Do you have a gravel driveway? A good first place to look for fossils in Wisconsin is in the rocks there. White or light gray stones found in most gravel drives are likely limestone or dolostone. These rocks fit the criteria for providers of crushed rock for infrastructure like roads—and they often contain fossils.
The gravel in your driveway likely came from a quarry near your home. After being crushed, it was transported to your home. Unless you know what kind of quarry it came from, you may only begin to guess what geologic formation it belongs to and it’s relative age. A geologic map of your area will provide some clues to the kind and age of rock around you. Go to our Bedrock Geology page to learn how to read a geologic map and find geologists’ descriptions of outcrops near you. [UPDATE LINK]
If you want to collect fossils the way geologists and paleontologists (geologists who specialize in fossils) do, you’ll need to find an outcrop of rock (a place where rock protrudes from the ground) likely to contain fossils. You have probably seen outcrops along the road where the highway cuts through rock. Which rocks might contain fossils? Look first in the dark blue areas of the map on this page.
Remember: there are safety and access issues any time you are doing geologic fieldwork—especially when collecting rocks or fossils. Outcrops can be on busy roads with dangerous traffic. Removing rocks and fossils can loosen or damage an embankment. Climbing on and breaking rocks with a hammer could cause injury. Quarries and gravel pits are almost always on private land. Outcrops along the road are often on private property, as rural property lines can be traced to the middle of the road.
If you want to find fossils that have been described by geologists, look for outcrop descriptions in the dark blue areas of the figure above. Look to the bottom of this page for descriptions of outcrops where fossils have been found.
In addition to fossil hunting using the resources described above, there are groups you may join and consult. Geology and rock clubs are often led by a school faculty member or have ties to scientists in related subject areas. If you’re close to a university, faculty members may be able to help you. Geology museums are also a viable alternative; these spaces are safer than hunting in a quarry and showcase fossils you won’t find anywhere else.
When collecting fossils, label specimens and record the locality, rock description, layer in the rock and any interesting features.
- Locality. Record the county, nearby roads and distinguishing features of collection site.
- Rock description. Describe the fossil-bearing rock type (sandstone, shale, limestone or dolomite) and include the rock color.
- Layer in rock. Describe the location relative to other visible layering.
- Interesting features. Sketch and describe the features of the location, including details like layering patterns.