Fossils are fascinating: they reveal secrets about types of creatures that are no longer with us. They are also beautiful. Is there an underlying meaning to this beauty? I believe there is. I suspect these creatures are individual testimonies to a Creator, one who takes time to achieve His ends. By the measure of human lifetimes, lots of time.
How many creatures have lived under the Sun while Earth has been in existence? One study provides a ballpark estimate of around 11 million species on Earth today. Yet it is fairly obvious that many, many more types of living creatures existed over the totality of Earth’s history. Wow!
I’m a professional geologist. My research has focused on marine invertebrates and fish in western North America, but the fossils that are easily accessible to me are in the Lower Peninsula of the state of Michigan. They tell a fascinating story.
The rocks flanking Lakes Huron and Michigan, two of the impressive Great Lakes along or near the United States-Canada border, are surf- and ice-etched shelves and cliffs of pale limestone and dolostone. The limestone here and elsewhere in the region is often suitable for making cement, and due to their economic significance, the limestones of the Great Lakes Region have been thoroughly charted and investigated in microscopic detail.
The Great Lakes limestone layers, or strata, are often densely-packed with fossils. Fossils here are hard skeletons or shells of marine invertebrates—the remains of organisms that thrived in some archaic version of Cancun or the Bahamas. When I show these fossils to grade-school children, most picture these creatures living and dying under an earlier and much deeper Lake Michigan or Lake Huron. Then I ask them, “where do corals live today?” Their eyes widen as they take in the notion that what is now high and dry land once lay under a shallow tropical seaway. Wow!
Fossils of corals and other marine invertebrates erode out of the limestone strata fringing the lakes, are rolled in the surf, and are naturally polished. They are collected by thousands of beach-goers every spring and summer. The official state stone of Michigan is actually a naturally-polished fossil coral with beautiful geometric shapes: the “Petoskey Stone”, named for the community of Petoskey on the edge of Little Traverse Bay, Lake Michigan. While the official Petoskey Stone is the fossil coral Hexagonaria, beachcombers commonly call all their surf-polished fossils “Petoskeys”.
Since 1985, I have collected these marine fossils from abandoned and active quarries, exposed shelves of rock, and beach gravels in Michigan, Illinois, Ohio, and Ontario. Perhaps 1,000 are housed at Calvin College in our geology teaching collection.
Of course, the limestone strata which are exposed near the shores of Lakes Huron and Michigan do not float in empty space! They are components of a large stack of sedimentary rock layers: limestones, dolostones, sandstones, shales, and some beds of rock salt, gypsum, and coal. In Michigan, the stack varies between 2 miles and 3 miles in thickness, bottoming out on very old volcanic rock. The layers are remarkably continuous around the Great Lakes and across the northern Midwest. They do, however, gently flex upward and downward; deformed by pressure from the movement of Earth’s tectonic plates. In the case of the lower peninsula of Michigan, the layers sag slightly toward the center of the state, like a huge set of stacked saucers of rock. If you walk toward the center of the state, you will encounter the “rims” of saucers that are higher in the stack.
Near the center of Michigan, one encounters the highest layers in this two-to-three-mile thick stack. Here, near the state capital city of Lansing, the rocks exposed at the surface are sandstone layers which include some thin beds of coal. The sandstone and coals are full of fossil plants. But there are no corals or other marine biota. What is the meaning of this widespread bed of fossil plants? Layers across the Midwest and extending as far afield as Pennsylvania and Kansa, which occupy the same vertical position in their regional stratigraphies, host a very similar group of fossil plants. There is evidence that these plants grew on the sites they now are preserved in. Interestingly, these preserved ancient forest ecosystems are very different from those of today. The floras are dominated by plants like horsetails, clubmosses and ferns, but of much larger size than those of today’s world. There are a few coniferous trees, but not many. And there are no flowering plants. Today, flowering plants (including grasses and most deciduous trees) dominate our floras but they are completely absent from these layers.
At the surface of Michigan and nearby states too, the stack of rock layers is capped by a bed of loose debris which varies in thickness from zero (= bare exposed rock) to about 300 feet at its thickest. This debris is interpreted to have been deposited by vast flowing sheets of ice, like those covering Greenland and Antarctica today. Geologic dates in Michigan on materials like logs, sticks, bones, and teeth in these glacial deposits are comparatively recent, dating back a mere 13,000 to 11,000 years before the present. At the top of these loose materials lie modern soils as well as small lakes, bogs and rivers. Every once in a while a bone or a tooth is eroded out of these sediments, and sometimes even a portion of a whole skeleton. These fossils usually turn out to be bones or teeth of mammals; sometimes like those of today, but often not. In Michigan there have been numerous finds of fossil mammoths and mastodons, as well as giant extinct beavers and even arctic muskox.
In 1999, a bulldozer flattening the bed of what would be a driveway for a new church in my area turned up a large tooth—a molar tooth of a mastodon. A group of geology students from my college and I were granted permission to salvage remains from the site while the driveway construction was delayed. During five months of activity, we uncovered a bit more than half of an adult male mastodon. The molar teeth were those of an advanced individual, probably 45 years of age or so, based on comparison with molars of living elephants.
The sequence of rocks and their fossils, taken at face value, argues that a series of living communities, or biotas, occupied what is now Michigan at some time in the past. With care, some details of the lifeways of individual creatures like the corals or the mastodon can be examined. For example, our mastodon demonstrated severe spinal deformation. The creature must have walked with a noticeable limp, and probably with a lot of discomfort, for several years before his demise.
As a Christian paleontologist, I often reflect on Proverbs 25:2, “The glory of God is to keep things hidden; but the glory of kings is to fathom them.” Studying fossils is literally about fathoming things which were hidden and are coming to light. This is a privilege.