Describe the nature and mode of origin of the main types of rock at the earth's crust.

Earth's crust eafels to the upper most layers and forms the part of lithosphere. [Rocks of Crust:] A) Nature & types & Mode of origin: i) Sedimentary Rocks refer to rocks as that are formed over years in layers after layers by Sandstone 2) Metamorphic rocks which are transformed over a period of time. by Shale rock 3) Igneous rocks which are formed

Nature : 1) Primary Rocks : Original volcanic 2) Secondary Rocks : derived from primary rocks. B) Igneous Rocks can be further divided into : a) Sill: sheet like rock formation b) Dyke: perpendicular collar c) Batholith: large magma inside rock d) Laccolith: Saucer type rock formation. 2) Hence, these are