Devil's Ridge is a Wildlife Area and Geological Preserve, with features formed by the last glacier that covered this area. Geologists generally agree there were four major glaciation events that covered Iowa, starting a million years ago, maybe a million and a half, with the most recent, the Wisconsin glacial epoch, melting away some 13,000 years ago.
As it retreated one of the features it left here was this lateral moraine, known as Devil's Ridge. A lateral moraine is a series of parallel ridges, or steps, made of debris which is deposited along the side of a glacier. The debris, or "till", is carried along the glacial margin until the glacier melts. Because lateral moraines are deposited on top of the glacier, they do not experience the postglacial erosion of land beneath the ice sheet and therefore, as the glacier melts, lateral moraines are usually preserved as high ridges. The steps of the ridge form as the glacier gradually thaws, with wind-blown loess, a rich dust-like soil, blowing in and settling with the assorted debris.
Lateral moraines stand high because they protect the ice under them from the elements, causing it to melt or sublime less than the uncovered parts of the glacier. Of note, this steep drop-off is believed to have been a 'bison jump site', where Native Americans harvested buffalo by herding them over the edge to be killed by the fall.
To receive credit and log a find on this EarthCache complete the following tasks: From the parking area, follow the fence line west, then walk along the ridge to the posted coordinates. Once there, use your GPSr to record your elevation, you will need this reading shortly. As you look over the ridge you can see steps, that almost appear to be man-made, but they're not. How do you think they were created?
Now make your way to waypoint DRM, N43 26.557 W095 34.189
When you arrive there record your elevation again. The difference between this reading and your first will give you an approximate height of the moraine, send this answer and how you think the steps were formed to the cache owner listed at the top of the page; click their name, then either the "Send Email" or "Send Message" links.
While photos are not a requirement for logging this, or any EarthCache, those you may decide to include with your log will be appreciated.
Thank you to the Osceola County Conservation Board for their cooperation in developing this EarthCache.
