Yellow Lake
From billsfield.org
The Yellow Lake is a very large underground cave reached from the beach, it's main feature being a lake of spermaceti at its deepest point. Trunks of hardened spermaceti fall from the foggy ceiling into a network of rivers, which all flow into the lake.
The corpses of animals float down the rivers and into the lake, where they eventually wash up on its shore. They can also be seen in the pillars of spermaceti, absorbed into its wax.
Swarms of rod-shaped insects can be found patrolling the dark passages and hollowed caverns, which cause blindness if one gets too close.