud. This composition places shale in a category of sedimentary rocks known as mudstones.
Intrusive rocks are a type of igneous rock. Igneous rocks are rocks that form from cooled magma. Intrusive rocks are igneous rocks that form from crystallized magma beneath the earth's surface. The other main category of igneous rocks is extrusive rocks, which are igneous rocks formed on the surface.