Old State Quarry State Preserve

Old State Quarry is a historic quarry whose limestone was used to construct the old State Capitol building in Iowa City. 

About the Land

This 8.5-acre preserve is located seven miles north of Iowa City in northern Johnson County. It was dedicated as a geological and historical state preserve in 1969. 

Directions

1. From the intersection of I-80 and Dubuque Street (exit 244) on the north side of Iowa City, take Dubuque Street north about 6 miles into the town of North Liberty. 
2. Turn north (right) onto Front Street (County Road F28), go north 0.75 mile, and curve east (right) onto Mehaffey Bridge Road.
3. Follow Mehaffey Bridge Road about 1.5 miles to Rice Ridge Road. Turn south (right) and drive to the end of this private road, keeping to the right. 
4. Park on the edge of the road, but do not block driveways. Please respect private property (sign: State Preserve Boundary).

Historical Significance

This preserve played an important role in the settlement history and architectural heritage of Iowa. 

During the late 1830s, a team of quarrymen hand-drilled hundreds of limestone blocks and transported them downstream on rafts for use in the construction of the State Capitol building in Iowa City. The north and west walls of the quarry still bear the century-old drill holes into which steel spikes were driven to break loose the huge blocks. 

From the 1840s through the 1860s, the quarry supplied building stones and foundation materials for several buildings in the Iowa City area. The beautifully crafted stones for the foundation of the “Old Brick” Church, the wall along the T. Anne Cleary Walkway between Market and Burlington Streets, curbing throughout the “Northside Neighborhood” area, and supports for the old Burlington Street Bridge are several places where stone from this quarry can still be seen.

During the 1870s, the quarry also supplied foundation blocks for the new State Capitol building in Des Moines. 

Geology

The limestone seen here is composed largely of cemented fragments of brachio­pods (shellfish) that lived in a shallow tropical sea during the Devonian period (375 million years ago). The fossil remains were concentrated in erosional tidal channels and cut into older sediments beneath them. 

Fish teeth and plates also are common in lower parts of the channel sequence. The rock is known as the “State Quarry Limestone,” and this preserve is the “type-section,” or the standard reference locality for this particular rock unit. 

The geographic extent of the State Quarry Limestone is limited to Johnson County, where it reaches a maximum thickness of about forty feet. A few feet of this limestone may also be seen nearby at the Merrill A. Stainbrook State Preserve near the Mehaffey Bridge, one mile north of the Old State Quarry. 

Visitor Information

Other historic or geological areas in the vicinity include Merrill A. Stainbrook and Palisades-Dows State Preserves, Lake Macbride and Palisades-Kepler State Parks, and Devonian Fossil Gorge.