Final answer:
The Piltdown skull was ultimately revealed to be a combination of a modern human skull and an orangutan jaw.
Step-by-step explanation:
The Piltdown skull was ultimately revealed to be a combination of two types of specimens: a modern human skull and an orangutan jaw. The skull was discovered in 1912 in England and was considered to be an important fossil of an early human ancestor. However, it was later revealed to be a hoax, created by combining these two different specimens. The jaw was from an orangutan, while the skull was from a modern human.