Complex sentence: It received it's name because from overhead, it resembles the portrait of a skull, but it is also believed that it was given its name because when surveyers were working on the north shore, they came upon two skeletons resting on the rocks.
Split into simpler sentences: It received it's name because from overhead, it resembles the portrait of a skull. It is also believed that it was given its name because when surveyers were working on the north shore, they came upon two skeletons resting on the rocks.