Partridge Point: Crinoid & Brachiopod Rockhounding in Alpena County, Michigan

Updated August 2026

Partridge Point is a mapped rockhounding spot in Alpena County, Michigan. Reported finds include crinoid, brachiopod, horn coral, blastoid. Below: coordinates, access notes, nearby spots, and trip-planning links.

Quick details

Access: Public area
County: Alpena County
State: Michigan
Coordinates: 45.00779, -83.43220

Geology at Partridge Point

This spot sits on Traverse Group, mapped as limestone that formed roughly 395 to 385 million years ago. Limestone like this typically forms in ancient seas, so marine fossils such as brachiopods, corals, and crinoids tend to weather out of fresh exposures.

Mapped unit: Traverse Group
Age: 395–385 Ma (Middle Devonian)
Rock types: limestone
Elevation: 570 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.

Best time to visit Partridge Point

Best months: April to October. Typical highs run 77°F in midsummer and 27°F in midwinter, with winter lows near 13°F.

Climate normals: NOAA 1991-2020 monthlies, ALPENA WWTP station (4 mi away).

Land & collecting status

Generally open to casual rockhounding

Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig.

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.

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

Found at Partridge Point

Each chip opens all spots that produce that material; the encyclopedia link opens the full ID and field guide.

Nearby rockhounding spots

Other rockhounding spots within driving distance of Partridge Point.

Partridge Point FAQ

Where is Partridge Point?+

Partridge Point is in Alpena County, Michigan, at 45.00779, -83.43220.

What rocks and minerals can you find at Partridge Point?+

Partridge Point is reported to produce Crinoid, Brachiopod, Horn Coral, Blastoid.

Is collecting allowed at Partridge Point?+

Generally open to casual rockhounding. Most public-tagged spots sit on BLM, U.S. Forest Service, or other federal land where reasonable hand collecting of common rocks and minerals is allowed. Confirm posted rules and active mining claims before you dig. Always confirm current rules with the managing agency before a trip.

What tools should I bring to Partridge Point?+

A rock hammer, a cold chisel, safety glasses, and newspaper or foam for wrapping finds cover most fossil ground. A trowel and a sieve help in soft exposures.

When is the best time to visit Partridge Point?+

The most comfortable months at Partridge Point are April to October.

How do I get to Partridge Point?+

Open the directions link to navigate to 45.00779, -83.43220 in Google Maps. Some spots are remote, so check road conditions before driving out.

More rockhounding in Michigan

See all 107 Michigan spots →

Open Partridge Point on the map

Use the RockHoundR app for live land overlays, weather, geology, directions, and saved finds.