Excavation

Excavation is Primal Idle's fossil-digging activity, run from the Excavation panel on the Delving page. Expeditions and cave delves occasionally turn up a biome's Dig Site Map; spending a map starts a real-time dig at that biome's site, which delivers a crate of common fossils, Delving XP, and — about one dig in twelve — the skull of a species that lives in that biome. Skulls are the keys to the Museum.

How excavation works

1. Get a Dig Site Map. Maps drop from that biome's patrols (uncommon), its Guardian (several times more often), and its cave delves (best rate). Each map is specific to one biome.
2. Start a dig. At the Excavation panel, spend a map to begin a dig in that biome's site. The biome must be unlocked.
3. Wait it out. A dig runs in real time on the game clock and continues while you are away — offline time counts in full. Durations climb up the biome ladder, from 30 minutes at the first site to 90 minutes at the last.
4. Collect. When the dig finishes it auto-delivers straight to your bank: a crate of common fossils, Delving XP scaled to the dig's length, and a chance at a species skull.

Dig slots. You can run more than one dig at a time. The number of slots grows with your Delving level, starting at one and increasing as you level up (to a maximum of four).

What you find

Common fossils

Every dig delivers a crate of common fossils. The crate deepens up the biome ladder: early sites give mostly bones, mid sites add ribs, vertebrae, claws and plates, and the deepest sites can turn up amber.

Fossil	Sell value	Notes
Fossil Bone	20	The staple; every dig produces several.
Fossil Rib	35	Common from the first sites on.
Fossil Vertebra	55	From the Murkwater site onward.
Fossil Claw	80	From the Scorched site onward.
Fossil Plate	120	From the Frozen site onward.
Amberized Insect	200	Only from the two deepest sites.

Species skulls

Every completed dig has about an 8% chance to surface a species skull, drawn evenly from the creatures that live in that biome. There are 42 skulls in all — one per species. Skulls sell for a tidy sum, but their real purpose is the Museum, where a skull plus the right common fossils assembles that species' skeleton.

Delving XP

Each dig grants Delving XP scaled to how long it took — longer, deeper digs award more.

Dig sites

There is one dig site per biome. Longer digs at deeper sites yield richer crates.

Biome	Dig site	Duration	Delving XP	Skull chance
Grasslands	Sunken Barrow	30 min	60	~8%
Redwood Wilds	Rootbound Boneyard	37 min	74	~8%
Murkwater Swamp	Peatlock Trench	43 min	86	~8%
Cavern Depths	Echoing Ossuary	50 min	100	~8%
Scorched Badlands	Scorched Wash	57 min	114	~8%
Coral Shallows	Reefbed Shelf	63 min	126	~8%
Frozen Wastes	Permafrost Cut	70 min	140	~8%
Ashen Peaks	Cinder Terraces	77 min	154	~8%
Skyreach Plateau	Skyfall Scree	83 min	166	~8%
the Sundered Vale	The Shattered Bed	90 min	180	~8%

See also

• Delving — the skill that runs digs and sets your slot count.
• Museum — where skulls and fossils become skeletons.
• Expeditions and Caves — where Dig Site Maps come from.