You find Meadela's Mantle Cave near Gerudo Highlands Skyview Tower.

Cave Location

This cave can be entered at -3977, -1250, 0429.

Explore the Cave

In the cave, you find an underground stream. You can read Billson's journal in this area if you wish.

Put a long wooden board flat on the water's surface and climb onto it. Before you go down the waterfall, look at the far wall to see this cave's Bubbulfrog. Then at the base of the waterfall, you can go through the waterfall to find a chest that contains a Topaz. There is a low tunnel near the chest that you can enter if you crouch. It contains Brightcaps and it leads to the bank of the pond at the base of the waterfall.

In the pond at the base of the waterfall, you will see some wooden beams in the water. This shows you where the tower is. Use Ascend on the part of the ceiling that is made up of flat wooden boards. You can gather Ice Fruit nearby and throw it at the water to make ice platforms to stand on and use Ascend from. This will allow you to reach the inside of the tower.