Big Bay Sandstone Cliffs

By Kevin Selkregg

great lakes view of lake with rocks in the water

It was a warm Thursday evening on July 31st, 1952, when an army officer marched into The Lumberjack Inn and shot the bar owner dead. A murder in a town such as Big Bay on the southern Michigan shore of Lake Superior would be so unlikely for a small community of around 200 people. Oddly, this murder became the town’s claim to fame through a movie adaptation of a book inspired by this event. The Anatomy of a Murder, starring Jimmy Stewart, was filmed on location a few years after the murder. The Lumberjack Inn still stands today and patrons can stroll up to the bar past the crime scene chalk line on the floor.

In early September 2022, my wife Brigitte and I vacationed on Big Bay. We were thrilled to spend a week on Lake Superior, our favorite of the Great Lakes. The largest of the Great Lakes, Lake Superior is also the largest freshwater body of water in the world. Unlike other Great Lakes, which often have silt and algae hiding the view of what’s beneath the surface, the clear waters of Lake Superior reveal it all unashamedly. The sandy bottom near the shore displays ripples formed by wave action, with many rocks visible in deeper waters.

Big Bay’s fishhook-shaped outline is about two and a half miles wide from the southeastern tip near Big Bay Point Lighthouse to Black Rock Point in the northwest. The land on the east side of the bay has a gradual slope to the waterfront, with many homes bordering the sandy beach. The west side of the bay, by contrast, is fenced in by red sandstone cliffs, some 50 feet high.

When I observed these cliffs through my binoculars from the back porch, I had a growing desire to explore the shallow waters beneath the cliffs. As a geologist who loves the rocks that the lake waters tumble onto the shores, the search for many rock types is addicting. Tumbled glacial deposited rocks and resident indigenous rock layers provide a variety of rocks the waters “choose” to leave. I knew there must be something of interest at the base of those red cliffs a mile away.

kayaking on lake superior to rock hunt

Sitting on the porch with my binoculars one morning, the desire to explore the rust-colored cliffs was irresistible. Waters, calm as a mill pond early in the morning can become an angry white-capped cauldron in the afternoon. When we pushed off the beach in our kayaks, red cliffs of sandstone gleamed brightly as they faced the rising sun in the east.

rock formations on lake superior

The water was flat that morning at the beginning of our 30-minute watery trek, but the wind gusts later turned a gently heaving lake to an unsettling chop. Brigitte’s ball cap was blown off in one gust and there was no way to retrieve it. We paddled over the creepy skeletal hull of a shipwreck in 20 feet of water near the break wall extending out from a marina.

jacobsonville sandstone lake superior michigan round red circles

Arriving at the beach edge under the cliffs, we were greeted by sharply contrasting reddish and white sandstone colors. The color in this sandstone formation, called the Jacobsville Sandstone, is a result of the oxidation of iron in the calcium and silica cement between the minute sand grains. Micron-sized hematite crystals form as a very thin paint-like coating over the sand grains, turning them light orange-brown color.

Kerber-Jacobs Quarry (Keweenaw Digital Archives of the Michigan Tech Archives). Calumet Theater, Calumet Michigan (Paul R. Burley). Waldorf Astoria postcard (New York Public Library’s Digital Library).

Left to right: Kerber-Jacobs Quarry (Keweenaw Digital Archives of the Michigan Tech Archives). Calumet Theater, Calumet Michigan (Paul R. Burley). Waldorf Astoria postcard (New York Public Library’s Digital Library).

Besides the unique geologic history there is an architectural history of the Jacobsville Sandstone. As early as the 1860s, it became obvious that the Jacobsville Sandstone was useful for building material because of its strength, durability, and aesthetic appeal. Quarrying operations began in and near Jacobsville Michigan, on the Keweenaw Bay side of the Keweenaw Peninsula. The very first use of this sandstone for building material was for blast furnaces in the production of iron. Its construction potential for commercial buildings is seen today in such buildings as the Calumet Theater on the Keweenaw Peninsula and the original Waldorf-Astoria Hotel in New York City.

lake superior rocks in the water

Looking up and down at the red sandstone cliffs from the water’s edge, we saw regions of white in the form of spots and wide, wavy bands. In these regions, either the iron was still present but was prevented from oxidizing, or there was no iron in between the sand grains. Large dots or bulls-eye patterns are a common feature with an unclear source. Some geologists have explained that the normal oxidation of iron was prevented by a stronger chemical reaction due to the presence of organic inclusions in the sandstones. The white dots and bulls-eyes are actually a two-dimensional view of a three-dimensional process within the original body of the rock. A similar behavior is seen in the thin white sandstone layers in the cliffs. A consequence of these layers are the white bands “bleeding” out into the shallow waters at the cliff base.

red sandstone rock cobbles and pebbles with smooth eroded edges

The glass-bottom-boat view of the shallow waters near the shore revealed plenty of collectible rocks. Mostly white and red sandstone rock cobbles and pebbles with smooth eroded edges were covering the bottom. Yet, dispersed throughout the bottom, I found solid black basalt rock with some white or pink veins. Alongside was its larger boulder “mother” rock. Some rocks displayed pink and black zones while others revealed salt and pepper patterns of black and whites.

These rocks are the glacial-deposited rocks from thousands of years ago. The high vertical sandstone cliffs are common along the lake shores. A combination of the uniform grain size in the massive sandstone, along with a weathering process of the freezing and thawing of water seeped in cracks, lead to large portions breaking off to the waters below. In addition, the severe waves and wind on the lakes also contribute to the steep features in the cliff walls.

Like the red and white bullseye patterns in the Jacobsville Sandstone, the town of Big Bay reveals a contrast in events, history, and natural beauty as a backdrop to this small Upper Peninsula community.

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This article appeared in the Beachcombing Volume 38 September/October 2023.

All photos courtesy of Kevin Selkregg except as marked.

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