"I will never kick a rock"

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Robert Titus

Robert Titus has 334 articles published.

Fossil Raindrop Prints

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Raindrops

On the Rocks/the Woodstock Times – March 20, 1997

Updated by Robert and Johanna Titus

 

We encounter many natural wonders in this field of geology and too often we take them for granted. There are so many things preserved in the rocks that really should not exist. Dinosaur footprints are good examples. How could something as ephemeral as a footprint in the mud be preserved 100 or 200 million years after they formed? The answer is that they really shouldn’t; it’s a one in a million chance. But what if there were ten million dinosaur footprints? Then ten of them would be preserved. If there had been a hundred million dinosaur footprints, then a hundred of them should still be around. One in a million shots become certainties if you just play the odds.

And geologists must learn to play the odds. Pretty much all of the fossils we find were originally one in a million shots. They were bones or shells or tree trunks that defied the odds, got buried, hardened into rocks, and were found. And then, when you have a million fossils, one of them is truly a grand discovery: a complete dinosaur skeleton, a mastodon frozen in the tundra, a little frog in amber and so on. Search for fossils long enough and you beat the odds.

We are used to this, but there are still things that we have a hard time believing, even if we see them myself. One of those odds-defying oddities can be found right here in the Catskills. They actually aren’t fossils, but the word fossil can be used to describe them. They are raindrop prints, often called “fossil” raindrop prints. Take a look at our photo. This surface just might display raindrop prints. At least that’s what they look like, maybe.

 

 

What could possibly be more ephemeral than a raindrop print? The drop falls out of the sky and leaves an impact crater in the soft earth. The crater is just that, a soft rim of earth thrown up by the impact. So far, so good, but how can something like this come to be preserved? Isn’t it likely that the very next drop will destroy the crater left by the last one? The answer is yes, of course, and the next 100 or 1,000 drops will also destroy any craters left about. And after the storm, won’t the earth be too soft to preserve an impact crater? Of course it will, the ground should be all mud, too soupy to preserve any such features.

And even if a raindrop print were to survive, wouldn’t wind eventually blow it away, wouldn’t animals’ step upon it, wouldn’t plants grow through it? Wouldn’t this and wouldn’t that! The answer is yes and yes, the raindrop should be destroyed.

And yet, there they are, . . . preserved in rock . . . little, bitty structures that look exactly like . . . raindrop prints! So, how did they get there? The prints are found on the surfaces of beds of red shales which are thought to have once been soil surfaces. That’s a helpful hypothesis and it adds some plausibility to the story. But shouldn’t the prints be lost in a mush of mud? To avoid that you have to imagine a very brief shower. A few drops sprinkle the landscape and then the “storm” is over, hardly before it had begun. But what about preservation? Next you have to let the soils dry out. This doesn’t turn it into rock, but dry soil is stiff enough to resist distortion. Next you want a flood to occur and submerge the flood plain. Floods are often not as catastrophic as the evening news coverage would suggest. Flood waters can often rise rather passively and bring blankets of new mud to bury the old soils. That can be done without much disruption of the rain drop prints. Continue this process for a very long time, bury the prints in a deepening thickness of sediment, and it will harden into rock. With that the raindrop prints are preserved. It’s a long shot, a very unlikely sequence of events, but it is possible, and it does happen. And that’s how it is that we can go and find such remarkably unlikely features in the rocks.

Such things are called primary structures. They are rather fun to watch for and they tell us so much about what the rocks represent. I would like to tell you where to go and find some raindrop prints, but that is hard to do. Look for red shales and these are common throughout the Catskills. Then pick through the shards of shale. If you are lucky, you may find some. If you are not lucky, well maybe next time.

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

Seeing a wind gap – Nov. 10, 2022

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What and where is a wind gap?

Windows Through Time; The Register Star

Updated by Robert and Johanna Titus

 

Sooner or later, every undergraduate geology major takes a course called geomorphology. It is the study of landforms and how they came into being. There are a lot of different landforms on the surface of our planet, and they go by a lot of names, a very large number of names. Do you know what a yardang is? Have you ever heard of a hoodoo? You should know what a drumlin is; we have written about them a number of times. And there are so many more names.

One of the most memorable terms and, at the same time, one of the most memorable landscape features is the “wind gap.” That is the subject of today’s column. What is a wind gap; where and how do they form? The term comes from the town of Wind Gap, Pennsylvania. That’s where the first wind gap was recognized, so that town got the honor of the naming of the feature. But we are not in the business of writing about Pennsylvanian geology; we want to describe a wind gap that is much closer to home.

The story of wind gaps picks up where we left off last week. If you remember that column, then you will recall that a geologist named Rudolf Ruedemann, back in the 1930s, postulated that Pennsylvania’s Lackawanna River once extended far to the northeast from where it is today. Today it is strictly a Pennsylvanian river. But Ruedemann conjectured that, about a hundred million years ago, the Lackawanna extended to the modern course of the East Branch of the Delaware and, from there, on to what is today the drainage basin of the Batavia Kill.

We recounted Ruedemann’s hypothesis, in that column, with some fondness. It is an old idea and it may be out of date, but we like it nonetheless. Well, if Ruedemann was right, then today’s Batavia Kill once flowed southwest as part of a once very much longer Lackawanna River. That is no longer the case. Today, the Batavia Kill indeed flows southwest, but only until it reaches the Schoharie Creek. It is a tributary of the Schoharie, and a small one at that. And it gets worse; in fact, we are not actually talking about the Batavia Kill. Our interest is in a smaller stream, a Batavia Kill tributary that branches off just a little east of Windham and follows Rte. 23 towards East Windham. Get out a good map and you can trace this creek; unfortunately it does not seem to even be large enough to merit its own name. But, even without a name, it may well have quite a heritage.

A hundred million years ago this little tributary might have been a part of Ruedemann’s very sizable Lackawanna River. But only if Ruedemann was right. We can test his hypothesis. If this little creek had once been a part of a larger river then it should have a valley much larger than is proportionate; let’s take a look. You can get an interesting view of this tributary if you take County Rte. 81 east from Rte. 145. At Dingman Road, and for the next mile or so, you can look up at the Catskill Mountain Front and see a cross section profile of the valley of this nameless creek. In fact, technically, it is not a valley at all; no water flows here; our nameless creek picks up a bit to the west; there is no stream right here!

Take a look at our photo. That profile seems big, disproportionately large. Even so, this feature is something that few would even notice. But we imagine that Rudolph Ruedemann did notice it and thought it was important. This is a classic wind gap. If Ruedemann was right then, long ago, the Lackawanna River flowed through this gap. Back then, the river continued back into New England. At that time this site would have been what is called a water gap. Wind gaps don’t have water in them; water gaps do. Ruedemann thought there had once been a powerful stream up there.

Make a visit to this location and look up. When we do, we find that we have traveled back in time to before there was a real Hudson Valley around here.  There is just a piddling unnamed creek now, but the old Lackawanna may have flowed by – up there – at that high level! Then its waters were diverted by the Schoharie Creek and, before that, by the Delaware River. Please take another look at last week’s column.  We can’t be sure if any of this is true, but it sure is interesting.

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

A Catskills wind gap, Part one

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The Lackawanna River? Right here? 

Windows Through Time

Robert and Johanna Titus

 

Have you spent much time in northeastern Pennsylvania? If so, then perhaps you have seen the Lackawanna River. It’s not one of the world’s great waterways, but it does count for something. It begins in the most northeastern part of Pennsylvania and heads southwest until it reaches a confluence with the Susquehanna River.

Did you know that it flowed right through Windham? Yes, the Lackawanna River. Well, it doesn’t flow through Windham today, but it very well may have a hundred million years ago. If it sounds like we have a lot of explaining to do, well we sure do. Carl Sagan said it best when he said “extraordinary claims require extraordinary evidence.’ We are obliged to come up with a good story. Let’s give it a try.

 

For starters, let’s be sure to make it clear that the idea that the Lackawanna was a local stream is not ours. This notion was conjured up by one the many fine scholars that have worked at the New York State Museum these past two centuries. This one was named Rudolf Ruedemann. His career at the Museum occupied most of the first half of the 20th century. He was, more than anything else, a paleontologist and he produced many fine works on New York State fossils. But that didn’t stop him from working on other branches of geology.

And that included river geomorphology, the study of river landscapes. Ruedemann must have had a way with spatial relationships, because when he looked at a map, he really looked at a map. Take a good look at today’s illustration. It is a slightly modified version of a map that Ruedemann published in the 1930s. Notice the prominent placement and labeling of the Lackawanna River. And then see how long he made the Lackawanna. Ruedemann meant his map to show local rivers as he thought they had been about a 100 million years ago. The East Branch of today’s Delaware River is what Ruedemann labeled at EB on his map. Ruedemann made it part of the Lackawanna. He does not label Batavia Kill but that is the eastern stretch of Ruedemann’s ancient Lackawanna.

Ruedemann had noticed how those three rivers all lined up so nicely. He hypothesized that they had once been joined together to form a very long Lackawanna. So, what changed all that? Why aren’t they all still joined? The villains in Ruedemann’s saga are the Delaware and the Hudson Rivers. The Delaware is the dotted line on the western part of his map. It, back then, was eroding its way north. It would get longer and longer until it intersected the old Lackawanna. Then it would divert much of that river. The upper Lackawanna became the East Branch of the now longer Delaware. The Delaware kept on eroding and eventually diverted the upper Susquehanna to make its West Branch.

River erosion like this is called headward erosion. The upper reaches, or heads of rivers, work their ways up into the hinterlands. If they encounter another river then they rob it of much of its flow. The word we geologists use for this sort of theft is “piracy.” Both the old Lackawanna and the old Susquehanna were pirated.

Ruedemann’s story is far from over. Look to the east on the map. Those eastern dotted lines are the Hudson and Mohawk Rivers, along with the Schoharie Creek. They too were the products of headward erosion. The Hudson, during the same span of time, had been eroding its way north. It gave birth to its tributary, the Mohawk, which, in turn, gave birth to its tributary, Schoharie Creek. And Schoharie Creek lopped off another large chunk of the old Lackawanna. That chunk is today the Batavia Kill drainage basin which flows right through Windham. That takes us back to the beginning of this column. The creek that flows through Windham used to be part of the Lackawanna River.

And that then gets us back to Carl Sagan. Did Ruedemann come up with enough extraordinary evidence to support his extraordinary claim? Well, to this day, that is something that they debate late at night in geology bars. Do we have our own opinions? Well, let’s just say that most couples fight over money. We are fond of Ruedemann’s ideas and we would like it if they turned out to be true. But even in the 1930s these ideas were conjectural. They can be, if one insists, dismissed as mere coincidence and who can say that is not so.

A longer version of this story will be in the author’s new book The Catskills, a Geological Guide, the expanded edition. Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

A Maze of streams – Oct. 20, 2022

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Into the Maze

On the Rocks – The Woodstock Times

Updated by Robert and Johanna Titus

 

Look at a good, detailed map of the Hudson Valley in the vicinity just east of West Saugerties and Manorville. If you focus on the streams long enough, you just might notice something odd. A series of rivers descends the Catskill Front. Plattekill Creek is the most prominent, but there are several others, mostly unnamed. They all start out fine, descending picturesque mountain canyons as typical mountain streams. Then something peculiar happens. They all enter into a confusing complex maze of streams. Almost all the rivers and their tributary systems display a prominent north-south orientation. Within that pattern there are a large number of abrupt left and right turns as well. That gives our drainage a lattice-like appearance. We have searched the geological lexicon and we are not exactly sure what this should be called, but we think “rectangular drainage” is the best choice. It’s a curious pattern and, of course, there’s a reason for all this.

It all has a lot more to do with the bedrock than the rivers. You see, throughout much of this area there are alternating layers of sandstone and shale. All these stratified rocks are inclined; they dip into the earth toward the west. What that means is that the crust was once actually moved, tilting to produce north-south ridges of very solid rock.

The bedrock geology has been like this for probably hundreds of millions of years, but in recent times there have been changes. A mere 15,000 years ago, the Hudson Valley glacier flowed south through the valley. The ice must have been several thousand feet thick, and it acted like a great sheet of sandpaper. The passing glacier eroded the bedrock. Naturally the ice has had little trouble scooping out the shales, they are so soft. But the ice had much more trouble with the sandstones. Tough as that stuff is, the glacier was still able to pluck loose large blocks of it and carry them off. The ice actually adheres to the rock and yanks it loose. That has sharpened and straightened the many ridges of sandstone.

All this leads us back to those rectangular river patterns. You see rivers have a very hard time getting through the ridges of sandstone, so they have followed the shales. They have eroded out their channels along the bands of the softer rock. Still, a Hudson Valley creek eventually has to east toward the Hudson River. So, from time to time, the creeks have found breaks in the sandstones and have worked their way through those ridges. That’s the origin of the sharp rectangular turns.

Plattekill Creek is typical. It is a gorgeous mountain stream as it drops out of the Catskills and passes through the village of West Saugerties. Everything continues well until it reaches the vicinity of Blue Mountain and the Saugerties Reservoir. There it abruptly makes a sharp south turn and follows a beeline in that direction for three miles. Here it is nestled between ridges of sandstone.

It’s in this vicinity that Plattekill Creek has entered that maze of tributaries. And it’s here where that north-south lineation of the drainage is best developed. We have worked the area and we believe that there are about 11 ridges of sandstone here. All of them offer barriers that can confine the tributaries into those north-south straightjackets. You can see some of these ridges and several more. Head east on Rte. 212 until you get to Shultis corner and the intersection with the Glasco Pike. From here, you can head east and count the ridges of rock that cross the pike. Or you can continue on Rte. 212 and count the ridges on your way toward Centerville. If you do count the ridges, don’t expect the numbers to come out the same. We get different numbers every time we take the route. Geology isn’t Physics and we don’t worry too much about exact numbers.

Plattekill Creek eventually has to cut through to the Hudson and it begins the hard part of its journey near where it is crossed by Rte. 212. Between here and its junction with the Glasco Turnpike, the Plattekill has to cut its way through the tough rocks of the Mount Marion ridge. In some stretches of this flow, the Plattekill has been forced to carve real canyons. You can take the Fish Creek Road north from High Woods and cross the Plattekill in this vicinity.

In the end, there is nothing all that special or mysterious about this maze of rivers. It’s just another among many landscape features, but a geologist does take a quiet satisfaction from noticing and understanding.

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

A maze of streams, Oct. 20, 2022

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Into the Maze

On the Rocks – The Woodstock Times

Updated by Robert and Johanna Titus

 

Look at a good, detailed map of the Hudson Valley in the vicinity just east of West Saugerties and Manorville. If you focus on the streams long enough, you just might notice something odd. A series of rivers descends the Catskill Front. Plattekill Creek is the most prominent, but there are several others, mostly unnamed. They all start out fine, descending picturesque mountain canyons as typical mountain streams. Then something peculiar happens. They all enter into a confusing complex maze of streams. Almost all the rivers and their tributary systems display a prominent north-south orientation. Within that pattern there are a large number of abrupt left and right turns as well. That gives our drainage a lattice-like appearance. We have searched the geological lexicon and we are not exactly sure what this should be called, but we think “rectangular drainage” is the best choice. It’s a curious pattern and, of course, there’s a reason for all this.

 

It all has a lot more to do with the bedrock than the rivers. You see, throughout much of this area there are alternating layers of sandstone and shale. All these stratified rocks are inclined; they dip into the earth toward the west. What that means is that the crust was once actually moved, tilting to produce north-south ridges of very solid rock.

The bedrock geology has been like this for probably hundreds of millions of years, but in recent times there have been changes. A mere 15,000 years ago, the Hudson Valley glacier flowed south through the valley. The ice must have been several thousand feet thick, and it acted like a great sheet of sandpaper. The passing glacier eroded the bedrock. Naturally the ice has had little trouble scooping out the shales, they are so soft. But the ice had much more trouble with the sandstones. Tough as that stuff is, the glacier was still able to pluck loose large blocks of it and carry them off. The ice actually adheres to the rock and yanks it loose. That has sharpened and straightened the many ridges of sandstone.

All this leads us back to those rectangular river patterns. You see rivers have a very hard time getting through the ridges of sandstone, so they have followed the shales. They have eroded out their channels along the bands of the softer rock. Still, a Hudson Valley creek eventually has to east toward the Hudson River. So, from time to time, the creeks have found breaks in the sandstones and have worked their way through those ridges. That’s the origin of the sharp rectangular turns.

Plattekill Creek is typical. It is a gorgeous mountain stream as it drops out of the Catskills and passes through the village of West Saugerties. Everything continues well until it reaches the vicinity of Blue Mountain and the Saugerties Reservoir. There it abruptly makes a sharp south turn and follows a beeline in that direction for three miles. Here it is nestled between ridges of sandstone.

It’s in this vicinity that Plattekill Creek has entered that maze of tributaries. And it’s here where that north-south lineation of the drainage is best developed. We have worked the area and we believe that there are about 11 ridges of sandstone here. All of them offer barriers that can confine the tributaries into those north-south straightjackets. You can see some of these ridges and several more. Head east on Rte. 212 until you get to Shultis corner and the intersection with the Glasco Pike. From here, you can head east and count the ridges of rock that cross the pike. Or you can continue on Rte. 212 and count the ridges on your way toward Centerville. If you do count the ridges, don’t expect the numbers to come out the same. We get different numbers every time we take the route. Geology isn’t Physics and we don’t worry too much about exact numbers.

Plattekill Creek eventually has to cut through to the Hudson and it begins the hard part of its journey near where it is crossed by Rte. 212. Between here and its junction with the Glasco Turnpike, the Plattekill has to cut its way through the tough rocks of the Mount Marion ridge. In some stretches of this flow, the Plattekill has been forced to carve real canyons. You can take the Fish Creek Road north from High Woods and cross the Plattekill in this vicinity.

In the end, there is nothing all that special or mysterious about this maze of rivers. It’s just another among many landscape features, but a geologist does take a quiet satisfaction from noticing and understanding.

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

The Greenport Mastodon 10-6-22

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The Greenport Mastodon

Windows Through time; The Register Star; July 8, 2010

Updated by Robert and Johanna Titus

 

Our topic today is one of the most notable paleontological discoveries ever made here in our region: the discovery of the first mastodon. This was a big find and was made a long time ago: way back in 1705. That’s when a Dutch colonist found a huge tooth in a bank of clay along eastern bank of the Hudson in Greenport. It weighed almost five pounds, and our Dutchman must have been most impressed. Not so impressed, however, that he was not willing to sell it for a half gill of rum to a local assemblyman.

The tooth worked its way up the political food chain to Lord Cornbury, then Governor of the New York Colony. He sent it off to the Royal Society of London. Today, that would be like sending it to the Smithsonian Institute. The tooth attracted a lot of attention in London, and from just the right people.  n 1705 not much was known about prehistoric monsters, in fact very little was known about prehistory. The scientists of the time were puzzled.

There were two hypotheses. Some thought that the tooth belonged to a remarkable beast or fish, but they could not imagine what type of creature it had been.  Lord Cornbury and others had another idea; the tooth belonged to a “giant” and they were talking of a biblical giant, referred to in Genesis 6:4. This tooth had belonged to a huge human being!

To his credit Cornbury sent people to search the original site for more skeletal remains and they found parts of a very decomposed skeleton. It was estimated that the beast had been 70 feet long. In fact, they had greatly overestimated the beast, but you can imagine how they reacted to the very notion!

From the very beginning there were others who speculated that the remains belonged to an elephant, but what kind of an elephant and how did such an animal get to the Hudson Valley? For the second part of the question, here again, contemporary religious views offered a solution: the beast had been carried here by Noah’s Flood. That would be difficult to prove, but it was an appealing idea.

It would take decades to solve the other half of the problem – what kind of elephant had it been – and that came when many more mastodon bones were found in the Ohio River Valley and a complete skeleton was unearthed in New York’s Orange County. Now, at last, scientists could see a whole skeleton with tusks and, clearly, they were those of an elephant, or at least a distant cousin of today’s elephant. But only a distant cousin; now there was a new scientific problem.

The mastodon did not match the Indian or the African elephants; it was a separate and new species. But nobody had ever seen such a creature in the wild. That was still another problem. At this time the very notion of extinction was a new and very troubling concept. Could the mastodon have once lived and then gone extinct? Not many people were comfortable with that thought. Theologians, especially, argued that no such thing could have happened; God would not allow extinction of species he had created. Perhaps not, but if so, where were the living mastodons?

That was a serious scientific question in the early 1800’s and President Thomas Jefferson, a pretty accomplished amateur scientist in his own right, thought he could solve it. The Lewis and Clark expedition was soon to head west, and Jefferson specifically asked its members to be on the lookout for mastodons. Certainly, the animals were extinct here in the east, but perhaps they still lived somewhere out there beyond the Appalachians.

Well, Lewis and Clark found a lot of things all across America, but they never saw and elephant. The results were clear: mastodons were extinct and, like it or not, extinction was something that really could happen – and really had happened.

All this adds up to some very important early progress in the science of paleontology. Our Greenport mastodon was among the very first prehistoric monsters to be discovered. Later generations would find the dinosaurs, but these great mastodons are still quite something to contemplate. All this would lead, with time, to a great understanding of the exotic nature of our planet’s paleontological history; it was one of the first glimpses into life’s distant past.

But equally important was the introduction of the very concept of extinction. We take that for granted today but it was a most remarkable, and disturbing, discovery two centuries ago.

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

 

 

Edison and Burroughs at Boyhood Rock. Sept. 29, 2022

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THE CATSKILL GEOLOGISTS BY PROFESSORS ROBERT AND JOHANNA TITUS

Burroughs And Edison – At Woodchuck Lodge

One of the true treasures of the Catskills is the heritage of famed nature writer John Burroughs. We have long admired his writings, dating from the 1860’s to the 1920’s, and we are proud to have a complete set of his books in our library. Have you read any of Burroughs works? You really should; there are some very good anthologies available at local bookstores and at Amazon. One of them, “In the Catskills,” focuses on Burroughs Catskill essays. We have been invited to run a geology walk at Woodchuck Lodge, Burroughs’ summer home in Roxberry, that’s at 1:00 on Saturday, Oct 1st. We expect that Woodchuck Lodge will be open for tours on that day. But, not surprisingly, our focus will be on the geological history of the site. We plan to do an easy hike around the property and look at the evidence for its distant past. Burroughs favorite science was ornithology. He had a lifelong fascination with birds. But we always like to say that his second favorite science was geology and that is borne out by the many geological discussions he includes in his books. Another lifelong fascination? We think so.

   

Burroughs was well aware of the ice age history at Woodchuck Lodge, and we have spent time documenting some of it. His favorite single spot there was famed Boyhood Rock. See our first photo. He spent many an hour sitting upon it, no doubt contemplating the nature all around. So have we. We will visit that rock on our walk. It’s a very large boulder composed of local Devonian sandstone. That gives it an interesting Devonian history, but it is also a glacial erratic, brought there by a glacier descending south, down the valley. We will stand by Boyhood Rock and gaze into the past and envision the passage of the ice. Boyhood Rock is Burroughs gravesite, and we hope he will be listening. But there is something else. See our second photo. That’s John on the right. And that is Thomas Edison on the left. The photo is from an old book about Burroughs’ life and the caption claims that Burroughs was showing glacial striations to Edison – at Woodchuck Lodge. We are going to see if we can find that exact spot on our walk. If we can, then perhaps we can see what the two of them saw, some very good ice age history! We will be sharing a moment in time with two very great men.

Burroughs was likely the most famous and important person ever born and raised in our Catskills. Our walk will be a good introduction to the man – and his second favorite science.

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

An autumnal view 9-22-22

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Fall Vistas – Atop the Hudson River

The Register Star – Windows Through Time, Sept. 2010

Updated b Robert and Johanna Titus

 

Autumn is the season to get out and see the outdoors before it is too late. Winter will be here all too soon and we ought to enjoy ourselves and our landscapes now, while we still can. We are fortunate to live in such a scenic region. There is so much to see. We have, in recent years, added a very fine vista to our Hudson Valley. That is the Cross Hudson Pedestrian Bridge which links the west bank of the river with Poughkeepsie. Officially it is the Walkway over the Hudson State Park, but whatever you would like to call it, it is a marvel.

The bridge was originally built in 1889 as a steel cantilever railroad bridge and it served that way for decades. It was considered an engineering marvel in its day and for a long time it was the only cross Hudson bridge south of Albany.  Use of the bridge declined after 1960 and it closed for railroad traffic in 1974 and lay unused for a quarter of a century. Then in the late 90’s plans were developed to turn it into a pedestrian and bicycle bridge and all that came to fruition in 2003. Since then, it has been open to the public for recreational enjoyment. You can walk from one side to the other and soak in the views of the Hudson Valley to the north and to the south. It’s well worth the effort.

But this is alleged to be a geology column and we are not supposed to be singing songs about bridges, are we? How do we justify all this? Easy. we just had to go and look around. We went down to the west end of the bridge and hiked out onto it a few weeks ago. We brought a camera and resolved to find something we could write about. It didn’t take long. About halfway across we began to take note of a series of relatively small hills on the east side of the river. One was due east of the bridge, right in the heart of Poughkeepsie. Then there were four more arrayed as if in a line, extending off to the north.

It would have been easy to have not noticed them at all; none of them are all that big. But we quickly guessed that we were looking at a kind of hill that is common farther north in the Hudson Valley. These appeared to be remnants of the Ice Age – hills called drumlins. We have written about drumlins several times before. They are beautiful little hills sculpted by the ice of passing glaciers. They are perfectly symmetrical with steep slopes dipping east and west. The north slopes are also steep, but the south slopes have much more gentle inclines. Drumlins are shaped just like upside down spoon bowls, and they are common, – very, very common throughout much of the Hudson Valley.

When we came home, we dug out our topographic maps and confirmed that these were drumlins. We even found that Dutchess Community College is built upon one of them. One of their academic buildings is even called Drumlin Hall.

It all got more interesting when we continued to study the maps. It seems that these are just about the most southern of all the Hudson Valley drumlins. To the south they just disappear; to the north they become very frequent. Everywhere we looked, these drumlins lay atop all other landscape features. They had to be younger than all other features. That clinched it; we were looking at the record of the one last final advance of the ice. We had been looking at the last gasp of the Ice Age!

Now, in our mind’s eye, we returned to the Cross Hudson Bridge and gazed east. we watched as that glacier moved south. It wasn’t very large and just barely rose above the horizon. Compared with earlier chapters of glaciation, this one was puny. It was near the end of the Ice Age and this small glacier was all that could be managed. But all around us, the Hudson Valley was bleak and baron. This was still very much an ice age landscape.

We watched the glacier advance to the center of what would someday be Poughkeepsie and then it slowed down and ground to a complete halt. This last chapter was running out of steam (or running out of cold?). We continued to watch and then the ice began to melt. It melted away and vacated this part of the Hudson Valley. As the glacier disappeared the drumlins emerged from the ice and took on the appearance that they still display. Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.”

 

Foothills of the Catskills Sept.8, 2022

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The Hoogebergs

Updated by Robert and Johanna Titus

On the Rocks – The Woodstock Times

 

We often use lots of words without having a precise notion of what they mean. English is designed for that as sometimes its words need to have just a touch of (appropriate) vagueness. For example, just what does the word “mountain” mean? There are many good answers to that and each one is different from all of the others, and each one may still be correct. Similarly, what exactly does the word “hill” mean? It gets worse. What does “foothill” mean? Hills don’t have feet, so let’s pursue the issue and do it with a good local example.

The Catskills are often called mountains although many debate that heatedly. Our Catskill Mountains have foothills and some of those are very close to Woodstock. The foothills that we are speaking of are the hills of the Hoogeberg Range. If you have never heard the term that’s quite excusable, the Hoogebergs are not great or famous peaks.

The Hoogebergs are a series of small hills lying parallel to the Catskill Front, the great eastern escarpment of the Catskills. They are found just a few miles east of the Catskills and rise to only 600 or 700 feet in elevation. That’s merely a third of the elevation of the Catskills themselves. Thus, they are adjacent and parallel to Catskills, but just not very elevated. They are like a practice run before the big mountains, hence the term foothills. You can see the Hoogeberg Range if you drive north on the Kings Highway (Rt. 31), south of Saugerties and Rt. 32, north of Saugerties. The ridge looms to your left (west). It forms a fairly impressive horizon.

 

 

            Hoogebergs – lower right

You can easily go and see the rock that makes up the Hoogeberg Range. There are several locations where there are gaps in these hills, and they let you drive right through the bedrock. Rt. 212 cuts through at the village of Veteran, Rt. 32 cuts through at Quarryville and the Glasco Pike cuts through at the village of Mt. Marion. In each of these locations there are fine exposures of the bedrock right along the road.

What is the Hoogeberg and why is it here? Visit the Rt. 212 exposures and you will observe some very fine, thick, rugged sandstones. These are tough rocks and they have resisted the efforts of weathering and erosion. To the east and west, softer rocks have eroded away, and as they did the Hoogeberg came to be sculpted into a series of hills. These sandstones belong to a geological unit called the Mt. Marion Formation. It is mostly sandstone, and it makes up the Hoogeberg Range. Park along Rt. 212 here and poke around for a bit and look the sandstones over. You may find the fossils of some marine shellfish. That tells us a lot. The Mt. Marion sands accumulated at the bottom of an ocean, sometimes called the Hamilton Sea. The sands once made up the floor of that sea.

At the Glasco Pike exposure you will learn more about the Mt. Marion and the Hoogeberg. This outcropping is at the bridge which crosses Plattekill Creek. The lower levels of the exposure are mostly black shale. Up above, however, those sandstones make their appearance. We talked about this in an earlier column. This sequence of strata records a transition from an offshore, deep water setting to a nearshore, shallow ecology. The offshore accumulated muds that hardened into the shales while coastal sands would eventually harden into the Mt. Marion sandstones.

If you look carefully, you may notice that the strata at these locations are not perfectly horizontal; they dip gently to the west. These rocks were all here during the late Devonian time period and they were involved in crustal tilting that was part of a mountain building process, then going on in New England. The tilting of these resistant strata raised those sandstones and exposed them to erosion. They responded by eroding into the hills we see today. The tilting accounts for much of the form of the Hoogeberg. Its west-facing side is generally a gentle slope, reflecting the original tilting, while the east-facing front was eroded into a steep slope, often a cliff.

Crustal tilting, shallowing seas, ancient shellfish, there’s a lot of history in these pretty little foothills and they do make up a significant feature in our local landscape, even if they are just foothills.

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

A winding stream 9-1-22

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A winding river

On the Rocks; The Woodstock Times

Robert and Johanna Titus

 

Congressman Faso has introduced a resolution in Congress that recognizes the natural resources and economic importance of the Upper Delaware River watershed. It was supported by something called the Coalition for the Delaware River Watershed. As       much as anything, the resolution is looking to improve the area’s tourist trade and we are in full support of that. This picturesque region is well worth visiting. Have you spent much time there? Well maybe we can give you a good reason to visit.

We have often enjoyed driving west on the valley of the East Branch of the Delaware. It passes through a largely rural region which presents us with a very scenic drive. What you are bound to notice very quickly is how the slopes on each side of the river are so steep. The valley is narrow here and its slopes rise up and tower over the river itself.

That’s unusual in the Catskills region. Our river valleys typically slope down far more gently. The story becomes more interesting when you get a good map out. Take a look at our first picture.

It traces the river from Corbett to Linden. Notice the broad sinuous curves that the river follows. These sorts of curves are commonplace among rivers but, not with this sort of river. These river bends have quite a story to tell.

This is properly called a meandering stream and the derivation of the word meandering is obvious; it refers to our sinuous curves. The problem is that meandering streams are supposed to be found on rivers that flow across enormous wide floodplains but there are virtually no floodplains here. The Mississippi is very good at meandering. And the other problem is that meandering streams are not supposed to be found at the bottoms of canyons. We geologists have a lot of explaining to do.

The story goes back to the 1930’s when a New York State Museum geologist named Rudolf Ruedemann began looking at these rivers and did some deductive thinking. Ruedemann knew that meandering streams had to have formed on broad floodplains and so he, in his mind’s eye, traveled back in time and saw our western Catskills as they may have been during the Cretaceous Time Period, about 100 million years ago. Ruedemann deduced that the western Catskills region must have been flat at that time. No hills or mountains rose up as they do today. That flat landscape, he reasoned, was ideal for the production of meandering streams. And so it was that rivers which would become our modern East and West Branches of the Delaware, found themselves flowing in those broad sinuous meanders. And they were flowing across an enormous flat landscape.

Then things changed. The crust of our whole region began a long slow uplift. The East and West Branches found themselves in a rising landscape. Their meanders had no choice but to begin eroding into that rising land. The meanders were trapped as, above them, were those rising slopes. That is how our distinctive landscape came into being.

All this speaks of the East Branch occupying a very old river channel. It could be that the banks of the river date back to the Cretaceous, 100 million years ago – or more. If you get a chance to go out there, and can climb down to the edge of the river, then think about all this. During the Cretaceous the river was right where it is today. There were dinosaurs in abundance during the Cretaceous. Stand on the edge of the river and look to your left and then to your right. There once were dinosaurs there, drinking the waters of this stream!

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

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