SYCAMORE – It all started when David Glaum stumbled across an interesting rock while working in a Kingston field last spring.

When he took it home and washed it off, he noticed an odd imprint and decided to have an expert look at it. Glaum, of Genoa, took the rock to the Burpee Museum of Natural History in Rockford and found out that the imprint created by a form of algae – 450 million years ago.

"That got me interested," he said Saturday while kneeling beside a small ridge of rocks with a brush, hammer and shovel nearby.