Wilderness State Park #26: Stromatolite & Jacobsville Sandstone Rockhounding in Emmet County, Michigan

Plan your visit

Pay-to-dig site

County

Emmet County

State

Michigan

Coordinates

45.75747, -84.96873

Coordinates are approximate. Confirm the exact ground in the RockHoundR app, where land overlays show which agency manages the area.

Land & collecting status

Pay-to-dig site

This is a fee-dig location. Hours, prices, and what you can keep vary by operator. Call ahead before driving out.

Public-land rules vary by agency, season, and field office. The RockHoundR app pulls live BLM, USFS, NPS, and tribal overlays so you can see exactly which agency manages the ground at this spot.

Best time to visit Wilderness State Park #26

Comfortable months (45 to 90°F highs)

Best months: April to October. Typical highs run 75°F in midsummer and 27°F in midwinter, with winter lows near 14°F.

Climate normals: NOAA 1991-2020 monthlies, CROSS VILLAGE 1E station (8 mi away), adjusted for elevation.

Geology at Wilderness State Park #26

This spot sits on Bois Blanc Formation, mapped as limestone that formed roughly 420 to 395 million years ago. Chert and agate nodules typically form inside carbonate rock like this and weather out as tough, waxy lumps in soils and creek beds.

Mapped unit

Bois Blanc Formation

Age

420–395 Ma (Early Devonian)

Rock types

limestone

Elevation

580 ft

Geologic mapping via Macrostrat and the underlying state geological survey maps (CC BY 4.0). Bedrock at the surface can vary within a mapped unit.

Sources & verification

Spot details combine the public RockHoundR location dataset, normalized mineral labels, agency land-status checks in the app, and community submissions. Coordinates are approximate until verified in the field.

State guidance last verified: April 1, 2026

• Michigan DNR, Rockhounding rules
• Michigan Geological Survey
• Isle Royale National Park, Rules
• Community submissions reviewed against published agency rules