Glaciers at Sam’s Point
On the rocks
Robert and Johanna Titus
Woodstock Times
Sept. 19, 2013

The Shawangunk Mountains are certainly one of the most scenic locations in our region, and uniquely so. The Ridge of resistant quartz sandstone towers above the Hudson Valley and offers numerous views of that landscape. One of the most popular locations is Sam’s Point Preserve, near Ellenville on the south end of the mountains. It is a sizable nature preserve with 4,600 acres of land, most of it perched at the top of the mountains at elevations well above 2,000 feet. It’s owned by the Open Space Institute and managed by the Nature Conservancy.
Today this area is valued as a scenic preserve but, in the past, there were commercial uses. The mountaintop here has abundant blueberries and it used to be that people were hired every summer to come here and pick them. Then, in addition, there were several resort hotels; it was, after all an ideal vacation destination.
But we came here to learn about the geology. How had the area’s geological history given rise to this scenic wonder? We came early on a Saturday so that there would still be spaces in the parking lot. We toured the museum, but not for long; our hearts were in climbing atop the mountain. We headed up the trail.

 
It didn’t take long to figure out why the Shawangunks are there. All along the trail were massive outcrops of quartz sandstone and conglomerate. Quartz is very resistant to weathering and a mountain made out of quartz sandstone will stand out as all other bedrock around it erodes away. The “Gunks” are Silurian in age; that makes them perhaps 420 million years old. Way back then there must have been some sort of coastal plain composed of quartz sand. That would have been similar to our eastern North American coastal plain of modern times. The conglomerates are composed of quartz sand mixed with quartz pebbles. If anything, they are an even more resistant form of rock.

We got up to Sam’s Point itself and soon learned much more about the geological history that went into creating the mountains we see today. We arrived at the easternmost of two platforms, composed of bedrock and seemingly designed for sight-seeing. Naturally, we were more interested in looking down at the rock than gazing at the scenic views. It was, of course, more quartz sandstone, but there was something special that caught our eyes.
There was a polished sheen to the surface of the rock and there were faint striations cut into that surface. We quickly recognized these to be ice age features, common ones at that. Sam’s Point had a long ice age history. Probably going back to the time when glaciers first came down the Hudson Valley, and lasting until the last glacier melted, this site had ice flowing across it. The ice was dirty, carrying a great deal of sand along with it, mostly concentrated at its base. The sand, probably mixed with a lot of silt and clay, actually did polish the bedrock. It sanded it down and planed it off. The generations of people who passed before us had, with their footsteps, worn this down until it was not all that easy to see, but it was there to the trained eyes.
There was more. The glaciers carried with it a large number of cobbles and boulders. As these were dragged across the surface, they gouged scratches into the bedrock. We call these glacial striations. We have seen surfaces like this many, many times so it was hardly a great revelation, but it did speak clearly to us of the fact that there had been a sizable glacier here once. Then we saw more.
We looked up and there was the cliff that defines Sam’s Point. It is another natural platform of quartz sandstone but this one is bounded by a vertical cliff, a big one. Most people would enjoy it as a fine scenic overlook, but our eyes saw back into the ice age. Geologists call this sort of thing a scour and pluck topography. These are common and they are the products of the advance of a glacier. The Hudson Valley glacier advanced from the north and, as it crossed Sam’s Point, it scoured that platform at the top of the cliff. That’s the scour part. Then, as the ice continued south, it yanked enormous masses of rock loose and carried them off. That left a gaping scar in the mountaintop and that is the cliff of Sam’s Point. That is also the pluck part of this landscape.
The cliff faces a compass direction of south-30 degrees-west. That, presumably, was the direction the glacier was traveling. We looked at the striations beneath us, and we had a compass. They too were oriented south-30-west.
Now we had a nice coherent explanation for the topography of Sam’s Point, a real scientific theory to explain everything we saw there. It’s what scientists call an elegant solution to a problem. Everything in the explanation fits the evidence. We would have been flushed with pride at having made such a marvelous discovery were it not for the fact that, no doubt, thousands of other geologists had preceded us here, and had come to the very same conclusions.
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Reach the authors at randjtitus@prodigy.net. Join their site “The Catskill Geologist” on Facebook.

Through the Green forest
Poems in Stone
Robert Titus
Columbia County Independent 2007

My candle burns at both ends; it will not last the night; but ah, my foes, and oh, my friends – it gives a lovely light. Edna St. Vincent Millay, 1920

Many, perhaps most, poets are like Edna St. Vincent Millay; they celebrate, and even live, the quick passage and rapid burnout of life. But geologists are different; we appreciate the endless nature of time and the slowness of the changes that it brings. Geologists and poets are alike, however; they both seek out truths that lie just beneath the surface. My wife and I found this out when we visited Poetry Walk, just down the road from “Spindletop,” Millay’s home in Austerlitz.

The walk had originally been a farm path, carrying cows and firewood. Vincent (as she rather insisted upon being called) valued the walk for its bird sounds, birch grove and mountain laurels. It came to be even more spiritual when her mother Cora was buried there. Vincent and her husband Eugen Bossevain eventually joined Cora in repose at the end of the trail.
Our walk was a search for the truth beneath the surface. However it was not poetry but rocks that we sought out. As we entered onto the walk we found a cairn of rocks. Proudly placed at its top was a small boulder of pure quartz. It was a strange and beautiful rock and I soon noticed quite a few smaller versions lying along the path. I wondered about this odd lithology. Surely, just beneath my feet, the soils graded into quartz-rich bedrock but what was it? The quartz was associated with other rocks: shards of something called phyllite littered the path too. That’s a dark and thinly layered rock. Its laminations are shiny, folded and crinkled. It starts out as shale and is later quite literally crushed and cooked during mountain building events, and turned, or metamorphosed, into today’s rocks. I found metagraywackes too. These had once been dark sandstones but they too had been cooked into something new. Now I guessed one truth beneath the surface, and my geological map confirmed it. Down there, hidden beneath the soil, was something called the Walloomsac Formation, a thick sequence of phyllites and metagraywackes
There was more; a geologist can deduce much from a few rocks. There may be little poetry to words like phyllite and metagraywacke but there is much meaning. The phyllites were mud before they were shale; the metagraywackes were sand before sandstone. And that mud and sand once lay at the bottom of an abyss, the deepest realms of the deepest oceans. Eventually a great mountain building event did the crushing and cooking.
Was I geologist or poet? I had been metaphysically transported to the darkest and deepest realms of an ancient ocean while mountains rose around me. All the while I was physically standing on a modern forest trail.
The end of the trail brought an end to some of my mysteries. Millay and her husband were buried there and a boulder serves as their gravestone. It is a fine metagraywacke with a large thick seam of quartz running along one side. I looked it over carefully and also found numerous small seams of quartz.
The gravestone was a large piece of the Walloomsac, truth that had been brought to the surface. It had been mud and sand in the depths of an Ordovician age abyss, about 440 million years ago. Those sediments had hardened into rock and then they had been cooked by a mountain building event, probably the one called the Taconic Orogeny. Still later these rocks were fractured and hot groundwater penetrated the cracks. It was then that large and small seams of nearly pure quartz had crystallized and filled the empty space.
Rocks burn their candles only very slowly and only at one end. At Poetry Walk they are turning very slowly into soil and “ah, my foes, and oh, my friends – that gives but little light.”
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Reach the authors at randjtitus@prodigy.net Join their facebook page “The Catskill Geologist.”

Visions of an Ice Age past – Sunset Rock
On the Rocks
The Woodstock Times
August 1, 2013
Robert and Johanna Titus

We have been following the Hudson River Art Trail in our recent “On the Rocks” columns. The Art Trail project has been under the primary sponsorship of Cedar Grove, the Thomas Cole National Historic Site. That’s Thomas Cole’s old home, located near the Rip Van Winkle Bridge in the Village of Catskill. The two of us have been associated with Cedar Grove since its founding, a little more than ten years ago. We have taken great pride in watching as this historic site has blossomed into a center for the study of America’s great landscape art of the 19th Century. Our role in all these columns has been to bring an understanding of the geological history that lies just beneath the surface of those landscapes. This is almost all a story of the Ice Age and we continue that today. We have arrived at site seven on the Art Trail: Sunset Rock.

Sunset Rock is a sizable boulder, lying at the top of a sizable ledge of sandstone which overlooks North Lake and one of the Catskills most memorable views. It’s another one of those locations where all the personalities of the Hudson River School came to look and often to paint. Not surprisingly Thomas Cole got there first and, not surprisingly, all of the rest of them followed. We like Cole’s view done in 1843. Jasper Cropsey followed suit in 1855, and we are very fond of the canvas he did there. Our favorite is one done by Sanford Robinson Gifford. You will have no trouble finding these and many more online.

The view here is grand, even by standards set in the Catskills. You stand next to Sunset Rock, or better still, climb up on it and gaze to the south. To your left is the expanse of the Hudson Valley. Out there you can see the Shawangunks as well. More immediately, in front of you are North and South Lakes. South Mountain rises above them. You have to imagine what is lost: The Mountain House Hotel and the Hotel Kaaterskill once were both clearly visible from here. In the far distance you can sense the presence of Kaaterskill Clove far more than actually see it. Above the Clove you can observe both High Peak and Round Top. Hikers come to Sunset Rock at all times of the year and they are always rewarded with a variety of scenic images. Everybody’s favorite season is at the height of the fall colors, but every time of the year pays dividends to the avid hiker. In short, if you have not gone there – you must!
Our very first visit, together, brought us a strong sense of what the glaciers had done to shape this view. Earlier chapters in this series have described the formation of the two lakes down below; this visit will focus on the glaciers descending and flooding in from the north. Are you interested? If so, you are likely to take the yellow trail when you are coming to Sunset Rock. You need to have a sharp eye and you need to know exactly what to look for, but the signs of glaciation are to be found on this trail. What those signs speak of is the immense weight and power of the glaciers that were once here.
You watch the trail carefully and you begin to notice that the sandstones beneath your feet frequently display cobbles, rocks long ago buried with the surrounding Devonian age sands. What happened is that, with the advance of the ice, some of these were literally cut through and planed off. The ice contained a lot of sand at its bottom and the weight of the glacier pressed down on the sand and turned the ice into a sheet of sandpaper. That ground into many of those cobbles and planed them off. What you see today are shiny, flat surfaces at the top of all such cobbles, surfaces that are level with the ground all around.

All of this speaks of the advance of a glacier, but there is more: there is Sunset Rock itself. That scenic boulder is what geologists call a glacial erratic. That’s a boulder that was transported within the ice of that same moving glacier. It was picked up, somewhere to the north, and dragged to where it is found today. We have located erratics that appear to have arrived in the Catskills after journeys from as far away as the Adirondack Mountains. This one probably only came a mile or so; it is a local rock type. But it does speak to us of the enormous power of the glacier that brought it here, and it also speaks to us of glaciers that were once this high up in the mountains. That goes to the heart of our story.
Sunset Rock begins its story at a time just as the Ice Age was approaching its peak. We stand there and see thick glaciers filling the Hudson Valley below and then rising up to overflow the very Wall of Manitou, the Catskill Front. The story continues right before us. Glaciers are now advancing out of the Hudson Valley and flooding across the sites of North and South Lakes. Nothing seems able to stop or even slow the rising tide of ice. We watch as South Mountain is first encircled by the glaciers and then entirely submerged by them. Across the valley, the Taconics and Berkshires are disappearing beneath the frozen white, engulfed by the vast swelling of the eastern flank of the Hudson Valley glacier. We turn and look north in time to see more ice advancing south, crossing the crest of North Point. All of the Catskill Front is soon enshrouded in ice. It’s the weight and power of that ice which has produced almost all of the scenery here. It accomplished the planing off of those cobbles and brought that erratic to where it is today. How big and thick was this glacier? We can’t tell for sure, but this ice will not stop rising until it has covered virtually all of the Catskills. Right now, it has another 2,000 feet to go.
But when we stand atop the ledge at Sunset Rock we gaze ahead of us, and our mind’s eyes take us into the another important moment in the past. Now the climate has changed; it has warmed and the ice is melting. We stand upon the great ledge just when the Sunset Rock boulder is emerging from the snow and ice. All the lowlands beyond are still encased in thick ice; both lakes and even South Mountain are still invisible. It’s all a blinding white in the noonday sun.
Nobody ever painted this scene.
Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their articles in the Mountain Eagle and Kaatskill Life.

THE GILBOA FOREST
Oct. 10, 1996
On the Rocks
The Woodstock Times
Updated by Robert and Johanna Titus

It’s autumn and once again the leaves are in color. This annual event has not always been. Autumn color is a characteristic of today’s advanced deciduous trees, but there was a time when the world’s forests were composed only of the most primitive plants. In fact, there was a time when there were no forests at all. We New York State paleontologists get to see the transition from a world without forests to one with them. We have very old terrestrial deposits here, Silurian in age, which have no fossil trees at all. Then there are the Devonian age Catskill red sandstones. They are only about 40 million years younger, but they have a great abundance of fossil trees. During the interval, trees evolved and spread out across the Earth as the first forests.
Fossil trees this old are extremely rare, but you can go see some of them yourself, and enjoy a fine autumn drive at the same time. Take Rte. 28 to 42 from Shandaken to Lexington. Then take Rt. 23A west until you reach Grand Gorge. Take Rt. 30 north 2.8 miles and turn right. Go downhill another 1.2 miles and you will reach Schoharie Creek where it passes through the village of Gilboa. Just before the bridge is a little park with seven fine fossil tree trunks. This humble site is one of the world’s most famous fossil locations, the Gilboa forest.

                                                                             Early reconstruction of Gilboa Forest

The Gilboa forest was discovered after the terrible Schoharie Creek floods of late 1869. Extensive erosion along the river ripped through the soft shales and exposed a number of fossil tree stumps. The discovery caused quite a stir and well it should have. This was the oldest known fossil forest; before them nobody had ever guessed that trees were this ancient.
It got better in the early 1920’s. Excavations for the Schoharie Reservoir revealed about 200 more fossil stumps. The trees in the little park were among these. The famous Gilboa fossils offer us a rare view of what forest ecology was like very early in its history. Gilboa was forest of trees, most of them called progymnosperms. In common terms that means that these were essentially very big fern-like trees with tall wood stems (trunks). In time they would evolve into today’s common cone-bearing trees, called gymnosperms.
Beneath the trees was simple ecology of even more primitive plants. Hiding among them was an animal ecology of simple arthropods. These were an abundance of centipedes, millipedes, and simple insects, along with many truly exotic creatures. One of note is that Gilboa is the home of some of the oldest known fossil spiders. This is certainly a peculiar, but truly remarkable distinction for a small town. Spiders are among the most abundant and successful groups of invertebrates on the planet and some of the oldest one are from right here!
There are ironies in the story of Gilboa. The trees are a metaphor for the great cycles of time. They grew not along the Schoharie, but along some ancient nameless stream of the old Catskill Delta. They were long ago buried in the muds of a long-forgotten flood. There must be a story here: What kind of flood was this? How bad was it? There is no answering such questions. For hundreds of millions of years, they lay entombed in those flood sediments. During that time, they hardened into rock. If it was floodwaters which buried them then it would be flood waters which would release them. These trees of stone lay in wait for the day when another awful flood would bring them back to the light. The last irony came when so many of them were once again submerged in the waters of the Schoharie Reservoir.
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Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

INSPIRATION POINT
On the Rocks
Oct. 17 1996
Updated by Robert and Johanna Titus

It doesn’t take much to get a geologist to go outside, but in autumn we find ourselves ever more drawn outdoors, especially as the season progresses. There is something compelling about the annual foliage scenery. There are only so many leaf seasons in a lifetime and to waste or miss one seems a sin. Each is something to be savored.

There are special places in the Catskills which we like to visit at any time of the year. One of those is Inspiration Point in Kaaterskill Clove. The site has been a favorite for Catskill hikers for more than 150 years, and there’s good reason. Inspiration Point towers above the rim of Kaaterskill Clove, a place which has often been referred to as the “Grand Canyon of the East.”

Take Rte. 23A to Haines Falls and turn east onto County Rt. 18. Turn right on Laurel House Road, and park at the end of the road. The new dirt trail will lead you to Kaaterskill Falls. But we want you to find the Blue Trail. (get a hiking map of the North Lake vicinity.)
The Blue Trail takes you south to the Layman Monument. Poor Frank Layman died there early in the 20th Century while he was fighting a forest fire. They have cut the foliage there so that his monument has a fine, but distant, view of Haines Falls. Beyond the monument, the trail turns east and soon brings you to the brink of Kaaterskill Clove itself. If you have not been here before, be prepared for a great surprise; Kaaterskill Clove is a lot bigger than you imagine. It’s about three miles long, a mile wide and a thousand feet deep. The slopes are steep, dropping those thousand feet in less than one half mile, and the visual impact of this makes the clove seem bigger than it is.

On an autumn day the clove is at its best, deep, rugged and picturesque. Hike eastward and the Hudson Valley soon comes into view. Continue along the blue trail and you soon pass some large rocky knobs which caught the eye of Thomas Cole. The renowned Hudson Valley artist painted at least one canvas right here. So did Sanford Robinson Gifford.

There is of course a geological story here. The great canyon is a relatively new landscape feature. A hundred thousand years ago, or so, the Hudson Valley was glaciated, filled to the brim with a stream of ice called the Illinoian glacier. This river of ice passed the escarpment of the Catskill Front which was, back then, unblemished by any large canyons. Only after the ice melted did Kaaterskill Creek form and start to erode its deep canyon. That makes the clove less than 100,000 years old. Big as it is, the clove is extremely young by geological standards.

Inspiration Point is just a little farther down the clove. Look for a fine platform with a cliff in front. People have found this the best place to take in the clove’s view. Landscape artists have seen the same. But Geologists have discovered that this is the best place to understand the glacial history of the clove. Look at that platform carefully; it has been scoured by the passing ice into a beautiful smooth polished surface. It’s only marred by the striations gouged into it by the passing ice. The cliff here is the product of glacial work. It faces westward and was formed when great masses of rock were broken loose and plucked away by the passing and westward moving ice.

About 18,000 years ago the Hudson Valley witnessed another glaciation. Once again, a great stream of ice, the Wisconsin glacier, flooded the valley. This time some of the ice branched off and flowed westward up Kaaterskill Clove. This stream of ice would not stop until it reached nearly to Prattsville. It’s this ice that made Inspiration Point.
Gaze down to the bottom of the valley and then to the other side of the clove. Look up and down the valley. When you realize that all this was filled with moving ice you begin to get a sense of just how great an event this glaciation was. For a century and a half hikers and artists have come here to marvel at the landscape as it is; geologists come here and marvel as to how it was.
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Contact the authors at randjtitus@prodigy.com. Join their facebook page “The Catskill Geologist.”
Figure captions

Jurasstock Park

On the Rocks

Robert Titus

Woodstock Times

July 3, 1997

I went and saw Jurassic Park recently. I happen to be a paleontologist, so I thought that it was about time I saw the kind of life that I should be leading. The movie was a lot of fun and there was plenty of action and adventure. There were good-guy paleontologists and bad-guy paleontologists which is an angle I had never reflected upon before. I have enjoyed my own career in fossils very much so far, but it is clear, from this vicarious experience, that I have missed out on a lot of excitement. Chasing fossil brachiopods is just not the same as being chased by a Tyrannosaurus.
If you see the movie you may wonder what it was like here in Woodstock back during the Jurassic. The answer is that we don’t know. There are no Jurassic age rocks in this area. No rocks/ no history is the way it works in Geology. Nevertheless, it is fair to speculate as to what it was like around here way back then. And, in fact, there are some Jurassic age rocks not all that far away. They can tell us a lot.

It was the Jurassic and the earlier Triassic times that witnessed the origins and early history of the dinosaurs. In New York State there are late Triassic and early Jurassic sedimentary rocks in Orange and Rockland counties; there are more in central Connecticut. Only a few fossil dinosaur skeletons have been found in these sequences, but the strata are just crawling with dino footprints. And there is an especially interesting species of dinosaur whose footprints are quite common in these rocks, a dinosaur that certainly once lived here in Woodstock. Its Latin name is Coelophysis, and it was a very fine specimen. It belonged to a group called the ostrich-like dinosaurs. Coelophysis wasn’t especially large, being only five feet tall and nine feet in length. It was, however, remarkably athletic. They were agile and light-weight, weighing in at a little more than 100 pounds. It’s probable that they were among the earliest predatory dinosaurs. Coelophysis had small forelimbs, but they were armed with long recurved claws. Its large mouth possessed numerous, knife-like teeth. All in all, the animal would have been quite effective at ripping its prey apart, making it an excellent movie monster.
But that’s wasn’t the scariest thing about this dinosaur. There are sites in New Mexico where their skeletons are so abundant that paleontologists have speculated that they must have hunted in packs. That really gets us to the Jurassic Park stereotype of dinosaurs as vicious marauders. And there may be a great deal of truth to the stereotype. I once saw a series of dinosaur trackways. They were all the same species, all the same size, they were spread out evenly, and all heading in the same direction – a skirmish line of predatory dinosaurs! I had 15 of my students place their feet in the tracks and, on signal, they all stepped forward, laughing, growling and retracing those 190 million year old trails. Dinosaurs can be fun, at least the dead ones that can’t eat you are fun.
Coelophysis likely did live here in Woodstock and dinosaurs are part of our local geological heritage. It’s too bad we can’t go out and hunt their bones. I don’t know if there ever were any Jurassic age strata in Woodstock, but if so, they would have eroded away millions of years ago. All evidence of local dinos has been gone all that time. Want to see some real dinosaur fossils? Travel to Dinosaur State Park, near Rocky Hill in central Connecticut. There is an outdoor display of footprints there. Maybe one of the dinos that left its footprint in Connecticut came from Woodstock.

Raindrops
On the Rocks
The Woodstock Times
Mar. 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 a piece of 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 ourselves. 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.

                                                                        “Raindrop prints” scattered across surface

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

Halfway measures
On the Rocks
Feb 13, 1997
Updated by Robert and Johanna Titus

We usually think of mountains as emblems of permanence. “Old as the hills” is certainly a common enough old chestnut. It implies that the hills (and mountains) are just going to be there forever and ever.

That may not be. George Halcott Chadwick found it otherwise. Chadwick was one of the great Catskill-area geologists of the first half of the 20th Century. He spent a lot of time looking at regional maps and he gradually came to the conclusion that the eastern Catskills are, quite literally, not all there. Take a look at a good regional map. Kaaterskill and Plattekill Cloves divide the Catskill Front into three east-west ranges: the Jewett Range in the north, the Roundtop-High Peak range in the center, and the Sugarloaf to Plattekill Mountain range in the south. Each of these three ranges is sharply terminated on the east by the steep, straight slopes. It’s as if something had chopped off those eastern parts. The three eastern slopes are called “truncated spurs” and together, they define the “Wall of Manitou” of the Catskill escarpment. The “Wall” is a straight, ten-mile long front. Chadwick found that to be remarkable; he thought that the truncated spurs and the steep, straight nature of the wall required some unusual erosional processes to explain them. He believed that it was glaciers which did the job.

The story begins a bit more than 100,000 years ago when there was an event called the Illinoian glaciation. A massive glacier, advancing from the north, seems to have descended the Hudson Valley and gradually filled it. Picture a stream of ice, at least to the brim of the valley and probably a lot higher. In many ways it behaved like a river, the ice slowly flowed down the valley. Now some sort of a Catskill Front had already existed, but it probably wasn’t the steep straight wall that we know today. More likely, gentle slopes descended gradually, well east of today’s wall. In fact, Chadwick thought the slopes may have reached out one or two miles into the Hudson Valley. That included Overlook Mountain which would have been, Chadwick thought, about twice its present size.
The passage of the ice had an erosive effect upon the old slope. Moving glaciers pluck and grind away at landscape’s bedrock. The ice likes to carve a steep-walled trough and that’s what the Illinoian glacier set about doing. The lower slopes of the Catskill Front were largely composed of soft shales and these eroded easily. The upper slopes were of resistant sandstones and these put up much more of a fight. Given time, the steep slopes of the Wall of Manitou were the result. But not before quite a bit of Overlook (and the rest of the Catskill Front) was worn away.
With the return of warmer climates, the Illinoian glaciers eventually melted but the respite was brief. About 25,000 years ago the climate deteriorated again and once more a stream of ice flowed down the Hudson Valley. This has been called the Wisconsin glaciation. The whole process was repeated and again the Wall of Manitou suffered even more erosion.

This had a real effect upon Overlook. We described the final stages in the process in a Times article last August (1996). The steep ledges up there date back to those last moments of glaciation. In the end, after the Wisconsin glaciers retreated, Overlook Mountain was literally half the mountain it used to be. Fully two miles of eastern Overlook were gone. It’s quite a thought, half a mountain lost. That is, if Chadwick was right.
George Chadwick’s story is a fine one and we are very fond of it. We hope that it is true, but the hypotheses of science are not always so simple. Sadly, there are modern geologists who very much doubt that this is what happened. They just do not think that passing ice is capable of removing so much rock. One of the problems with their objections, however, is that they don’t have any better ideas. So–is Overlook a whole mountain or is it half a mountain? That is the question.
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The Worm Turns
On the Rocks – The Woodstock Times
June 26, 1997
Updated by Robert and Johanna Titus

On Rt. 9W, at Glenerie, the Esopus River descends two ledges of rock known as the Glenerie Limestone. These ledges make up what are either high rapids or low waterfalls, depending on your point of view. In any case they also make a very nice setting and the shores of the Esopus there attract a lot of people. We sat on the banks for a while and watched people go by. There were two fishermen, who had no luck. A couple walked by with their dogs. Several young boys came by on their bicycles. One elderly man wandered along the shore, we think just for the pleasure of it.
Such is life for human beings who are not at work, but just intent upon enjoying a little leisure. The Glenerie Falls provides a setting to idle away a few minutes or a few hours. As I sat along the Esopus, we was watching just a few random moments in the history of life. Nothing special occurred, nothing historic or even meriting the slightest of note. Most of what goes on in this world is like that. Little that happens is really of very much significance. Such is life.
It’s easy to forget that this spot has always been here. The world is four and one half billion years old and this precise longitude and latitude has been here all that time. What was it like here a century ago? We don’t know, but with the help of a historian we could easily guess. How about 500 years ago? A little harder, but good guesses might come from an Indian archeologist. How about a million? or a hundred million? or a billion years ago? Even a geologist has a hard time answering those questions.
So much of earth history slips off into the past without leaving any monument or even a clue as to what had transpired. But none of these moments is likely to have amounted to much, just simple events during average times. Countless living creatures have passed by the Glenerie Falls site and almost all are gone and have been entirely forgotten by history. Disappearing into the oblivion of the past is a sad fate that we all share eventually. . . almost all.
But sometimes, hundreds of millions of years after their deaths, signs of the lives of ancient creatures return to light. And we mean that very literally. Memories of ancient organisms are often revived when weathering and erosion of bedrock brings to surface the evidence of lives long lost. We geologists call these “trace fossils.” They are not the bones or shells of ancient organisms, but the evidences of ancient activity, the very behaviors of the past. The best known trace fossils are dinosaur footprints. People have marveled at them for more than a century. They forget that these “marvels” are only evidence of the most every day and literally pedestrian moments in the lives of dinosaurs. Unfortunately we don’t have dinosaurs or their footprints anywhere near Woodstock. But we do have other trace fossils.
A lower ledge of the Glenerie Limestone forms the lower cataract of the falls. The rock is tough and brittle stuff and it has held up well against the elements. On the bank, just below Rt. 9W, this ledge has been brought to the surface by folding of the bedrock. The upper surface of the inclined stratum is a fossil wonder. It’s densely littered with the trace fossils of worms that lived here about 400 million years ago.

The animal has a name – it’s Zoophycos. It was a common marine worm, much like many that live today. You probably know that earthworms make their living by burrowing through soil, consuming and digesting it as they slowly move forward. Similarly, Zoophycos burrowed and ate its way through the marine sediments, including the limestone sediments of the Glenerie. Zoophycos was extremely meticulous in the way it dined on sediment. It burrowed forward for a while, its path taking it in a broad, round loop. The worm then turned abruptly and returned, closely paralleling its first path. Then, once again, it turned on a dime and paralleled its second path. Back and forth it continued, carefully consuming all of the sediment. Eventually the back and forth path took on the form of a rooster tail and that is the common name it goes by. “Rooster tails” are common throughout the marine sandstones and shales of the Catskills, but this is the first time we have seen them in a limestone. They are fascinating fossils and marvelous insights into the details of ancient life, but they record such mundane moments: Worms eating mud!
If you carefully examine this ledge of rock you will be surprised at how densely burrowed it is. A large population of these worms must have lived here. To survive on a limited food resource, they had to evolve the careful feeding patterns that we see. We doubt they missed anything. There is, we suspect, a message here.++

Rocks with Sole
The Woodstock Times
A long time ago
Updated by Robert and Johanna Titus

The Austin Glen Formation is not all that impressive a rock to look at. It’s made up of alternating strata of gray sandstone and black shale. But in many ways, it is one of the most awe-inspiring rock units in the area. It makes up much of the bedrock on the east side of the Hudson River. Travel across the Kingston-Rhinebeck Bridge and it makes up the first outcroppings of rock you will see. These are the low cliffs on either side of Rt. 199. We made the trip recently and took a good look at these outcrops. About 30 paces east of the beginning of the west-bound lane’s exposure we found a remarkable sedimentary structure: One overhanging stratum of rock displayed a crenulated surface. We recognized the form as a type of “sole mark” and it conjured up quite an image from the past.
The sands and muds of the Austin Glen were deposited in some of the deepest waters that make up ocean basins. There is a wonderful word, “abyss,” used to describe great depths in the sea. The abyssal plain is a great vast flat sea floor, about two miles down. But we are talking about something even deeper. We are speaking of a sea floor zone called the hadal zone, that’s a great deep trench at the bottom of the sea and it can be several tens of thousands of feet deep. Today’s Marianas Trench is the best such example we can go see. It is 36,000 feet deep, an incredible depth. We don’t think that the Austin Glen was quite that deep, but who knows for sure.
Not only is a marine trench of this sort deep, but it is also very steep-sloped and that gets us to today’s story. You see, the shales of the Austin Glen formed originally as black muds. It’s typical for such great depths to accumulate muds; the fine clay particles settle to the deep-sea floor and make up the muds. But the sands are different; sands are usually shallow water deposits. Obviously, the sandstones of the Austin Glen weren’t shallow water deposits so how did they get there?
The answer it that the sands were once part of something called turbidity currents. These are very fast-moving currents of dirty (turbid) water that rushed downslope at speeds of up to 50 mph. More likely than not, an ancient earthquake struck and displaced a large amount of shallow water, sandy sediment. Billowing masses were thrown up into suspension by the quake and then they began to flow downhill under the influence of gravity, soon accelerating to their rapid pace. A turbidity current is one of those very powerful forces of nature. Fortunately, there are few animals that stand in the way and few deaths result. There is some destruction, but only in the form of rapid erosion of sediments crossed by the current.

At the bottom of the slope the turbidity currents slow down but, still moving rapidly, they spread out across the soft muds and deposits their sandy sediments. The sudden deposition of sandy sediment upon soft muds has an interesting effect. As the sand spreads out across the sea floor, it presses into the soft muds. The results are the crenulated surfaces we described earlier. They are called sole marks. There are a number of different types of sole marks and, technically, these ones are called “squamiform load casts.” Let’s not get too concerned with the exact terminology and instead try to appreciate the aesthetics of these structures.

They are rather remarkable in the details of their sculpturing and we have trouble finding just the right adjectives for them. Take a look at our illustration and you will get a good impression of them. These soles are common throughout the Austin Glen Formation and, once you have an eye for them, you may be able to find others. We origins: underwater avalanches, triggered by great earthquakes; it’s quite a scenario and very typical of what we find when we know what to look for in the rocks.
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Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”