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Jimmy Dolan Notch 180 Jan. 2, 2020

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On the Rocks, The Woodstock Times
Nov. 9, 1996
Updated by Robert and Johanna Titus

The fair-weather hiking season begins slowly. In April the first clear, dry, warm days lure us out into the mountains. We take a professional interest in that time of the year; there are no leaves yet and we can see all the bedrock exposures very well. As the weeks advance the foliage appears and the green, even if it does hide the rocks, adds much to the views. The richness of the color increases until late August which is gorgeous with its dense botany of spinach green. Nature seems to celebrate its own bounty at that time of the year. But it gets even better as autumn approaches. Now nature deems appropriate a grand and glorious climax to the season. There is a brief but intense explosion of color like the end of a long fireworks display. What hiker can resist this seasonal finale?
And, so it was, in the middle of October, as the foliage hit that climax, that we had the opportunity to accompany a small group from the Adirondacks down for their first hike into the Catskills. Our goal was Twin Mountain. This peak, being right in the heart of the Catskills was a natural choice for newcomers.

As luck would have it, this long-planned hike fell on a perfect autumn day. We began our ascent at the Prediger Road trailhead and soon entered into the forest preserve. The trail takes you up along an unnamed creek to a fine gap in the mountains called Jimmy Dolan Notch. From there we turned west and continued up the slope of Twin Mountain itself. A final 500-foot climb took us to the top of the easternmost of the two summits that collectively make up Twin Mountain. There before us were the southern Catskills in full autumnal regalia. To the east was Plattekill Clove, to the southeast was Overlook Mountain, and to the south was Cooper Lake. On the distant horizon was the Burroughs Range, with Slide Mountain reaching the highest. But it was to the southwest where the slopes of Olderbark Mountain could be seen that we found most picturesque scene. The whole autumn season could be seen there. The lower slopes of Olderbark were mostly green; it was still September down there. Above, the slopes steepened and graded into a yellow gold, and there it was October. From there to the top, the mountain was brown and then gray. There it was already November and the leaves were gone.
The top of Twin Mountain made for a wonderful stop before pushing on and we enjoyed the view as much as any landscape artist might. But geologists never go off duty and we had seen something on the way up which gave our mind’s eye a very different view of this landscape. Jimmy Dolan Notch was peculiar; it was asymmetric. The northern slope to the notch was steep but unremarkable. The southern slope was different. Looking south through the notch, there is a lovely view of the mountains beyond, but the view is through a surprisingly vee-shaped notch. This vee had caught our eyes, and on the way down, we explored it. It was the kind of notch usually carved by a powerful whitewater stream. We could easily imagine loud, raging, foaming currents passing down the mountain here. But there was no stream and no evidence of one. And where could the creek have come from anyway? Whitewater streams are common on the lower slopes of mountains, but not at the tops; there is no source of water up there. Then we found a theory to explain what we were looking at.
About 17,000 years ago a massive ice sheet abutted the central Catskill Mountains along a line that extended from Plattekill Mountain to Twin Mountain to Stony Clove and then westward. It’s been called the Wagon Wheel ice margin. Some of the ice probably poked its way through Jimmy Dolan Notch, but then, as the climate warmed, it began melting. As we turned north and looked back through the notch, we could now “see” that great ice sheet rising just a little higher than the notch itself. It glistened wet in the sun that was melting it. Between the ice and Twin Mountain was a small meltwater lake. From it, water was cascading through the gap. There was the whitewater stream that we had needed to explain our landscape problem.
Such beautiful but different scenes at the same site and at the same moment: we looked south through Jimmy Dolan Notch and there was a perfect golden autumn afternoon. Then we turned north and looked through the notch to see an ice age vista during one of the high points of glaciation. Twin images at Twin Mountain.

Learn more about Catskill glaciers in the Titus’ new book The Catskills in the Ice Age, the expanded and revised 3rd edition from Purple Mountain Books and Black Dome Press.
Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Name that Tomb 12-27-2019

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On the Rocks
The Woodstock Times, Oct. 24,1996
Updated by Robert and Johanna Titus

Prattsville, along the banks of the Schoharie River, is steeped in Catskills history. It’s emblematic of the most progressive aspects of the area’s story, and at the same time, it represents many of the mistakes people made as our region developed. Zadock Pratt was the towering, overwhelming personality in the town’s development. Even today his influences permeate the village.
Pratt was a founder of the Catskill tanning industry. From 1833 to 1846 his Prattsville tanneries turned out shoe leather for the New York City market. His tanneries, however, were dependent upon the bark of the hemlock tree, and when they were all cut down, the industry closed. We frown upon the wanton destruction of the Catskill hemlocks that characterized the 19th century, but our collective wisdom is based upon a history of trial and error. It was men such as Pratt who provided the errors.
But Pratt is also remembered for progressive attitudes toward urban planning. His Prattsville was a pioneering model in that field. Pratt laid out the streets, built the Greek Revival homes and planted the 1,000 trees that lined the village streets. Pratt founded churches and the town’s academy as well. Prattsville today is still truly Pratt’s town.
Zadock Pratt was a great man, but we suspect that history would have mostly forgotten him except for the one singular act of vanity that he was responsible for. Pratt, the Rameses II of the Schoharie, is remembered for Pratt Rock, his would-be tomb.

Pratt Rock consists of a series of stone carvings on a glacially plucked cliff along Rte. 23, just east of town and overlooking the old Pratt farm. The site is now a town park and open to visitors. You can hike the winding path up the steep slope toward the main carvings. If you tire along the way you can sit upon stone seats thoughtfully carved into the mountain. The main level of carvings displays images and symbols of his life. There are carvings of the hemlock tree, a horse which hauled the bark to the tanneries, a strong arm to do the work and other emblems of the great man’s life. There is a bust of Pratt himself and a poignant carving of his only son who died in the Civil War. Then there is the Pratt burial chamber itself.
Unlike the pharaohs, Pratt was never buried in the grotto carved out for him. One story is that the chamber was unsuitable for burial as it leaked water when it rained. The chamber is still there, and when we looked it over, we found that there may be some truth to that tale, along with a good geological story about Pratt Rock.
Pratt Rock is carved into sedimentary strata from the old Catskill delta. Deposited nearly 400 million years ago, the sediments here record the coastal regions of a delta similar to that of the Mississippi River today. This was once the coastline of the old Catskill Sea. Rivers flowed across this location and poured their waters into the old ocean.
There is a lot of history here. We had little trouble finding bits and pieces of the old Gilboa forest, and we could picture its foliage along the old stream banks. But the most interesting horizons we found were those at the burial chamber itself. The ceiling of the chamber is made up of inclined strata. This horizon of rock formed on the floor of an old stream channel. The beds slope down to the right, which was once one side of a river, and farther along the outcrop they rise up again on the other shore. When we looked at the chamber ceiling, we found a horizon rich in a hash of broken plant remains. This stratum is likely very porous and it’s quite possible that this accounts for the leakage that caused the burial project to be abandoned. The pharaohs of arid Egypt faced no such problem.
And so, this is one of the many ironies of geology. The great Zadock Pratt is buried in a nearby graveyard with all the other common folk of old Prattsville. That may be because about 375 million years ago some small river made a wrong turn. It’s not Pratt buried in Pratt’s tomb, but the sands of an ancient river!

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

A River of Rock 12-19-19

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A River of Rock
The Greenville Press
Updated by Robert and Johanna Titus

One of the most scenic descents out of the Catskills is along Rte. 23, downhill from East Windham. To your left is the vast expanse of the upper Hudson Valley stretching, it would seem, forever. We enjoy a good view as much as anybody, but when we travel along this road, today’s scenery has to compete with an ancient one. There are a many excellent, large exposures of bedrock along the way. They are all of an eye-catching red and thus are typical Catskill lithologies.
Brick red is the emblematic rock color of the Catskills bedrock. It is the color of the red soils and sediments that accumulated on the great Catskill delta complex of the Devonian time period. In your imagination, take yourself back almost 400 million years to the Devonian time. All around you are the low swampy bayous of a great delta. It’s an ancient version of Louisiana. To the east a great mountain range rises above the horizon. This is an ancient version of the Himalaya. There is a lot of imagery in these old Catskill Delta deposits and this stretch of Rte. 23 may be one of the best locations to learn how to interpret them. And, of course, we don’t just mean learning to make cold scientific judgments about the rock, but to really travel through time to this place as it once was.

Heading up the road from the south, watch for the Cornwallville Road. Just past it is a parking area with a fine panoramic view to the northeast. The view certainly deserves some attention, but we are here to see the rocks. Across the road and between 0.1 and 0.2 miles farther uphill is a fine and very typical outcropping of the Catskill Delta. As you approach it, watch for two striking channel-form structures (A&B on picture). These are actually the cross sections of two Devonian rivers, stacked one upon the other. The upper channel is composed of massive beds of sandstone, the very sands that filled the old channel. This channel eroded its way into an even older channel (A); the lower one is composed of thinner-bedded sandstones. At the bottom of this river of rock can be seen a deposit of gravel (C), it was carried here by strong currents and left at the bottom of the channel. To the right is a steep bank margin (D), this was probably the erosive side of the river. Beyond that is a sequence of red sandy shales (F). These sediments accumulated upon the floodplain, probably during floods. Floodplain deposits, of our Devonian time, were turned red by oxidation. That’s common throughout the Catskills and the origin of that brick red color that I extolled earlier.
To the left of the channels you might notice some dark, sometimes rusty-looking horizons (E). These strata are thinly bedded, just laminations. Dark sediments, like these, were never oxidized, they were waterlogged instead. Floodplain organic matter was preserved and darkened the beds. This appears to be a floodplain swamp. Below it you can see a peculiar horizon. It has an olive color with many blotches of yellow and green. This has been interpreted as a fossil floodplain soil.

Think about what is here. This is an ancient river and floodplain. The channels, river banks, floodplain soils and swamps are just as real now as they were about 375 million years ago. Back then, however, this was a living environment, composed of soft sediments and inhabited by green plants and breathing animals. Today that’s all still here; it’s just been converted into a stone sculpture. What we see is just the surface exposure, a fragment of what is truly here. The rest must be imagined. Beyond our seeing and buried in the mountains, an ancient river of rock flows through a stone landscape. The river, a meandering ribbon or rock, reaches westward, today as it did in the Devonian, and flows into a buried ocean of rock.
All this is routine for geologists. We approach outcrops expecting to be transported to some ancient habitat. We grow accustomed to this, but we never forget what a miracle it really is.

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

A shallow sea at 5 Mile Point in Cooperstown 12-12-19

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A Shallow Sea
The Cooperstown Geologist
Updated by Robert and Johanna Titus

Geologists are deductive scientists. We go out and study outcroppings of sedimentary rock with the purpose of gathering evidence of how they came to be formed. The evidence is mostly descriptive; we look at the rocks and see things in them that speak to us of ancient environments. Each small observation leads to a deduction and a series of observations and deductions leads us to broad conclusions. Let’s go out and see how this works.
An especially fine outcrop can be found in Mohican Canyon just west of Lake Otsego’s Five Mile Point. Five Mile Point is a mass of sediment that projects out into the lake. You guessed it; it’s five miles north of Cooperstown. Take Route 80 north until you get there and then turn left onto the road that ascends the hill. On each side of the road you will encounter very fine exposures of rock. The rock is made up of layers; it is stratified. That leads us to our first deduction; layered rock forms at the bottom of the sea. We learned earlier about the Catskill Sea which once covered our region. We have gone back about 375 million years and found that sea once again.
The strata are a mixture of sandstones and shales. We can make more deductions. Shale forms as mud on the bottom of quiet, probably deeper, seafloor. Sandstone accumulates in more active, perhaps more shallow seas. When shale dominates, then we deduce deeper water; when sandstone predominates we can deduce shallower settings. When sandstone and shale are evenly mixed we are in between.
The thickness of the strata helps too. When the beds are thin we can deduce the likelihood of quieter, and probably deeper, conditions. When the beds are thick we can deduce rapid current activity which is associated with shallow seafloors.

The lower stretch of our outcrop is mostly of thin bedded shale. We can deduce that this sequence represents fairly deep water sea bottom. But as we ascend the road, things change. More and more sandstone starts to appear in the outcrop and more and more often the sandstone is thicker bedded. Some sandstone strata are a foot thick.
If you have a chance to take the trip, then start at the bottom and stroll slowly towards the top of the outcrop. See if you can agree with our observations. But what all does this mean?
We need to do a little stratigraphy. That’s the science of stratified rocks and it’s practiced a lot in the Leatherstocking Country. All of our rocks up here are stratified. The rocks at Mohican Canyon are classified as belonging to something called the Otsego Sandstone. That’s a unit of rock which is commonly seen at outcrops in our area. The lower stretch of the Otsego is called the “Otsego A” and the upper part is the “Otsego B.” That’s fairly informal but quite functional stratigraphy and it leads us to our most important deductions.
The sequence here speaks to us of a shallowing sea. During Otsego A times, the Catskill Sea was quiet and accumulated lots of mud. Still water runs deep and that’s the case with the Otsego A; it was a relatively deep body of water. Today, you would have to go quite a distance offshore to get to a modern Otsego A. But time never stops and as our region passed from the time of A to the time of B, the waters of the Catskill Sea were shallowing.
We geologists find shallowing sequences quite often. Our observations and deductions lead us to recognize times when seas were shrinking away. We call such events “regressions” and the one at Five Mile Point is a gem. We are looking at real history here; this actually happened. Once there was a deep beautiful saltwater Catskill Sea here in Otsego County. It spread across upstate New York for an enormous length of time and then it began to disappear. Where did is come from and where did it go? We have just begun our story; we need many more observations and many more deductions.

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

A Gelogical Tourist Trap Dec. 5, 2019

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Flocks of geologists
Windows Through Time, The Register Star
June 4, 2009
Updated by Robert and Johanna Titus

Dear Robert and Johanna – I have been enjoying your columns in the Hudson-Catskill newspapers. I have a question. I wonder what so many college groups have been studying at the Leeds exit along Rte. 23? – WJM – Athens

WJM: Thanks for the good question. Over the years we have heard this one from a lot of people. Anybody who frequently drives this stretch of the road in the autumn or the spring will have seen sometimes large groups of college students climbing over the rocks at this site. You will be interested to know that this is one of the great “geological tourist traps” of the American northeast. Any eastern geologist who is anybody in geology has been to this location. I wonder if we even know any geologist who has not been here. So, what is the big draw?
The answer is that this outcropping displays something called an “angular unconformity,” and this one is a very historic structure. Read on and learn about this peculiar feature. If you are going by it sometime soon, you might want to stop and see for yourself that which captivates so many young geologists. If you do, you will see some interesting geology.

The right (east) side of the outcrop displays what are called stratified sedimentary rocks. These are thick horizons of alternating gray sandstone and black shale. Each layer of rock was once deposited as sediment at the bottom of the sea. Back then, these were horizons of sand and mud. That’s a most surprising observation. Look around. Do you see and saltwater here? This does not look like the bottom of an ocean, but it once was. That’s incredible but true.
We see these rocks; we look into their distant past and see the ocean that was once here. It has been a very long time since the earliest geologists figured this out. So long that we have forgotten who first made this amazing deduction. The first person to write these thoughts down was Scottish geologist James Hutton in the 1790’s. This was not only one of the most important discoveries in the history of geology but of science itself. Look around and think about it. You are standing at what really was the bottom of a sea. These strata of sand and mud formed on that long-ago seafloor. Turn a full 360 degrees; hold up your hands and feel the saltwater that was once here. Times have changed!
But there is something else here and it is also important. Notice that the sandstone and shale strata are tilted, they are nearly vertical. When sediments are deposited on the floor of an ocean they are laid down in horizontal sheets. These strata should have stayed that way, but that is not the case here. Again, they are nearly vertical. They must have come to be tilted and that’s where the story gets even more interesting. Think about how heavy these rocks are and how much energy it would take to tilt them. The only processes that can lift and tilt such rocks are those of mountain building events.
These rocks are from something called the Ordovician time period; they are about 450 million years old. That’s when North American was enduring a great collision with an eastern landmass much the size of today’s Japan. You would call it Europe or – better – “proto-Europe.” Collisions, of this sort, initiate chapters of downwarping. The crust folds downward and the seas flood the region. Those seas accumulated the sand and mud that hardened into today’s rocks. Then continued collision came to reverse the whole process and caused a massive mountain building uplift. All this is how those rocks formed, and how they were tilted and raised to above sea level. But, of course, there is still more.
The rocks on the left (west) side of the outcrop are limestones. They formed during a time that is called the Devonian Period and they are only about 420 million years old. They formed in a shallow tropical sea and the rocks are sometimes rich in marine fossils. If you stop here, perhaps you can find a few. This was the bottom of a second ocean!
These too are stratified, but these strata dip to the left. Once again, North America was enduring a collision with another Japan-sized land mass. It was “déjà vu all over again!” Once again, the crust was folded downwards and that is when the limestone formed – in a shallow tropical sea. That downwarping would eventually be followed by another uplift. That’s when the second tilting occurred.
The boundary between these two units of rock is what we call an angular unconformity. The word angular refers to the angle between the strata of the two rock units. The word unconformity refers to the period of period of erosion that followed the first mountain building event and preceded the second.
And that is the centerpiece of what we, and all those college students, are looking at. This is a petrified record of two mountain building events. There is a lot of history here and young geologists come from all over to see it. You can too.

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

Name Your Poison Nov. 28, 2019

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Name Your Poison
On the Rocks; The Woodstock Times
Updated by Robert and Johanna Titus
June 18, 1998

Black sedimentary rocks are occasionally seen in the Hudson Valley. Recently [1998], we described some along Rt. 209, south of Sawkill. The dark appearance of these strata makes them remarkably eye-catching and, when they make up tall cliffs, they loom, dark and menacing, over the landscapes.
It’s the shiny, jet-black shales that we are talking about. They are often rich in undecayed organic matter; it’s the carbon that makes these rocks black. This generally suggests to the geologist that there were low-oxygen conditions in the sea waters at the time of deposition. Without oxygen, most decay bacteria cannot function; they die before they can completely destroy the organic matter. But why low oxygen? That takes us back in time.

Back in the early Devonian Period, these shales were accumulating in a deep sea, immediately adjacent to the rising Acadian Mountains of western New England. Thick soils formed on the rapidly weathering mountainsides. The soils were easily and rapidly eroded and provided sediments that were eventually transported into the nearby Catskill Sea. This material was rich in dissolved nutrients, such as nitrates and phosphates. They fertilized the water and that led to the next step in what was to be a complex chain of events.
The fertilized waters were ideal for algae; they experienced algal blooms, great population explosions in the surface waters of the Catskill Sea. A whole ecology became established as dense mats of floating, or planktonic, plants and animals grew, somewhat similar to that of today’s Sargasso Sea. While all this was great for the plankton it was deadly for just about every other category of marine organisms. As the plankton died, they were attacked by decay bacteria; the algae bloom led to a bacteria bloom. But the decay process consumed so much oxygen that the seas soon became oxygen depleted. The hapless bacteria had, in effect, poisoned their own habitat, because they needed oxygen too. Their numbers quickly plummeted and very soon, all types of animals suffered as well, suffocated in the oxygen depleted sea. But the algae just kept on proliferating in the surface waters where there was plenty of oxygen, diffusing in from the air above. Soon, large masses of undecayed biological material were sinking to the floor of the ocean. The climate was tropical, and the nearby coastal lowlands provided lots of vegetation, much of which drifted into the basin, adding more organic matter to the black shales. Almost all of these organics accumulated as thinly laminated, shiny black shales.
Back then, the Catskill Sea was largely isolated from other deep bodies of water; it was nearly surrounded by land or very shallow water. To its east, land blocked weather patterns and shielded the basin from most storm activity. All of these conditions promoted what are called stagnant, thermally stratified waters. The sunbaked surface layer was hot, while deeper water remained cool. Depth stratification and a dense planktonic mat combined to prevent agitation and mixing of the waters, causing stagnant sea floor conditions to develop. Virtually nothing could live in this sea, except at the surface where there was always plenty of oxygen. This was truly the poison sea.
Many of the earliest Catskill shales are jet black, and they form the Bakoven Shale at the base of what is called the lower Marcellus Group. As we have seen, they are the record of the Catskill poison seas. The upper beds of the Marcellus Group are similar looking but very different deposits. These are fossiliferous black shales and dark gray sandstones. They sometimes have rich assemblages of brachiopods, clams and even corals. These were still mud-bottomed seas, but they were deposited at times when there was a fairly large amount of oxygen in the water, at least enough to allow marine shellfish to survive and even flourish. These can be fun rocks to poke through as they are occasionally richly fossiliferous, and the preservation of those fossils can be very good.
See the Bakoven Shale on Rte. 23A where it crosses Kaaterskill Creek east of Kiskatom. Go visit that large outcrop along Rte. 209, between Kingston and Sawkill. The far south end is the real poison sea; as you travel upwards and north from those beds you are looking at shallower waters which had more oxygen.

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

Gaps in our knowledge Nov. 21, 2019

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Gaps in our Knowledge
On the Rocks/ The Woodstock Times
Jan. 22, 1998
Updated by Robert and Johanna Titus

Take Rte. 28 west from Woodstock, turn right at Dancing Rock Road (it’s two miles east of Boiceville) and go up one mile to the end of the paved road. Look south and, there below, is the Ashokan Reservoir. Above it, on the horizon, is High Point Mountain. The mountain profile is nothing particularly unusual except for one feature. There is a notch cut into the top of the mountain. It is the sort of landscape feature that you pay little heed to; it doesn’t seem all that strange until you look at it carefully and ask a simple question. How did it get there?
The notch has a name: it’s Wagon Wheel Gap. we suspect that the name came from the deep ruts that old fashioned wagon wheels carved into roads before the auto age. The gap is at least 200 feet deep and steep on both sides. It seems to be something cut into the mountain. It was. Not surprisingly this odd landscape feature does have a story to tell and it is a surprising one.
Wagon Wheel Gap is a glacial feature, but different from most. Glaciers are very good at eroding landscapes and they can carve notches into the landscape. But that kind of glacial erosion produces a nice, smooth, U-shaped gap. West Kill Valley is a good example. It’s relatively wide and rounded at the bottom. Stony Clove is narrow like Wagon Wheel Notch but it has been cut right down to the level of the valley. Wagon Wheel Gap is altogether different. There’s nothing broad and round about it. It’s a sharp slash, like something cut by a knife. The bottom of the gap lays well above the level of the nearest valley, in fact 700 feet above. Wagon Wheel Gap seems something quickly and violently cut into the High Point mountain.

The story of Wagon Wheel Gap takes us back about 17,000 years. At that time a large glacier was pushing up the Esopus Creek valley. It passed the present site of the Ashokan Reservoir and pushed on; we are not sure how much farther. This ice did reach a still-stand and then, with warming climate, it began a slow retreat. The warming halted briefly, and the glacier reached another still-stand, just exactly abutting against the present-day gap.
The ice acted as a dam and so it blocked the whole upper Esopus Creek which then filled with a reservoir of cold water. The water had to drain off somewhere and it made its way across the slopes of High Point and drained off to the south. In what had to be a very short period of time, that flow of water cut into the mountain and carved the gap we see today. It’s quite something to imagine. There would have been an enormous amount of water pouring through the gap back then. There would have been all of the normal flow of the Esopus Creek plus all the water provided by the region’s melting glaciers. That’s a lot.
The flow must have positively raged through the Wagon Wheel, perhaps the mother of all whitewater flows. And loud too, a thunderous, pounding cacophony. It must have torn into the mountain with an effect something akin to a buzz saw. At any rate, the flow must have continued while the Esopus glacier retreated down the valley. Eventually the flow of water must have found other ways out of the valley and Wagon Wheel Gap would have been very abruptly abandoned. The whitewater flow would have dried up overnight.
And there it lies today, an abandoned notch, lying there silently in the mountain. It’s a landscape oddity with a colorful past. But how many people know even to notice such a thing. It’s, to most, just a notch in the mountain, nothing of note. What a marvel it is that glacial geologists can come along and understand these things.

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

Voyage to the bottom of the sea – Nov. 14, 2019

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Journey to the bottom of the Sea
On the Rocks; the Woodstock Times
April 30, 1998
Updated by Robert and Johanna Titus

We geologists, over and over, are used to seeing vivid moments from the past, recorded in the rocks. We never become blasé’ about this, and we shouldn’t; we are privileged to have these visions. We were reminded of this recently when we encountered an especially fine outcrop along Rte. 9W, at Glenerie Falls about a mile and a half south from its intersection with the Glasco Turnpike. It’s the Glasco Limestone which is commonly seen along the highway hereabouts. There was one very broad surface which caught our attention. It’s a bed of rock so steep that we found it difficult to climb, but that mattered little as the bed slanted down to the level of the road. The strata, dipping to the west, are typical of this vicinity. These rocks got caught up and tilted in the deformation associated with ancient mountain building in New England.

What makes this such a fine exposure is that there is one particular stratum which is expansively exposed. That’s unusual. We geologists spend a lot of time looking at strata in cross section, but we rarely get to see a broad surface like this. Once again, we had become time-travelers; this bit of geology had taken us back in time to the Late Silurian time period. We don’t mean that figuratively, but quite literally; this stratum of sedimentary rock was deposited on the floor of a sunlit shallow sea perhaps 425 million years ago. For a time, it actually was the sea floor and, upon it, grew the seaweeds and crawled the shellfish of the old Silurian age sea.
But time is fleeting, even geological time. Sooner or later (and in geology it really can be later) a sea floor is condemned to be buried. Storms blow up and the winds generate currents which bring new masses of sediment to be spread about. Many of the plants and animals that populated the old sea floor remain, but only as fossils. Layer after layer of sediment piles up and the sea floors of old harden into strata of rock lost in time. That’s what geologists see in cross section when they study layered road outcrops such as most of those on Rte. 9W.
But not all of the strata here have shared that inglorious fate. There is, for example, this one fine stratum. It’s an example of something unusual, an exhumed sea floor. Nature (helped a lot by the highway department) has stripped the overburden off of this old sea floor and exposed it for us to see.
You have, quite likely, been on a boat that cruised above the floor of a shallow sea. It’s a lot of fun; you can look down and observe the marine life going by below. Glass-bottom boats are specifically designed for this. In Florida or the Bahamas, you can’t beat it for a fascinating afternoon. It’s nice that we can do the same thing right here in Ulster County.
Our stratum, along Rte. 9W, can’t quite compete with a glass-bottom boat in the Bahamas. All of the old seaweeds are gone, so too are most of the animals. All those creatures without skeletons or with only delicate skeletons are lost to time. Only those shellfish that had sturdy shells remain, but there are plenty of them. We found quite a few brachiopods, those bivalve shellfish that remind us of clams. They occurred in clusters of specimens, all about the same size. We think that these were what biologists call “spatfalls,” clusters of larval brachiopods that settled here and grew up together. These are “families” of shellfish, if you can imagine such a thing. We found a few clams here as well, but they weren’t common. Finally, we found the weathered and forlorn tail of a trilobite, all that remained of a once fine-looking animal. All in all, what we were looking at was a snapshot of the old Silurian sea floor, just a moment in time, nothing special and maybe that’s why it is special.
Because of its steepness, this old sea floor is difficult to climb around on. If you visit the site, be very careful. One slip and down you go. The fact is, however, that there is no real need to climb up the exposure at all, most all the good things you can see are found at the base of the outcrop. There’s no real need to climb any higher. So do go and see this little natural wonder. You don’t get many opportunities to explore a sea floor, especially one that existed 400 million years ago.
Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Floods on Overlook Mountain 11- 6 – 19

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

It’s autumn and it’s a time when we in the Catskills are given some of the best weather there is to enjoy the outdoors. There are few places better suited to the mood of the season than the Overlook Mountain trail. The word trail is a bit of misnomer. This was once a highway of some significance, but those days are over; it’s just a hiking path now.
The trail takes you past Echo Lake and onward toward Plattekill Clove. There are the subtle signs of a history along the way. You can see where quarry stone was used to reinforce the road for heavy traffic. It was needed; the Overlook Road once carried wagon loads of heavy Catskill bluestone. There were a lot of active quarries up there once, especially at the north end of the one-time highway. Look for a fork in the trail there, where the Blue, Red and Green Trails intersect. Within a few hundred yards of that spot are quite a few of the old quarries.
Some quarries are overgrown, but most are very much as they were on the day that operations halted. Quarrymen sought after flat-lying stratified sandstone, sometimes called flagstone, but mostly called bluestone. The rock easily split along its strata into stone useful for sidewalks and as various types of building stone. If the rock wasn’t made of flat-lying strata they left it be; it was of no monetary value and therefore of no interest. But it’s that odd stone that is of the greatest interest to a geologist; the non-flat lying strata tell the best stories.
Much of the rock which ended up left behind is what we call cross-bedded sandstone. These are very nicely defined strata which occur in sets that are never horizontal but intersect each other at all sorts of angles. The pattern is eye-catching; the rock seems to possess a written record of its own history, a hieroglyphic if you could only read it. It does and you can.

Most bluestone was once sand that was deposited in ancient stream channels. That was about 380 million years ago during the Devonian time period. Cross-bedded sands of this sort form in the deepest, most rapid flowing part of stream channels, a churning, swirling time in the history of those ancient rivers. Rapid and strong currents scoured out troughs on the stream bed. Later, when the currents slowed down, sand was deposited, and it filled in the original troughs. Over and over the process was repeated and eventually the cross-bedded sands formed. Streams of this sort tend to shift their channels as they meander across the flood plain, and the sands were left behind under a thickening accumulation of flood plain deposits. When thick enough the pressure began to harden the sediment into the sandstone we see today.

These deposits accumulated at times of maximum flow and these are likely to have been floods. Floods to humans are awful events, powerful and destructive episodes when stream banks collapse and plants and animals are killed. Nowadays when floods happen, newspaper headlines scream of the damage. Remember last January [1995] in the central Catskills.
But these were events which occurred long before people. All the terrible events that we associate with modern floods occurred here; surely many primitive animals died, and perhaps whole forests were washed away. But no one was there to mourn the losses, nobody cleaned up or repaired the damage. No newspapers or history books recorded these awful events and life just went on. Only the rocks carry the “hieroglyphs” of these terrible moments in the deep-time history of our region and only geologists can read them.
If you get a chance, pick one of those beautiful, clear, dry, warm fall days and go hike the Overlook trail. Find some of these cross-bedded strata. These were awful moments that Nature prefers to forget. There is violence and power here, there is noise and turmoil, there is the struggle for, and giving up of life. Take a good look at these strata and appreciate the history they record. Such things can give you a whole different point of view on rocks.

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

Some fine boulders in Cooperstown 10-31-19

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On the waterfront
The Cooperstown Geologist
Feb. 2007
Updated by Robert and Johanna Titus

When you are a geologist you have to get used to the idea that you are always (pardon this!) a stone’s throw away from a journey into the distant past. We had such an experience recently at Lakefront Park in Cooperstown. There, at the end of the Pioneer Street, are eight sizable boulders. We imagine they are there to keep people from driving into the lake. But they helped us to “drive” into the early Devonian time period. That’s a journey back in time of about 400 million years.

These boulders aren’t from the area; they were quarried somewhere else, but we recognized them immediately. They are from something that geologists call the Helderberg Limestone. They may well be from the Helderberg Mountains near Albany.
Limestones are special rocks for geologists. They carry us off to tropical places, and we mean that quite literally. The material of limestone is called calcium carbonate, stuff that mostly forms in shallow tropical seas. Have you walked the pink sandy beaches of Florida or the Bahamas? Then you have walked on carbonates. Petrify one of those beaches and, presto: sediment becomes rock, and the rock is limestone.
These boulders, however, did not form on some ancient beach. If you get a chance, take a good look at them. They are stratified, that is to say that the rock is layered. Each horizon represents a Devonian sea floor. We found some sandy sea floors and some muddy ones too. This was a mixed marine ecology.
There were plenty of creatures living on these sea bottoms. The boulders are all fossiliferous; look them over, and it won’t take very long for you to find some of these fossils. A visit here is a very colorful journey to the bottom of the sea.
It was the corals that most caught our eyes. Yes, we said corals, and right here in upstate New York! Take a look at the fifth boulder from the right (east) side, especially on the right side of the rock, about two feet from it’s top. Our field notes tell us that there are two types of corals to be seen here. The first is called the honeycomb coral (C on second illustration) and that’s a good choice in terms. It looks like petrified bee’s wax. The second is the horn coral (A on second illustration). It’s called that because it looks like a cow’s horn, wide and round at the top and tapering to a point. You will see something that looks like the cross section of a cut orange. Horn corals have compartments that remind me of the segments of an orange.

There are enough corals here so that we have to wonder if these rocks did not come from a reef ecology. That could be, as the Devonian was a time of many large reefs and there are many Helderberg coral reefs known in New York State.
The story gets better when you learn more about Helderberg stratigraphy. As we said earlier, these limestones are exposed in the Helderberg Mountains. But the limestone strata are known to plunge underground as you head west towards Cooperstown. That means that some of the Helderberg lies buried deep beneath Cooperstown. Hundreds of feet beneath Lakefront Park is a great thickness of Helderberg Limestone and a good bit of it is probably fossil reef.
That means (and this is astonishing) that Cooperstown was certainly once the site of a beautiful shallow Bahamas-like tropical sea. Look around you and imagine the pink sands and green seaweeds that were once right here. Look up and see aqua colored waters above you. Imagine the primitive fish that once swam here.
And it only gets better, the more you think about it. Cooperstown is also very likely to have been the site of a Devonian coral reef. This is a pretty area, especially in the autumn, but have you ever, in your wildest imagination, envisioned coral reefs and all their beauty . . . right here?
Geology changes your perspective on things, doesn’t it?

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

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