Intrusive igneous rocks are formed when magma solidifies beneath the Earth's surface. The shapes they form are based on their structure and are correctly described as follows:
Lacolith (Dome shape): A lacolith is a large, lens-shaped mass of magma that pushes the overlying rock layers into a dome-like shape.
Lopolith (Saucer shape): A lopolith is a large, saucer-shaped intrusion where the magma sinks into a basin-like structure.
Phacolith (Lens shape): A phacolith is a small, lens-shaped intrusion that occurs at the crest of an anticline or the trough of a syncline.
Batholith (Irregular shape): A batholith is a massive, irregular body of intrusive igneous rock. It is the largest of the intrusive rock forms and is often exposed only after erosion of the overlying material.
