J. N. Marsh

J.N. Marsh is a professor of Anthropology at Miskatonic University in The Illuminatus! Trilogy.

Conspiratorial
In TIT, Joshua N. Marsh was dishonored in the scholar community from his claims that Atlantis was real, in addition to further claims that the Gods of Atlantis were real as well.

Spoiler
In TIT, he disappears after he is dishonored and his disappearance is investigated by Daniel Pricefixer who concludes that he was lured into a drug cult and committed suicide during drug psychosis. It is strongly implied that he was converted to a neophile via tomato juice dosed with Aum (administered in Chicago by Joe Malik). The actual cause of his disappearance, and his eventual fate, is left unresolved.

J. N Marsh, despite being dishonored because of his writings, is correct in thinking that Atlantis existed and that the 'Gods' were real according to TIT.