Stand on a Devonian Coral Reef at the Ohio Statehouse

Ever since Lady Diana Spencer arrived on the scene in February 1981, I’ve emulated my role model’s downcast gaze.

Looking down at the ground while walking has its advantages. Careful observation of sidewalks has led to finding plenty of stray coins and even a few larger bills. While Washington and Lee University’s Speaking Tradition taught me to glance upward more often, this symbol of shyness has been a hard habit to break.

Today, I was in the company of 14 other downcast-gazers at the Statehouse. Why were we so fixated on the floors and steps of this august building? We were on a fossil tour of the Ohio Statehouse and Capitol Square that the Capitol Square Review and Advisory Board offered to celebrate Earth Day.

Luke Stedke, CSRAB’s volunteer coordinator, met us in the Map Room on the ground floor of the Statehouse. He introduced us to Dale Gnidovic, curator of Ohio State University’s Orton Geological Museum and our tour guide.

We first looked down at the floor to study the large map of Ohio that illustrates our state’s 88 counties. The map is constructed of five types of marble from around the world, as well as limestone. On the Franklin County shape, we saw Clear Carthage, a gray fossiliferous limestone from Carthage, Missouri (also known as Carthage Limestone). Dale pointed out Dark Cedar, a reddish limestone variety from the Holston Formation, on the Union County shape. Pink Tennessee, another variety of the Holston Formation, contains natural, dark-colored, irregular seams known as stylolites, on the Licking County shape. Verde Oriental, a green marble from Taiwan, composes the shape for Delaware County. The Italian Breccia Oniciata on the shape for Fairfield County is a light-brown travertine, a limestone deposited by fresh-water springs, with multicolored banding. The marble representing Pickaway County is Light Emperador, a dark-brown marble quarried in Spain that contains white calcite.

Dale explained that while present-day Columbus lies 40 degrees north of the Equator, it was located 20 degrees south of the Equator long ago. The area was covered by an ocean populated by stromatoporoids, a class of aquatic invertebrates now classified as sponges. The ocean was also home to other creatures like corals, brachiopods, cephlapods, gastropods and trilobites. While there are thousands of trilobites, Dale said there’s only one Isotelus trilobite, and that’s Ohio’s state fossil. Dale enthusiastically explained the difference between all these fossils and passed around examples of each.

The Statehouse is constructed of large blocks of Columbus Limestone of the Devonian age. Named for the quarries west of the Scioto River where it has been procured, Columbus Limestone is about 380 million years old. It crops out in a north-south line from Kelleys Island in Lake Erie to south of Columbus. Because the limestone was formed in a clear, shallow, tropical sea that covered the state, fossils of marine animals are abundant in the Columbus Limestone. During the Statehouse’s construction in the 19th century, inmates from the Ohio Penitentiary cut an estimated 55,000 tons of Columbus Limestone from the Sullivant’s Limestone quarry. Fossils abound in the walls, stairs and columns that make up the Ohio Statehouse and Senate Office Building, so we started exploring with downcast eyes.

“We’re standing on a Devonian coral reef!,” Dale exclaimed as we climbed our first staircase. Looking down at the steps, then looking up to study the walls surrounding us, we spotted horn corals, finger corals, colonial corals, cephlapods and gastropods. Some were whole; others were cross-sections.

When we reached the south hall on the first floor, Luke pointed out spiral snail fossils in the black squares on the floor. Dale told us that this was an example of Crown Point limestone from Vermont. Since it was used in the construction of Radio City Music Hall in New York City, it is known to the trade as “Radio Black.” Luke continued that the white squares on the floor were made of Pennsylvania marble. While expensive Italian marble was used in the House and Senate Chambers, the halls feature less-costly domestic marble.

In the Capitol Atrium, which connects the Statehouse and the Senate Building, we inspected huge limestone columns that were filled with fine examples of horn corals, brachiopods and stromatoporoids.

More downcast-gazing continued on the steps on the south side of the Statehouse. We saw more colonial corals, snails and even a small piece of rose quartz.

To conclude the tour, Dale suggested that we walk down State Street to take a look at another fine example of stone on Capitol Square: Berea sandstone, which also comes from the Columbus Limestone period. I knew right where we were heading: the Old, Old Post Office at 100 South Third Street. The exterior of the building is made of golden-tan rock-faced (rough-finished) Berea sandstone of Mississippian age, about 350 million years old. This particular stone is thought to have come from the quarries at South Amherst in Lorain County.

Standing on the steps of Bricker & Eckler, Dale told us that Berea sandstone is famous for three things: being a major oil producer; being used for grindstones; and as a building stone. Dale explained that in the 1870s, northeast Ohio produced three-quarters of the world’s supply of grindstones. Taking out examples of a grindstone and unweathered Berea sandstone from his “Ward’s Study Pack,” he said that the stone’s sand grains are naturally glued together at just the right hardness, and it has a nice, fresh surface for grinding. He added that Berea sandstone is an exemplary building stone because it can be carved in any direction and it won’t split.

The Ohio Department of Natural Resources’ Division of Geological Survey offers many resources for learning more about fossils and other geological features of Ohio. Building Stones in the Vicinity of Capitol Square, Columbus, Ohio, a walking tour created by Garry D. McKenzie and Dale Gnidovec, and Building Stones of the Ohio Capitols, an educational leaflet by Mark E. Wolfe, are two of the publications you’ll find on its website.  They helped me fill in some of the gaps in the notes I took during today’s tour.

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