"I will never kick a rock"

Erratic behavior – Alligator Rock 10-24-9

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Erratic Behavior
On the Rocks
The Woodstock Times, 1997
Updated by Robert and Johanna Titus

North Lake Campground has always been a wonderful place to visit at any time of the year, but autumn is a special time. We never need too many excuses to make the trip. We almost always start out at the parking lot at North Lake itself, then we take the trail south along the shore of the lake. The trail will take you out to the point of rock that separates North and South Lakes. Travel around the point and in another quarter mile or so you will encounter a most remarkable boulder. It is enormous, it must be twenty-five feet or more across and perhaps eight feet high. That’s a lot of rock, but that’s not all.

A rock that big deserves a name and this one is called “Alligator rock.” We are not convinced that was a good choice, how about dinosaur rock? Nope, that name has already been taken for an equally large boulder about 50 yards away. But we don’t get to change names anyway: Alligator rock it is.

A person is entitled to ask where a boulder this large came from. It’s a good question and there is an answer. Boulder rock is what geologists called a glacial erratic. About 15,000 years ago all of North Lake was buried under a large glacier, a sheet of ice that was flowing southward down the Hudson Valley.
Moving ice is good at two special things. First it is very good at ripping up large blocks of rock and second it is even better at carrying those blocks of rock away. You have to use your imagination to get a fix on all this. Travel back to the Catskill Mountain House ledge and gaze at the horizon to the north. You have to be able to see ice coming down the valley and slowly filling the Hudson. Then it rises up the highest slopes of the valley wall right beneath us. Soon ice is coming over the ledge just to the north. The ledge is soon overwhelmed by the moving ice. As the glacier shears across those barriers of rock it adheres to the rock and plucks loose many large boulders.
Nobody can actually see such a thing. You really do need a good imagination to imagine all this. In real ice age life such events go on in the darkness at the bottom of a glacier. But we understand that the bottom of every moving glacier is replete with many such boulders. Some of them are a lot bigger than Boulder rock. Some are truly the size of houses. Neither Alligator nor Dinosaur Rocks are that large, but they are big enough.

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

Boulders at Mink Hollow 10-17-19

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Boulders of Mink Hollow
On the Rocks\
The Woodstock Times
Updated by Robert and Johanna Titus

If you live in Woodstock, then one of the most accessible of the Catskill hiking trails is the one at Mink Hollow. Head west on Rte. 212 and then, just past Cooper Lake, turn north on Mink Hollow Road. At the end of the road you will find parking and the trail head. Soon you can begin your hike on the Blue Trail. The hike will take you up what was once actually a highway of some importance. Vehicles, loaded with people and goods from as far away as Prattsville, traveled on it with destinations in Woodstock and beyond. There are still paved Mink Hollow Roads both north and south, but here in between, the trail stopped being a public road long ago. Today the path takes you up to Mink Hollow itself. That’s a deep, narrow gap in the mountains, mostly cut during the Ice Age. Beyond Mink Hollow the trail veers off to the northeast and takes you along Roaring Kill to another trail head on Elka Park Road. It’s an easy walk through the woods, and that’s especially nice in the summer. It stops being easy if you want to climb Sugarloaf or Plateau Mountains. Those are tough climbs, but well worth the effort. They are, however, another story for another day.
There is one very nice geological feature to see here, however, and that is our subject for today. In Mink Hollow itself there is a lean-to, built to give hikers a place to spend the night. Just south of this lean-to there is a wonderful example of what glacial geologists call pedestal rocks. You can’t miss them. They are immediately east of the trail, just about 100 yards short of the lean-to. They make a most striking feature. There are three good-sized boulders. Two of them are next to each at the bottom of the heap, while the third is a cross bar, lying atop the others and bridging the two.

Just how on earth could such natural Stonehenge happen? First of all, nobody stacked them here; there were never any Druids in the Catskills and the boulders are far too large and isolated for any other people to have bothered with them. There are some who think that such things were human in origin. But we think there is a natural explanation. Nature did this, and geologists long ago figured out how. Our story takes us back to the end of the Ice Age. At that time, probably about 16,000 years ago, there was a large glacier, filling all of the Schoharie Creek Valley to the north. A large tongue of that glacier poked through Mink Hollow and pushed on a short distance to the south.
This was a dynamic tongue of ice and it was actively advancing through Mink Hollow. If the leaves are not too thick, you can look upward from the lean-to and see a number of rough ledges on the western slope of Sugarloaf Mountain. These formed when large masses of rock were plucked from the mountain by the moving ice. And that gets us to the heart of our story.
That huge tongue of ice passing through Mink Hollow had a great number of boulders in it. These were routinely being broken loose from the ledges above and carried through the hollow. Most were dragged off to the south by the currents of moving ice and deposited at the south end of the glacier.
But eventually the climate warmed and the glaciers began melting. At that time blocks of rock would have been lowered through the melting ice until they made a soft “landing.” As luck would have it, some boulders would land next to each other, while on much rarer occasions, a boulder would end up lowered onto one or two others, forming a pedestal. That’s what happened along the Mink Hollow Trail.
Pause here for a moment and imagine Mink Hollow filled with ice. Look around and you will see all the boulders that are here. Each one was once the baggage of a glacier. It’s a nice story and just one of those many interesting phenomena that remind us of the influence glaciers have had on our landscape. And it is nice not only to appreciate the beauty of a landscape, but to understand it as well.

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

The Old Mountain Turnpike 10-10-19

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The Old Mountain Turnpike
The Greenville Press
Sep. 4, 2007
Updated by Robert and Johanna Titus

One of our region’s most historic roads is also one of its least known. It’s the Old Mountain Turnpike. Long ago, the road was the gateway to the Catskills. As far back as the 1820’s guests of the famed Catskill Mountain House Hotel rode carriages up the road to get to the hotel. As the Mountain House prospered, so did the road. When the hotel got too successful it built the Otis Elevated Railway right up the Catskill Front and the turnpike fell into disuse. Today the old road is just a horse and hiking trail, but it still has much of its 19th Century atmosphere. It makes a nice walk in the woods and, of course, along the way there are many rocks.
To get to the old turnpike take Rte. 32 south to the turn at Game Farm Road. Soon you must turn left onto Boggart Road and head south to a right on Mountain Turnpike Road. The trail head is at the end of the road. You can hike all the way up to North Lake State Park if you like, or any part of the trip.
You don’t have to go far before you are in the thick of the geology. The road makes a bend to the right and alongside is an outcropping of red rock. The rocks are floodplain deposits of the Devonian age Catskill Delta. Red strata are old flood deposits, silts and clays deposited by very long-ago floods and hardened into red shale. The darker deposits are the old muds of back swamps. Away from the river channels swamps formed in low-lying areas and dark muds accumulated. Watch for fossil plant fragments in all of this.
As you continue up the road you will encounter, at frequent intervals, a number of sandstone ledges. These are first seen in the slopes above the road, and, as the road rises, the ledges descend to its level. The sandstones are old river channel deposits. They are composed mostly of sandy strata that dip one way or another. These are called cross beds and they are the product of river currents. The currents drove masses of sand into large “dunes” which migrated downstream. Most of those cross beds dip to the northwest as that was the direction that the rivers flowed. In between the sandstone ledges the road tends to be pink or red. These are hidden floodplain deposits. The pattern is clear: River sands are followed by red floodplain shales and then more river sands and so on. The Catskill Front is made up of sandstone and shale “stories” of stone, like a great, tall building. When we make such a hike, we almost always count the stories.
The second story had some prominent ripple marks in a layer of red shale that crossed the road. This recorded Devonian breezes that blew across a shallow floodplain pond and generated currents that, in turn, created the ripples. Those ripples were a recording of a breeze of about 375 million years ago. It is incredible to think of.

At the fourth story we found a vertical ledge of sandstone that had been scoured and striated by a passing glacier. This event had occurred a mere 14,000 years ago, a twinkling of time compared to the age of the rocks themselves.
The 14th story was particularly massive sandstone. This must have been a very large river. These rivers were what are called distributaries. In a large delta complex the trunk stream breaks up into many such distributaries. Each one flows into the ocean. Look at a map of the Mississippi Delta and you will see good examples of distributaries. Better still, look at a map of the Ganges River Delta of Bangladesh and you will see a better example.

The road ascended into a hollow and made a sharp bend. Here had once stood the Rip Van Winkle House; it had been the halfway stop for carriages headed up to the hotel. The hollow was naturally air conditioned with cool heavy mountain breezes descending through it. It must have been a nice place to stop.

Just ahead was one of the largest, thickest stories of the hike. We thought that this must have been one of the greatest rivers of the Catskill Delta. These distributaries meander back and forth across a delta plain. A river that is here today, may be gone tomorrow, replaced by a floodplain. That’s why these rivers sandstones alternate with red floodplain shales. The geology here is actually very easy; the sandstones are river deposits and all the rest is floodplain. Everything is Devonian and none of it is less the 350 million years old.
The 24th story brought us to a great overlook. The trees have been cleared away here and a picnic table set up. We interrupted our journey and sat and gazed out at the Hudson Valley. We had seen a lot of geological history already. We had watched as 24 times rivers had crossed this location back in the days of the Catskill Delta. Much of this had been sandstone and sandstone is made of sand. But where had all that sand come from? The only place such large amounts of sand can come from is the erosion of a great mountain range. From our picnic table seat, we gazed across the Hudson Valley and saw the profile of a great mountain range rising above the Berkshires. These were the Devonian age Acadian Mountains. They may once have rivaled the Himalayas, but now they have been eroded away. All that is left are those picturesque hills of western New England. Now we really had seen a lot of history, but there was so much more.

The old trail and we continued up the mountain in a zigzagging pattern. Sometimes the way was very steep, and we thought of how the horses must have struggled here in the 19th century. The sandstones came to be much thicker and prominent. Very large ledges lay left and right of the old path. The road cut right through some of them in several locations. Now we understood what they represented. These sandstones were a record of the destruction of the Acadians. As the old mountains came to be weathered and eroded, they shed their sands into New York State and made the sediments that would eventually become the Catskills. And the Old Mountain Turnpike was a history of all this.
Close to the top of the Catskill Front the old highway levels out. The horses must have been relieved, they had had a very hard haul up the mountain and now they had a little rest. But there was one more sharp turn. In the 19th century, that turn had brought travelers to within a short distance of the Catskill Mountain House hotel, but then it took them away. The highway had to climb one more great ledge and it zigzagged in order to manage that. That last ledge is the thick one that makes up the crest of the Catskill Front. It is the grand ledge that the old hotel stood on itself.

When we finally reached the top, we visited the hotel site and sat and gazed into the Hudson Valley. It had been quite a hike and we had passed through a lot of history. Before us was that ghost image of the old Acadian Mountains. As we pondered it all we realized that there was some pretty strange geology here. We were sitting upon the sandstones of the Catskills that, themselves, were made of sands from the Acadians. The death of one mountain range had given birth to another. Nature does wondrous things.

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

The Ghost Mountains – Devonian Pt. 14 – 10-3-19

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Ghost Mountains
The Devonian Part 14
The Greenville Press
Oct. 26, 2006

We have made a long journey through time. Last summer [2005] we started out along the highway in Leeds and visited the Helderberg Limestone there. Through 13 chapters we have traveled through a thick sequence of thousands of feet of Devonian age strata. Most of those are exposed along Rte. 23 and most of those are sandstones. All of these rocks were once sediments, mixtures of sand, silt and clay. Geologists have long recognized that thick sequences of sediment must have taken very long periods of time to accumulate. Our sedimentary sequence is estimated to have needed 50 million years or so to form.
But there is a second question. Where did all that sediment come from? Thousands of feet of sand a mud must have come from somewhere and it must have been somewhere very big, but where? The answer to that question takes us across the Hudson River and into the Berkshires. If you make this trip you will soon find very different sorts of rocks there. Visit Bash Bish Falls, in Columbia County, sometime and you will see rocks that are not sedimentary. Instead of being composed of sedimentary material, the rocks there are crystalline. We call this stuff gneiss and it formed deep within the crust of the Earth. There enormous temperatures and pressures “cooked” the rock and in that setting all the crystals were able to form. The marvelous thing about the Bash Bish Falls rocks are that they take us not only far back into time but also into the deep depths of the Earth’s crust. We are looking at rocks that formed many thousands, even tens of thousands of feet down.

We are looking at the bowels of an ancient mountain range. We have mentioned those mountains a number of times in past columns; they were the Acadian Mountains. The Acadians were an early version of the Appalachians. They began to form nearly 400 million years ago when a continent we would call Europe today drifted westward and began to collide with North America. The collision is duplicated today in Asia where India is Colliding with Tibet. The result is the great Himalayan Mountain chain. These are the highest mountains on Earth. The Acadians were very possibly just as tall.
Gaze eastward on the horizon and, in your mind’s eye, see the mountains that once were there. Their snow packed peaks are thought to have reached elevations of about 30 thousand feet. That means Bash Bish Falls and its rocks were once about five miles beneath the tops of those peaks. Climb to the top of Mt. Everest someday and then look down five miles into the earth and, presto, you understand Bash Bish Falls a lot better.
Here in Greene County we can’t see any crystalline rocks, but we can look into the depths of the Acadians. A record of those mountains is found along many of our area’s roadside outcroppings. Take a ride east on Rte. 23 to the famed outcrop on the off ramp that leads to Leeds. The rocks here display the deformations that come with two periods of mountain building. The strata stretching off to the left are Devonian in age. They dip steeply to the left. These strata were deposited as flat sheets on the bottom of the ancient sea floor. But now they are nearly vertical. What happened? They were affected by the deformation of the Acadian Mountain building event. As Europe collided with North America the crust here was lifted and crumpled. The strata were tilted steeply their original horizontality.

On the right side of the outcrop are even older rocks, dating back to the Ordovician Period, about 450 million years ago. These rocks were tilted twice. First, they were involved in a mountain building event called the Taconic Orogeny. Later they came to be tilted by the Acadian Orogeny. If you are an old sequence of strata then, eventually, you will become involved in multiple mountain building events. That’s why the angles of dip for the older and younger rocks are different. Two angles of dip – two mountain building events; it’s as simple as that.
If you continue down the off ramp and turn right, you will see a long low cliff across the road. There’s more mountain building to see there. The rocks of that cliff have been fractured. The fractures are nearly vertical and there are a lot of them. There has been some movement of the rocks along those fractures and so, technically, they are geological faults. You won’t confuse these with the San Andreas Fault; these never caused too much commotion. But you can see evidence of the motions. Some of the vertical fractures have coatings of the white mineral calcite on them. If you look very carefully you will see that the calcite has been striated. Striations are delicate scratches etched into the minerals during the motion. The blocks on each side of the fracture moved past each other and that caused the scratching. Once you have developed an eye for this you will find a lot of striations. Geologists call these slickensides.

If you return to Rte. 23 and head west, you will find more excellent cliffs of limestone. Stop from time to time along the fine cliffs here, you will soon see more evidence of mountain building deformation. A short distance down the road the strata are not only tilted, but they are folded as well. Watch the rocks carefully and you will large sweeping folds in some locations and tight complex folding elsewhere. It is a most remarkable thing to first observe folded rocks. After all, rock is pretty brittle stuff. Have you ever even thought of bending a rock?
The folds we see here are a testament to the enormous powers that are generated deep with the crust of the earth. Down there, the rocks have been heated to extraordinary temperatures and their deep burial has subjected the rocks to enormous pressures. Under these two circumstances, folding becomes a very plausible, indeed mandatory phenomenon.
But these rocks are not deeply buried within the earth’s crust; they are right at the surface. And that is the whole point. We are privileged to be looking deep into the earth’s crust while standing on its surface. How can that be? The answer is simple: the rocks that we see in Leeds were once buried under thousands of feet of other thick strata. That was hundreds of millions of years ago. And since that time weathering and erosion have been destroying the overlying rocks, the “overburden,” until nowadays what was once buried is now exposed. It is a remarkable thing but at Leeds we are indeed peering into the bowels of the Earth.

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

A Gem and Mineral show

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A Gem, Fossil and Mineral Show
The Catskill Geologists

The Mountain Eagle

Sept. 2019
Robert and Johanna Titus

There’s an event coming up that should be of great interest to all of us, that includes the two of us and all of you, our readers. That’s the annual Mineral, Jewelry, Gem and Fossil Show at Howe Caverns. It’s sponsored by the Howe’s Cave Museum. That’s on Saturday, Sept 28 from 9 to 5 and Sunday, Sept 29, from 9 to 4. It will be held in the indoor pavilion which lies above Howe Caverns. There is a $5 admission charge. The event is sponsored by the Cave House Museum of Mining and Geology. We went last year and found it to be a very fun and educational event.

The primary attraction is a sale. There will be 25 venders set up in the indoor pavilion. You can wander the room and look at and pick among a large and very wide variety of rocks, minerals and fossils. Then, of course, there’s the jewelry It’s like going to a museum except that you can buy pretty much anything you see. We saw some very nicely made gemstone jewelry. Then there were the mineral specimens themselves. They are beautiful and fascinating to look at. The fossils were equally good, in fact we were quite surprised at the high quality of some of them. Your house really needs a good trilobite in it, doesn’t it? Or how about a nice fossil fern? Many of these have been made for placement on coffee tables or knickknack shelves. They will dress up anyone’s home. Overall, we thought the prices were quite reasonable. And here’s a thought. Christmas shopping is coming up soon. And how many birthdays will you be celebrating this coming year? How many people do you know who are impossible to find gifts for? Well the show is perfect for that sort of shopping. Give it a try.
And the dealers are such interesting people. They are mostly collectors themselves, so they are in the business to support their habits. They are fun to talk to and fountains of good information. Don’t worry about food; there will be venders.
You can make a full family day of it. Do you enjoy Antique Road Show on TV? Well the Cave House Museum will have a booth where you can get your fossils, minerals and rocks identified. The Capital District Mineral Club will be operating a sand box where kids can sift out fossils and minerals. Don’t forget to take the tour of Howe Caverns itself. Have you been there? It’s well worth the trip. Then we hope you will go over to the Cave House Museum. There will be free tours there. You can see a collection of local fossils, minerals and rocks. There is a museum rock garden, a row of fascinating boulders donated to the Museum over the years. As part of the tour you will be led into the old and original Lester Howe Cave. That was the very first Howe Caverns, open during much of the 19th century. Something we are very much looking forward to is a lecture on fluorescent minerals by Bob Ballad. If you have never seen such minerals, you will find them astonishing. The lecture will be on Sunday at 1:00. All in all, his show is a fine local tradition, a true community event. Don’t miss it.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.” They will be on WIOX 91.3 FM at 6:00 on Oct. 1st and 15th. That’s also at wioxradio.org.

Puddingstone at North Lake Sept. 19, 2019

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Top of the Mountain
The Devonian of Greene County Part 13

The Greenville Press
Oct. 6, 2006
Updated by Robert and Johanna Titus

It was been a long time ago, November [2005], since we wrote our last installment on the geology of Greene county. We are sorry for the delay. But now it is high summer, and it is time to finish up our saga. When last we left off, we were at North/South Lake State Park, heading north on the blue trail. We had also been traveling through the great Devonian age Catskill Delta. We had been looking at gray sandstones that were deposited in the ancient delta’s rivers, and red shales that had originated as soils in between those rivers. Our trek had taken us almost to Sunset Rock. Let’s belatedly resume our hike.
The blue trail follows a course that takes hikers just west of the knob of rock that displays Sunset Rock. That stretch of the trail takes you along a shady route that has a towering cliff above it. That cliff is composed of remarkable sedimentary rocks and these tell the story of a changing Devonian landscape. This cliff is largely composed of a very coarse-grained sedimentary rock called conglomerate. The unit is called the Twilight Park Conglomerate. The grains are pebbles and cobbles. Many of them are very much rounded. Remarkably they are stream worn and that is key to understanding them.

These cobbles indeed did travel in Devonian age streams and along the way they came to be rounded. You can see this in many modern rivers. It is important to understand that it takes a powerful flow of water to carry cobbles along in a stream. That kind of current can only occur where the stream is descending a steep slope. The steep slopes we are speaking of were the lower slopes of the Acadian Mountains.
We have mentioned the Acadians before in this series. Off to the east, in what is New England today, was this great rising chain of mountains. They did not yet exist during deposition of the early Devonian limestones that we saw along Rte. 23 in Leeds. They were just coming into existence at the time of the black shales we visited north of Greenville on Rte. 32. They were getting fairly well elevated during deposition of the early Catskill sandstones that we visited as we ascended Rte. 23 going toward East Windham. But now, at the time of the Twilight Park Conglomerate, the Acadians had developed into very tall mountains. Indeed, many modern geologists suspect that the Acadian were as tall as today’s Himalayas. Look east across the Hudson and imagine that!
Great, powerful, white water streams must have descended the Acadian slopes and often these carried gravel and cobbles. That is what we see in the Twilight Park. Take a good look at these and you will not have to be a very good geologist to recognize that there are a lot of different types of rock that make up the cobbles. These are all that is left of the Acadians; you are looking at fragments of ancient mountains and those mountains were made of all sorts of different types of rock. It is just a bit awesome to realize that all of the rest of the mountain chain has weathered away to a virtual nothingness. You are looking at the last fragments of mountains.
Continue north on the blue trail and, if you want to, take a side trip down the yellow trail. It will take you to Sunset Rock with its fabulous view of North and South Lakes. Our journey, however, will take us farther along on the blue trail. We will first see the Newman’s Ledge cliff, to our left, just short of the yellow trail and it is that ledge that continues our story.

Newman’s Ledge is a massive unit of gray sandstone. It is many tens of feet thick and that is a lot of stratified rock. It is composed of river sandstones; all of the rocks you see were once the deposits of river channels. You will see most of the river features we visited last autumn. There are cross-bedded sandstones that accumulated in the fast flowing, deep parts of the channels. Then there are flat bedded sandstones that formed out in the middle of the channels. There are a few concave surfaces, and these are small, petrified channels that formed within the river complex. It can be a bit confusing, but for our purposes the simplest way to view this sandstone is as a massive complex of rivers sands.
In this sort of science, the hardest thing to see is what is not there. It takes a while but eventually you notice that the are virtually no red shales along this elevated stretch of the trail. We had seen a lot of these along Rte. 23 as we ascended towards East Windham, but we will see almost none of them for the rest of our climb at North Point. What happened?
Red shales are typical of inter-stream areas, bits of floodplain between delta river channels. Such landscapes are flat and low-lying. If these deposits are missing, then these habitats must also be missing. Our guess is that, once again, we are ascending the lower slopes of the Acadian Mountains. You can’t have low-lying, flatlands on a slope so you can’t have the red shales. Instead, we are imagining the lower Acadian slopes as being draped with great masses of sand. The rivers that flowed across those deposits were themselves glutted with sand and when they hardened into rock, they produced what we see at Newman’s ledge.
In other words, our journey across the Catskill Delta plain has ended and our ascent of the lower Acadian slopes has begun. And that will pretty much be the case for the rest of our ascent to the top of North Point. If you continue up the blue trail you will ascend Newman’s Ledge itself. Notice all of the very large cobbles that are displayed at the top of the ledge. Soon the blue trail will head into the forest and continue toward North Point. It won’t take long before you reach Bad Man’s Cave. Here you will see another massive ledge of cross-bedded sandstone. It is very much a match for Newman’s ledge. There is a little red shale here, but just a little.
The trail continues with relatively long, flat stretches and a few ascents through more sandstone ledges. Eventually, however, we reach the last incline that leads to the top of North Point. It’s a steep final climb but well worth it. The view from North Point is one of the best in all of the Catskills. Before us are North and South Lakes. Then there is South Mountain and a glimpse of Kaaterskill Clove. Best of all is the seventy-mile stretch of the Hudson Valley running from Kingston to Albany.
All around, however, is more strata of sandstone. And they continue to speak of rivers, struggling across sandy landscapes at the base of the Acadian Mountains. It is one of the ironies of Catskill geology that the climb to the top of one mountain range takes you to the bottom of another.
We have reached the highest and youngest rocks of this part of Greene County and thus our journey through Devonian time has ended. We do, however, still have one more episode to go.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “thecatskillgeologist.com.

Devonian Rivers at North Lake 9-12-19

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Stories of Catskill Geology
The Devonian of Greene County Part 12
Robert Titus

Our journey through the Devonian of Greene County has slowly and gradually carried us uphill. Our first chapters were along Rte. 23 in Leeds, not much above sea level, but gradually we have worked our way up and have recently been climbing Rte. 23 towards Windham. We are getting toward the highest elevations of Greene County and that’s where our story will eventually end.
Today let’s travel to North/South Lake Campground and continue our trek. It’s late in the season now and good weather is getting hard to find, but there still may be time. The park is closed now, but you can drive to South Lake and park there. It’s only a modestly long hike to where we would like to start today. Let’s meet on the ledge at the Mountain House site. The cliff beneath us is about 30 feet of light gray sandstone. These, we have recently learned, represent Devonian age river channels. We are looking at something that geologists call the Oneonta Formation. It is a complex of river and delta plain deposits which is quite extensive. The unit is hundreds of feet thick and it extends all across the Catskills to Oneonta and beyond. It makes up a sizable portion of the Catskill Delta, the enormous deposit that, in turn, makes up much of the Catskill Mountains.
There were two dynamics going on during deposition of the Oneonta Formation. First the crust of the great Catskill Delta was subsiding. Then, as it subsided, the delta’s rivers migrated back and forth across the delta plain and they deposited all the sediment that eventually hardened into the rocks that make up the mountains today.
These wandering streams are called “meandering rivers.” They literally snake back and forth across the delta plain. One side of the river has a deep channel, with fast flowing currents. This is the erosive side of the stream. The other side is shallow with relatively slow currents. There deposition of sediment occurs. With erosion on one side and deposition on the other, you can see how rivers can migrate. That allows them to lay down great thick layers of sediment all across the delta. But, by the time they have migrated “back” and then “forth” the crust beneath them has sunk. The forth deposits thus end up being laid down on top of older back river sediments. This happens again and again, and thick sequences of sediments pile up. Each back and forth sequence runs about 50 feet thick and is called a “story.” Is that confusing? Well let’s go see. It might make more sense in the field.
Take the unmarked trail south from the Mountain House site and follow it a very short distance. You will very soon be climbing uphill. You will pass across red shales and red siltstones. These, as we have seen in recent chapters, represent the delta plain deposits. Some of them were flood sediments; some of them are delta soils. If you continue uphill, you will soon encounter a great overhanging ledge of sandstone. The thick sandstone represents another river channel complex. The Mountain House ledge and this overlying delta deposit represent the first two “stories” on our journey.
Take a look at the underside of the large ledge we have just climbed to. You are actually looking up at the bottom of an ancient river. Look around and you will see small channels cut by Devonian river currents into the floor of that stream. To realize that you are looking at the evidence of nearly 400-million-year-old currents is quite something.

  Trough cross bedding.

Turn around and find your way north past the Mountain House ledge and start up the Blue Trail towards Sunset Rock. You won’t have to go too far before you will encounter another great sandstone ledge. The climb up it is quite a scramble. Along the way we would like you to look for what we call “cross bedding.” The strata are inclined to the left here and to the right there. The two sets intersect each other. We are again looking at evidence of ancient river currents. These formed in the deepest, fastest flowing part of the river. Currents first scoured the channel sand this way and then that way; the results hardened into the sandstones that you are looking at. With some searching you may find sandstone strata all dipping in one direction; these are called “planar cross beds.” These represent what were, essentially, dunes of sand that had been migrating in a downstream direction. The beds dip in the old downstream direction. Then too, you may also pass by horizontally bedded sandstones. These formed in a quieter part of the stream; it was shallower here and the flow was much less.

  Planar cross bedded sandstone below; horizontal beds above
Again, what a marvel all this is? We are looking into the deep past and seeing the very currents of very old rivers. Each grain of sand came to rest during the Devonian and each one has not moved one bit in all the time since, and that is about 375 million years.
Our hike will take us farther north along the Blue Trail. We will pass “Artist’s Rock” and that represents another ancient stream story. Eventually we will find our way to what has been called “Sunset Rock.” (It probably should be called “Bear’s Den.”) This is one more great sandstone ledge and, of course, it represents another complex of stream channel deposits. Look for more cross bedding and horizontal laminations along the way. You may see some more of those red floodplain deposits as well. The view from this site is one of the greatest in all the Catskills. We will end today’s hike here.
We are getting towards the end of our Devonian saga, but the blue trail continues north and climbs to higher elevations. We will come back soon and continue our journey.

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

Stratigraphy on Route 23

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The Devonian of Greene County Part 11
The Red Delta
The Greenville Press
June 5, 2006
Updated by Robert and Johanna Titus

The year 2005 will long be long remembered as the year that the great hurricane hit New Orleans. In many parts of the city the destruction was nearly total, and rebuilding the city was a difficult, expensive and perhaps futile endeavor. Even rebuilt there is no guarantee that another, even worse, storm won’t come along. We, in Greene County, can rest easy. We shall not see that sort of flooding. But, back during the Devonian, that was not the case; back then Greene County must have suffered many such floods. It’s an interesting story and there is a lot about New Orleans that can be learned right here.
You will, we hope, remember from our last chapter that Greene County was once covered by a great delta, called the Catskill Delta. That Devonian age structure was easily as large as the Mississippi Delta and it displayed most all of today’s delta habitats. There were swamps and bayous and floodplains, but most importantly there were rivers, lots and lots of rivers. The general public has recently learned a great deal about such deltas, especially about the flood threats they are exposed to. We talked about some of them in our last chapter.
We learned that it is normal for such deltas to be subsiding. The mass of the sediment deposited on them presses down on the crust and the delta simply sags beneath its own weight. That has been going on in Louisiana for millennia. Some parts of the state are subsiding about an inch per year. That’s fast. What went wrong with all this began centuries ago. Back then the levees of New Orleans started being built to prevent floods. Those levees worked quite well and, in fact, relatively few floods have occurred. But, ironically, the absence of floods has increased the threat of bad floods. It has meant that there has been no new deposition along most of the Mississippi River, especially at and upon New Orleans. You see, normally, flood waters carry sediment onto the delta plain and the resulting sedimentation keeps up with subsidence. As the delta presses down, flood deposition maintains a constant level just above sea level. But since New Orleans came to be “protected” by levees it has sunk but no new sediment has been able to “keep up” with the sinking. Instead, as New Orleans continued to subside, people have just kept raising the levees. It was a race between man and Nature; Nature has won, she always does, and the results were very predictable.
Few people can appreciate the relentless nature of such subsidence. How can they; they just can’t see the results? Subsidence buries all the evidence of itself. Well, surprisingly, here in Greene County, we can see the evidence. Go south on Rte. 32 until you reach its intersection with Rte. 23 where that road begins its ascent towards Windham. All along the road from the bottom of the mountain to on past Point Lookout you will observe a seemingly endless sequence of mostly red shales and red sandstones.
This is, all of it, the Plattekill Formation. We learned a lot about the sandstone and shale in the last installment. The sandstone represents the channels of many ancient, Devonian Catskill Delta rivers. The sand had been carried in the stream channels. Eventually it came to be lithified into sandstone. Most of the shale formed originally as soils and flood deposits on the floodplain surfaces in between the channels.
We saw all of this in the last episode when we visited the Ashokan Formation, along Rte. 23 in Cairo. The difference here is that red color. That brick red is particularly handsome, and it is characteristic of the Catskills as a whole. We owe a lot of our region’s picturesque appearance to it. Why is it there? This red is from the mineral hematite, an iron oxide which forms mostly in well oxygenated terrestrial landscapes. Also, it is most common in tropical settings; red soils are very common in the Amazon and Congo Basins.
So, the Catskill Delta was a great red tropical Devonian landscape. But our interest is in relating it to New Orleans. Let’s get back onto Rte. 23 and head up the mountain. Just a short distance past and across the highway from the Cornwallville parking area is a fine exposure of a Catskill Delta river. You can see a cross section of the entire channel. The deep side of the stream is on the right and the shallow side is on the left. It is, in short, a “fossil” river. We are not sure if you have ever heard of such a thing as a fossil river, but they do occur, and this is a very good one. And let us tell you, you don’t see them this good just anywhere.
This outcrop sets the tone for the rest of the uphill journey. Watch as you drive along and stop along the way and look at the ledges. There are long thick sequences of red shale; these speak of great delta floodplains. Then, periodically, there are thick sandstone sequences. Those speak of other fossil rivers; none of them, however, are nearly as nicely preserved as the Cornwallville specimen. Horizons of gray and red shale are usually ancient fossil soils. When you come to understand what you are looking at you get a great sense of the time involved. Each of the layers of stratified rock that you pass represents a large amount of time. As you continue uphill you are traveling through a vastness of time, almost more than a person can comprehend. All together, from Cairo to East Windham, you are rising through a thickness of about 1,500 feet of sedimentary rock. That’s a lot of stratified rock and that’s where New Orleans comes in.
One of the critical things to remember in all this and that all of these sediments accumulated at an elevation of just a few (really, a few) feet above sea level. The Cornwallville channel formed at sea level. About 1,500 ft. uphill and across the highway from Point Lookout is another sandstone channel deposit. It also formed at sea level. You might ask “how can 1,500 ft. of sediment be deposited, all of it at just about sea level?” You might think that deposition should pile up to an elevation rising well above sea level, but you have to remember that, just like with the Mississippi Delta, as the Catskill Delta subsided more sediment was deposited. Subsidence and deposition always just keep up with each other.

There is nothing whatsoever unusual about this East Windham sedimentary sequence, these thicknesses are typical of large deltas. And that includes New Orleans. Beneath New Orleans there are many, thousands of feet of sediment that were all deposited at sea level. Above New Orleans there will someday be many thousands of feet more. That will take many millions of years. And after all of that sedimentation, the area will still be at about sea level. And that’s where we really come to understand what has happened to the (once great?) city. Over the centuries, as it was being built, it was being dragged downward along with the subsiding crust. Nothing can stop that process. New Orleans will continue its subsidence. And no matter how high we build the levees, Nature will eventually catch up (as it already has) . . . again, and again, and again. In the end New Orleans will be a “fossil” buried under hundreds and then thousands of feet of sedimentary rock.
Today Rte. 23 takes us to a wonderful place; there is great scenery here. On one side of the highway are beautiful red stratified rocks, on the other side is one of the best panoramic views of the northeast. To relate all this to the tragedy in New Orleans leads to some pretty somber thoughts. It is almost a sacrilege, but it is what we see as we drive up the highway towards Windham.

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

TheSinking Coast 9-30-19

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The Sinking Coast
The Devonian of Greene County Part Ten
Updated by Robert and Johanna Titus

We usually think of environmental disasters as great, awful catastrophic events. What could be worse than a sudden earthquake or volcanic eruption? But sometimes these disasters proceed quietly, even stealthily with almost nobody taking notice until the worst of the damage has been done. People are alarmed about catastrophic events, but it is easy for them to remain blissfully unaware of those more subtle, downright sneaky problems.
One of those today is the sinking coastline of the Mississippi Delta in southern Louisiana. There the great mass of earth that is the delta has been subsiding, very slowly so that coastal regions have sunk into the Gulf of Mexico. Homes and villages, right on the shore, have had to be abandoned to the advancing waves. Millions of acres of coastal land have thus been lost over the decades and centuries. But, have you ever heard about this? Quite possibly not; it is such an inconspicuous process, who notices?
Why is the Louisiana coastline sinking? Many of the reasons are quite natural. Over the millennia, as the Mississippi has carried sediment to this coastal realm it has piled this material up in increasingly thick masses. Just the weight of all this sediment has pressed down on the crust and caused subsidence. Then too, there is the normal process of compaction. The sediment has simply settled and that causes still more sinking.
It probably won’t surprise you to learn that man has interfered with Nature’s balance. Normally the Mississippi replenishes most of the land that has been lost. Floods rise up over the banks of the river and carry new sediment to fill in and replace volumes of sediment that have been lost to subsidence. The land surface is maintained. Sadly, that important process has been halted; over the past three centuries man has built levies along the banks of the Mississippi in a successful effort to thwart flooding. Now there are many fewer threats from flooding, but the benefits have also been lost. It is impossible for floods to carry new sediment onto sinking landscapes. Ironically man’s efforts to control riverbank floods have helped let coastal flooding get out of control. It gets worse; over the past century so many oil wells have been drilled in the region and so much oil has been pumped out of the ground that this has hastened the rate of subsidence. The oil had helped buoy up the ground, and now where it is gone the land is sinking.
Well, for these and other reasons, much of coastal Louisiana has been condemned to sink beneath the waves. It will take decades or even centuries, but a lot of Louisiana is doomed. Some have decried this as one of the greatest looming environmental disasters of our time.
It couldn’t happen in Greene County, could it? Well no, but it has happened and of course that was back during the Devonian. In the recent installments of this series we have watched Greene County rise out of the sea as a great expanding delta, the Catskill Delta, advanced westward across much of New York State. For a considerable length of time Greene County lay along the front of that delta and, just like the Mississippi Delta of today, it was subject to the natural effects of subsidence. There were no Devonian age levies or oil wells, but Nature herself caused just the sort of sinking that we see today in Louisiana. And, of course, we have the rocks to prove it.
Take Rte. 32 south from Freehold until you arrive at Rte. 23. Turn left and travel east a quarter mile, or so. There on both sides of the highway are some fine outcroppings of what is mostly Devonian age sandstone. It is the north side of the road where you can see the best exposures so find a good place to turn around and park at the outcrop.
Pause and survey the whole outcrop. You will, we hope, be able to see that it is broken up into three separate layers of stratified rock. In other words, there seem to be three packages of rocks here, laid out, one atop the other, in a vertical sequence. As geologists, we always start at the oldest layers of rock and those are the ones at the bottom of the outcrop at its western end. That first “package” of strata is the least well exposed but let’s start there. You will see a sequence of thickly bedded, light colored sandstones. Above them the stratigraphy grades into finer grained, thinner bedded material. This has a greenish gray to brick red color.
This stratigraphy is repeated in the next package and in the third. In other words, we are looking at cyclical events in a cyclical stratigraphy. In the second cycle you can see that many of the thick sandstones are inclined to the west (left). This is typical of river sediments and we have found, in recent columns, that such sandstones are, indeed, river channel deposits. That’s the case here; each of the three cycles begins with river channel sandstone. The overlying finer grained material is a petrified soil profile, literally a fossil soil. So, if you follow all this, each cycle represents the presence of a Devonian age Catskill Delta river channel overlain by a floodplain soil.
So, what is going on here and how does it relate to today’s Louisiana? There were two dynamics going on here back in Catskill Delta days. First those ancient rivers were what we call meandering streams. They formed beautiful, sinuous channels that literally snaked back and forth across their delta floodplains. This process, called river meandering, is a very slow one but it is effective over time and it can still be seen in many modern rivers. But it is slow and that gets us to the second dynamic.
Remember how Louisiana is sinking and that the sinking is slow? Well, our Catskill Delta was sinking slowly also. Slow river meandering was matched with slow crustal subsidence. There was a back and forth motion. First the river would meander one way and then it would return. “Back” was easy, but by the time a river meandered “forth” the crust has already sunk quite a distance. A new river channel/ floodplain “forth” deposit would be laid down on top of the old “back” one. If meandering continued, and it would, then given time a third deposit (cycle) would be deposited on the same sinking delta.
That’s what we see on Rte. 23. Did one river deposit all three cycles? We don’t know but it might have been. Was one river or several rivers meandering across this site? I don’t know but it doesn’t much matter. The important thing is that we can look into the stratigraphy here and recognize chapters in the history of the Catskill Delta. It was sinking and its streams were meandering, and it behaved very much like the Mississippi of today. And that is because Greene County, back during the Devonian, was very much like the Louisiana of today. Only time has changed.
Let us add a note about the names of these geological units. This Devonian sequence has been classified and reclassified over the decades. Different names have been applied to the several units of rock described in this series. The rocks described in this installment are probably the upper portion of the Ashokan Formation. I called the rocks in the last installment the Plattekill Formation but that is likely in error. Those outcrops probably belong to the lower Ashokan Formation. To the average reader these will not be very important issues but to professional geologists they are the subjects of often heated debate.

Rising out of the sea Aug. 22, 2019

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The Devonian of Greene County, Part Eight
Rising out of the Sea
Updated by Robert and Johanna Titus

On our journeys back to the Devonian time period we have been visiting a very different Greene County. It was, back then, a tropical land; surprisingly our landscape lay about 20 degrees latitude south of the Equator. That’s about as far from the equator as Cuba is, and it’s quite warm at such latitudes. We have seen the evidence for the tropical climate – right here! Our county has a great amount of limestone that dates back to the Devonian and limestone is the product of shallow tropical seas (it’s what the Bahamas are made out of). But we also see evidence of times when very deep waters covered Greene County, that evidence was in the black shales that are also common around here. None of this is surprising, it is, of course, a geological history and through long spans of time things gradually change.
Today’s episode takes us into a time of transition, and you can go and see some that change for yourself. What we have not seen much of on our journeys is sandstone. Sandstone is one of the most common rocks that a geologist is likely to encounter, but, around here, very little of it formed during the early stages of the Devonian. That would all change.

Go to Rte. 81, east of Greenville, and find your way about 8/10ths of a mile west of the Quarry Restaurant. There, along both sides of the highway, is a fine set of outcroppings. We found the north side offered the best views. Before we get started, we would like you to take a good look at the whole outcrop. You will see a series of closely spaced and nearly parallel fractures. They are very steep but are also inclined just a bit to the east. They give the image of stratification but that is deceiving. Geologists have to be careful not to be fooled by rocks and that is easier that you might think. The actual stratification is inclined gently to the west, but it is quite difficult to perceive. The fractures that we have been looking at are called rock cleavage. With such cleavage the rock breaks into numerous closely spaced and parallel fractures. Because cleavage planes have the appearance of stratification, they serve to hide the real thing.
Now, let’s forget about the fracturing and take a good look at the rocks themselves; they are what is important here. Look towards the downhill, east side of the outcrop. You will observe that, down there, the rocks are dark and very fine-grained. These rocks are pretty much the same black shales that we saw last time. They represent a deep-water marine environment. But, turn around and look uphill a bit and you will see that most of the outcrop is lighter in color. Get up close and you will find that this lighter colored stuff is composed of sand grains; this is sandstone.
Everybody remembers the story of Columbus crossing the Atlantic. After two months of westward sailing his crew was getting very anxious about when they would find land. They wondered if there even was land out there, was their journey a dangerous and futile effort? Well, the appearance of floating twigs of land plants reassured everyone; there was land ahead. Soon they found it.
Our discovery of sandstone plays much the same role as those twigs. We have been “sailing” across a Devonian sea and, so far, there has seemed to be no prospect of finding land. Those dark shales, at the bottom of our outcrop, belong to the open ocean. They are the last beds of the Marcellus Shale. But the rest of the outcrop tells a different story. This sandstone belongs to a new geological formation, which is the Mt. Marion Formation.
The Mt. Marion Formation was deposited at the bottom of a sea, the Catskill Sea, but it is a nearshore version of that ocean. Columbus’ twigs were found near to the shore and so too are large quantifies of sand. Grains of sand don’t weigh very much but marine currents have a hard time carrying them offshore, so sands accumulate near the coast. That’s the case here.
The Mt. Marion is a marine deposit and we relished the prospect of finding fossils at this outcrop, but we were mostly disappointed. In other places the Mt. Marion is rich in the remains of Devonian shellfish, but not in Coxsackie. We did a little fossil hunting, but we found nothing much, maybe you will have better luck. We did find something of interest; it was a fossil, but not the fossil of a shell. We found the fossilized burrows of worms. Back when this was marine sand, the Mt. Marion had marine worms living within it. Like today’s earthworms, these humble creatures consumed sediment and found nutrition within it. They left behind the evidence: the sands still retain the patterns of their burrowing. Look about ten feet below the top of the west end of the outcrop. We left a small white paint rectangle to mark it.
This sandstone is named after, of course, Mt. Marion, down in Saugerties. Maybe you have driven south along the Thruway and seen Mt. Marion. It towers above the western horizon. The mountain is so big and so steep because of its sandstone composition. Down there the Mt. Marion Formation is composed of fairly pure quartz sand. Quartz is very resistant stuff and it holds up well in the face of weathering and erosion. That’s why Mt. Marion is such a prominent feature in Saugerties.
But what about up here? It would seem that here the Mt. Marion is not quite so pure, there is a fair amount of silt and clay in it. Up here the rocks are a little less resistant to weathering. We do have a “mountain” up here, and you will probably know its name: Potic Mountain. But this mountain just barely deserves such a designation. If you drive east from Coxsackie to Greenville, you will be crossing Potic Mountain, but it just won’t feel very mountainous. Still, if you follow it on a map, Potic Mountain traces south right into Mt. Marion, only the composition of the sandstone has changed.
What the Mt. Marion lacks in altitude it makes up for in thickness; it’s about 1000 feet thick in our region. That’s a lot of sandstone and it was once a lot of sand. Where did it all come from? We answered that question in the last episode. Off to the east, there was a rising range of mountains: the Acadians. At that time, they must have already reached elevations of thousands of feet. Today all that is left of them are the hills of the Berkshires. What happened to the rest? Well, a lot of it was weathered into sand and much of that sand was deposited here in eastern New York. Our one thousand feet of sandstone was probably once several thousand feet of mountain range.
In the end, we have visited a humble outcropping of rock. Most of you have probably passed it numerous times without giving it a glance. But now you know better. This outcrop records the moment in time when the great Acadian Mountains of western New England were beginning a rapid and very impressive uplift. In terms of Greene County, this humble little outcrop represents a lot of history.

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

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