Two volunteers wear waders and dark red plaid shirts. The one on the left holds an algae-covered rock that is about 12 inches long. The volunteer on the right uses a red ruler to measure the width of the rock.
Two volunteers wear waders and dark red plaid shirts. The one on the left holds an algae-covered rock that is about 12 inches long. The volunteer on the right uses a red ruler to measure the width of the rock.