Silurian Reef at Racine, Wisconsin


R eef flank beds at Quarry Lake Park contain abundant crinoid fossils. In the southeast corner of the quarry, these beds are nearly horizontal, in contrast to their inclined orientations in much of the outcrop.

General views of beds with abundant crinoid fossils.

When crinoids die, their skeletons separate into broken lengths of stem and hundreds of small plates. This bedding surface shows crinoid stems surrounded by abundant debris of small, separated plates.

Close-up of crinoid stems and debris of small plates. The actual skeletal material has been dissolved from the rock, and the stems and plates are preserved as hollow molds.

Reconstruction of the crinoids as they appeared in life. Death and decay of immense numbers of crinoid individuals produced the beds of crinoidal debris at Quarry Lake Park.

© 1997, Milwaukee Public Museum, Inc.