What do these special spaces do in Elefant Hunt?
They score 3d6 points when returned to port.
From the rules:

When a player lands on the Elefant Graveyard, he
takes an Ivory marker. When he lands in the Lost City,
he takes a Relic marker. Ivory and Relics are worth a
variable number of points upon their return to port, as
determined by a roll of three dice.


The value of each Relic and piece of Ivory is determined by totalling the roll of three dice.