Waterman Rock is a house-sized greenschist erratic with a circumference of 155 feet (47 m) and height of 38 feet (12 m) to 40 feet (12 m) or greater in Saratoga Woods Preserve near Langley. It may be the second largest erratic in Washington State, after the Lake Stevens Monster. The property including the rock was acquired in 2002 or 2005 for conservation.