What are the two bones of the skull?

The skull or cranium is also called the brain case.

All the bones of the skull (except the mandible) are firmly interlocked along structures called sutures.

Cranium or brain case or helmet is composed of eight bones including the frontal, occipital, sphenoid, and ethmoid bones, along with a pair of parietal and temporal bones.

The skull, in an adult, is only one bone made of 8 fused bones. The lower jaw or mandible, is not part of the skull but is part of the face.