Divided Valley Riddle
"In the center of Sap-Meh Nome you can find me hidden in a canyon near Anthylla. I'm under a tree that thinks it's unique, but only because the nearby rock bridge is blocking it from seeing the others of its kind." Pick this one up at the Great Library in Alexandria, just down the stairs from the statue of Serapis.
The answer to the riddle lies in the Crocodile Lair of Sap-Meh Nome.
Halfway down the canyon, north of the alluded-to stone bridge, is a forked tree.
The treasure is at its base.