Very little is known about Carlton Marvell. It is known that he was an explorer in the early 20th Century, and by the 1930s he was looking to explore worlds other than Earth. Unsatisfied with the state of rocket technology, he was introduced to the concept of the Dreamtime by an Aborigine shaman.
Similar, in theory, to The Bleed, Marvell decided to travel between universes via the Dreamtime, and the best place to do that was at Ayers Rock in the center of Australia.
He initiated his gateway with Elijah Snow in 1931, but swore Snow to secrecy before he left this universe forever.