Floria River Upstream Excavation is south of Popla Foothills Skyview Tower, north of Utsushok Shrine.
Cave Location
Floria River Upstream Excavation is located at 0809, -2972, 0012, which is south of Popla Foothills Skyview Tower, north of Utsushok Shrine.
Cave Features
There is a treasure chest behind bars, and a battery in the corner. Take a spike from the shelf and attach one of the metal cubes to the top of it, then place the spike in the ground next to the battery so that the metal cube is electrified and is as close to the wire on the wall as possible. Then attach the other metal cube to the top of the first one so that the wire in the wall is electrified. Go through where the bars opened, and open the chest to get a Topaz.
Then go east from the chest and follow the path to find this cave's Bubbulfrog.