Final answer:
The two types of layering in rocks are foliation, occurring in metamorphic rocks, and bedding or stratification, which is found in sedimentary rocks. These layers can vary greatly and help geologists interpret geological processes and environmental conditions.
Step-by-step explanation:
The two types of layering that can occur in rocks are foliation and bedding. Foliation is a feature of metamorphic rocks where minerals are arranged in planes or bands due to the intense heat and pressure they were subjected to. Bedding, on the other hand, refers to the stratification observed in sedimentary rocks, where layers or beds are formed as sediment settles and accumulates in different environments.
These layers can be distinguished by their composition, color, grain size, or other properties. Bedding can lead to structures like cross-bedding, where inclined layers known as cross strata are formed on sloping surfaces, such as dunes or ripple marks. Foliation and bedding help geologists understand the environmental conditions and geological processes that formed a particular rock, aiding in the interpretation of Earth's history.