Here's why:

* Intrusive: The rock formed underground, when magma pushed its way into existing rock layers.

* Dome-like: The magma solidified in a shape resembling a dome or lens.

* Laccolith: The specific term for this type of igneous intrusion.

How Laccolitths Form:

1. Magma Intrusion: Magma rises from deep within the Earth and pushes its way between layers of sedimentary rock.

2. Pressure Build-up: The magma exerts pressure on the surrounding rock, causing it to bulge upward.

3. Dome Formation: As the magma cools and solidifies, it forms a dome-shaped mass.

4. Erosion and Exposure: Over time, erosion can expose the laccolith, revealing its unique shape.

Examples of Laccolitths:

* Henry Mountains, Utah: These mountains are classic examples of laccoliths formed by the intrusion of magma into sandstone layers.

* Shiprock, New Mexico: A prominent rock formation that is the eroded remnant of a laccolith.

Let me know if you'd like to learn more about igneous intrusions or other geological features!