Upper Ordovician Elgin Member, Maquoketa Formation strata exposed in a roadcut along Graf Road just south of Graf, Iowa, Dubuque County. A variety of marine fossils can be found here, especially nautiloid cephalopods in the upper section.

Upper Ordovician Period Maqoketa Formation, Elgin Member shaley limestone exposed in road cut along Highway 51 two miles north pf Postville, Iowa, Allamakee County. Has typical Ordovician age marine fossils .

Site near Gilead, Nebraska. ne1/4ne1/4 sec. 5, T2N, R1W Take Highway 136 west of Gilead in Thayer County for 1.6 miles. Then turn north on a gravel road for 1.7 miles. You will cross the Little Blue River. There is an excellent roadcut at a four-way gravel road intersection here, especially at the northwest corner. Exposed is at least 50 feet of limestone and shales of the Upper Cretaceous Greenhorn-Graneros Formation. In this area the contact between the two formations is not clearly defined but the more shaly interval at the base is part of the Graneros, whereas the upper limestone is part of the Greenhorn Formation. Fossils are very abundant in places including large pelecypods and fish scales and bone. Occassional shark teeth also occur. There is also a good exposure of the Greenhorn south of the river.

For fossil collectors of all levels Fossil and Prairie Center and Park Preserve at Rockford, Iowa is a must. Rockford is located in northcentral Iowa, southeast of Mason City. The former brick and tile pit is located along the north side of County Road B-47 just west of the town. The area has been noted for its marine fossils for more than 100 years. The Floyd County Conservation Board has turned the pit into a park and built a wonderful museum there. Unlike most parks, recreational fossil collecting is still allowed there. A wide variety of marine fossils can be collected but trilobites are virtually absent. The fossils occur in the Cerro Gordo Member of the Lime Creek Formation, upper Devonian. The unit varies from blue gray shales at the base to brown shales and thin limestones at the top. At the bottom of the pit is bluish gray shale of the Juniper Hill Member, also Lime Creek Formation but it virtually lacks fossils. There is a roadcut exposing the rest of the Cerro Gordo Member, and the ovelying Owen Limestone Member at the Bird Hill State Geological Preserve, three miles west of the pit along the same blacktop. Fossils can be collected there as well. Keep in mind this is the only preserve in the state where recreational collecting is allowed. visit www.fossilcenter.

Selected Works

Non fiction, geology, nature
Includes information on more than 150 collecting sites for the rockhound in Iowa and adjacent areas of Minnesota and Nebraska.
Nature
A comprehensive guide to Iowa’s state-owned parks, recreation areas, forests, and selected preserves.

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Paleocene Fort Union Formation exposed along the east side of Highway 16 at Buffalo, Wyoming, Johnson County, The site is 0.7 mile north of I-90. The shale has been melted by fire into a hard reddish slag. The fires were probably caused by lightening and is a common feature in the area. In some places the slag has an abundance of sequoia foliage, occasional cones, and other plant fragments. I've seen some great specimens from old quarries from the area and from this cut.. I only found a few plant fragments in the roadcut but am told the fossil bearing layer is actually about 20 feet up the slope.

Upper Cambrian Eau Claire Formation in an abandoned quarry north of Strum, Wisconsin.
The Upper Cambrian, St. Croixan Series, Eau Claire Formation is exposed in an abandoned quarry along the east side of County Road D 0.2 miles north of the junction of Highway 10 on the north edge of Strum, Trempeleau County, Wisconsin. Trilobite fragments, small brachiopods, and a few other fossils are abundant in places. The Eau Claire is the oldest fossil bearing formation in Wisconsin and this is one of the better exposures.

Mississippian Period, Osagean Series, Pierson Formation Limestone near Ridgedale, Taney County, Missouri. Three miles north of Ridgedale on Higway 65, four miles north of the Arkansas border, turn west on Highway 86. Continue west about four miles to Long Creek Road. There is a large sign there for the Cliffs at Long Creek. Exposures of cherty limestone occur along both sides of the highway. Some colorful chert can be collected as well as marine fossils but they are not overly abundant. Be on the lookout for black widow spiders as well.

Maynes Creek Formation exposed immediately east of LeGrand, along Highway 30, Tama County, Iowa. Cherty Maynes Creek Dolomite is interfingered with cherty Eagle City Member Limestone, the Eagle City has an abundance of brachiopods and a few other fossils. Beneath the Maynes Creek is about six feet of whitish oolitic limestone of the Chapin Formation. It has a wide variety of marine fossils. In the lowest part of the ditch is at least five feet of yellowish siltstone of the Prospect Hill Formation. It too has a wide variety of fossils but they are generally not as well preserved. At the top of the Prospect Hill is a burrowed zone. All the formations are lower Mississippian.

Middle Devonian Rapid Member at Jesup, Iowa
There is a small, old quarry north of Jesup Iowa, Buchanan County, which offers geode collecting. Take County Road V-62 (paved) north out of Jesup for 4 miles to County Road D-16 (paved). Go east on D-16 for about a mile to the Smith farm on the north side of the road. Stop at the house and pay a $5 per person fee to collect. Then follow the lane north past the house and to the old quarry east of the road. Exposed here is muddy limestone of the Middle Devonian Little Cedar Formation, Rapid Member. There are a few brachiopods and a zone of numerous trace fossils in the middle portion of the exposure. This has been a popular collecting site for years. Digging is required to find the geodes but the rock is soft.

Upper Cambrian Lone Rock Formation, Reno Minnesota

The Upper Cambrian Lone Rock Formation is well exposed along the west side of Highway 26 at Reno, Minnesota. There is a great view of the Mississippi River to the east. In the colorful sandstones and siltstones a fair abundance of invertebrate fossils can be found, but most are small or fragmented. Trace fossils are abundant. Others include trilobites, inarticulate brachiopods, and an occasional graptilite. Calcite vugs are also present. Prolonged exposure has caused the greenish minerals in part of the bluff to change to reddish brown. I've had my best luck at the southern end about six feet above the ditch. The upper levels are inaccessible.

Lower Purisima Formation, Lower Pliocene at Capitola Beach, California

The Lower Pliocene Lower Purisima Formation is well exposed at Capitola Beach. Capitola is located east of Santa Cruz on Highway 1 along Monterey Bay. Park in town and walk to the beach along the wharf. Farther west is the New Brighton State Beach where collecing is not permitted, nor farther east at another park. Mudstone and sandstone layers contain an abundance of marine invertebrates, mostly bivalves, but vertebrate material has also been found. It is legal to collect vertebrte material here. We didn't find any. Most of the matrix is soft and many of the specimens are fragile. Don't leave them out in the rain. High tides may make the site inaccessible.

Highway 12 at Stone State Park, Sioux City, Iowa

Iowa does not have a lot of Cretaceous age rocks with the exception of the Sioux City area in the western part of the state. Road cuts along High 12 south of Stone State Park in northern Sioux City and continuing north for at least 10 miles well expose three Cretaceous Formations. Included are sandy shales, sandstones, and some coal of the Woodbury Member Dakota Formation. It has some plant fossils, slenite crystals, and clayballs. It grades into the ovelying gray-brown shales of the Graneros Formation. The Graneros has pelecypods and fish scale and bone fossils but they are fragile. Entire fish fossils have been found in the Graneros in the area. It grades into chalky limestone of the ovelying Greenhorn Formation. The Greenhorn has abundant pelecypods, mostly Inoceramus. Some are quite large. They are thin shelled. Fish scales, teeth, and bones are also present.
Good exposures occur north and south of the junctions with County Road K-18. Not every cut exposes all three formations.