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A fossil tree on an ancient trail

The Catskills Geologists; The Mountain Eagle

Robert and Johanna Titus

Dec. 13, 2018

We get a lot of email from our readers and sometimes they send us good leads on potential columns. That happened recently when a reader sent us a photo of a fossil that he found along the trail that leads up to Kaaterskill Falls. Have you been on that trail? It’s been there forever but has been nicely renovated in recent years. It makes a scenic hike. It’s not a difficult one and you are rewarded with a view of Kaaterskill Falls from below. That’s the view that Thomas Cole made famous with one of his first truly successful paintings done in the 1820’s. That view was important in the history of American art itself. If you haven’t been there, then you should.

We have hiked the trail many times and never tire of it. We haven’t had a whole lot of success in finding fossils along it, but they are there. If you have a sharp eye and if your eye is a trained one, then you do find the occasional fossil plant. These are trees from the famed Gilboa Forest. Those are New York Sate’s most important fossils; they make up the world’s oldest known forest ecology, dating back about 380 million years.

We know! We know! December is not a very good time of the year to go fossil hunting, but when the weather warms up, you might give it a try. We, ourselves, have found some fairly decent fossil tree trunks in the massive sandstones of Bastion Falls. That’s right above the highway at the hairpin turn on Rte. 23A. Maybe you can do us one better.

Our reader did just that. He found the branch of a fossil tree, complete with a row of leaves. Take a look at his photo. We immediately recognized the specimen. We had

already seen a very similar specimen in Bearsville. One of our Woodstock Times readers had found it in a quarry above her home. Take a look at our second photo for that one which is a much better–preserved fossil. See how much better the leaves look. We thought that both specimens belonged to a tree named Archaeopteris, but we wanted to be sure. So, we sent both photos off to friend Dr. Charles Ver Straeten at the New York State Museum. Chuck sent them on to two of the most foremost experts on Gilboa trees. They both agreed that these were specimens of Archaeopteris.

Archaeopteris is an important plant in the history of the evolution of trees. It belongs to a group called the progymnosperms.  That is a group of trees just a little more primitive than the gymnosperms themselves. And, as you might know, the gymnosperms include all of the modern evergreens; this is an important group of trees in the history of life.

The trail at Kaaterskill Falls is a scenic one for everyone who enjoys the outdoors, but for the two of us, it takes us back through time to an earlier planet Earth which was witnessing the rapid evolution of trees and of forests themselves.

Do you have good photos of geological wonders? Send them along with descriptions and perhaps we will be able to use them in a future column.

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

Standing stones – Wisdom of the crowd?

The Mountain Eagle – The Catskill Geologists

Robert and Johanna Titus – Oct 26, 2018

Have you ever seen the Devil’s Tombstone? It’s quite a rock—located at Devil’s Tombstone Campground on Rte. 214 near Stony Clove. It’s right next to the highway and there is good parking, so it is easy to get to. Its peculiar name is easy to explain; the rock looks so much like a very large tombstone. However, we doubt that the Devil is buried there.

Such a rock is often called a monolith. It must be about ten feet tall and a few feet thick. It is composed of typical Catskills bluestone. These strata were once sands at the bottom of a Devonian aged river channel. Now these strata make up a boulder, standing on end. But, what exactly is the Devil’s tombstone? It seems that there should be a story here. Well, actually there are several stories. The first one is the most obvious; it is the notion that humans lifted the rock into its current vertical inclination—perhaps for religious or astronomical reasons.

The monolith notion is what scientists call a hypothesis. A hypothesis is an idea which has been advanced as a possible explanation for a scientific problem. A hypothesis needs to be tested through further observations. As more is learned, a hypothesis begins to look better or, if things go poorly, it can become falsified. After being sufficiently tested, a hypothesis may be elevated in science to the level of scientific theory. In science, the word carries a great deal of worth; a theory is considered the highest level of proof in science; it is viewed with great confidence.

But, in science, it is always thought that many hypotheses are better than just one.  The more, the better. What about the Devil’s Tombstone? Are there other hypotheses or is the human monolith concept the only one? There is at least one other; boulders of this sort can be the products of ice age activities. Advancing glaciers can be easily imagined as picking up and shoving forward boulders of this size. When a glacier reaches its farthest advance, it will halt and, sometime later, begin melting away. A boulder can be left behind, lying in any inclination. Many will lie at angles less than 90 degrees, but a few, logic tells us, should indeed, be at 90 degrees.

So, which is it? Were standing stones all or mostly all put in place by humans or were all or most of them bulldozed and dropped in place by glaciers? Well, before we decide, we have to learn as much as possible about standing stones and that’s where you come in. Do you know of any standing stones? Can you tell us where to go and see them? Do you know of any leaning stones? We need to see these too; in fact, those may be of more importance.

When we know about these boulders, then we can visit them and ascertain their geologic context. If all of them were found with glacial deposits called moraines, then that would be an indication an ice age origin. If most or all, lie outside of glacial deposits then that would be consistent with the human origin hypothesis.

The point is that all of you can find more of them than just the two of us. When we have a lot of them to look at, then we can gather enough evidence to make a good, sound conclusion—a theory.

So, think about it, we need your help.

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

National Fossil Day

The Catskill Geologists; The Mountain Eagle

Robert and Johanna Titus

Oct. 19, 2018

An event of some importance to the two of us is coming up soon. That’s National Fossil Day. That’s Wednesday, Oct. 17^th. It is primarily sponsored by the National Park Service, but it is also co-sponsored by about 270 other groups. The purpose is to “promote the scientific and educational value of fossils.” Hundreds of events are scheduled all across the country.

Let’s make you and “The Catskill Geologists” into group number 271. We have pondered what would be the most significant Catskills fossil and the choice was obvious. Our pick is something, a fossil plant, called a pseudosporochnalean cladoxylopsid. It’s also known to scientists as Eospermatopteris.” Those words are jawbreakers and so it won’t surprise you to find out that the plant is commonly referred to as “the Gilboa tree.”

The Gilboa tree was, of course, first discovered in Gilboa. That was back in the nineteenth century, but many more were found during excavations associated with the building of the Gilboa dam in the 1920’s. Those discoveries were of the stumps of about 200 trees. They were immediately recognized as being some of the most primitive trees known to science and their discovery generated a lot of excitement. Unfortunately, only the stumps were found. Those trees had apparently been growing along the banks of Devonian aged streams on something called the Catskill Delta. Floods deposited sands which buried and preserved those stumps. The middle and upper reaches of the trees were not buried and subsequently those parts decayed away. That was during the Devonian time period, about 380 million years ago.

What kind of tree, exactly, was the Gilboa fossil? Without any preserved foliage from the upper tree, nobody could tell. For about 80 years or so, this was one of the big mysteries of paleontology. Everybody understood that they were among the earliest and most primitive trees.  Everybody also understood that an important discovery was needed. If good foliage was found then, it was argued, we could determine just exactly what our planet’s earliest trees were.

That discovery came in an eastern Catskills quarry just years ago. Researchers from the New York State Museum were conducting a routine survey of the area when they stumbled across fossil foliage on a horizon of rock at the bottom of the quarry. The discovery was a bit of a disappointment because the foliage was so exotic and so primitive that we still don’t really know what kind of tree it is.

We would like it if you celebrated National Fossil Day by training your eyes to be alert for fossils in the rocks that you routinely pass by. Gilboa forest fossils are out there. But, we think it highly unlikely that you will encounter the foliage. So, let’s talk about what you might find on a good day—a very good day. And that discovery would be one of those tree stumps. We found one about 20 years ago and we include a photograph of it.

This seems to us, to be a very primitive stump. It lacks the sort of extensive root system that modern trees have. We look at it and are reminded of the bottoms of the stems of many mushrooms. How could this primitive tree have stood tall on windy days? We don’t know.

Well, take a good look and keep this image in mind. If you enjoy walking along Catskills streams, or through Catskills quarries, then you just might spot one of these. If you do, please send us a photo.

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

The St. Peters slide – an unhappy anniversary.

The Catskill Geologists

Robert and Johanna Titus

March 16, 2018

You remember that landslide on Nott Terrace in Schenectady in February, don’t you? We covered it right here in the Mountain Eagle. Well, it was just one of a number of landslides that have occurred in the Hudson Valley over the course of many years, even many millennia. The two of us have covered a number of them and that gives us a chance to be real conventional journalists. Who else can bring as much scientific understanding to the story as us? But logic and statistics tell you that there must have been a worst Hudson Valley landslide. There are usually two ways of estimating the magnitude of a slide. One is a measure of how many lives were lost; the other is in how much physical damage resulted. We are guessing that the terrible Haverstraw landslide of January of 1906 “wins” on both scores. A full six square city blocks of houses sank with that slide and 19 people died.

But another way of measuring the “worseness” of a landslide is in terms of its effect upon history. Our nominee for that category is celebrating its 159^th anniversary this week. That’s the St. Peters College slide in the evening of St. Patrick’s Day, March   17^th, 1859. We are not talking about St. Peters University in New Jersey, founded in 1872. This was an older St. Peters which was, in 1859, still being built. Ambitious plans had been underway; a five story building which would measure 200 feet in length was half constructed. It was a determined effort, and that St. Peters would have been a sizable college by the standards of its time. We wonder just how big would it have gotten?

Old St. Peters College lay at the foot of Mt. Ida in the City of Troy. The slopes of that “mountain” rose slowly and gently behind the college. There was no apparent danger. But there were real similarities between Mt. Ida and Nott Terrace in Schenectady. Both sites lay within ice age deltas and that’s what generated the landslide threats. In Schenectady, the Mohawk River had once flowed into Glacial Lake Albany and deposited the delta that Schenectady came to be built on. In the then ice age Troy, Poesten Kill Creek flowed into the east side of the same lake and deposited the Mt. Ida Delta. In both cases the deltas were composed of sticky muddy sediments. When those get too wet, they become unstable and landslides become more and more likely. When Lake Albany drained away, both sites were left high and dry.

Nobody died at St. Peters, a number of children had been playing there just minutes ahead of time, but they had left. The college building was destroyed but it did block the slide from entering a residential community just a bit further downhill. Nevertheless St. Peters College had been destroyed and it was not possible to rebuild it; the money was just not there.

And that’s what makes this such a historic event. We have to ask “what would St. Peters College have become?” It surely would have grown into a very sizable university. Would it have had a powerhouse basketball team? What about its economic effect? Would Troy have become a far more affluent city with a large thriving university in it, lying close to RPI? We will never know the answers to such questions. But something very bad and very long lasting occurred on that night.

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

You can have it both ways

The Catskill Geologists

Robert and Johanna Titus

The Mountain Eagle

Mar. 9, 2018

We write these columns in the hope that you, our readers, will come to pay closer heed to the rocks of our region. That’s a lot easier to do if we put together just the right sorts of articles. We hope that this is one of them. Some time ago we went exploring at the top Overlook Mountain. We have long enjoyed Overlook; it has a fine view of the town of Woodstock and the Hudson Valley beyond. Then there are the scenic ruins of the old Overlook Mountain House Hotel.

Not surprisingly, there is a lot of geology up there. At the height of the Ice Age, Overlook was overwhelmed by the glaciers. They swept up and over the mountaintop and left quite a record behind. If you climb up to the very top where the fire tower is, you can look about and find the scratches left behind by cobbles and boulders dragged across the mountain’s bedrock top by the passing ice.

But, our column today is about that bedrock itself. The Overlook Mountain trail is a very good one. It ascends the southwest slope of the mountain and, almost at the top, it makes a bend around the mountain’s peak. You will have very little trouble noticing the sandstone exposures along the uphill side of the trail. These are likely river channel deposits from the old Catskill Delta that is preserved here. Take a look at our photo. It’s                      a close-up view of one small stretch of the outcrop. Notice a peculiar aspect of the stratigraphy here. The uppermost half foot of strata dips strikingly to the left. Now look below and you will see some more strata that do just the opposite; they dip to the right. What a strange thing this is; it needs to be explained.

This is just the sort of thing that geologists, like us, always take note of, and it is just the sort of puzzle we like to unravel. Let’s take a crack at solving this mystery. We can start by considering one set of strata at a time. Those upper beds, by themselves, are called planar cross beds. Planar cross beds have distinctive inclines to them and they lie in contact, above and below, with flat-lying surfaces. In this case they speak to us of old river currents, flowing right to left. These currents carried sand and deposited it in inclined beds, dipping downstream.

The lower beds record exactly the same thing, but they speak of currents flowing left to right. How can that be? Rivers, after all, are only supposed to flow in one direction. Our solution to one problem has, ironically, opened up another. That’s very common in all the sciences. Now we need to solve that second one. Like any good scientists, we must do some hypothesizing.

Catskill geologists understand that the rivers which, long ago, flowed across the Catskill Delta were meandering streams. They wandered back and forth across the delta. So this river might have flowed right to left at one time and reversed itself later. But there is another possible hypothesis. If this river had been approaching the coast then it might have been a tidal river, like today’s Hudson. If so, then some of the planar cross beds might have been from some ancient high tide while the other set might have been from a following low tide. They might have even been deposited on the same day!

Which hypothesis is the winner? Is either the right explanation? That’s the sort of thing geologists debate late at night in geology bars.

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

A hillslope in winter

The Catskill Geologists

Robert and Johanna Titus

The Mountain Eagle

Feb 23, 2018

Being geology columnists we are on duty 24/7. Whatever we are doing, wherever we are going, we are on the alert. That is especially the case in winter, when conditions for doing geology are hardly at their peak. Well, a short time ago we were driving west on Rte. I-88. We had passed Cobleskill and were at about mile 88, when we spotted something we just had not noticed before. Take a look at our photo.

We were in the Schoharie Creek Valley and a fine hill rose above us to our right (north). During the summer there is nothing particularly special about this view, the hillslope is green with its forest. But, in winter it is all different. Two massive ledges leap into view, one at the hill’s bottom, the other high above. Now, we are pros, we know our way around the stratigraphy hereabouts, so we can describe these rocks without even climbing up there. Those two ledges are sandstones and those sands, about 390 million years ago, were deposited on the bottom of an ocean sometimes called the Catskill Sea. The rest of the slope is composed of endless horizons (strata) of dark shale. Shale is composed of sedimentary grains even smaller than sand; it is composed of hardened silt and clay. All this makes up a thin slice of time, something called the Devonian time period.

We pulled over and got out to take some photos and appreciated that, where we were standing, was once the bottom of the Catskill Sea. We became time travelers, all around us was salt water, and below us was a dark seafloor. It wasn’t a very deep ocean; we looked up and could just barely make out a very dim sunlight that came all the way down to us at the bottom. We looked around and saw, here and there, a handful of shellfish; the fauna of this sea bottom was pretty sparse. More than anything else, we sensed the absolute stillness of this marine setting; there were no currents and no sounds whatsoever. Geologists call this a stagnant seafloor, there was only very limited amounts of oxygen in the water, hence the scarcity of animals.
Then things changed. We felt a gentle current, coming from the east; it slowly picked up and we sensed sand grains being carried along, again from the east. What had happened? We had detected an influx of faster currents, carrying coarser grains of sediment; we were witnessing the very beginnings of the deposition of one of those sandstone ledges.

The question a geologist asks is – what is going on? What exactly caused a shale producing seafloor to become one that accumulates sand? And why were those currents and sands coming from the east? Those are very typical geological questions. Like any other scientists, when trying to solve such problems, Geologists focus on developing tentative solutions, called hypotheses. The two of us looked up at that hill again and quickly came up with several hypotheses.

We knew that, off to the east in Devonian times, there had been a rising chain of mountains; geologists call them the Acadians; they lay where the northern Appalachians are today. But, how was it that currents, carrying sand, had emanated from the shores of that mountainous terrain? That’s where our hypothesizing came in. Our first guess was that those mountains had entered into a phase of accelerating uplift. The rising mountains became steeper and that generated faster flowing mountain streams. Those streams became increasingly erosive and swept up vast amounts of sand. The currents reached out to where Cobleskill is today and deposited a thick horizon of sand, the first of our two ledges.

The second hypothesis was that the climate had changed; it had grown increasingly rainy. The heavy rains produced powerful mountain streams that flowed rapidly and powerfully down the slopes and washed massive amounts of sand into the Catskill Sea. That alternative hypothesis would have served equally well to make the sandstone ledges that we were looking at. Which hypothesis was the winner? Is either one correct?

We don’t know. Sometimes science is difficult.

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

A “youthful” stream?

The Catskill Geologists

The mountain Eagle

Robert and Johanna Titus

Feb. 16, 2018

   We have been trying to find “winter” topics to write about lately; after all, it is that awful season of snow and ice. This is not a geologist’s favorite time of the year and for good reason. We enjoy getting out during the warm months. We can do so many more things then. But actually, there are things that a geologist can do best in the winter, things that just don’t work out in the summer. Mainly, we can see features that we can’t in the summer. During those warm months all the foliage is decked out. Leaves are pretty; leaves are nice, but they get in the way of seeing the landscape.

Well, that is just not the case in the winter. Take a look at our photo; it shows a very small valley lying alongside a road. In the summer you can go there and hardly see the valley at all. It is small and all the leaves obscure the view. Take another look at our photo and start to form an impression of this valley. It is so small; the trees serve to give you the scale. There is a stream in it, but it too is very small, perhaps even tiny. This little creek dries up in the summer but it is active throughout the rest of the year.

Even a little creek would have few problems eroding a valley as small as this one, and that is the case here. This little creek is too small to have a name, but it did carve its own valley. And it is not likely that it took very long. You can be forgiven if you deduce that this is a young stream; it does not have much of a history.

The slopes of this little valley are pretty steep and that is of some importance. A long time ago (in human terms) this sort of stream was formally dubbed “a youthful stream.”  It was argued that streams had life cycles; they passed through stages called youthful, mature, and old age. Streams were supposed to have had lifetimes, just like we do. This view of aging steams was described as “the fluvial cycle.” It was the invention of Harvard geographer William Morris Davis. A century ago, it was a powerful, influential scientific concept.

W.M. Davis

When we were in college those views still commonly prevailed, but that would not be for much longer. This view of a fluvial cycle was very appealing but it just was too simple. Real streams do a lot more than just get older. They perform all sorts of erosional and depositional tasks, and they produce all sorts of landscape features. It is just too simple to call them young, mature or old age. The fluvial cycle has largely disappeared from geology textbooks. But hold on, maybe we should be careful about all this; let’s not be in a big hurry to be modern. Let’s look at this unassuming little stream some more.

Our little stream descends the slopes of Catskill Creek. On its way it cuts through deposits of glacial debris. Those deposits formed very late in the Ice Age, in fact these deposits were virtually the last things produced by ice age processes. They probably don’t date back more than 15,000 years. That’s a very brief period of time – in geology. These deposits are, in short, genuinely youthful. William Morris Davis regarded steep slopes as diagnostic of youthful streams. This one is just what he had in mind.

We will return to this theme in later columns, but for now we would like it if you, as you travel about, notice similar streams. Look for small streams with vee-shaped valleys. We think that there are a lot of them in the Catskills. They are mostly very late ice age features. William Morris Davis would have been glad to see them.

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

“Ramp and Pluck” — The Catskill Geologists

The Mountain Eagle; Jan. 26, 2018

Robert and Johanne Titus

  We have been nosing around, looking for geological features that work well in the winter. Last week we found an impressive view of Glacial Lake Schoharie, an image of that old lake that positively shined in the winter snow. That was on Rte. 145, just west of Middleburgh. Just a few minutes later, on the same drive, we stopped and took a good look at Vroman’s Nose, just east and again on Rte. 145. We noticed something we had not seen before. That’s this week’s column.

Take a good look at our photo. It’s a cross section view of the Nose; it’s the best view you can obtain. It show’s all the structure of what is called “ramp and pluck” topography. Notice that the right (north) flank of the mountain tapers off gently; its slope is relatively low. The left (south) flank, however, is far steeper. All this reflects the behavior of the glacier that once passed across the Nose.

That was the Schoharie Creek Valley glacier. It moved right to left, or north to south in our photo. The ice scoured its way up the north-facing ramp of the mountain. Then the ice passed across the crest of the mountain and soon it yanked, or plucked, an enormous mass of rock right out of the south side. That’s the south facing cliff. Well, hence the name ramp and pluck. It’s a very descriptive term, an unusually good choice of words for science.

Well, we already knew all this; we have been here so many times before. But on this visit, there was something different. It was in the snow. Notice the nice thick blanket of snow on the ramp side. Then see how the snow is nearly absent from the darker, steeper south facing slope. The plucked slope is a virtual cliff. Snow can accumulate on the ramp side but it cannot on the plucked cliff. The two sides stand out in sharp contrast, thanks to the snow.

None of this is terribly important; you won’t find anything like this discussed in a glacial geology textbook. But it is an aesthetic; isn’t it? And it helps train the eye, doesn’t it? And perhaps that does add some “importance” to what we are talking about. Geology is an experiential science; it is widely said that the best geologist is the one who has seen the most rocks. But, also, perhaps it is the best geologist who has seen the most rocks in the best way!

And that is the point here. We seem to have found a new way to look at geology in this season of the snow, and that new way is likely to offer insights as we continue our explorations. We intend to devote ourselves to noticing more winter images of this sort; there may be other interesting snowbound features out there.

But, in the meantime, it is training your eyes that we are interested in today. Ramp and pluck topography is important and common. Perhaps this is the time of the year when we should be looking for it. Perhaps you can keep out a sharp eye too.

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

The Schenectady landslide.

The Catskill Geologists

The Mountain Eagle; Feb. 2018

 Robert and Johanna Titus

Have you heard about the recent (2018) landslide in Schenectady? A mass of mud slid down a steep hill along Nott Terrace road and did major damage to two houses. It injured at least one person and left perhaps two dozen others looking for a home. This is the type of story that we have been covering for more than ten years now. Landslides are frequent geological hazards up and down the Hudson Valley and throughout parts of the Catskills. We think that this threat should be better known by you, the public.

    Reporter covers Landslide story on Albany Channel 10

We need to give you a little background first. Back in the later stages of the Ice Age, much of the Hudson Valley was submerged in a body of water called Glacial Lake Albany. That included all of the land that is now Schenectady and Rotterdam. The Mohawk River was a powerful flow back then, carrying large amounts of water from melting glaciers. It flowed into Lake Albany and carried huge amounts of sediment, which were deposited into what became a very sizable delta. Those deposits were mostly sand, silt and clay; when wet enough they become mud.

The lake eventually drained, and the delta was left behind, literally high and dry. It provided ideal conditions for people to settle. Delta tops are flat and easy to develop. It was simple to lay out roads. Settlers could build homes with deep, well-drained basements. Those homes were high enough above the Mohawk River so they did not have to fear flooding. It’s a remarkable thing to realize that both Schenectady and Rotterdam are where they are because of the Ice Age.

Over the millennia, rivers cut canyons into the delta and there lies the problem. Those canyons often have steep slopes and, when the delta deposits become wet from rainfall, they turn into mud and that mud can let go and slide downhill as mudslides. That happens from time to time. One of the most recent such events occurred in the spring of 2004. Heavy rain, the previous autumn, had soaked the ground at 1^st Avenue in Western Schenectady. The Mohawk River and an unnamed creek had eroded into the delta deposits there and created a steep slope, 80 or 90 ft. tall. When the slide began, it caused six houses to slowly subside. It is our recollection that they were all condemned. In January of 1996 a similar event occurred on Broadway, near Rte. 890 where Pleasant Valley Creek created a similar steep slope. That landslide, occurring after heavy rains, killed one man. The Nott Terrace slide is an event very similar to these.

As geo-journalists, we have been following this story for years. We have seen similar events in Delmar, Greenport, Rennselaer, Germantown and just a few years ago in New Baltimore. We fear that many more such slides will occur throughout the Hudson Valley, including at historic sites in Hyde Park. All of these slides involved the sediments of Lake Albany. These silty lake sediments soak up a lot of rainwater. When they reach a certain point, they become unstable. Great curved fractures open up and masses of earth slide along the curves of what are called rotational slumps.

All this is important; it is our region’s greatest geo-hazard. This will happen again.

Reach the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.” Watch for their columns in Kaatskill Life and Upstate Life magazines. They are frequently in the Woodstock times.

Our reader’s rocks – Ice in Grand Gorge Gap?

The Catskill Geologists

Robert and Johanna Titus

Sept.15, 2017

We always give our email address at the bottom of each of our articles. And we can always be approached on our facebook page, so we hear from a lot of our readers. Often, they have questions, and we are usually able to help them with answers. Every once in a while, we thought we would answer one of these queries in the form of a column so here goes the first.

Recently we heard from a Gerry Hubbard. He sent us a photo of Grand Gorge Gap and wanted to know what the rounded hump on the right is. Take a look at our photo and you can see that hump. We had been wondering the same thing for years and so Gerry’s request got us to do something about the problem.

The first step is to get our topographic maps out and look at them. We found that the Roxbury 7 1/2 minute quadrangle map displayed the Gap. We found that the hump has a name; it is Jump Hill. Then we went back to our photo. The “hump” is actually something that lies in between two valleys. The contour lines on our map indicated a steep but steady slope for each of the two valleys. Each one of those is what geologists call a U-shaped valley. Every trained geologist on the planet Earth quickly recognizes the ice age history of such a valley. They record the passage of glaciers. As ice squeezed through a valley it ground away and eroded the bedrock. The shape that offers the least resistance is the U. Not surprisingly, over a period of time, glaciers will carve those U’s into the bedrock landscape. It gives each of them a path of least resistance. That forms a remarkably picturesque image and that helps make glaciated landscapes so attractive. We geologist are most fond of these U-shaped valleys.

Well, we studied the map and our photo and started speculating about what had happened here, way back, near the end of the Ice Age. Speculation is a word that scientists like to avoid; it sounds so – well speculative. So we use the word hypothesize instead. It sounds better. We hypothesized the following story: We hypothesize that the larger U-shape, on the left, is the older of the two. We think that a sizable glacier entered Grand Gorge Gap and began eroding the large U-shaped valley. Somewhere along the line, the ice was diverted and a second stream of it passed through what is the smaller, and we think younger, U-shaped on the right. All this erosion left Jump Hill in between.

We hope that Gerry likes our hypothesis. It conjures up quite an image. We travel north on Rte. 30 to where we can park and see this view. In our mind’s eyes we can imagine the advance of these glaciers; we can watch them carve the shapes of Grand Gorge Gap. That view gives us a whole new perspective on this site.

We hope you enjoyed our hypothesis. Perhaps you have a location that we could write about. Let us know.

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