Christopher O'Non

Staff Writer

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Walking along the Lake Michigan shoreline, feeling the sand and water beneath your toes while hunting for rocks, is a favorite pastime for visitors and locals alike. But when you pick up a stone to admire its unique characteristics, have you ever stopped to wonder where it came from?

 

Every stone tells a story, offering a glimpse into a different chapter of Northern Michigan's fascinating geological and industrial history.

 

Some began their journey hundreds of millions of years ago when the region was covered by ancient seas. Others traveled enormous distances, carried south by massive glaciers during the Ice Age. And some aren't rocks at all, but remnants of the iron industry that flourished in Leland in the late 1800s. Together, these shoreline treasures reveal a remarkable history.

 

Many of the fossils found in Northern Michigan's shoreline were once living organisms that shared the same tropical waters during the Devonian Period, more than 350 million years ago, long before the Great Lakes existed. At that time, much of what is now Michigan was submerged beneath a warm, shallow saltwater sea, located approximately 25 to 30 degrees south of the equator, at a latitude comparable to present-day Chile. Over millions of years, the movement of Earth's tectonic plates gradually carried the region northward to its current location. These tropical waters supported thriving reef communities of corals, sponges and other marine organisms.

 

Like the Petoskey stone, the Charlevoix stone is another remnant of Michigan's ancient seas, formed from colonies of Favosites coral. Although similar in color to Petoskey stones, Charlevoix stones have a much finer honeycomb pattern of tiny, tightly packed cells. Their delicate fossil markings resemble miniature lace or finely woven mesh which are more pronounced when wet or polished.

 

Named for the Petoskey area, these stones can be found along much of Northern Michigan's Lake Michigan shoreline, particularly around Petoskey, Charlevoix, Grand Traverse Bay and Leelanau Peninsula.

 

Like the Petoskey stone, the Charlevoix stone is another remnant from the ancient seas, formed from ancient colonies of Favosites coral. Charlevoix stones are similar to Petoskey stones with the same coloring but have a finer honeycomb pattern of tiny, tightly packed cells. Their delicate fossil markings resemble miniature lace or a finely woven mesh which are also more pronounced when wet or polished.

 

The Charlevoix stone was named for the Charlevoix region and can be found throughout the Northern Michigan shoreline including Charlevoix, Petoskey, Grand Traverse Bay, and Leelanau Peninsula.

 

Other ancient marine fossils found along the shoreline include horn coral, chain coral, crinoid stems, brachiopods and fossil-bearing limestone. Each offers another glimpse into the diverse marine life that once inhabited Michigan's prehistoric seas.

 

Millions of years after these ancient seas disappeared, enormous glaciers made their way across the Great Lakes region during the Ice Age. These massive chunks of ice reshaped the landscape, deepened existing basins and carried rocks and sediment from distant geological formations.

 

As the glaciers retreated, they left behind granite, quartz, jasper and other colorful rocks that mingled with the region's ancient fossils. Among the more distinctive finds are puddingstones, recognizable by their colorful pebbles embedded in lighter-colored rock, and the occasional Lake Superior agate, known for its bright red, orange and white colors.

 

Both puddingstones and Lake Superior agates were formed long before the Ice Age but traveled here with the glaciers. This journey helps explain why rocks with vastly different geological origins can now be found alongside ancient coral fossils on the same stretch of Lake Michigan beach.

 

Not every colorful stone along the shoreline is a product of nature. What was once considered industrial waste discarded into Lake Michigan has become one of Northern Michigan's most sought-after beach treasures: the Leland Blue.

 

This striking, glass-like material appears in shades ranging from pale turquoise to deep blue-green. Although it resembles a naturally occurring gemstone, Leland Blue is actually slag left behind from an iron-smelting operation in Leland during the 1870s and 1880s.

 

During the smelting process, iron ore was heated in a charcoal-fired furnace, separating the molten iron from unwanted minerals. As the remaining material cooled, it hardened into slag. Depending on its mineral composition and cooling conditions, some of that slag developed the beautiful blue and green colors that make Leland Blue so distinctive. Over time, discarded fragments found their way to the shoreline, where Lake Michigan's waves helped smooth and round their edges.

 

Today, Leland Blue is highly sought after by collectors and can be found primarily along the shoreline near Leland. These colorful pieces of industrial history are often collected, polished and transformed into jewelry, decorative pieces and keepsakes.

 

You can discover these pieces of history firsthand along Northern Michigan's beautiful shoreline. From Peterson Park near Northport and Van's Beach in Leland to the rocky shores of Grand Traverse Bay, Charlevoix and Petoskey, each stretch of shoreline offers its own unique rock-hunting experience. Spring and the days following strong winds or storms are great times to explore, as shifting sand and waves reveal new stones that may have been buried beneath the surface.

 

And the shoreline's story is far from finished. Wind, waves, ice and changing lake levels constantly reshape the beaches, exposing new stones while burying others. What you find on one visit may be entirely different from what appears on the next.

 

So the next time you find yourself walking along Lake Michigan, take a moment to look down. That cool stones beneath your feet might be more than beautiful souvenirs. It just might be a piece of Northern Michigan's history, millions of years in the making.