July 23, 2019
Did you know the limestone that goes into many Iowa roadways is full of prehistoric creatures? Throughout millions of years of geologic history, when present-day Iowa was covered by oceans, sea creatures were everywhere. Fossilized fragments of sea creatures were left behind in the rocks that were deposited by these oceans.
One of most prominent groups of fossils are the crinoids. Also referred to as sea lilies, researchers say the fossils have survived about 500 million years of Earth history and crinoid skeletal fragments make up a significant portion of Iowa's limestone deposits. This limestone is used for road base, as agricultural lime, as building stone, and as a component in concrete.