Microfossils of the Salem Limestone (DS-01)
First quarried in south-central Indiana in the early 1800's for local use, the Salem Limestone (called Indiana Limestone commercially) was widely used as a building stone after the Civil War. Since 1900 it has been the leading dimension stone in the United States.

It is composed of tiny fossils and small fossil fragments deposited in large sandbars in a shallow sea that covered Indiana about 300 million years ago. One of its most common fossils is the tiny shell of a single-celled animal called Endothyra baileyi. These shells were at first mistaken for small spherical particles called oolites, meaning petrified fish eggs, and the limestone was knows locally as oolite limestone.

Our Hoosier State Beneath Us: Dimension Stone