This means that the bottom layers of its waters do not mix with those above. McGinnis Lake is 16 m deep with a limestone bottom. Beyond the 12 m level, the water contains no oxygen. So, the sediments on the lake bottom are left undisturbed by any organism, since most cannot survive without oxygen. The accumulated sediments therefore contain valuable information for scientists and park staff regarding the environment around the lake during the past 10,000 years.
Useful information Established for day-use only, the park has no campsites.
Visitors must be prepared for at least a short walk, since the petroglyph site is about a kilometre from the main parking lot. There is space designated for handicapped parking closer to the petroglyph site and two wheelchairs are available upon request at the front gate. During the months of July and August there are evening programs offered on Tuesdays and Wednesday nights. Taking photographs or videotaping of the petroglyphs is not permitted.