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June 2020

The abyss at Olana June 25, 2020

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The Abyss at Olana

Robert and Johanna Titus

                          

But the real tourist attraction in the area is Olana. We stood on the bank in front of the south-facing porch of the old mansion and gazed at its fine view of the Hudson Valley and Catskill Mountain. This is one of the great vantage points from which to see the Catskills. There are days when the atmospheric conditions are just right, and the mountains seem to reach out to you. It’s not just a view; this is also a genuine work of art. Frederic Church intended the porch should have this vista; it is, among many others, one of his “planned views.” For thirty year he was able to enjoy the scene and we envy him that.

But as geologists, we are privileged to see some other views at Olana. On that wonderful site our minds drifted back into deep time. We were at the bottom of the abyss that was once here. The waters were cold and black, but more than anything else they were still and silent. This was a dead seafloor. Nothing crawled across the mud and nothing swam in the waters. We scooped up some of the mud; it was soft and sticky. It was foul with the remains of dead microbes that constantly rained in from above.

With time the avalanches came. The stillness was abruptly interrupted as the seafloor was jolted by seismic shocks. Shortly thereafter great masses of sediment began tumbling down the slopes. For long minutes there was the rush of dirty water. The torrent boiled as murky clouds billowed upwards all around us. Then the current slowed and gradually the water cleared. The Olana seafloor returned to it silent dead, stillness.

Our mind’s eyes rose through tens of thousand of feet of quiet water until they reached the surface of the sea. We gazed eastward and saw dense black clouds rising above the horizon. The blackness drifted my way and soon it rained volcanic dust into the water all around. Then we looked back eastward again and now a rising landmass had replaced the black clouds on the horizon. The stark profile of volcanic mountains defined this new horizon

The passage of time accelerated. As we watched, this landmass grew taller and its shores swelled out toward us. We were soon lifted out of the sea by the rising gray crust. Occasional, the earth beneath us shook with powerful quakes as the land rose higher and higher. Eventually, we found our imaginary selves high atop a still rising Taconic Mountain range. To the north and south, volcanoes erupted in violent spasms. Below, to the west, what was left of that deep sea retreated away from the rising mountains.

There should have been a great deal of green in this image but there was none. This was a fine range of mountains, but it was a dead landscape that had replaced a dead seafloor. We were in the Late Ordovician time period, and life, especially plants, had not yet managed to colonize the lands. All around us was a bleak, blue-gray landscape. There were not even proper soils, just a litter of gray gravel lying upon bare rocks. Only the dry channels of gullies and ravines broke the monotony of the desolation.

We realized that we had come to the very spot where, 450 million year later, Frederic Church would stand. But we were not seeing what he would see. No, below us and stretching off to the west, a large river delta had formed adjacent to the rising Taconic Mountains. A complex of murky streams crossed the dark gray of that delta. Farther away we could see the retreating waters of the sea. It was bleak and lifeless vista, but there was grandeur in this, Olana’s great unplanned. view.

   Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.

Fossil corals of the Catskill Mountains June 17, 2020

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Fossil corals of the Catskill Mountains
Robert and Johanna Titus
From chapter 7 of their book The Catskills, A geologic Guide, 4th edition

Corals: Film and still photos of coral reefs portray some of the most vivid and colorful images of today’s seas. Such images are difficult to associate with the Catskills but, as in today’s tropical seas, corals were sometimes quite common in the old Appalachian Basin. While there is nothing in the Catskills that can match the Great Barrier Reef of Australia, there were some fairly decent reefs in those times. Many of the Devonian forms were horn corals (see right figure below; (A) horn coral; B) digitate corals C) honeycomb corals. Courtesy of the New York State Museum) so named because they had skeletons shaped like a cow’s horn, wide and open at one end and curving to a point at the other.
The chamber within was divided into compartments by walls much the way you see in a cut open orange. Other types are called digitate corals (figure 7-2B), that is they grew long slender branches similar to fingers (the digits). A third common group, the honeycomb corals, grew massive honeycomb-like skeletons (figure 7-2C) that are similar to some modern-day corals. Corals are only occasionally found throughout the strata of the Appalachian Basin, but they can sometimes be common in the Onondaga Limestone.

 

Stromatoporoids: The stromatoporoid is a peculiar fossil (left figure above), intermediate in appearance between sponges and corals. They were colonial- and reef-building animals, much like the corals. But they seem to have been simpler creatures, like the sponges. They appear to be entirely extinct, so we know nothing of their soft anatomy, and we will thus never be exactly sure what they were. They grew abundantly in the very shallow, nearshore environments of the Manlius Limestone and are seen within that unit, especially to the east as at John Boyd Thacher State Park (see Chapter Three). We have seen them in blocks of the Manlius that make up the Bronck homestead in Coxsackie.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.com.”

Fossil trilobites June 11, 2020

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National Fossil Day
Windows Through Time
Robert and Johanna Titus
Register Star – Oct. 2014

It’s coming up on National Fossil Day once again, and we have put it onto our calendar as something worth observing. But what will be we do to celebrate? We haven’t decided. We can’t put up a Fossil Day tree or carve a fossil pumpkin. We don’t really know what you are supposed to. Maybe we should just go out and do some fossil hunting. It’s, after all, a very nice season to get out and do such things. One of us, Robert, was trained as a professional paleontologist, so he has spent a lot of time doing just that, so, why not this year? National Fossil Day, 2014, is Wednesday, October 15th. It has been organized by the National Park Service in association with the American Geosciences Institute.
Last year we wrote a column about a very common fossil, a shellfish called a brachiopod. It was a form named Mucrospirifer (lower left in our picture) and it is very commonly found in our local Devonian aged sandstones and shales. Brachiopods, like clams, have two shells, but brachiopods are not mollusks; they belong to a very different group of invertebrate animals. Some species of brachiopods still live in our oceans, but they are quite rare. Back during the Devonian, however, they were enormously commonplace seafloor dwellers.


This year, let’s describe a wholly different type of Devonian animal – the trilobite.
Trilobites belong to a major group of invertebrates called the phylum arthropoda or simply the arthropods. Those are invertebrates that have external skeletons and jointed legs (actually “appendages”). We can‘t think of a better living example of an arthropod than the lobster. They possess very well-developed external skeletons and wonderful jointed appendages.
So too did the trilobites. Their external skeletons were divided up into three lobes – one running down their centers and two lateral lobes as well. That describes their backs, but underneath there was a long series of jointed legs. At the front end was a head which also had three lobes. They are not likely to have been terribly intelligent, but they did have something of a brain in the center of their heads. At the tail end of a trilobite was, of course, a tail! It also had three lobes, but it usually came to a pointed end.
Trilobites lived on sea floors. They date back to the early Cambrian time period which was more than half a billion years ago. They were very humble creatures; often they were scavengers, living by finding things to eat that were just lying on the bottom of the ocean. They were numerically important seafloor dwellers back then. In fact, whenever a geologist thinks about the Cambrian, it is likely with an image of trilobite. Trilobites were important bottom dwellers for several hundred million years, but they never surpassed their Cambrian success. They endured a long very slow and progressive decline. As the eons passed by, they just became less common and less diverse. Their final chapter came at the close of the Permian time period. That was about a quarter of a billion years ago.
Their final extinction is considered the event that brought the Permian Period to an end. We have to think that there was a final day, and a final hour, and a last minute, when the absolutely last trilobite experienced its final heartbeat. At that solemn moment, a great group of animals had disappeared. Extinction is, after all, forever.
But they remain, sort of. They are all dead but their fossils still can be found. Trilobites are among the most coveted and treasured fossil finds that a collector can hope to bring home from a day of hunting. Good ones are, however, very scarce. They had jointed skeletons, and, after death, the processes of decay caused those skeletons to disaggregate and fall apart. Because of that it is not very common for collectors to happen upon a complete and fully articulated skeleton. The two of us have only found a few of them.


The one that we have chosen to illustrate is called Phacops rana. It is named that because paleontologists have decided that it closely resembles a type of frog call Rana. It is a beautiful trilobite and it has been found here in our part of New York State. It was native to the Helderberg Sea and is sometimes, but not commonly, found in the Helderberg Limestone. That’s the unit of rock that makes up the great ledge at John Boyd Thacher State Park. It is the same limestone that you see along Rte. 23 at the large outcrop just west of Catskill. Can you go and find one for yourself? That is VERY unlikely.

Have you found a good fossil trilobite? Send us a picture at randjtitus@prodigy.net. Join our facebook page “The Catskill Geologist.”

Fossil Crinoids of the Catskill Mountains June 4, 2020

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Crinoids in the Catskills
From: The Catskills: a geologic Guide. 4th edition, Chap. 7
By Robert and Johanna Titus

Crinoids: Another living but largely unknown group of organisms found in the Catskills are the crinoids, also known by their common name, the sea lilies (figure 7-13; Drawing of a full crinoid, courtesy of the New York State Museum.- see below). Sea lilies are most remarkable animals. They commonly have five arms and that clearly indicates their relationship to the starfish. Although five arms may be an odd trait for an animal, what makes them truly unusual are their stems; they are stemmed animals! At the base of their stems are root-like structures called holdfasts, which tether them to the sea floor. Again, they are animals, but their plant-like morphology is what gives them their common name. Sea lilies grew in “meadows;” dense populations of them swayed in the currents much as meadow grass sways in the breeze. Today’s crinoids are brightly multicolored, and this adds to their plant-like image. They are especially common in the Coeymans and Becraft Limestones, although they are rarely well preserved. Look for abundant scattered stem remains.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” 

  7-13 – Typical crinoid, courtesy NY State Museum

  Living crinoid.

 

  7-14 – Limestone ledge, rich in crinoids

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