Fox Island Alliance

Where Are the Dunes?

Memories of the Fox Island Alliance, the Park and the Dunes

by Dr. Jack A. Sunderman, Geologist

I joined the Fox Island Alliance in its first year, 1974, and my recollections of the first Board meetings are that of an interested bystander. I’m sure I was in awe of the enthusiastic and knowledgeable experts who were shepherding the Park into existence, for among them were Bob Weber (the Ultimate Biology Expert), Tom Dustin (the Ultimate Conservationist), and Pat Bowman (the Park’s First Naturalist).

However, it wasn’t long before I became engaged in supporting the establishment of a Nature Preserve within the Park. In order to have part of the park approved by the State as a Nature Preserve, that part of the Park had to be scientifically described, both biologically and geologically. At that time a rumor was circulating (initiated by anonymous geologists from outside Allen County) that the centerpiece of the Park, today called “The Dunes,” were not dunes at all, but instead were glacial features called eskers or kames!

Even though eskers may be about the size and shape of our dunes, no knowledgeable geologist (or Fox Island Trail Guide) would today call our dunes eskers! Eskers are stream deposits that form in meltwater tunnels in or beneath glaciers, leaving sinuous ridges on the land surface after the glaciers melt away. Eskers contain both sand and coarse gravel, in irregular layers and lenses. Kames also are meltwater stream deposits that contain interlayered sand and gravel. Kames are formed by small streams that flow into depressions in glacial ice or that flow down across an ice front, depositing poorly sorted sediment against the ice. Melting of the ice causes the sediment to slump, producing mounds of sand and gravel with contorted layers.

Today, geologists, trail guides and visitors to the park recognize the characterizing features of the Fox Island Dunes. Their most obvious feature is their overall shape - the dunes are formed into elongate ridges some 30 to 40 feet high. Their most defining features, however, are the characteristics of their sediment: the grain size, sorting, and composition of the sand. The dune materials are unconsolidated (not cemented) material and are entirely fine sand size (by definition, about 0.1 to 0.5 mm diameter). The sand is almost perfectly sorted into this one grain size; it has no pebbles or larger grains (no gravel), and has very little clay or silt. Most of the sand grains are clear grains of quartz, with minor quantities of smaller black grains of magnetite that can be attracted to a magnet. Park visitors find it fascinating to watch the magnetite grains march across a sheet of paper as a magnet is moved beneath it.

The following event emphasizes the importance of the educational tasks performed by the Park Staff and Alliance Trail Guides in communicating an understanding of the Fox Island Park’s marvelous natural features to its many visitors. A few years ago a very capable and talented reporter interviewed me for an article about the Park that appeared in the News Sentinel. The article was carefully written, gave a marvelous and accurate picture of the need for preservation of the Fox Island Park’s natural features, and gave a vivid description of things to do at the Park.

During the interview, we walked back to the dunes. The reporter had done some cross-country skiing at the Park, but didn’t remember seeing the dunes (which I wrongly assumed was because the dunes were snow-covered at the time). We climbed the main dune ridge and walked along it, looking at wildflowers and handfuls of dune sand. We even talked about sorting of the sand by the wind into fine sand sizes, and looked at a few small grains of black magnetite. All the while, the reporter wrote furiously, taking down information and checking and rechecking to make sure the details were absolutely correct.

To meet the reporter’s schedule, we walked slowly back along the dune crest to get back to the parking lot on time, when suddenly, the reporter turned to me and asked, rather incredulously: “But, Dr. Sunderman……where are the dunes?”

Twenty-five years of educational explanations, and the very reason for establishment of the Nature Preserve and the entire County Park flashed before my eyes. “Where are the dunes?? …… We’re standing on them,” I stammered.

Then I made a quick apology to the Reporter. “These are not ordinary dunes,” I said. “They’re called stabilized dunes. They are so old (10,000 years or so old) that they have become tree-covered, or vegetated. They are no longer active, moving dunes like those along our Lake Michigan shores that the wind still modifies from year to year. The Fox Island Dunes are fixed in position by a marvelous carpet of trees and undergrowth that also harbors a great variety of animals, some of which find the dune sand unusually easy digging for constructing their underground homes.”

“Oh,” cried the reporter, “now I do see the dunes!”