"I will never kick a rock"

The Glaciers at Fly Creek Aug. 2, 2024

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The Glaciers at Fly Creek

The Catskill Geologists; The Mountain Eagle 9-3-19

Robert and Johanna Titus

 

We are scheduled to be at the meeting of the Fly Creek Historical Society at 7:00 on Wednesday night, Sept. 25. (2019) Robert will be giving a PowerPoint presentation. His topic will be the ice age history of the Fly Creek vicinity. If you come from the south on Rte. 28, then the best way to get to there is to turn left, west, onto County Rte. 26. That takes you past some of the most fascinating ice age landscape in the region. And it’s a great way to get ready for the talk.

After making that left you drive a short distance uphill. We would like to take you back through time to the late Ice Age. To your right and left are sweeping mind’s eye vistas of ice age history. Rising above you, on the right, we would like you to envision a towering glacier. It had advanced from the north during a recent episode of especially cold ice age climate. But things have turned and is now warming. The glacier is melting and melting quickly. We look again and see that great volumes of meltwater are pouring out of wide fissures in the ice.

The glacier is actually still advancing. An enormous sheet of ice extends north, all the way to Labrador. The climate up there is still very cold. Heavy Labrador snowfalls are producing new ice which is pushing the ice south all the way to Fly Creek. At Fly Creek the ice is melting just exactly as fast as it is advancing; the front of the ice is at what is called a stillstand. We look again and listen. The advancing ice is making all sorts of cracking, popping and grinding sounds. Then there is the sound of those roaring torrents pouring out of fractures all along the glacier’s front. It is, in short, a loud landscape, the noises of the advance are balanced by the sounds of the melting. This is an audio stillstand!

Next we turn and look to the left, the south. The landscape before us is barren. Wet, bare ground rises and falls in smooth sinuous curves much as you can see today. This is called kame and kettle landscape. Each sinuous hillock is a kame; each smooth downward swale is a kettle. The kettles mark the locations of isolated blocks of ice that had recently been part of the glacier. Now they are melting, and each block of ice will leave behind a kettle. This kame and kettle landscape defines what geologists call a glacial moraine, a heap of earth bulldozed to where we see it by advancing ice and left behind when the ice melted.

Off in the distance is a wet plain of sediment that has been washed out of the kame and kettle lands by those meltwater flows. It glistens in the sun. A braiding of crisscrossing streams flows across what geologists call an outwash plain.

We continue west on Rte. 26 and soon drop down onto a broad flat farmland. In our mind’s eye we are looking at a landscape from which our glacier has retreated. The moraine is still there, off to our left, but it acts as a dam for meltwater.  We are now driving across the floor of and ice age lake. Let’s call it Lake Fly Creek. We continue to drive slowly toward Fly Creek We have seen a lot of ice age landscape in an otherwise modern world

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

 

A Hot Day in the Sun July 25, 2024

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Mud Cracks at Cave House

Robert and Johanna Titus

August 9, 2029

 

We recently visited the Cave House Museum of Mining and Geology and we would like to continue writing about it today. The Museum is part of a 50-acre complex of industrial and educational facilities located well east of Howe Caverns. When you visit, we know that you will want to descend into the old Lester Howe cave. Back in his day you could take quite the tour but now you can only visit what was the beginning of Lester’s cave. You need to go to Howe Caverns itself for the long tour. Still, even If this is just a short tour, there are good things to see. Almost as soon as we entered the cave our guide shined his flashlight upon the thinly laminated limestone strata that make up the cave walls. There we immediately saw something that was very familiar to us. The cave is composed of a unit of rock called the Manlius Limestone, something that we see all across eastern New York State. It’s thinly bedded, fine grained strata took us back about 420 million years to a time when most of New York State was submerged by the shallow waters of something called the Helderberg Sea.

 

 

This was a very warm sea; North America lay just a little south of the equator. The Cobleskill area was enjoying a very tropical climate at that time. The thin laminations of the Manlius tell us a lot about what the whole region was like back in what geologists call the early Devonian time period. The thin strata here are the products of what are called algal mats. Once these thin strata were composed of sediments laying upon a mud flat and sheets of primitive algae grew across their surfaces. You might have to travel as far as the Persian Gulf so see something like this today.

But there was much more to see here. Our guide shined his light on the cave ceiling and we immediately recognized one of those little wonders of geology; something called mud cracks. Mud cracks are polygonal imprints that formed at approximately the time of deposition. They speak to us of single moment in time all those million years ago. Mud cracks are also called desiccation cracks, which is to say that they formed at a time when the sediment was baking in the sun.

We looked up and gazed at that surface. To see such a rock is to literally see the past. Now we became time travelers, and in our mind’s eyes, we went back those millions of years and saw that mud flat. We had arrived at noon on a clear day in early August. The Sun’s heat seemed to pound down on the surface. There was not even the slightest of a breeze and the hot air pooled on the ground. In the distance, we could see rising currents of air distorted by the heat. This is the stuff of mirages and near the horizon there was the illusion of an expanse of water.

But there was no water. In fact, recent months had witnessed a terrible drought. The ground was bare marine sediment and it positively blistered in the sun. Over time, all moisture had been baked out of the ground. The sediment then slowly shrank and, as it did so, it began to contract into those polygonal masses bordered by polygonal cracks: classic mud cracks. We looked around again; an endless flat expanse spread out all around us. It was a dead landscape. We felt very small and alone in this vast, inhospitable Devonian land.

Then we turned our eyes away from the cave ceiling and suddenly, all around us, was the coolness of a dimly lit cave. This is the Cave House of modern times, but certainly not as it has always been.

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

A visit to Lester’s Cave July 11, 2024

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A visit to Lester’s Cave

The Catskill Geologists; The Mountain Eagle; Aug. 2, 2019

Robert and Johanna Titus

We are guessing that virtually all of you have visited Howe Caverns. It’s the premier tourist attraction of our region. But there is a relatively new attraction in the same area

and we think that you will enjoy visiting it. That’s the Cave House Museum of Geology and Mining. Take Rte. 7 east from Cobleskill and turn left at Cave Road and left again at Blowing Rock Road. Drive a quarter mile and, presto, you are there.

 

You will see what’s left of Lester Howe’s old hotel, Cave House. It had been in serous disrepair but is now on its way to restoration with the help of the Callanan Industries. Howe opened the hotel during the middle of the nineteenth century and its guests were mostly people who came to see his cave. There used to be a larger hotel building next door but that one built of wood and it, long ago, burned down.  Cave House still needs lots of work but is on its way to becoming a genuine museum with a focus on the local geology. Staffed by dedicated volunteers, the museum is open every other summer Sunday. Check their facebook page before you go. When you get inside you can view a host of geologic specimens, most of them are local rocks, minerals and fossils. These have been donated by local geologists.

 

But here is the best part. Cave house is located quite some distance from the modern entrance to Howe Caverns.  But in Lester Howe’s day the entrance was located right beneath the hotel. Guests would step outside, climb down a staircase and be led into and through the cave. You can do some of the same today; at least you can see some of the old cave.

The walls of the cave are composed of limestone, most of it specifically belonging to a unit called the Manlius Limestone. These rocks take us back almost 420 million years ago. The rocks are layered; we call each horizon a stratum; this is a stratified rock. Such limestones accumulated in a very shallow tropical sea. You would have to go to the Persian Gulf to see this type of sea today.

If you did visit the Persian Gulf and walked its beaches at low tide, you would see just the sorts of sediments that harden into strata like the Manlius. In fact, starting a half century ago, many geologists did just that They studied those sediments and compared them to the Manlius. What they learned about the Manlius was something of a scientific breakthrough.

We remember being shown Cave House many years ago, when it was literally falling down, so it is such a pleasure to see it going through this rebirth. We applaud all those involved in this project. There is more for us to write about here so we will return to this topic again – soon. We hope you will visit.

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

A Visit to the Side of the Road – July 4, 2024

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A visit to the side of a road

The Catskill Geologists; The Mountain Eagle; July 26, 2019

Robert and Johanna Titus

 

We try hard to get columns out every week here in the Mountain Eagle. The secret is getting good photos to work with. Once we have the right picture, it is usually easy to put together an interesting geological yarn. It’s such a blessing for us that today’s smart phones come equipped with cameras and good ones at that. When we were younger, we could have never dreamed of taking pictures with a telephone, but we depend on that now. Wherever we go, we keep a sharp eye out and whenever we see something good, we just pull out our phone” and shoot. Pretty soon, you are reading about it.

That brings us to today’s yarn. One recent Tuesday evening we were on our way to WIOX in Roxbury when there it was – some fine road work. We love road work; so often it brings to light an exposure of bedrock. Take a look at our photo. It was taken alongside the Susquehanna Turnpike, a few miles west and uphill from the village of Durham. Look again, you might not guess it but there is a lot of geology in there. We geologists always start at the bottom and work our ways up from there. That takes us from the oldest to the youngest – a trip through time.

In this photo the oldest strata are of typical Catskills bedrock, a horizon of sandstone. You might prefer to call this rock Catskills bluestone, it doesn’t much matter. In either case, we looked at the rock and were transported about 385 million years into the past. There we found ourselves in the channel of a substantial river. That’s where the sand of this sandstone had been originally deposited. We walked up to the exposure and held our hands out. We could feel the powerful river currents that had once passed by here. Then they slowed down and then they stopped. This stream had jumped its channel; right here it would never flow again. That’s not as unlikely as it sounds. Streams don’t flow on forever in one channel; they do alter their courses and, long ago, that happened right here. Those sands came to be buried under more sediments, then more and then thousands of feet more. They would soon begin a process of compaction that would, with time, turn them from sediments into the bedrock we see here.

What happened to all those other sandstones – the ones that used to lie above? The answer is that they were all eroded away. We looked up into the sky and “saw’ thousands of feet of sedimentary rock rising above us. And we knew that they had, again so long ago, eroded away. And the last of that erosion is represented by the platform about halfway up our photo. That surface is important. Once, out of the north, an erosive glacier had ground its way across it.

Our photo shows that, above that erosion surface, lies a few feet of – what? – soil? Actually no, this is something else. It’s a few feet of earth that is called a ground moraine. A ground moraine is a relatively thin horizon of material that dropped out of a melting glacier at the end of the Ice Age.

We had stopped along the side of the road, attracted by something that looked of interest. We had taken a photo and had found ourselves another good yarn. This yarn involved an ancient river and a passing glacier. Our yarn was spread out across hundreds of millions of years. It is a good yarn.

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

A Leaning Tree??

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A leaning tree?

The Catskill Geologists by professors Robert and Johanna Titus

The Mountain Eagle ; July 19, 2019

Take a look at our photo. Do you see anything of note? Well, if you don’t then you don’t have the trained eye of a geologist. We think you can be forgiven for that, but let’s work on it. After all, that’s what our column is supposed to be all about.

This photo was taken down at the Roosevelt Estate in Hyde Park. We go there for events all the time, so we have learned a lot about the area’s geology. The estate is spread out across the top of an ice age delta and the photo shows the edge of that delta. You probably would never guess it, but the whole bottom of the Hudson Valley was once a great, deep glacial Lake called Lake Albany. All of Hyde Park lies on a delta of that lake. The top of any delta is a very flat surface called a topset. The edge of the delta is a steep slope called the foreset. Our photo focuses on the boundary of the two. The topset is spread out to the right and all of the library buildings lie upon it. The foreset drops off quickly to the left.

A typical delta is composed of cohesive silty sediments and, with its steep slope, the foreset can be a very unstable landscape feature. Delta foresets commonly display what are called rotational slumps. Large mases of the cohesive silt break loose along curved faults and rotate downhill. You might think of this sort of thing as a slow landslide. Take a look at our second illustration. It shows a mass of earth sliding in a clockwise motion down a curved fault line. At the top of the slide trees lean backward; at the bottom, they sometimes lean forward. Now, look at our photo again. Do you see something that you didn’t minutes ago?

So, why are we writing about a feature on the east side of the Hudson River? This column is supposed to be about the central Catskills; isn’t it. Well, again. We want you to have a trained eye, alert to all sorts of geological features that you might be passing on a routine day. Have you ever noticed a leaning tree? Even if you did, did you know what it might portend? Could you possibly have suspected a landslide hazard?

And, in this case, there is something very important: is there a danger that the Roosevelt mansion, Springwood, might break loose and slide downhill? Our photo was taken just a short distance north of Springwood. We were certainly concerned when we first visited so we explored the area. But the news was good; we found no leaning trees close to Springwood and only a relatively few in the vicinity. But there was more: we found few, if any, leaning trees at the bottom of the foreset slopes. It has been our experience that with dangerous slopes, the trees at their bottoms come to be shoved forward. Take another look at our second illustration.

So, in the end, we are not overly concerned about the safety of Springwood and the whole of the Roosevelt Library and Museum. But you can never be entirely certain about these things. You might take a look at the trees where you live.

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

Some Shiny Rocks in Plattekill Clove. 6-20-24

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Some shiny rocks in Plattekill Clove

Robert and Johanna Titus

The Catskill Geologists; The Mountain Eagle; July 12, 2019

 

It’s not unusual for us to hear from one of our readers. That’s, after all, why we publish our email address at the bottom of each article. It is also not unusual for them to send us a photo of something worth writing about. That happened recently when someone we know as “Catskill Bear” sent us this week’s photo. Mr. Bear found this rock along the road in Plattekill Clove. He was most curious about the striated and shiny surface he saw on it. That makes up the whole left side of the rock in his photo.

Well, we recognized what this was right away, but we still needed some help on it, so we contacted our friend, Dr. Charles (“Chuck”) Ver Straeten at the New York State Museum, and asked him about it. Chuck is a geologist who knows just about everyhing there is to know about the Devonian age stratified rocks of the Catskills so we knew he would be able to help.

We already knew the fundamentals: what our reader had found was a shiny surface called a slickenside. We had been transported back to a landcape called the Catskill Delta. It was about 385 million years ago, the middle of the Devonian time period, and that delta was spread out across all of today’s Catskills. There was a tropical climate here way back then. And many geologists think that the climate was seasonal with dry months and wet months every year. Much of the delta was blanketed in a common soil type called a vertisol.

Scientists know a lot about vertisols because they exist today. They possess clay minerals that shrink during the dry seasons and expand when they get wet. That creates a back-and-forth motion within the soil. One mass of soil expands and slides past the other during the wet season. It contracts and slides past the other mass in the following dry season. The result of all this are soil slickensides.  And that is exactly what Catskill Bear had found.

But there is more; it seems like there is always more. Chuck has, himself, been interested in Devonian soil slickensides. He has noticed that they are concentrated in certain horizons within Catskills stratigraphy. There are stretches of Catskills stratified rock where they are common and other stretches where they are not. He wondered why.

It’s common for Nature to present scientists with patterns like this. Nature is challenging us: where there is a pattern, then we must seek to learn why. If we meet the challenge and answer that question, then we are likely to have discovered something. It’s a common way that science works, and a fun way.

Chuck developed a hypothesis to explain this. A scientific hypothesis is a tentative explanation. It has not been properly tested and thus has not been proved – not yet. Chuck has long understood that volcanic eruptions can produce the clay minerals that promote expansion and contraction in vertisol soils. His hypothesis is that explosive Devonian eruptions in New England might have showered our region with ash that, potentially, could have been be altered into those “shrinking clays” and thus subjecting local soils to seasonal expansion and contraction. Slickensides would be concentrated in certain stratigraphic sequences because those represent times of volcanic activity. Sounds good, doesn’t it? But this is just hypothesis; it still needs work.

In the end, slickensides are among many, many phenomena that we routinely encounter in the Devonian strata of the Catskills. You too can learn about them. With time, you learn to notice these things. They speak to you about the past. You have become more knowledgeable. Your hikes in the Catskills become such different, more enriched, experiences. And it all starts from reading these columns.

Have you found some interesting geology? Write us about it. We are at randjtitus@prodigy.net. Join our facebook page “The Catskill Geologist.” Read our blogs at “thecatskillgeologist.com

 

 

 

 

 

 

The Devonian at Prattsville. June 13, 2024

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The Devonian at Pratt’s Rock

The Catskill Geologists; The Mountain Eagle, June 28, 2019

Robert and Johanna Titus

 

We have been doing a series of columns about Pratt’s Rock, which is, of course, in Prattsville. The stone carvings up there have, for 150 years or so, been attracting visitors. Today Pratt’s Rock is showing its age; it needs more than a cleaning; it needs a full refurbishing and that is what is being planned. Renowned landscape architect, Michael Van Valkenburgh, has been recruited to play a leading role. We have been wanting to contribute to all this by describing the geological heritage of the site. We think that’s an important aspect of the history of Pratt’s Rock and Prattsville itself. In our last two columns, we have described the ice age history there. That was only about 15,000 years ago. But today, we go back almost 380 million years to visit what geologists call the Devonian time period. All of the stratified rocks at Pratt Rock are as they were when first deposited during the Devonian Period.

Actually, we will start off by visiting what was intended to be Colonel Zadock Pratt’s crypt and then, from there, we will travel into that Devonian past. Take a look at our photo. You will see the Pratt chamber opening on the lower left. Our understanding of the story is that Colonel Pratt would have been interred there except that it started leaking. Just above that chamber, are some curious strata. Do you see how they are inclined to the right? We think that most local geologists would recognize this as being the left shore of a Devonian river. It needs a name and we love to name things; let’s call it the Pratt River.

               

   April 3, 379,998,163 BC – We are the mind’s eyes, and we have gone back those almost 380 million years and we are hovering above what will someday be Prattsville. We slowly turn a full 360 degrees and survey the landscapes below. We are just a few hundred feet above what has been called the Catskill Delta. Off to the east, a hundred miles or so, rises an enormous mountain range. These are the Acadian Mountains. They tower above what are the Berkshire Mountains today.

The Catskill Delta lies spread out before and below the Acadians It passes beneath us and continues perhaps another hundred miles to the west. Out that way is a broad shallow ocean, called the Catskill Sea. We turn another 360 degrees and appreciate how flat it all is. As far as we can see, there are rivers, an endless number of them. This is not surprising; large deltas always display large numbers of rivers. They are called distributaries and they always fan out across a delta. These rivers eventually “distributed” their waters into the distant Catskill Sea,

We, the minds eyes, drift downwards and we approach the nearest of these distributaries; it’s the Pratt River. We hang in the air, just a few feet above its waters. We look upstream and downstream. On this day there is only a lazy current slowly passing by. It is high noon on a sunny day, and we can see to the bottom. Down below are what we think are fish. But they are clumsy looking animals, thickly armored with heavy bones. Fish have only recently evolved into such river ecologies and they are not yet very good at it.

Below the fish, on the stream bottom, are scores of three-inch long clams. They sit there, all of them facing upstream. They face into the river currents and are able to sift out bits of biologic matter. This is, for them, food. Similar clams still live in Catskill lakes.

The riverbanks are densely populated with trees. But they are all so primitive looking. Long straight trunks rise up about 20 feet. There are no branches, but a strange foliage crowns each tree. It’s hard to find the right words to describe these crowns. There are no flowers, no seeds, no nuts; there are not even proper leaves. There are “appendages” that are green and photosynthetic; there are others that are reproductive. Those have black spore-producing bodies dangling from them. We look again, far and wide; there are no broad-leafed trees; neither are there any evergreens. This is a primitive forest, populated by primitive trees.

On the forest floor are some relatively familiar creatures We see millipedes, centipedes and spiders. Then we spot silverfish. These six-legged invertebrates are among the world’s most primitive insects. But there are no mammals, none at all. Neither are there any reptiles or even amphibians. There are no birds high above, singing in any of these “trees.” It is a quiet day and there are no sounds whatsoever. The silence is unnerving.

All this is the famed Gilboa Forest. It is evolution’s first-ever attempt at forest ecology, and it once grew and thrived right where Pratt’s Rock is today. Our journey through time has been a journey through the history of life itself.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.” But mostly, go and visit Pratt’s Rock sometime this summer.

A glacial Lake at Prattsville, June, 2019

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A glacial lake at Prattsville

The Catskill Geologists; the Mountain Eagle, June 21, 2019

Robert and Johanna Titus

 

We are pleased to hear that Pratt’s Rock will be refurbished. A sizable sum of money has been set aside to repair the site in the “same spirit of Zadock Pratt.” Pratt’s Rock, long regarded as the “Mt. Rushmore of the east,” has always drawn thousands of people to the town. They walk up the trail there and explore the sculptures. It is hoped that the numbers of tourists will increase with the restoration.

We have climbed the rock and have always enjoyed visiting but, for us, there is more there than just the carvings. Last week we wrote about the effects that advancing glaciers had on the site during the Ice Age. We saw that the steep slopes of Pratt’s Rock were the products of the ice passing across this hill and plucking masses of rock out of the ground, leaving a near cliff behind. Much of Schoharie Creek displays similar cliffs and they formed in the same manner. But glaciers did not just advance; they also melted back. When they did, they left other ice age features.

Take a look at our first photo. It shows the top of that plucked cliff. That advancing glacier passed across it and smoothed it into form we see today. A lot of rock was yanked out of the ground, leaving a cliff behind. We talked about all this last week. But look again; in the distance is a flat valley floor. That should simply be a floodplain. Right? Well, wrong; this is the floor of a glacial lake that was once down there. It has a name; it is Glacial Lake Grand Gorge.

Here’s what happened: Something called the Schoharie Creek Valley glacier advanced southward almost to Lexington. It came to a halt there as the climate started warming up. Great masses of earth had been bulldozed toward Lexington and left behind when the ice melted back. This was sediment that served as an earthen dam so that the retreating glacier left lake waters. Lake bottoms accumulate great quantities of silt and clay as lake deposits. Lake bottoms are always flat and that is what we see in the distance from the top of Pratt’s Rock.

If you go down there you can prove this for yourself. Bring a barbeque skewer and try to drive it into the ground. Throughout most of the Catskills skewers won’t go very far into the ground; they will hit rocks or pebbles. But down there, east of Prattsville, those lake deposits are all silt and clay; a skewer will always slide easily into the ground.

This was a big lake and deep too. Take a look at our second illustration. The lake level is thought to have been about 1,600 feet in elevation. Prattsville is at about 1,165 feet so the lake was more than 400 feet deep.  When we stand atop that ledge, we always see the image of Lake Grand Gorge spread out before us; it’s quite the sight.

We hope that, as part of renovations, a path to this ledge will be marked. Perhaps a placard can be placed there with an explanation of this ice age history. It’s an important part of the Pratt Rock heritage.

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

Glaciers at Pratt Rock – May 14, 2019

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A glacier at Pratt Rock

The Catskill Geologists; The Mountain Eagle May 14, 2019

Robert and Johanna Titus

 

We were happy to read in the Mountain Eagle of plans for the upcoming restoration of Pratt’s Rock. It’s quite an unusual location; it’s been there a long time and does need an upgrade. We look forward to seeing what will happen, and we hope, when things are done, there will be some appreciation for the geological heritage of this fascinating site.

Had all gone to plan then Zadock Pratt would have had quite the Mausoleum up there, but that did not happen. Nevertheless, Pratt does still have a most impressive monument. Probably most all of you have visited it. Many of you have climbed up and seen closeup the carvings that are there. There is still a chamber where Pratt planned to be buried. Then there is the poignant image of Pratt’s son George who died at the Civil War’s Second Battle of Bull Run.

None of this would have or could have been if there had not been such a steep slope there to begin within. Take a look at our first illustration; it shows a topographic map of Pratt’s Rock. Can you “read” contour lines? Then you will recognize the steep Pratt Rock slope from the closely spaced contours. It’s nearly a cliff and it faces the valley of Schoharie Creek which flows through Prattsville. Ledges of Catskill sandstone tower above the valley. A ledge is just a ledge, isn’t it? Well, not where we come from; we are geologists and we know there is a deeper story here

We hike up to the carvings and then continue onwards to a ledge that offers a fine view of the valley. See our second illustration, a photo of that ledge. Notice the smooth surface and the sharp drop-off of the ledge; there is a cliff there. Less obvious, but quite important, are the scratches on that surface. There is a lot of ice age history here. We look and we see what is called the Schoharie Creek glacier passing by. It has flowed south, swelled up to fill the valley and passed across this sandstone. The ice carried a lot of sand with it, mostly concentrated at its dirty bottom. That sand acted as sandpaper and produced the flat surface. There was more, the glacier carried cobbles and boulders along with the sand. They were dragged across this surface and that produced those scratches which geologists call striations. Knowing this, now you can see that they parallel the glacier’s movement down the valley.

What about that cliff? That’s all part of the same story. Glaciers can be sticky. A glacier, when it passes across a mass of rock such as this, forms a tight bond with it. The glacier continues its journey south, it exerts a tug upon that rock. It is quite possible that the tug will break loose a mass of rock and yank it loose. That’s what happened here. There is nothing unusual about this; we geologists see such things frequently. It has a name; we call it glacial plucking. We stand at the top of this cliff, look down the valley and know that somewhere down there is all that missing rock, buried in the floodplain.

Well, the story we have just related, goes a long way to explain how it was that Pratt’s Rock came to be. It started out as an ice age feature. But there is a lot more to this story. Let’s continue next week.

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

A Summer Hike with the Mountain Top Historical Society. 5-24-24

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A hike to South Mountain

The Catskill Geologists; The Mountain Eagle, June 7, 2019

Robert and Johanna Titus            

                      

The hiking season has arrived for the Mountain Top Historical Society (2019). The two of us have been members for decades and have long enjoyed going exploring with them. On Saturday, that’s tomorrow, renowned hiker Bob Gildersleeve will be leading a trek to the edge of the Catskill Front at South Mountain. That’s a remarkably scenic location that rises above Kaaterskill Clove and overlooks the vast expanse of the Hudson Valley.

It looks like most of the hike will be on or near the Blue Trail. That path rises up the slope just south of the old Catskill Mountain House Hotel site. That will take the hike up a slope that was carved by the glaciers of the Hudson Valley glacier. Participants can expect to see views of the valley from the tops of sizable cliffs. Today’s scenery is spectacular but try looking at the alley and see it filled with ice! That was perhaps 16,000 years ago.

The Blue trail will pass by ledges of rock called the Twilight Park conglomerate. That’s a thick mass of petrified gravel and cobbles. It will take us another 380 million years into the past. You look at the strata to the west of the trail, and then turn to the east. Now, rising high above you, towers the image of an enormous and ancient mountain range, the Acadian Mountains. Those cobbles and gravels formed as a mass of sediment, that was transported down the old mountain slopes, mostly by gravity. That range is nearly gone. Only the Taconic Mountains, across the valley, remain as remnants of what once were colossal mountains, rising between 15 and 30 thousand feet above the eastern horizon.

The trail and its environs are littered with enormous boulders, most of them left behind by the actions of glaciers. Does Druid Rack sound interesting? How about Boot Jack rock or Sphinx Rock? They are all there, near or along the trail. For the most part, they were yanked out of the ground by passing glaciers and then dragged to where we see them today.

This is a classic trek; it’s been a tourist destination for generations. People have been hiking these pathways since the early 19th century. Visitors to the old hotels enjoyed these trails. Countless postcards were made here. We remember our first visit and the impact it had on us. Have you been? If not, then you should not miss this hike; you will not forget it.

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

 

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