Tour of the Turtle’s Back: Ancient Mackinac Island

Approaching Mackinac Island by boat offers excellent insight of ancient geological forces which shaped the landscape we enjoy today. As the last glaciers retreated about 11,000 years ago, a tremendous amount of meltwater filled ancient Lake Algonquin to a depth of about 220 feet higher than current Lake Huron. At that time, only the highest point of Mackinac Island stood above the water, being about ½ mile long and nearly ¼ mile wide. For many generations, Native Americans have referred to this high point as the Turtle’s Back, as its domed shape creates the perception of a giant turtle floating on the water.

Although exaggerated, this 1817 illustration by Francis Belton clearly illustrates the high point of ancient Mackinac Island.

 For about 3,000 years, the churning waves of Lake Algonquin eroded softer portions of limestone along the shores of this ancient island. As softer sections were removed, harder portions of recemented limestone, known as Mackinac breccia, were left behind, creating features which are still visible today. The two most prominent of these are among Mackinac’s oldest natural wonders – Skull Cave and Sugar Loaf.

 Both of these formations are examples of sea stacks which resisted the erosive power of Lake Algonquin waves. These pillars of breccia became separated from the ancient island as softer rock was gradually washed away. Both features also include caves, which were slowly excavated by the pounding surf, thousands of years ago.

This 1915 map, drawn by Morgan H. Wright, clearly outlines the features of the Turtle’s Back.

 Start your tour of the Turtle’s Back by heading north from Fort Mackinac, along Garrison Road and Rifle Range Trail. Upon your approach, high bluffs of the ancient island rise before you, with reconstructed Fort Holmes perched at the top. Skull Cave is located near the southwestern corner of the ancient island. At first, it may be difficult to imagine this formation as a sea stack, as it is smaller and more eroded than Sugar Loaf. The cave itself largely collapsed by 1850, and was subsequently filled in further. Like other formations across Mackinac Island, this cave was used as a sacred gathering place by nearby Anishinaabek residents, who interred their dead here for centuries. As a measure of respect, and to help preserve this ancient formation, access beyond the fence is not permitted.

 Published on August 19, 1842, an article in the Sandusky Clarion, of Sandusky, Ohio, included the following description of Skull Cave. “Not far from Fort Holmes is a small cave, called Skull Cave Rock, because the Indians were in the habit of interring the dead here. The passage in is necessarily on the hands and knees. The cave itself is about twelve feet square… The rock is light colored limestone, and is constantly crumbling away. The little stone that breaks off from the main rock have many holes in them, and are very easily reduced to a powder.”

This 1897 depiction of Sugar Loaf includes a ladder which once allowed park visitors to access its cave.

 As you leave the cave, continue along Garrison Road, towards the cemeteries. Here, the high bluff of the ancient island largely remains hidden by trees. Venture past the Protestant Cemetery and turn right on Fort Holmes Road, winding your way up a hill to the high promontory known as Point Lookout. From here, a grand vista opens below you, foremost being the 75-foot pyramid of Mackinac breccia known as Sugar Loaf.

 During her visit in 1852, Juliette Starr Dana climbed a ladder which once allowed tourists to enter a small cave in the side of Sugar Loaf, about 15 feet above the ground. Crouching down and examining its surface, she wrote, “It seemed water-worn & the whole rock within & without was full of strange little holes, with the insides nicely polished as by the action of water.” Today, safety concerns prohibit climbing the formation or entering the cave, but a tour around its base is well worth the journey.

 In 1945, geologist George M. Stanley noted that Sugar Loaf stands about 300 feet east of the ancient island, and the top of this formation was a small island of its own. He wrote, “It is a magnificent display of limestone breccia. One may see by close inspection, fragments of bedding limestone of various sizes from vary small fragments to blocks several feet long, tilted in random directions and all cemented into a solid mass.”

 Leaving Point Lookout, continue down the road to Fort Holmes, located at the southern exposure of ancient Mackinac Island. The renowned geologist Frank B. Taylor visited this spot in 1890 and 1891. During the period of Lake Algonquin high water, he noted that we “would stand alone in a wide expanse of water. The nearest mainland would then be about 30 miles to the south and the nearest islands about 20 miles to the north and southwest. In all other directions open water would stretch away 100 to 200 miles.”

 In more modern times, this grand view of the Straits of Mackinac has been celebrated time and again by visitors for the last several centuries. In 1836, theologian Chauncey Colton exclaimed, “I may venture to assert that there are few scenes in nature which are equal to the view from Fort Holmes… To the west, the eye follows the straits until it rests on the bluffs at the northern extremity of Lake Michigan, or is lost in its transparent waters; while all around stretches the vast expanse, with here and there an island, looking pure and peaceful as if the impress of sin had never been laid upon it.”

Rock bluffs at the Durrell or Mill Creek Quarry, circa 1915

The Untold Story of the Mill Creek Quarry

Originally established by Robert Campbell about 1790, the sawmill, gristmill and farming activities at Mill Creek remained active for about half a century. Known as Private Claim #334, the site was bought by wealthy Mackinac Island merchant Michael Dousman in 1819. Sawmill operations ran until about 1839, and after Dousman died in 1854, his heirs sold the property for just $400. When the township was resurveyed in 1856, updated maps showed no trace of buildings on Campbell’s original 640-acre claim. Local lore states that William Myers removed gristmill stones from the abandoned site about 1860 to use at his mills near Cheboygan.

A 1917 photo of Lime Kiln ruins on Mackinac Island

Lime Kiln ruins on Mackinac Island, 1917

 About 1864, a new resource was tapped for the first time along the rocky bluffs of Mill Creek – limestone. People have quarried and processed limestone at the Straits of Mackinac since the construction of Fort Mackinac from 1779-1781. For many years, the old lime kiln on Mackinac Island was a tourist destination, and Lime Kiln Trail can still be enjoyed by visitors today. By the summer of 1827, a kiln was also in operation near the northwest shore of nearby Bois Blanc Island.

 Limestone in Michigan was formed millions of years ago, being composed of sediments at the bottom of ancient salty seas, filled with billions of fragments of corals and shelled creatures. Limestone is high in calcium carbonate, and when burned in a kiln, crushed, or pulverized, is valuable for making cement, concrete, mortar, and many other uses. Larger pieces of quarried stone were used to make roads, the stone walls of Fort Mackinac, its blockhouses, and officer’s stone quarters.

 Lime was first processed at Mill Creek about 1864 by a man with the last name of Young who stayed for a couple of years. The next record of limestone quarrying at the site can be found in a Cheboygan Democrat article, dated April 12, 1883. It reads, “Parties have begun to work preparatory to burning lime extensively at Mill Creek. They say that have orders for forty bushels per day during the season.” This record corresponds closely with the Michigan Central Railroad running tracks through the site in November 1881, making it easy to ship finished products to market.

 The first and only large quarrying operation at Mill Creek was operated by Willis G. Durrell, of Cincinnati, Ohio, from 1914-1923. Before organizing his company, Mr. Durrell began taking summer vacations in the vicinity of Burt Lake, Michigan. While there he learned of the Mill Creek site, which a local paper noted, “most of the county people know as a vast deposit of very pure lime rock, and which efforts have been made in the past to get capital to develop.” As his Cheboygan Limestone Products Company was being organized in 1913, an article in the Chicago publication Rock Products, detailed Mr. Durrell’s plans and described the site, noting, “It is known as the ‘Old Dausman tract.’”

 Mr. Durrell, assisted by his son Lawrence, was busy throughout 1914, hiring workers, purchasing and installing equipment, constructing kilns, and adding a railroad spur off the main line for easy hauling of finished products. Products included three grades of stone for road construction and “agricultural limestone” which was sold throughout lower Michigan.

Rock bluff at the Durrell or Mill Creek Quarry, circa 1915
Rock bluffs at the Durrell or Mill Creek Quarry, circa 1915

Rock bluffs at the Durrell/Mill Creek Quarry c.1915

The November 13, 1914 issue of the Cheboygan Democrat described the growing operation as follows:

A photo of Willis G. Durrell

Willis G. Durrell, 1856-1942

“Mr. Durrell, president of the Cheboygan Limestone Products Co., located near Mackinaw City was in the city Monday and he informs the Democrat that they are installing at the plant new machinery for pulverizing limestone rock for agricultural purposes and as soon as it is in shape they will turn out two car loads of this product a day. It is taking the place of land plaster and vast quantities of it is new being used by farmers. It is especially needed in southern Michigan where they have vast tracts of sour lands and pulverized limestone is being used to bring the land value back… The pulverized limestone will be sold at the quarry at $1.25 per ton, which is reasonable, and already many farmers of this county are preparing to make a test of it on their lands. The company is also engaged in crushing rock for roads and other purposes. They have fifteen men at work now and will gradually increase their force.”

 To maximize production, Durrell purchased a Jeffrey Swing Hammer Pulverizer for use at the quarry. Installed in late 1914, this new technology crushed limestone to a fine powder, eliminating the need for burning lime in kilns. It also produced material for other uses such as top-dressing roads, fluxing stone for glass factories and steel plants, and concrete for cement walks.

 The Durrell, or Mill Creek Quarry, boasted an exceptionally pure product, being 98.71 percent calcium carbonate. Their advertisements in southern Michigan newspapers asked readers, “Why use low grade when pure stuff costs no more?” To verify its composition, 40 samples of Mill Creek limestone were taken in 1915 and examined by scientists at nine laboratories, including the Michigan Geological Survey, University of Michigan, and Emery Institute of Cincinnati.Vintage ad for limestone at Mill Creek Quarry

A vintage ad for the Mill Creek Quarry
A vintage ad for limestone at the Mill Creek Quarry

Advertisements from various Michigan newspapers, 1914-1915

 Eclipsed by larger operations at Afton (near Indian River) and Rogers City, the Mill Creek Quarry ended operations after the 1923 season. From the 1930s through the 1950s, the abandoned quarry pits were featured stops for students to examine limestone strata during field excursions of the Michigan Academy of Science Arts and Letters and the Michigan Basin Geological Society. During this time, the greater portion of Private Claim #334 reverted to State ownership and was incorporated into the Hardwood State Forest, under the jurisdiction of the Department of Natural Resources.

Limestone rocks along Mill Pond Trail Located near today’s grassy picnic area, west of the mill pond, the old quarry pits were filled in before Historic Mill Creek Discovery Park opened in 1984. Archaeologists speculate that footings of the original sawmill may have been obliterated by quarry operations along the stream bed. The fact that other historic remains, including footings of the dam itself, were not destroyed is a fortunate footnote of history. Today, only a pile of rocky rubble remains along the Mill Pond Trail as evidence of a once thriving operation which remains an important part of the Mill Creek story.

Mill Creek – What Happened Next?

Mill Creek – What Happened Next?

The earliest known photograph of the Mill Creek site, taken in about 1915. The bridge carries the state highway across the stream and the lake would be to the back of the photographer. The “MC” markings are noting the location of the Michigan Central railroad. The bluff at left center is where today’s overlook is.

Visitors to Historic Mill Creek Discovery Park learn about the Campbell and Dousman families and their employees operating the saw and grist mills and farm at the site. What happened next? (more…)

Gibraltar Craig

Gibraltar Craig

Stereoview of Gibraltar Craig, ca. 1880s

Gibraltar Craig from near Anne’s Tablet, August 2018.

Many striking limestone formations are scattered around Mackinac Island – Arch Rock, Sugar Loaf, and Devil’s Kitchen, to name a few. One of the most seen, yet probably not considered as a formation, lies in front of Fort Mackinac as one looks towards the cannon firing. Gibraltar Craig is the rocky outcropping of limestone just below the upper gun platform of the fort. (more…)