How to Complete Survey No. 261
The objective is to survey points of geological interest. To do that, just check on all the sparkles on the ground.
The enemies here can inflict many status ailments.
The Tonberry King can inflict Stalk on a unit. The Tonberry King can then attack the Stalked unit with Karma or Knife, both of which cause a lot of damage and are likely to kill the unit.
The Reaver starts the battle with the Reflect status, so any spells that you try to cast on it will just bounce back to you.
If you kill an enemy, more will appear.
You can use the Mage Cannon by checking on the purple spots around the field.
However, since the objective is just to check on all of the sparkles on the ground, you can ignore the enemies if you prefer.