Here's why:

* Intrusions are igneous rocks that have been forced into existing rock layers. They are formed from molten magma that cools and solidifies within the Earth's crust.

* Compressed layers of sedimentary rocks are formed by the accumulation and compaction of sediments over long periods. The pressure of overlying layers causes the sediments to become compressed and cemented together, forming sedimentary rock.

Here are some terms related to sedimentary rocks and their formation:

* Strata: Layers of sedimentary rock.

* Lithification: The process of transforming sediments into solid rock.

* Compaction: The process of squeezing out water and air from sediments.

* Cementation: The process of minerals precipitating from groundwater and binding sediments together.

Let me know if you have any other questions!