By KAREN MADORIN
As a gal who grew up bodysurfing every warm and sort of warm day of her teenage years, I love the ocean. Relocating to my birth state required readjusting until I realized I heard the reverberations of pounding waves when I stood atop windy Kansas hills. Adding sight to sound, high-ground overlooking windblown grainfields reveals that blowing wheat rolls like the Pacific waves of my childhood. After digging into Kansas geology, I realized an ancient seabed forms this landscape, offering OLD rocks and fossils to seekers of such.
The Western Inland Sea that split our land mass from the Gulf of Mexico to the Arctic Ocean during the late Cretaceous left treasures for the curious. During our early years of marriage, I’d find septarian nodules near Cedar Bluff. They were so common, I kept none. They’re harder to find now so I celebrated when a recent adventure delivered two weighty prizes to my house.
The first time I spotted a septarian nodule, I swore I’d found a petrified turtle. The segments of limestone and calcite or carbonate mineral look like turtle shell scutes. I’ve since learned no turtle created this stone. Anywhere from 144,000,000 to 65,000,000 years ago during the Cretaceous period, mud, limestone, or silt may or may not have compacted around a bit of organic matter, creating a round or oval conglomeration in that shallow seabed. Once dried, the orb cracked. Another wet cycle began and suspended minerals then collected in radiating fissures, creating eye-catching dividing lines to dazzle future collectors. Finding a septarian nodule is a journey across time. Listen for the sounds of lapping waves.
Speaking of dividing lines—that’s where these rocks got their name. That little flap of skin that divides nostrils is called a septum. Some Latin speaking scientist made the connection between his schnoz splitter and these rocks and named them septarian nodules. Tuck that tidbit into your trivia collection for future reference.
For those who love interesting looking rocks, these meet such criteria. Mixtures of colors, including hues of ochre, brown, yellow, orange, tan, white, and grey create geometric designs throughout the stone. Because the original mudstones split and filled with carbonates, calcites, or other minerals, these easily fracture which results in oddly shaped and sized stones. In fact, hounders often find parts instead of whole nodules. After millions of freeze and thaw cycles, it’s amazing we still discover intact specimens.
On that note, weathering takes its toll. Often times folks recognize septarian nodules because the outer crust or matrix covering the filled-in fractures erodes. I’m guessing more than one inexperienced nodule hunter walked right over a stone that recently emerged from protective soils and still has a limestone coating.
Because some nodules formed around organic matter, some collectors saw them in half to see what’s inside. It’s possible to find crystals or a small fossil. The ones I’ve found are just mudballs that cracked and filled with calcite or carbonate suspensions. When I want to see hidden treasure, I visit rock shops and museums.
When the day comes I can no longer find reminders that I live on an ancient seabed, I hope our daughters position my septarian nodules outside my window. I’ll see them and recall the thrill of finding rocks created millions of years ago by receding, shallow seas--a recollection that even beats body-surfing memories.