Super Mario Infinity 2: The Cursed Gem/Goals/Desert Plateau and Desert Depths

From SMWiki

Desert Depths 2 Secret Exit

In the second area, follow the skulls into a small passage after you get off them to find the secret exit.

Super Mario Infinity 2: The Cursed Gem Guide
Verdant Valley | Glass Greens | Sinkhole Sewer | Machine Mountain | Desert Plateau and Desert Depths | Rocky Ruins | Ambient Island and Frozen Frame | Bowser's Bastion | Kamek's Keep and Big Boo's Base | Post-Kamek's Keep and Big Boo's Base | Shrine Island | Vacant Void