A Big Geology Fan
The Woodstock Times
July 17, 1997
Updated by Robert and Johanna Titus

Striebel Road is one of the those out of the way lanes that you tend not to notice. It’s near Woodstock, but you hardly ever travel upon it. It doesn’t go anywhere in particular and, if you don’t happen to be visiting anyone there, you are not likely to use it. Unless you are a geologist; you see, we like to prowl around everywhere. We look for things. Recently we turned off of the Glasco Pike and onto Striebel Road, and, indeed, we found something.
We rode south on Striebel directly above Rt. 212, which itself runs immediately above the Saw Kill. we found that the landscape to our left was a nondescript plateau, flat and undistinguished. But, to our right, came quite a surprise. Just beyond the road the landscape dropped off a real, no-kidding-around, parachute-type cliff. We had been along Rt. 212, many a time, but we had never realized how steep the slope was here. It’s heavily forested and nearly invisible.
Cliffs aren’t all that unusual, but this one bothered us. A steep cliff is normally composed of bedrock, usually only rock can hold a vertical slope. But this one wasn’t a bedrock cliff; it was composed of a boulder-rich, sandy gravel. It was very likely a glacial deposit, but we wondered what kind of glacial debris would form a cliff along the upper Saw Kill. We knew that there was an interesting glacial story here, but what was it?
As we continued along Striebel Road, it gradually began a descent. The slope steepened and soon we had dropped down into Bearsville. We crossed Rte. 212 and turned onto Cooper Lake Road. As we ascended this other out of the way road, we found ourselves repeating what we had just done on the other road, only in reverse. At first our ascent was steep, then it leveled off higher up the road. So, we knew that the valley of the Saw Kill had once had a large glacial deposit in it. The deposit was composed of course-grained materials, largely boulders, cobbles and gravel. The smooth curved surface of the deposit was relatively flat at its top and then steepened down slope. Long after it had formed, the Saw Kill had gone to work on the deposit. The steep narrow valley of the Saw Kill here was eroded through this mysterious deposit. But, again, what was it?

  Bearsville fan is dotted

The next thing to do was to study the literature, and that’s where we found our solution. A 1930’s New York State Museum Bulletin mentioned the deposit, and the story, as we had guessed, was a good one. It takes us back about 16,000 years to the time when much of the upper Saw Kill still had a glacier within it. Earlier that glacier had descended Overlook Mountain and flowed down the Beaver Kill valley to Mount Tremper. But now it was melting rapidly; only a small portion of the ice remained. The landscape was just starting to recover from its glaciation and there probably were few, if any, trees in the area. Erosion rates, on the bare soils, were very great. The flow of the Saw Kill, brown or gray with sediment, gushed out of the steep mountains and descended to the valley flats at Bearsville. There the rushing flow slowed down, and enormous heaps of sediment were deposited. We call the deposit an alluvial fan. The Saw Kill flowed across this, probably breaking up into a large number of criss-crossing streams which descended the fan. At the bottom there likely were some substantial ponds. Off to the east, where Woodstock is today, the Saw Kill probably reformed and flowed onwards.
This was a big fan, a mile and a half wide, stretching from Byrdcliffe, in the east, to Bearsville in the south, and then halfway back to Cooper Lake. It originally had the form of a partial hemisphere. It would have been relatively flat on top and then sloped downward, maybe steepening. It must have pretty much filled the valley here; the sediments are about 200 feet deep.
Bearsville must have been a bleak sight at this time with its terrible rush of dirty waters in a barren post-glacial landscape. But this time was limited. As forests returned, they stabilized the earth, the rates of erosion slowed, and the glut of sediment ended. That’s when a more sedate Saw Kill began to erode that alluvial fan and it carved the narrow valley with the steep slopes that caught our attention. It is a good story and just another glimpse into the ancient history of our region.

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

Bash Bish Falls
The Columbia County Independent
April 16, 2004
Updated by Robert and Johanna Titus

Taconic Park is one of the leading scenic areas of Columbia County and Bash Bish Falls is the centerpiece of the park. It’s certainly a fine place just to go and enjoy the outdoors, but of course, people like us can’t just enjoy themselves like that. We are compelled to look at the rocks and there is much to see at this location.
When we visited the falls, we went up to the parking lot at the top of the road and descended the stairs down towards the falls. It didn’t take long to start seeing rocks and to start seeing a geological past. We have talked about mountain building events that affected our area hundreds of millions of years ago. These rocks seem to have gone through two episodes of uplift and they wear the scars of those events. The rocks here are called metamorphic rocks. They once lay many thousands of feet (perhaps miles) beneath the surface of the rising mountain range. It’s very hot that deep into the crust and, not surprisingly, these rocks came to be baked. They were subject to very high pressures as well; imagine just how hot it is and how high the pressure is that far down within the earth’s crust.

That’s why these rocks are metamorphosed. The term means, literally, to alter the rock from its original state. You can see what happened. These rocks are layered; we geologist prefer to say that they are foliated. If you look at them, you can see the layering. If you had a high-powered magnifying glass, you could see that the metamorphism had resulted and large numbers of crystals growing into this layered fabric. The rock is called a schist and within it are many crystals of a pale mica called muscovite. These give the rock its layering. You may know muscovite as the “glass” of old pot belied stove windows. The morphology of the rock reflects its metamorphic history. This sort of thing doesn’t just happen, there had to be a lot of heat and pressure back then. And “back then” was probably in the Devonian Time Period, almost 400 million years ago
Back then a land mass, that today we would probably call Europe, was colliding with New England. This is going on today where India has been colliding with Asia. Today, the result is the Himalaya Range, back then it was the Acadian Mountains of New England. You can imagine the pressures on our rocks at this time. But you don’t have to imagine them at all. Take another look at the rocks. Many of them are intensely folded. We hadn’t gone much farther than the bottom of the first staircase before we saw very intensely folded schists in a knob of rock just left of the stairs.
There was more, we saw folded, (contorted is actually a better word for it) horizons of white quartz. These seem to have formed when fractures opened up within the schist. As the fractures widened, the quartz crystals formed and filled up the space. This is simply another testimony to how dynamic rocks can become when they are buried that deeply within the earth.
We kept going down the staircase and we noticed that there was something else in the silvery schists. We saw speckles of a Coca Cola colored mineral which we recognized as garnet. Garnet is a gemstone, but these were too small to be of any value. They did indicate to us that this had been a relatively low grade of metamorphism. Our Bash Bish Falls rocks had not been all that deeply buried, and the amount of metamorphism could have been a lot worse.
The staircase and trail continued downward and twisted back and forth until, at last, we arrived at the base of Bash Bish Falls itself. This had been our goal, so we were happy to be there. The falls tumble over a massive outcrop of schist, https://www.facebook.com/?ref=logobut they spoke of a different moment in geological time. We suspect that Bash Bish Falls formed as a glacial spillway. Most falls in our area have an ice age origin and we bet these falls do as well. We gazed at the thunderous flow and imagined a time, about 14,000 years ago when even more water rushed out of the mountains above. This was when the ice age glaciers had only partly melted. Up in the hills above there would still have been a lot of ice and it was melting quickly. Most of the valley in front of the falls was still filled with ice. The flow of meltwater quite likely dwarfed today’s Bash Bish Falls. This must have been a glorious sight in its time.
Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Burroughs’ Boyhood Rock
Poughkeepsie Journal
Updated by Robert and Johanna Titus

Every rock has a story within it that can be read if you just know how to. As geologists, we know that this is so. Like so many of us we learned, long ago, how to read these tales of the distant past. So, it was no surprise that, upon visiting “Boyhood Rock,” we found a story worth repeating. This is certainly one of the Catskills best known rocks. It’s at Woodchuck Lodge, John Burroughs’ hideaway home in the western Catskills. Burroughs was the beloved turn of the 20th Century nature writer. His boulder is on his old family farm. He spent many an hour sitting upon it, gazing at its magnificent view and pondering the natural history all around him. Best known for his writing about birds, Burroughs, especially late in life, was an avid amateur geologist. He understood at least part of the story of Boyhood rock. He knew that the boulder was a glacial erratic. There is a photo of him, proudly pointing out to Charles Edison the nearby glacial striations.

The boulder is from the Oneonta Formation which makes up the local bedrock of the upper Pepacton Valley. The Oneonta sandstones are, for the most part, river deposits of the old Catskill Delta. The fossil delta is very well known within the geological community; it was an enormous complex of streams that originated in the Acadian Mountains in what is western now New England. From there these rivers flowed westward down into the Catskill Sea of today’s New York State.
There was a problem, however, that bothered us for a while. We were puzzled by the many small holes that littered the boulder’s surface. At first. we guessed that these were fossil animal burrows. Could these be the burrows of Burroughs rock? Alas the gods of nature writing would not be that kind to us. No, they just did not look right for burrows. Eventually, we found an especially well-preserved one and quickly recognized it as the cast of a fossil tree root. They were fossils of the Gilboa trees from one of the world’s oldest fossil forests. These were tropical plants, and so Boyhood Rock, a product of the ice age, must have had an older, equatorial ancestry.
Gilboa tree roots are common in the Catskills, but it was the first time we had ever seen them in a river sandstone. How could trees have been growing in the channel of a fossil river? In science, the solution of one problem often leads to another. A possible answer is that this stretch of the old channel had once been a great bend in the river. During an especially bad flood, the river carved a new route and the old bend was abandoned, leaving a large, curved lake called an oxbow. The lake gradually filled with sediment, and then trees began to grow, their roots penetrating the old river sands. That’s what we see today.
But there was another mystery that bothered us a lot. There are three boulders here, all of which match each other in terms of lithology, and all have fossil tree roots. This can’t be a coincidence as the odds are too great; the three rocks must once have been joined. Our guess is that there once was a much larger Boyhood Rock, transported not beneath a glacier but within it. As the ice melted this boulder was lowered toward the ground. Stresses generated at this time caused the original rock to break up into the three pieces, each of which “landed” near each other and remain as we see them today.
And, so it was that Boyhood Rock gave up its geological secrets. There is a great deal of satisfaction that comes from cracking a scientific problem, even if it is a problem of absolutely no practical significance.
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Contact the authors at rndjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

The Fall of the House of Vanderbilt
Stories in Stone
Oct. 29, 2004
Robert and Johanna Titus

Do you remember the story of that neighborhood in Schenectady that suffered the slump late last winter (2018)? Two houses and the earth beneath them suddenly began a slow collapse. A dozen or so people had to be evacuated. It made quite the splash in local news, for a while, and then faded from our regional consciousness. Well, we have followed the story and the end was sad, but predictable. It was ordered that both houses be razed. The danger was deemed too great to allow people to return to their homes.
We wrote about this back then and warned that this was no isolated event. Slides of this sort are common where there is uniformly fine-grained sediment, and that is throughout much of the Hudson Valley, including many areas in Columbia County. Our valley once lay beneath the waters of Glacial Lake Albany. Thick sequences of soft clayey sediment accumulated and, periodically, masses of this stuff slide downhill. The formal term is earth flow. It has happened in a lot of places. It will happen again.
You can go and see for yourself one other place where this has been going on and get a good look at how it affects the landscape. At the same time, you can see how a fine piece of architecture is threatened by a future earth flow. Head south down Rte. 9 to Hyde Park and visit the grounds of the Vanderbilt mansion there. The place belongs in Newport, Rhode Island, a great edifice of Indiana limestone. Around it, and to the north and south, is a sprawling estate that lies on a great bluff towering above the Hudson River. The Vanderbilts had a fine view of the Hudson and that must be why they chose this location. In the long term it may have been a fatal choice.
If you look around the mansion you will quickly notice that the grounds are smooth and flat. It might seem unnatural and you might suspect that the landscape was bulldozed, but Nature did this herself. There is an ice age heritage here. About 14,000 years ago this was Glacial Lake Albany. And back then the local stream, “Crum Elbow Creek,” flowed into the lake. This little stream carried a lot of sediment and deposited it in the form of a large delta that expanded out into the lake. It is the nature of deltas to have flat tops and very steep fronts. That accounts for the flat landscape here and also the steep slopes that face the Hudson Valley. The Vanderbilt mansion was built on the edge of the ice age delta. While you are walking the grounds, imagine yourself in chest deep icy lake waters.

Walk south from the mansion, towards the formal garden, and notice that the forested slope has a scalloped appearance; it looks as if a large ice cream scoop took out masses of earth. This is typical earth flow landscape. Each “scoop” represents an old slide. These have had the time to “heal” with the return of the forest.

Return to the south end of the mansion and take the dirt path downhill. Beyond is a long grassy meadow. If you look along the edge of this meadow you will, once again, see that scalloped appearance.
Now head north from the visitor’s center on the estate driveway. Soon you will find a very nice vista of the Hudson Valley. It’s worth the trip by itself. But, once again, look over the edge of the steep slope here and see the scalloped appearance. Over the eons many earth flows have occurred all along the edge of the old Crum Elbow Delta.
There is no reason to think that any of this has stopped. We would expect that every century or so, more of these events will occur. Now look and see how close to the edge of the delta the great mansion is. We are predicting that someday, much as was the case in Schenectady, a sizable portion of the Vanderbilt mansion will begin a downhill slide. Earth movements are very egalitarian; they affect the rich as well as the poor.
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Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Palenville by air
The Catskill Geologists
The Mountain Eagle – June 15, 2017
Robert and Johanna Titus

We would like to welcome what we hope are a large number of new readers from Palenville. The Mountain Eagle has expanded its coverage to your town. Palenville has an extensive historical heritage. It has been a place where visitors have long begun their ascent into scenic Kaaterskill Clove. Originally a tough trek, nowadays there is a modern highway so the journey is easy. In the 19th Century Palenville became an artist’s colony. Landscape painters of the famed Hudson Valley School of Art commonly spent their summers there and devoted themselves to sketching and painting the area’s scenic landscape. A lot of very good work was done in the vicinity of the clove. Palenville has always seen a great number of tourists passing through on their ways to the mountains.
Let’s visit the town of Palenville as geologists; and, let’s ask a deceptively simple question: why does it exist? The answer takes us back to the Ice Age. Geologists have long been drawn to Kaaterskill clove to view its landscape with a more scientific eye. That’s where we fit into the story. We love to hike the clove and the mountains north and south of it. There is an awful lot of very good geology to be seen there. So, when we got the chance to fly over it, we welcomed the opportunity. We had a pretty good idea of what we would see. Kaaterskill Clove is a great gash in the Catskill Front. Most of it was carved during the Ice Age, especially during the closing phases of that time. Melting glaciers provided enormous amounts of water that cascaded down the canyon, eroding it. Think of it as an oversized gulley!

Kaaterskill Clove had been there before our most recent ice age. It probably began eroding at the end of the Ice Age’s previous chapter. But about 13,000 or 14,000 thousand years ago there was another time of melting . . . and another time of erosion. You have to visit the clove and imagine it with deafening masses of raging, foaming, pounding whitewater thundering down its canyon. Erosion would have been going on at an alarming rate. Where there is erosion, the destruction of rock, then there must also be the production of large masses of sediment. Rock is converted into sediment, and it must be deposited somewhere. That is exactly what we were going to see.
Palenville has long been recognized by geologists as something that is called an “alluvial fan.” That is a large, fan-shaped heap of earth. Such fans spread out across a dry valley floor at the bottom of the sediment’s source. In this case, large amounts of sediment traveled down an eroding Kaaterskill Clove, and then spread out into a fan shaped heap at the bottom of that clove
A trained geologist can recognize such a feature on any good topographical map, and we did this a long time ago. But now, we were up in a plane, and there it was. As we flew by, we gazed into the great wide yawning clove. And spread out before it was the alluvial fan. We could recognize three roads that we knew. These were Bogart Road, Rt. 23A, and Rt. 32A. The three of them radiated out from the bottom of the canyon and spread out across the top of the fan. Nobody knew it at the time but, as laid out, those roads all descend the gentle slopes of the alluvial fan. The fan made an ideal location to build homes and, one by one, they appeared. And that is the geological story behind the origins of Palenville.
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Reach the authors at randjtitus@prodigy.net and see more at their facebook page “The Catskill Geologist.

Family Day Trip: Cohoes Falls
Windows Through Time
The Register Star
Robert and Johanna Titus
Nov. 27, 2015

There’s probably some good weather ahead of us so let’s go for another “family day trip.” That’s when we tell you how to get to some wonderful geological location that just happens to be far enough away so that you have to spend the day getting there, seeing it, and coming back. That’s something that the two of us enjoy doing, especially when the children and grandchildren are visiting. This time let’s go to the town of Cohoes.
You have probably heard of Cohoes, but perhaps you have not visited it. The town is famed for three things: 1) the Cohoes mastodon, whose skeleton is now housed at the New York State Museum; 2) the old Harmony Mills factory, which was one of our state’s premier industrial centers back during the 19th Century; and 3) the Cohoes Falls which the Mohawk River tumbles over. As it happens those all three are very closely associated with each other. An elephant, a factory, and a waterfall? How could they have anything in common, never mind a lot? Obviously, we have a great deal of explaining to do. Today let’s hold off on the mastodon and focus on the other two.
Harmony Mills is typical of New York State industrial might, not so much today, but back in the 19th Century when the “Empire State” was almost truly imperial. You have to go there and see them to believe them. To properly describe Harmony Mills we have to use two words that we usually hate to use: the Mills are an awesome icon of 19th Century industry. Those words have come to be used far too often in modern vernacular. They should only be employed when they are truly needed; here they are. The mills were based on water power and all that water power came from just a little upstream; that’s where the falls are. In the 19th Century waterfalls were an important component of our energy needs. Where there were awesome waterfalls then there would soon be large iconic factories. Harmony Mills was an enormous textile mill complex. It was constructed in 1872; it fell into hard times and closed in 1988. Today, it has been converted into upscale lofts.

The falls were harnessed to provide the awesome amounts of energy needed, so let’s talk about them. You can visit a site that has been developed to provide the most awesome possible view of this natural icon. Find your way to North Mohawk St. and head north through town until you can turn right onto Cataract Road. There you can park, get out and walk to the viewing stand. It provides an iconic vista of the falls, which lie maybe a mile to the northwest. Why are they there?
The falls are mapped as belonging to one of the most important rock units in all of the Hudson Valley – that is the Normanskill Formation. It is a mass of dark gray sandstone and black shale. The sediments that formed these first accumulated in an awesomely deep marine basin. The Normanskill Basin was likely tens of thousands of feet deep. Sediments, mostly awesome amounts of sand, tumbled down its steep slopes as submarine landslides, and piled up at the bottom. Those sediments eventually hardened into dark gray sandstones. During the awesome stretches of time that passed in between the landslides, muds accumulated and those hardened into the black shales.
When, and just after they were deposited, these materials formed flat sheets of sediment. But, if you look at our photo, you will see that the once horizontal strata are now steeply inclined. They were deformed during one of several mountain building events that shaped the Appalachian Mountains as they are today. A geologist looks at such deformation and interprets it as evidence for ancient mountain building. Our guess is that this event was the one called the Taconic Orogeny and that it occurred during a time called the Late Ordovician, about 450 million years ago.
If we could we would climb down to the falls and take a good look at the rock types that make them up, our guess is that a lot of those strata are composed of those dark sandstones. Sandstone is mostly composed of quartz and that’s a very resistant mineral. It makes very good cliffs and even better waterfalls.
We are guessing that, a long time ago, those strata came to be tilted during that mountain building event. Many hundreds of millions of years later, the Mohawk River started cutting across the Normanskill rocks. When the river encountered those tough sandstones, it had a very difficult time cutting through them. The result was the waterfalls.

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

Name Your Poison
On the Rocks/
Updated by Robert and Johanna Titus
June 18, 1998

Black sedimentary rocks are occasionally seen in the Hudson Valley. Recently, we described some along Rt. 209, south of Sawkill. The dark appearance of these strata makes them remarkably eye-catching and, when they make up tall cliffs, they loom, dark and menacing, over the landscapes.
It’s the shiny, jet-black shales that we are talking about. They are often rich in undecayed organic matter; it’s the carbon that makes these rocks black. This generally suggests to the geologist that there were low-oxygen conditions in the sea waters at the time of deposition. Without oxygen, most decay bacteria cannot function; they die before they can completely destroy the organic matter. But why low oxygen? That takes us back in time.
Back in the early Devonian Period, these shales were accumulating in a deep sea, immediately adjacent to the rising Acadian Mountains of western New England. Thick soils formed on the rapidly weathering mountainsides. The soils were easily and rapidly eroded and provided sediments that were eventually transported into the nearby Catskill Sea. This material was rich in dissolved nutrients, such as nitrates and phosphates. They fertilized the water and that led to the next step in what was to be a complex chain of events.

The fertilized waters were ideal for algae; they experienced algal blooms, great population explosions in the surface waters of the Catskill Sea. A whole ecology became established as dense mats of floating, or planktonic, plants and animals grew, somewhat similar to that of today’s Sargasso Sea. While all this was great for the plankton it was deadly for just about every other category of marine organisms. As the plankton died, they were attacked by decay bacteria; the algae bloom led to a bacteria bloom. But the decay process consumed so much oxygen that the seas soon became oxygen-depleted. The hapless bacteria had, in effect, poisoned their own habitat, because they needed oxygen too. Their numbers quickly plummeted and very soon, all types of animals, as well, suffocated in the oxygen depleted sea. But the algae just kept on proliferating in the surface waters where there was plenty of oxygen, diffusing in from the air above. Soon, large masses of undecayed biological material were sinking to the floor of the ocean. The climate was tropical, and the nearby coastal lowlands provided lots of vegetation, much of which drifted into the basin, adding more organic matter to the black shales. Almost all of these organics accumulated as thinly laminated, shiny black shales.

Back then, the Catskill Sea was largely isolated from other deep bodies of water; it was nearly surrounded by land or very shallow water. To its east, land blocked weather patterns and shielded the basin from most storm activity. All of these conditions promoted what are called stagnant, thermally-stratified waters. The sunbaked surface layer was hot, while deeper water remained cool. Depth stratification and a dense planktonic mat combined to prevent agitation and mixing of the waters, causing stagnant sea floor conditions to develop. Virtually nothing could live in this sea, except at the surface where there was always plenty of oxygen. This was truly the poison sea.
Many of the earliest Catskill shales are jet black, and they form the Bakoven Shale at the base of what is called the lower Marcellus Group. As we have seen, they are the record of the Catskill poison seas. The upper beds of the Marcellus Group are similar looking but very different deposits. These are fossiliferous black shales and dark gray sandstones. They sometimes have rich assemblages of brachiopods, clams and even corals. These were still mud-bottomed seas, but they were deposited at times when there was a fairly large amount of oxygen in the water, at least enough to allow marine shellfish to survive and even flourish. These can be fun rocks to poke through as they are occasionally richly fossiliferous, and the preservation of those fossils can be very good.
See the Bakoven Shale on Rt. 23A where it crosses Kaaterskill Creek east of Kiskatom. Go visit that large outcrop along Rt. 209, between Kingston and Sawkill. The far south end is the real poison sea; as you travel upwards and north from those beds you are looking at shallower waters which had more oxygen.

Contact he authors at randjtitus@prodigy.net

A Petrified Delta?
The Catskill Geologists
Updated by Robert and Johanna Titus

We’re back! Did you read us back when The Mountain Eagle was part of Columbia-Greene Media? Well, here we are again. We will be making frequent contributions to the “new” Mountain Eagle and hope you will be watching for us. We are Robert and Johanna Titus, and we have a long history of writing geology columns here in the Catskills. Run a search on us and you can learn a lot more.
When you begin writing for a newspaper the first thing you ask is about where does it circulate. The Mountain Eagle can be found throughout all of Schoharie County and a good part of Greene and Delaware Counties. That is the heart of the Catskills and that gives us a lot of geology to write about. So, a good place for us to start today is to describe the geology of our mountains in the broadest terms. Let’s ask a deceptively simple question: What are the Catskills?
And (without a drumroll) the answer is – the Catskills are a petrified delta. A what?? Does that surprise you? Well then, maybe you need to start learning some geology. Let’s begin by looking at a typical outcropping here in the Catskills. See our photo; the upper half of this outcrop is typical Catskill sandstone. It’s often called bluestone, but it is actually brown to gray. There is a lot of similar sandstones found throughout the Catskills. We would like you to be watching for these stratified rocks as you travel around.
That sandstone was once sand and that means there must have, long ago, been an environment of deposition that accumulated this sediment. What was it? Geologists have been studying these sandstones for more than a century and they have concluded that these sands were deposited in the channels of ancient rivers. When you find a thick sandstone of this type, we would like you to pause in front of it, and imagine the currents that once passed through right where you are standing. Hold your hand up and feel those long-ago currents; you are now using your mind’s eye, and you have traveled into the distant past; what geologists call the deep past.
How old are these sandstones? Geologists have been collecting fossils in the Catskills for almost two centuries. The ages of these fossils goes back to a time called the middle Devonian. That makes these stratified rocks roughly 380 million years old! Can you imagine anything being that old?

The strata at the bottom of our photo are red shales. The key is the color. This sort of red is an iron oxide, typical of an ancient terrestrial setting. These shales were originally muds and they were deposited in what geologists call overbank settings. That means these red shales were the soils on the floodplain that our river flowed across. All around the world today we see similar red soils. They are almost always found in tropical settings; you will see a lot of such soils in the Amazon and Congo Basins. So, now our typical Catskills outcrop has brought our mind’s eyes onto a Devonian age, tropical floodplain, watching a river flow by. But, why is this a delta?
Geologist have found that these Catskills sediments lapped up against the western Appalachian sequence. These, the rocks of New England, are the roots of an ancient mountain range. These were not the Appalachians; instead geologists call them the Acadians. It is estimated that these Acadians were, back during the Devonian, between 15,000 and 30,000 feet tall. Only the Berkshire and Taconic Mountains remain; what happened to the rest?
They eroded away.
These lofty mountains were destroyed by weathering and erosion, and their bedrock crumbled into enormous quantities of sediment. That sediment was transported by sizable rivers and it came to be deposited on something called the Catskill Delta. The delta was spread out west of the Acadians. And it is that delta, now petrified, that makes up the Catskills where the Mountain Eagle can be read.
Contact the authors at randjtitus@prodigy.net Join their facebook page “The Catskill Geologist.”

The Hoogeberg Range
On the Rocks – The Woodstock Times
Updated by Robert and Johanna Titus

We often use lots of words without having a precise notion of what they mean. English is designed for that as sometimes its words need to have just a touch of (appropriate) vagueness. For example, just what does the word “mountain” mean? There are many good answers to that and each one is different from all of the others, and each one may still be correct. Similarly, what exactly does the word “hill” mean? It gets worse. What does “foothill” mean? Hills don’t have feet, so let’s pursue the issue and do it with a good local example.
The Catskills are often called mountains although many debate that heatedly. Our Catskill Mountains have foothills and some of those are very close to Woodstock. The foothills that we are speaking of are the hills of the Hoogeberg Range. If you have never heard the term that’s quite excusable, the Hoogebergs are not great or famous peaks.

The Hoogebergs are a series of small hills lying parallel to the Catskill Front, the great eastern escarpment of the Catskills. They are found just a few miles east of the Catskills and rise to only 600 or 700 feet in elevation. That’s merely a third of the elevation of the Catskills themselves. Thus, they are adjacent and parallel to Catskills, but short. They are like a practice run before the big mountains, hence the term foothills. You can see the Hoogeberg Range if you drive north on the Kings Highway (Rt. 31), south of Saugerties and Rt. 32, north of Saugerties. The ridge looms to your left (west). It forms a fairly impressive horizon.
You can easily go and see the rock that makes up the Hoogeberg Range. There are several locations where there are gaps in these hills, and they let you drive right through the bedrock. Rte. 212 cuts through at the village of Veteran, Rte. 32 cuts through at Quarryville and the Glasco Pike cuts through at the village of Mt. Marion. In each of these locations there are fine exposures of the bedrock right along the road.
What is the Hoogeberg and why is it here? Visit the Rte. 212 exposures and you will observe some very fine, thick, rugged sandstones. These are tough rocks and they have resisted the efforts of weathering and erosion. To the east and west, softer rocks have eroded away, and as they did the Hoogeberg came to be sculpted into a series of hills. These sandstones belong to a geological unit called the Mt. Marion Formation. It is mostly this sandstone and it makes up the Hoogeberg Range. Park along Rte. 212 here and poke around for a bit and look the sandstones over. You may find the fossils of some marine shellfish. That tells us a lot. The Mt. Marion sands accumulated at the bottom of an ocean, sometimes called the Hamilton Sea. The sands once made up the floor of that sea.

At the Glasco Pike exposure you will learn more about the Mt. Marion and the Hoogeberg. This outcropping is at the bridge which crosses Plattekill Creek. The lower levels of the exposure are mostly black shale. Up above, however, those sandstones make their appearance. We talked about this in an earlier column. This sequence of strata records a transition from an offshore, deep water setting to a nearshore, shallow ecology. The offshore accumulated muds that hardened into the shales while coastal sands would eventually harden into the Mt. Marion sandstones.
If you look carefully you may notice that the strata at these locations are not perfectly horizontal; they dip gently to the west. These rocks were all here during the late Devonian time period and they were involved in crustal tilting that was part of a mountain building process, then going on in New England. The tilting of these resistant strata raised those sandstones and exposed them to erosion. They responded by eroding into the hills we see today. The tilting accounts for much of the form of the Hoogeberg. Its west-facing side is generally a gentle slope, reflecting the original tilting, while the east-facing front was eroded into a steep slope, often a cliff.
Crustal tilting, shallowing seas, ancient shellfish, there’s a lot of history in these pretty little foothills and they do make up a significant feature in our local landscape, even if they are just foothills.

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

Honk of You love Reefers
ON THE ROCKS – The Woodstock Times
May 21, 1998
Updated by Robert and Johanna Titus

We geologists owe a great deal to the highway departments. It is necessary for them to cut great slashes into the hills and mountains so as to allow the passage of roads. And thus it has been that they have, especially since the 1950’s, been providing us with thousands of beautiful exposures of bedrock. Many of these are quite impressive – great, towering cliffs of rock, rising above the passing traffic. They are like magnets to geologists, they lure us to stop and explore.
Rte. 209, south of the Saw Kill, displays one of the area’s better exposures. It’s a very impressive cliff of black stratified rock. The beds of rock here are called the Mt. Marion Formation. That’s one of the area’s more important units of rock. It’s a big, thick sequence of sandstone and shales; the beds piled up to a thickness of about 500 feet. Not surprisingly, these are the layers of rock that make up Mt. Marion itself.
The sedimentary rocks of the Mt. Marion Formation record a distant moment in the history of this region. They were deposited as black muds and dark sands at the bottom of the relatively deep ocean that once existed throughout all of eastern New York State. But that was about 380 million years ago.
As we said, these exposures are irresistible magnets for all geologists, and we are no exceptions. We drove down Rte. 32 and turned onto the Rte. 209 ramp and took a nice slow drive along the great exposure. It was well worth the effort; our luck was very good.
Practically the very first thing that we noticed was a fine specimen of a fossil coral. That was a big surprise, as we had never imagined that this would be a place to search for corals. We usually find fossil corals in limestones. Limestones record ancient shallow, tropical seas, places ideal for corals to grow and flourish. In such locations, corals grow into the great colonies that we know as coral reefs. Each reef is composed of thousands of individuals living together in a single colonial skeleton. But as we looked up at the strata of the Mt. Marion Formation, we could not imagine such an image for this unit of rock.

Black shales and sandstones are different from limestones. They accumulated on murky, dark sea floors, places not usually well-suited for corals. But the corals we found here were not the regular run of the mill forms; these ones are known as horn corals. Horn corals are, as the name implies, uncanny duplicates of the horns of cattle. They are widest at the top and taper downwards to a point. The specimens we had collected are probably called by the Latin name Cyathophyllum. They would have been pretty well-adapted to life on the dark, muddy sea floor. We suspect that they grew upwards so that their sharp pointed bottoms stuck into the mud like golf tees. Their wide openings would have projected above the sea floor and they would have avoided being clogged with mud.
Corals are predators of sorts; obviously they do not stalk their prey. Instead they are known as “awaiters;” they lay upon the sea floor and wait for some unwary prey to come by. They have tentacles that capture their prey and pull these victims into their gullets for digestion. That’s not a very exciting life, but it works well; corals have been around for about half a billion years and they are likely to be around for another similar length of time.
And, so it was, as we drove along the black shales of Rte. 209, that we imagined ourselves at the bottom of an ancient sea. All around us, on a dark muddy bottom, lay numbers of horn corals with their light colored, fleshy tentacles waving back and forth at the surrounding waters, each one grasping greedily in hopes of food. There is certainly a great difference between the world as it is, and the world recorded in the strata.
Contact the authors at randjtitus@prodigy.com. Join their facebook page ‘The Catskill Geologist.”