A Geologist's Jaunt through Staatsburgh

Our guest essayists for this blog, local geology luminaries Robert and Johanna Titus, are faithful supporters of Staatsburgh’s "Gilded Age Tea & Talk" series. They made several geology finds while here for a Tea this winter! Their latest book, The Hudson River Schools of Art and their Ice Age Origin, was recently published by Purple Mountain Press. For information about their upcoming lectures, geology hikes, and new publications, visit their Facebook page @TheCatskillGeologist

Guest essayists Johanna and Robert Titus.
Courtesy of the Catskill Center.

Stylolites at Staatsburgh

If you are going to a “Tea & Talk” at Staatsburgh, you are likely to spend a little time in a waiting room behind the gift shop. That, long ago, was sort of a reception room in a section of the house reserved for single male visitors. We love the Teas at Staatsburgh and have spent a fair amount of time in that room. We are always looking for and are attracted to things that are geologic, and there it was—at the south end of the room–a fine stone fireplace mantle.

Even from across the room this is a geologic wonder, but it only gets better the closer you come to it. Take a good look at the mantle sometime when you are there. Most people would identify this stone as being marble and that is technically right–sort of—but there is so much more to this particular stone. Take another, more careful, look. 

Detail of one of Staatsburgh's marble fireplace mantles. 

You should be able to make out a crystalline structure within it. We spotted this as indeed being marble and that meant that all these crystals were composed of the mineral calcite which is calcium carbonate or CaCO3. But long before this became marble it was limestone. That is a sedimentary rock which originated as a deposit in a special ecology - the bottom of a shallow tropical sea. We gazed into the marble mantle and looked into its distant past. We saw a sea that closely resembled today’s Bahamas. There were currents of aqua colored waters flowing across pink sand with algae growing out of it. Geologists have those sorts of experiences all the time, especially when stuck in a waiting room for just a little too long – and when being just a little bit too hungry!

Palimpsest ripples in a sedimentary rock.
Courtesy of Wikimedia Commons.

But how did the Bahamas turn into a marble fireplace mantle at Staatsburgh? That is not as hard as you might think. It is actually very commonplace geology, but it does take a lot of time. All that “Bahamian” limestone sediment came to be buried under deeper and heavier masses of thicker sediments. It was gradually squeezed and hardened into true limestone. Much later that limestone got caught up in a collision of tectonic plates. That collision lifted it up into the core of a rising mountain range. The intense pressures that accompanied all this squeezed the limestone even more and that is when it began to be converted into marble. You see, under intense pressures limestone becomes soluble. Sooner or later the dissolved material recrystallizes; it becomes converted into the coarsely grained crystalline mass that we call marble.

"The sharp transition from limestone and mudstone
to the bedded sandstone of Rudeis Formation."
Courtesy of ResearchGate.net

Stand back a few feet and gaze at this stone – then peer into it. Think about all the places it has been and all the things that it has done. It originated in a beautiful tropical sea. It sank into the ground as it was buried by many thousands of feet of other sediments and that hardened it into rock. It was then compressed by a great mountain building event and hoisted thousands of feet upward by that event. Erosion stripped away most of that rock and exposed what we see to quarrymen and sculptors.

Jagged, dark horizons known as "stylolites" in 
one of Staatsburgh's marble fireplace mantles.

But then there is something else. Look closely at the structures within the stone. Those jagged dark horizons are called stylolites. They are solution surfaces that were turned sideways by those sculptors. The weight of overlying rock pressed down on this marble and increased its solubility. It dissolved the calcium carbonate which escaped sideways from within this stone. Black, insoluble biological matter was left behind to clog the solution surfaces and make the stone more attractive, especially to members of the Mills family. And now to you too.

A Tabletop at the Bottom of an Ancient Sea

Upstairs, it is easy to admire the fine furniture that fills Staatsburgh State Historic Site. And, if you know your way around antiques, then there is a lot to see there. That includes the two of us. But we are also geologists, and we look deeper into these “antiques.” And so it was that as we passed through the mansion’s Oval Room, we noticed a fine tabletop tabletop  on a console table. 

Staatsburgh's Oval Room

Louis XIV-style console table

The table, according to Staatsburgh's curator, is a late 19th century Louis XIV style console table made out of wood that is carved with a gesso and gilt overlay. The tabletop had been cut and polished to produce a handsome shiny surface. We recognized it as a brown siltstone. That is a type of sedimentary rock. That stone had once been a mud at the bottom of an ancient sea. That mud had, millions of year ago, hardened into the stone we were looking at. But there was more; we spotted a fossil in the old silt. We were suddenly looking at an animal that had actually lived in that ocean- it swam in that sea. Take a look at our first photo.

A fossil in the old silt.

[Editor's Note: A similar table—"Grey Derbyshire Fossil Marble Table Top”—is housed in the collection of Sir John Soane’s Museum, London, while the floor of London’s Natural History Museum contains little fossils such as these.] 

We recognized the fossil as what paleontologists call a coiled nautiloid. You might call it a chambered nautilus – that is what the modern living ones are called. See our second photo.

A modern Nautilus.

The modern chambered nautilus lives in the southwestern Pacific Ocean. It is a distant cousin of the squid. It has the eyes and tentacles of a squid. It is sort of a squid with a fine-looking chambered shell. The modern nautiloid is likely largely unchanged from the ancient ancestral tabletop form. But this one is an isolated fossil: we don’t know where it came from, nor what ocean it lived in and, of course, we don’t even know exactly how old it is. But seeing it on that tabletop adds so much to the story. But we can’t help but wonder, did the Mills family know that story? They may have noticed it but what did they think of it?

Look, still one last time, and see the fine craftmanship. There sure is a lot to see here if you know what to look at.

Thank you again to our guest authors, Robert and Johanna Titus. Contact the authors at randjtitus@prodigy.net and join their Facebook page @TheCatskillGeologist