Well now that all of Myst is charted...
The mountain north of Blackrock is called Obsidian Tooth.
The plains that Verdant is in is called Shimmering Field.
The forest that Tranquil is in is called Forest of the Elders.
The island Luna is on is called Isla Blanco.
The bay by Caronea/Myst border is Laguna Azul Draco
