Robert Titus - page 3

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

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.”

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 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 19^th 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.”

Looking into the future

The Catskill Geologists

Robert and Johanna Titus

We frequently travel about in the Catskills, and we are always on the lookout to find a new topic for one of our columns. One day, recently, we were approaching Mt. Utsayantha from the northeast on County Rte. 14. On the mountain’s slope, rising in front of us, we noticed a fairly nondescript mountainside feature. Take a look at the left center part of our photo. You will see what is sometimes called a niche. That is, there is a depression in the side of the mountain.

Well, “so what,” you might ask, “big deal, what is there to get excited about?” And you would be right; this is not an especially big deal; it is indeed just a depression in the slope. But we are geologists, and we are writers. We are always looking for an angle. After all, we have to send off a column almost every week.

We started taking this image and projecting it into the future, of course we mean the distant geological future. What, we wondered, would happen if another ice age came along? Our niche in the mountain would soon fill up with snow. And that would initiate a sequence of very predictable events, typical of the latest chapter of an ice age.

First that niche would accumulate thicker and ever thicker amounts of snow. Then the thickening snows, under the influence of their own weight, would start compacting. The snow would be squeezed down into a material that would resemble the packed snow of a snowball. Geologists call that material “neve”. But the process would not stop there; the compacting would continue until the neve’ would harden into genuine ice.

Once enough ice accumulated in the Mt. Utsayantha niche, it would start to become dynamic. Ice can flow like a great rigid mass of water. Its flow will be very slow, but it will move. It has become a glacier, in fact it has become an Alpine glacier, at least a future Alpine glacier.

We had slowed down but now, intrigued, we pulled over, got out and stared up at our Alpine glacier. Usually, we gaze into the past but this time we found ourselves looking into the distant future. We had traveled to a time when the Catskills had come to resemble the Alps of today’s Switzerland.

When will this future Switzerland descend upon the Catskills? We don’t know; we haven’t gotten any of the ice age geologists that we know, to commit to a precise prediction. But current ice age theory argues that glaciations occur in cycles that recur about once every 100,000 years. So don’t hold your breath. It gets worse; Alpine glaciers don’t form until late in ice age chapters. After all the ice, everywhere else, has melted away then the cold mountaintops become active and Alpine glaciers form.

That happened in the past. At the end of the last ice age, Alpine Glaciers formed atop the highest peaks of the eastern Catskills. The best example that we know of are found at North Point, near North Lake Campground and to the south at Overlook Mountain. Another very fine Alpine peak is Hunter Mountain.

But why didn’t Mt. Utsayantha develop some Alpine glaciers the last time? It may be that the mountain is just not tall enough. It reaches an elevation of 3,200 feet; the others are just a bit taller. So, sadly, Mt. Utsayantha may not be tall enough the next time. But we can dream.

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

Something called planar cross beds

The Catskill Geologists; May 18, 2018

Robert and Johanna Titus

We would like to get you to take closer looks at the rocks you find yourself passing by. We do it all the time. When we are out driving, we pass outcrops along the sides of the roads. It takes a very well-trained eye to see anything at 55 miles per hour, but it can be done. If you are like so many of us, then you will find yourself out hiking in the Catskills. That’s when we want to help train your eyes to see what has always been there, right in front of you. Let’s do some of that today.

Take a look at our photo; it’s a close-up view of some very typical Catskill strata that we took in the western Catskills. It’s something you might see almost anywhere in our mountains. Notice the structure of the strata. There is an obvious horizontal line running across the photo, starting about halfway up. The strata above that line are all horizontal while those in the lower half are sharply inclined. What is going on here?

We always draw a parallel between what we see in the rocks and what we see on roadside signs in a foreign country. Perhaps you have driven through Quebec and have seen signs written in French. Unless you know French you can’t tell what the sign is trying to say. It’s much the same with the strata of sedimentary rocks. The strata in our photo seem to be trying to speak to you, but you have to be able to read rocks in order to find out what they might be saying.

It must be obvious that the strata in the lower half of our photo are telling a different story from those above them. Indeed they are. We need an English/Rock dictionary, don’t we? On one page would be a photo and on the opposite page would be its translation into English. Well, they don’t publish English/Rock dictionaries so we will just have to get along without one. Let’s give it a try.

The strata on the lower half of this photo display what is called planar cross bedding. Each stratum is inclined to the left and all of them are piled up on top of each other. This records a day in the history of the old Devonian age Catskill Delta. We are at the bottom of a stream that flowed across the delta, perhaps 385 million years ago. There had recently been some sort of a flood event and fast flowing water currents had been carrying a lot of sediment. But that flood event was coming to an end and the currents were slowing down. They were losing speed and losing their ability to transport sediment.

That sediment, most of it being sand, was dropping to the river bottom and forming a dune of sorts. More currents, carrying more sand, rose up over the “dune” and deposited sediment in the form of those left sloping strata. Each represented a moment of deposition. That moment was followed by another and then still another until the whole sequence came be as you see it.

There was a momentary return of high speed flow and that eroded the horizontal line which you will see, cutting across all of the planar cross beds. Normal stream conditions then returned and all of those horizontal strata came to be laid down to complete the sequence. Millions of year passed and those sands hardened, petrifying into sandstone. Then hundreds of millions of years passed and the sequence was exposed by processes of erosion and photographed by us.

Keep an eye out and you too will see things like this

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

A real geological mystery, and at Pratt’s Rock

The Catskill Geologists, May 31, 2019

Robert and Johanna Titus

We were invited to speak at the Pratt Museum recently. Our topic was the glacial geology of the Schoharie Creek Valley. After that, a group of us went to Pratt Rock and climbed up the trail there. We took a look at Colonel Pratt’s carvings and continued on to see some nice ice age features. But, along the way, we ran across one of those mysteries we have long struggled with.

We were first alerted to this particular mystery by Paul Misko, a veteran Catskills hiker. Paul told us of some “very strange structures he had found in Phoenicia. Paul has a real eye for unusual geology, so we paid attention to his “very strange” claim. We saw his Phoenician structures and now we have found more of them at Pratt’s Rock. Take a look at our photo and then climb up the steep incline at Pratts Rock and keep an eye out. Towards the top you will find sizable ledges of sandstone. This is rather commonplace stuff: very typical Catskills bluestone ledges. These ledges are, in essence, the cross sections of a very old streams. It’s, like all rocks in the Catskills, Devonian in age, something a bit less than 400 million years old.

None of this surprised us in the least but that’s where we encountered that mystery. Take another look at our photo and see what you think. See the cluster of closely spaced and very strange cavities just above the hand. Their shapes vary considerably, but they all show a sort of boxy nature, and they seem to form an interlocking network. We would like to use the term honeycomb here, but honeycombs show a consistent hexagonal shape; we don’t see that with these. The rock remaining in between these cavities is narrow. The cavities do not penetrate too far into the rock, just a few inches. And there is no reason to think that there is another horizon of these cavities under the ones that are visible. Thus, they appear to be surficial features. Many of these cavities are spaced so close together that they comprise a bigger compound cavity. Whatever it was that formed them was focused.

All in all, this is one of the most puzzling phenomena that we have seen in the Catskills. There is no trouble putting a name on what is here; these structures are called “tafoni.” Each individual cavity is a tafone; lots of them are tafoni. And the terminology keeps getting better; when tafoni occur on cliff faces, as here, then it is called lateral or sidewall tafoni. But putting a name on something is not the same as understanding it.

What are these features? They seem to be chemical weathering phenomena. Somehow, they appeared on the rock surface and grew slowly into their observed shapes, but exactly how? And, also, how is it that they grow in size until they abut each other but do not grow into each other? How do they grow in size without intersecting? Those are very puzzling questions and just naming these things does not provide answers.

Tafoni have been weakly associated with poorly defined stratification on the sides of cliffs and that is the case here: sort of. But that still leaves a lot unsaid. Why does this “association” occur? What are the specifics? Salt is commonly cited as an agent in tafoni development. They are sometimes found on coastal outcroppings, splashed by ocean waves. But there is certainly no source of salt here on a sandstone cliff in Prattsville, and certainly no waves. And why do only a few Catskill Cliffs display these? That begs the question: what exactly is different about his cliff? Why don’t all cliffs have tafoni? Why isn’t it that none of them do? There must be something here, right in front of our eyes, which we have missed. This is the sort of thing that makes science so much fun.

Do you have any ideas or questions? Have you seen tafoni somewhere? Contact the authors at randjtitus@prodigy.net. Join their Facebook page “The Catskill Geologist.”

An ice age torrent – and you can see it

The Catskill Geologists; The Mountain Eagle; June 8, 2018

Robert and Johanna Titus

We have long enjoyed joining in on the hikes sponsored by the Mountain Top Historical Society. This Saturday (2018) there will be one that takes its participants right into the thick of an ice age meltwater torrent. If that sounds like fun then you might consider coming along. The hike will trace the path of what is called the Horse Trail; it can also be called the Harding Road Trail. It ascends from the bottom of Kaaterskill Clove to near the top of South Mountain. It was put together in the 1880’s to bring guests up to the then newly built Hotel Kaaterskill.

The story of the Hotel Kaaterskill is an oft told tale. George Harding had been a long-time guest at the famed Catskill Mountain House, but then there had been an acrimonious argument between him and Mountain House owner Charles Beach. Beach told Harding that if he didn’t like the Mountain House then he should build his own hotel. Harding was a very wealthy man and he did just that; his hotel would be just across South Mountain from the Mountain House. He needed a road to bring guests to his hotel and that was the improbable origin of the Harding Road Trail.

The Harding Road Trail follows a zigzagging path up the south slopes of South Mountain. Take a look at the small, dashed line near the bottom of our map. Our hike will follow the trail and ascend about 1,700 feet before we get to the top. It is billed as a 7.6-mile hike and rated as moderate in difficulty.

But what about that ice age torrent? Well, that will require a little use of the mind’s eye. Can you read a topographic map? Well, once again take a look at our illustration. Our trek will cross a relatively small canyon at an elevation of about 1,400 feet. It has a small stream in it (see the blue line). If you trace the vee-shaped contour lines then you can follow this canyon all the way up to an elevation of about 2,400 feet. But the canyon is mapped as being dry most of the way to the top. It wasn’t always like that. We did an article in Kaatskill Life many years ago about this canyon. We reckoned that it had been an active and powerful torrent of glacial meltwater toward the end of the Ice Age. We are guessing that all of the Hudson Valley, along with Kaaterskill Clove was, at that time, still filled with ice. We see all of the North Lake vicinity and all of North Point and South Mountain as rising above the ice.

There is a lot to the story that we don’t know. We are guessing that there was some sort of ice dammed lake at the top of South Mountain way back then, a larger version of North and South Lakes. But we have not been able to find much physical evidence for the shores of this lake. That remains a mystery.

Our stream was thus a subglacial one. Water from that lake plunged down a hole in the ice, a glacial feature called a Moulin. It’s quite something to imagine. Raging, foaming, pounding, thundering torrents flowed down the subglacial tunnel. It must have been loud, but its sounds were all but muffled in the complete darkness beneath the ice. And our hike will, spiritually, pass through the flow.

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

The Glaciers got There First

The Catskill Geologists; May 19, 2019

Robert and Johanna Titus

Have you been to the Walkway across the Hudson at Poughkeepsie? It’s a pedestrian bridge that, high up in the sky, crosses the river; We promise you, it’s quite the experience. But, opening next week, (2019) is something just as good and a lot closer. That’s the Hudson River Skywalk. The Skywalk also spans the Hudson, this time across the Rip Van Winkle Bridge. In so doing, it links two important historic sites: Frederic Church’s onetime home, Olana, and Cedar Grove, the Thomas Cole Historic Site. The new trail extends from Cedar Grove, across the bridge. and then it ascends the hill to Olana. Can there be a “theme’ to a walkway? If so, with this one it’s the Hudson River School of Art. Cole and Church were that “School’s” two leading lights.

We said that the Skywalk was just as good as the Walkway, but maybe we can write about something that makes it even better. If you get a chance and you head out over the Hudson, we would like you to look and see how steep the slopes are on either side. We are talking about the slope just beneath the western end of the bridge and the other slope just beneath Olana. That steepness is something that is not always easy to take notice of, but it is important. Shouldn’t there be a floodplain? Rivers are supposed to flow across broad, flat floodplains, aren’t they? So, why not here?

The Skywalk – Picture courtesy of Olana

We got to thinking about that and came up with an answer, a good geological answer. Halfway across the bridge we looked east and west and then north. In our mind’s eyes we saw a glacier. It was perhaps 14,000 years ago and, for the most recent time, an ice age glacier was advancing down the Hudson Valley. That glacier rubbed up against the slopes on both sides of the river. Glaciers can be very erosive and this one was no exception. It cut into Church Hill where Olana is perched. That would greatly improve the view that Frederic Church would eventually paint. It also cut into the western side of the river. All this erosion left no room for any kind of floodplain. Instead, it formed a rather boxy valley with a sizable river flowing down a surprisingly narrow pathway. You probably never noticed this, did you? Well, go out onto the Skyway and take a look.

The official opening is set for June 1^st (2019). People will congregate at Olana and at Cedar Grove. Each group will set out on a “parade” to the Skywalk Trail. If all goes well, they will all meet at the middle of the bridge. There will be a ribbon cutting at the park near the bridge’s toll plaza at noon. We don’t think there will be a golden spike, but it should be a fun event.

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

Joints along Rte. 145

The Catskill Geologists; The Mountain Eagle, May 16, 2019

Robert and Johanna Titus

Science may seem cut and dried to many. We scientists just know everything, don’t we? We look at things and figure them right away. Don’t we? Well – no, and no again. Sometimes we see things that we just can’t figure out. The two of us have been having that sort of a problem lately and it all began along Rte. 145, That’s at the top of the hills you see as you approach Middleburgh from the south. On the right side of the highway is an impressive outcropping of typical Catskill sandstone. Take a look at our photo.

That outcrop makes up a very fine wall of rock. It actually seems too fine. The rock exposes several nearly perfect, smooth and upright surfaces – too smooth and too upright.  What is going on here? Rocks are supposed to break up into jagged rough blocks, aren’t they? It looks like we have some explaining to do.

These surfaces are fractures in the rock that are called geological joints. There is a good bit of scientific theory behind this. Joints record chapters in the tectonic history of a region. They began to form when the rocks, long ago, came to be compressed during a tectonic event. It may be hard to imagine that rocks can be squeezed, but they can. That requires immense pressures, but such pressures do occur within the Earth’s crust – deep within the crust.

Now the funny thing about all this is that rocks do not fracture when they are being compressed; they have enough “give” to absorb that stress. But compression does not last forever; it eventually does end. Rocks then expand and that is when the fracturing begins. There is a sort of relaxation which occurs as the pressure eases. At that moment we find that rocks are brittle, and it is exactly then that they crack to form joints. So, what triggered all this? We need more scientific theory.

Cycles of compression and relaxation, strong enough to deform and fracture rocks, can only be associated with the truly great tectonic events. These are not just run of the mill earthquakes; these are the towering mountain building events. And the one which triggered our Rte. 145 joints was one of the biggest mountain building events ever. That was the collision of Europe with North America, about 400 million years ago; it made the northern Appalachians. Episodes of compression and relaxation, associated with massive uplift of the crust, is what created these joints.

All this is good sound scientific theory, so what’s the problem? Take another good look at our photo. Do you see how it appears that large masses of jointed rock came to be yanked out of the ground and carried off toward we, the photographers. How on earth did that ever happen? Well, that’s our problem. We can tell you how we would like it to have happened. We stand there and imagine a glacier rising up the valley. The west moving ice passes by and forms a bond with the bedrock. Ice does that; stick your tongue to the bottom of an ice tray and you will find out for yourself. Well, as the ice continued up the valley, it did that yanking; blocks of rock were plucked out of the ground and dragged off toward Middleburgh.

At least we would like that to have happened; it would be such a nice vision of ice age history. But just can’t convince ourselves that it happened that way; road building seems very likely to have helped out, and that takes the Ice Age out of the story. So, where does that leave us? Well – with an unsolved mystery. We’ll figure it out someday -and get back to you about it.

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