409 to 439 million years ago, marine creatures were living out their lives in a shallow, highly-saline inland sea floor. Corals, algaes, crinoids, and brachiopods were abundant in the Silurian sea. The earth dried, puckered, shifted, and slowly ground its way from the warmth just south of the equator up to the 42 parallel. The hard, calcium-rich skeletons and shells of the sea creatures were fossilized into smooth, thinly layered, or laminated, dolomite stone.
As part of Indian Creek Nature Center’s Amazing Space building, we are celebrating the natural history of Iowa. Using a stone veneer provides us with an opportunity to showcase the limestone that forms the bedrock of our region. The Anamosa limestone for our project is quarried just 21 miles northeast of the Nature Center at Weber Stone in Stone City.
The beauty of the buff colored laminated layers, and the occasional calcite crystal, or vug, that formed during the formation of the magnesium-rich rock is evident in the natural random splitface veneer.
The smooth layers of the stone is a testament to the calm sea conditions of the upper Silurian period of the Paleozoic Era the organisms once lived in.