The Greenport Mastodon

Windows Through time

Feb. 28, 2013

Columbia Greene newspapers

Updated by Robert and Johanna Titus

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

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

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

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

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

It would take decades to solve the other half of the problem – what kind of elephant had it been – and that came when many more mastodon bones were found in the Ohio River valley, and a complete skeleton was unearthed in New York’s Orange County. Now, at last, scientists could see a whole skeleton with tusks, and clearly its bones were those of an elephant, or at least a distant cousin of today’s elephant. But only a distant cousin; now there was a new scientific problem. The mastodon did not match the Indian or the African elephants; it was a separate and new species.

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

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

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

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

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

Reach the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Watch for more articles in Kaatskill Life, the Woodstock times and the Mountain Eagle.

The Myth of Spook Rock

Stories in Stone

The Columbia County Independent; Nov. 23, 2004

Updated by Robert and Johanna Titus

MAYBE YOU READ the Independent’s recent (2004) review of Pasquale Morrone’s book “Spook Rock.” It’s a work of fiction based on a mythology. That, of course, is not something that usually attracts the attention of a scientist. We don’t devote a lot of time to myths, but in this case we think that we can be forgiven. Morrone’s book is centered on a real rock and we always like a rock with a good story. Spook rock is located south from Rt. 23B on Spook Rock Road where it passes very close to Claverack Creek.

The legend has it that, long ago, an Indian maiden fell in love with the son of a chief of another tribe. Her father, also a chief, predictably, did not approve of this. One thing led to another; the two lovers met in the darkness at Claverack Creek.  Great. A  great boulder was hit by lightning and fell from the cliff above and landed upon them. They ended up crushed to death. The rock is still right where it fell and, presumably, the unfortunate lovers remain beneath it. Stay away on full moon nights!

Naturally, we could not resist going and seeing such an ill-mannered rock. It’s easy to find; it lies near the western bank of the creek, conveniently close to the road and there is very good parking. Unfortunately, we had to wade out to it. Our first scientific discovery was that spook rock has many very sharp corners to it and these are hard on bare feet.

We quickly recognized the rock; it is a piece of what we geologists call the Devonian aged (about 400 million years old) Manlius Limestone. That’s a type of rock that makes up a sizable portion of Becraft Mountain. With this, we had confirmed one important element of the myth. This rock certainly had tumbled down from the Manlius Limestone ridge above.

But soon another story began to emerge. We looked at the gray limestone and saw many thin laminations within it. We knew what these were; they are called algal laminates. Geologists have long recognized these laminations as being the fossils and ancient algae. You see, some colonies of very primitive algae grow into sheets on tidal mudflats and coat the surface with their own stickiness. As the winds and the tides rise and fall, grains of silt and clay adhere to the sticky algae and thus the laminates come to form. We looked at this and we were transported through time.

June 10, 400,002,000 BC, high noon. All around us lies a bleak flat landscape. To the west, quite some distance away, we can see an ocean. It is a beautiful aqua color. This is a peaceful sea, with virtually no waves breaking on its distant shore. It’s called the Helderberg Sea; we have been here many times before and knew what to expect.

At this distant time, Columbia County lies very close to the equator, and at this noontime hour an intense tropical sun beats down mercilessly. In short, we have arrived at a bad time. To make things worse, the Devonian age atmosphere has much less ozone in it. Today ozone shields us from ultra-violet radiation which minimizes the threat of sunburn. We feel the difference; we would not be able to stay here long before we were seriously sunburned.

All around us lies a sticky mat of dark olive colored algae. These creatures should, like us, have been baking to death in this awful sun, but they weren’t. They belonged to a breed of algae called the blue-green algae, and by the time of the Devonian they are a very old type of microbes. They have been on earth for three and a half billion years and in that time they have evolved a tolerance for intense sunlight. This noon time will pass and they will be just fine.

A wind begins to blow and soon it picks up. Now billowing clouds of dust are blowing from the highlands to the east. The dust coats the sticky algal mats and they turn white. Another lamination is being added to the countless numbers that lie below. If they are turning white, we are turning red. It is time for us to escape the Devonian and return to Claverack Creek as it is today.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their columns in the Mountain Eagle.

HUNTER MOUNTAIN BESIEGED . . . AGAIN

On The Rocks

August 29, 1996 1996

Updated by Robert and Johanna Titus

They say that it is human nature that the end of one conflict often bears the seeds of the next. This somber observation may be the case with Hunter Mountain, the second highest mountain of the Catskills. Recently (That was in1996) there was a proposal to alter the New York State constitution in order to allow the development of about 3,000 acres at the summit of Hunter Mountain. This would have allowed the expansion of the Hunter ski complex into something comparable to what we now see in Vermont. Currently skiing on Hunter is confined to the “Colonels Chair” which lies on the slopes of Shanty Hollow. If the proposal had gone through (It didn’t), skiing would have been expanded to Taylor Hollow to the northeast and Becker Hollow to the east. These three hollows have origins that date back to the last time the mountain was besieged. That was during the ice age when the proposed ski bowls of Hunter were occupied, not by skiers, but by Alpine glaciers.

Few people realize the role that glaciers played in making our Catskill landscapes. The story takes us back to a chapter in glacial history described as the Wisconsin glaciation. Catskill glacial history is complex, but there were two very different phases. First there was a time when a great, half mile thick sheet of ice swept across our mountains. The Catskills then resembled the high ice plains of today’s Antarctica. By 16,000 years ago, however, the Catskills had escaped the worst grip of this phase. The great thick ice sheet was gone, but all was not over yet. Glaciers were still found in the shaded valleys, and also in the high mountain niches that were giving birth to a number of Alpine glaciers. If you are familiar with the images of the Swiss Alps of today then you know that high up in the Alps, large glaciers form in pre-existing hollows. These are nourished by snowfall and, with cold conditions, these picturesque Alpine glaciers descend the slopes and flow into the valleys below. That was the case with Hunter Mountain.

As time went by these glaciers modified their own Alpine niches. Glacial ice forms a sticky bond with the rock beneath it, and as the ice moves, it plucks loose large amounts of this rock. Alpine ice is thus a very effective agent of erosion. Given enough time, this expanded the niches and enlarged them into beautiful, bowl-shaped features called “cirques.”

There are a lot of cirques in the Catskills, but few of them are as well developed as those of the Alps. This phase of glaciation was too short for Swiss-like landscape to develop. Warmer conditions returned, and the Alpine glaciers melted. Nevertheless Hunter Mountain displays some of the best cirque landscape seen in the Catskills. In addition to the three hollows we mentioned earlier, there are the hollows at Myrtle Brook, Diamond Notch, West Kill and Hunter Brook. All seem to have once harbored glaciers. Some of these can be seen from Rte. 23A, below.

                                                                          Cirques, left and right of the ski slopes.

                                                         A map of Hunter Mt. showing its seven Alpine glaciers.  

The effects of glaciation persist long after the ice is gone. These bowls initiate what we call “watersheds.” The hollows are ideally suited for the purposes of gathering rainwater and passing it on to the river systems below. Of the seven hollows which surround Hunter Mountain, five of them feed water into the Schoharie Creek watershed. Only one of these five, Shanty Hollow, is currently a ski slope, but Taylor and Becker Hollows were planned to be added. Watershed protection was one of the most important reasons why the State purchased the land in the first place, and was one of the primary reasons for opposition to the ski slope expansion.

You can see some of this Alpine landscape. From West Kill Valley take the Devil’s Path up the western slope of Hunter Mountain. There is a fine ledge at the top of the trail. That is the top of a cirque. The cliff below drops off into an Alpine glacier’s niche. Look west into the valley of West Kill. The beautiful U-shaped valley you see is the product of the glacier’s erosion as it flowed down the valley.

                                                                             View of U-shaped West Kill Valley

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

Yellow Alert?

Stories in Stone

Columbia County Independent

May 13, 2005

Updated by Robert and Johanna Titus

We have, recently, had a growing sense that something has been going on geologically, here in our upper Hudson Valley. We think a pattern has been developing. Scientists notice patterns and we seek to understand them. We had better explain.

We commonly drive past the Gilboa Reservoir. Lately, the water has been pouring over the top of the dam. That’s unusual; most of the time the reservoir is well below the dam’s top, sometimes the reservoir is nearly empty. It’s easy to say that it has just rained a lot recently, but we wonder.

Over the last few years there have been a number of damaging slumps in the upper Hudson Valley. First came the Delmar slump, south of Albany, which put a major road out of commission for quite some time. It had been built on the muddy sediments of an old ice age lake, Glacial Lake Albany. The sediments simply gave way and slid into Normans Kill. Well, these things happen, or so we thought at the time.

But then, last year there was another slump, this one in Schenectady. The edge of an old Lake Albany delta slid downhill and that doomed six homes. Soon we had a small slide just a mile from the Titus family home in Freehold. Again, this spring, we have seen still another nearby bank give way and now it seems to be oozing water. That’s too close for comfort.

Slumps are an ongoing problem in the Hudson Valley and we have written about them before, but there seem to be a lot of them lately. Two weeks ago there was a new slump in Amsterdam. This one also seems to have involved the sediments of another ice age lake delta. That’s alarming; why are these events coming at such a rapid rate?

But then it got even worse. we began receiving E-mails from people in Valatie, complaining about flooding basements. Three houses on New Street have been experiencing serious problems for weeks. Basements flood; that’s their job, but some of these folks claim that they have never seen the likes of this even after decades of residence and they are worried.

All this may just be coincidence and might mean next to nothing. Or, all this may just indicate that we have had a lot of rain lately. That would explain this year’s problems, but it would not tie in the events of recent years.

In the end, it seemed to us that there was enough to warrant a little investigation. It looks to us, on the face of it, that the region’s water tables have been rising and that the recent heavy rains have triggered a series of problems. This trend may be something that has been developing over the last several decades. Can we document this the way scientists should, and can that lead to an explanation? Well, we can try.

We checked with the National Oceanic and Atmospheric Administration website and found some interesting things. New Yorkers have seen some climate change over the past century. Our average temperature has climbed only about one degree Fahrenheit. More interestingly, however, our rainfall has climbed about six inches, from 36 to 42 inches/year, that’s 16 percent.

If we have seen a lot more rainfall, then it follows that there should be more groundwater and higher water tables. Add a few heavy rains and it seems logical that basements would start to flood and slumps might be triggered. People might well remember that these things didn’t happen in the distant past because they really couldn’t have.

What we are suggesting is that if we have a wet summer or, worse, a snowy winter and rainy spring next year then we may see serious problems. Is all this good science? Certainly not; it is the result of just a little work over a short period of time in response to some rapidly occurring events. It’s not theory, just hypothesis.

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

A VIEW FROM THE MOUNTAIN HOUSE PORCH

The Woodstock Times

Oct 3, 1996

Updated by Robert and Johanna Titus

The view of the Hudson Valley from along the Catskill Escarpment is one of the great sights of the east. You can enjoy it anywhere along a ten mile stretch from Overlook Mountain to North Point, but the most famous vantage point is long gone. That was the 130 foot long piazza of the old Catskill Mountain House Hotel. A 70 mile stretch of the Hudson lowlands lay visible below the hotel site. On certain days, when the clarity and humidity are just right, the atmosphere becomes a magnifying glass and that landscape seems to reach out to you.

Mountain House guests commonly arose just before sunrise. With a little luck they got a special treat. The cool morning fogs would enshroud the valley below. Then the Sun would slowly rise above the clouds, illuminating them brightly from above. It’s still a sight to see.

Beautiful as it is, this view thwarted the efforts of artists to capture it. Seventy miles is just too much to put on a canvas and anything less just won’t do. Only Frederic Church solved the problem. In his “Sunrise in the Catskills” he painted the view at dawn. He showed the Sun rising above a valley filled with clouds. That left all these unpaintable 70 miles of valley floor to the imagination of the viewer. It worked; the painting is a gem!

The twentieth century brought something new to the view. With electricity, the nighttime valley gradually lit up. On a clear, dry, moonless night, with the starry sky above and the lights below, the view is another great sight to behold.

The hotel is long gone, but the view remains. The Mountain House site remains a popular goal for the hikers and picnickers at the North Lake area. It’s a popular draw for visiting geologists as well. Our colleagues and we come to see the view just like anyone else. But we get to see two views at North Lake: One is the landscape as it is, and the other is as it was during the Devonian age. To the far east is the low profile of the modern Berkshires. These humble mountains are the erosional remnants of older and very larger mountains. They are the roots of the old Acadian Mountains.

Out there, between 350 and 400 million years ago, a great mountain building event took place. If you sat on the Mountain House piazza for 50 million years or so, the mountains would rise before your very eyes. It was one of the biggest such events to ever occur in eastern North America. At their greatest, these peaks, called the Acadian Mountains, stood maybe 15,000 feet above sea level, and maybe more, even a lot more!

As we look east from the hotel piazza we can still see those old mountains through our mind’s eyes. The jagged peaks are snowcapped. It’s a tropical climate here, 370 million years ago, so only the highest slopes are white. Below the snow, the mountains are a uniform smoky blue. There is enough haze so that the details of the landscape are not clear, but you can see many deeply cut gullies in the upper mountain slopes. It’s common for heavy rains to activate the gullies which then tear into the mountain. Farther downhill, the gullies merge into very substantial and extremely jagged canyons. During rainy times, great cataracts of water plummet down these valleys. The waters are brown with freshly eroded sediment; there is no flood or erosion control in the Devonian.

Toward the base of the mountain range the canyons empty out onto great heaps of sediment. These are beautiful; they have been sculpted into gently sloping fans and their light colored sediments shine brightly in the sun. There is no foliage to cover these fresh sediments.

But there is foliage farther below. In front of the fans is an enormous landscape of swamps, shallow ponds and many streams. It’s a huge delta complex which geologists have come to call the Catskill Delta. The delta is teeming with life, mostly primitive plants. There is an irony here. In looking at this ancient delta environment we are looking at the Catskills of today. That’s because, with time, the sediments of that ancient Catskill Delta spread out across much of today’s New York State. They hardened into rock and are now the sedimentary rocks of the Catskills of today. In the great cycles of time, one landscape is the parent of another.

And so it is that we sit upon the porch of a long gone hotel and gaze at mountains which eroded away 300 million years ago. Such are some special moments in the lives of geologists.

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

Time in Winter: The Catskill Front again

Windows Through Time

Revised by Robert and Johanna Titus

Daily Mail   Feb. 2011

Last year, about this time, we gazed up at the Catskill Front. That‘s a good thing for a geologist to do this season of the year. Winter is when it is so easy to see the ledges of rock that make up the stratigraphy. With all the leaves down we can see a lot more geology, and that is good. But some readers have written and asked us about some of the numbers we cited. We claimed that there are about 9,000 feet of strata up there and some astute readers wondered how that could be. After all, the Catskill Front only rises to about 3,000 feet at the top of places like North Point. “Where are the other 6,000 feet of rock?” they ask. Good question.

Well, fair enough, and the answers to their questions leads us to something important about the whole Catskill sequence.  First, let’s document our estimate. We asked Dr. Charles Ver Straeten, of the New York State Museum, about this and he confirms that there are eight or nine thousand feet of strata in the Catskill Sequence, depending on exactly where you measure. Plenty more strata have eroded away over the eons. These strata begin at the bottom of the Hudson Valley and stretch up to the top of Slide Mountain. Dr. Ver Straeten has spent many years studying this sequence; his opinions carry a great deal of weight.

But, how come all these strata don’t’ rise up higher over the landscape? How come we don’t have Catskill Mountains that tower a full 9,000 feet? The answers to those questions take us back to the processes that created the Catskill Sequence and the Catskill Mountains themselves. We have to travel back about 380 million years of so, to a time when the Catskills first formed. Back then North America had been enduring a great collision with a landmass which you might call part of Europe. The collision led to the uplift of all of Northern New England and the creation of a mountain range called the Acadians. This event is known to geologists as the Acadian Orogeny.

We have talked about this in several columns. Weathering and erosion of the Acadian Mountains produced the sediment that eventually formed the Catskills. But there was a lot more than just sedimentation going on. There was plenty of real warping of the rocks. The notion of deforming rocks may well be a novel one. How, on Earth, can rocks be deformed? They are, after all, pretty rigid materials. And they are very stable too; at least that’s as it would seem.

Well, rocks certainly are rigid, stable entities, at least under the normal circumstances that we are all familiar with. But most rocks have been around a very long time and they have had many long “journeys.” Our Catskill rocks are mostly a little less than 400 million years old and that was plenty of time for them to have gotten into a lot of “trouble.”

By that we mean that our rocks have seen themselves buried under thousands of feet of other rocks–many thousands of feet. Look up at the Catskill Front and imagine that great thickness of strata rising high above it. That rock would weigh a great deal and the weight we speak of is what allows much of the deformation. Imagine how you would feel if several thousand feet of rock were pressing down upon you.  But there is more.

Our rocks suffered deformation in another fashion. They were there when North America experienced the worst of that continental collision. Again we have to use our imaginations. Try to envision what it is like to be “hit” by another continent. If Europe slowly collided with North America the pressure of the impact generated would be truly enormous.

Now we have seen two processes ganging up on our poor rocks: first there was the weight of burial and then there was the shove of a massive continental collision. The effect of each, individually, would be enormous, but we want them to be occurring at the same time. That’s, in fact, what happened. As Europe collided with North America, it generated a massive uplift and tilting within the whole northern Appalachian realm. Those mountains, the Acadians, eroded away and their sediments buried our Catskill region under thousands of feet of sediment. It was compression, however, that had the better of it. “Europe” pressed in from the east, shoved our Catskill sequence, and then tilted the strata into a broad incline. Incredibly, later in time, Africa collided and all this was repeated. It is such monumental tilting that allows about a mile and a half of strata to make a mountains range only 3,000 feet tall. See our illustration.

Tilted strata of the Catskill Front – Courtesy of Alan McKnight

Reach the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Watch for them in the Mountain Eagle, the Woodstock Times and Kaatskill Life.

Clove encounter

On the Rocks

The Woodstock Times

April 10, 1997

Revised by Robert and Johanna Titus

It can often be difficult to teach a science, even one as interesting as geology. Many people are adverse to the sciences. One problem is that a lot of people really would rather not know the technical details behind some remarkable piece of nature. They believe it’s better to harbor romantic images and not spoil them with harsh factual science. Let’s try this out at Stony Clove.

Stony Clove is a magnificent sight to see. It is a very steep, very narrow notch in the Central Escarpment of the Catskills. It is a remarkably scenic location, especially in the autumn when the leaves are in color and when the lake there reflects their image. A person might very well be tempted to not want to know too much about the notch. How could the science improve upon such natural beauty?

Maybe science is the wrong word to start out with. A better word is mystery. What is this wonderful notch and how did it come to form here? That sounds better, and if the mystery of Stony Clove catches your interest, then it must be the science of the site which will solve that mystery. Certainly no geologist can pass such a landscape feature without wondering how it came to be, and there is quite a story behind the notch, one that takes us back into the ice age.

When you get a chance, travel to Stony Clove. As you approach the top of the clove on Rte. 212 from the south, there is a lake to your left. Beyond that is the clove. Park in the lot next to the lake and hike north to the top of clove. In your mind’s eye go back 17,000 years. It’s a time in the history of Catskill Mountain glacial history called the Wagon Wheel Ice Margin. From the Hudson River, valley glaciers have advanced up Plattekill and Kaaterskill Cloves. Some of this ice has turned south and entered into Stony Clove. From the crest of the clove you can picture this glacier; it’s just to the north. Its front is a mess, a jumble of broken blocks of ice. There is a small lake at the base of the glacier. Its waters reach up to your feet. All along the front of the ice where it bounds the lake, great masses of water are welling upward and the surface of the lake is churning with turbulence. It’s evident that the climate has been warming and the ice is melting. The glacier is disintegrating and from time to time one or another of those blocks of ice proves unstable and collapses into the lake with a violent crash. With that, a tidal wave radiates quickly across the lake. It’s a big wave in a small lake so the agitation is immense; a lot of that water spills over the crest of the notch.

In your mind’s eye look back south, down the valley from the crest. With all that melting, there is only one place for all the water to go and that is in this direction. Stony Clove is a great, loud, cataract of raging, foaming, pounding white water racing down the valley. The strength of the flow is manifest in the cracking sound of tumbling, colliding boulders. Competing currents of water crisscross around the largest boulders and collide with each other sending white fountains into the air. The hissing spray catches the sunlight and forms rainbows.

Many of the most powerful currents abut the stream bank. Where this occurs muddy gravels collapse into the flow and this sediment is rushed away. Beneath the white surface, the water is brown with erosion. It’s this scouring that has carved the great notch in the mountain.

On a quiet summer or autumn day Stony Clove can be a site of serene natural beauty, a quiet place to picnic or just sit and gaze. But the serenity is deceptive; there is real violence in the clove’s origins. You can’t really understand Stony Clove unless you understand its past. You have to use your mind’s eye and you need to know its geology to do that. This is the science of it all.

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

Tafoni: A real mystery, and a local one at that

On the rocks

May 29, 2014

Updated by Robert & Johanna Titus

Phoenicia has been in the news a lot over the years. It is best known as a place that has had serious flooding problems. Various northeasters, along with the occasional hurricane, are enough to fill Stony Clove Creek to overflowing. The creek swells up over its banks and makes a mess of the town. Engineering efforts to improve flow beneath the bridge there have been controversial. Their effectiveness is questioned.

But, that’s not the topic of this column.

We were recently invited to go to Phoenicia and take a look at some very strange geological phenomena. Our host was Paul Misko, of the Catskill 4000 hiking club. As a veteran hiker, Paul can be found just about anywhere in the Catskills and he has a real eye for unusual geology, so we paid attention to his “very strange” claim. He had piqued our curiosity and, when we got there, we weren’t disappointed; we found a real puzzle. Across the street from the St. Francis DeSales Roman Catholic Church, is a small park. If you walk into the park from Main Street and bear toward the right (east), you will soon find a small hiking trail. It’s called the Tanbark Trail (you can run a search and get a map of it). Climb up a steep incline, and towards the top you will find a fairly sizable ledge of sandstone. It’s rather commonplace stuff; it is a very typical Catskills bluestone ledge. We recognized what are called cross beds. That is to say that a lot of the strata here dip in one direction or another. They were not very well defined, but they were there. That is normally the case with bluestone that was deposited in river channel sandstones. This ledge is, in essence, the cross section of a very old stream. It’s, like all rocks in the Catskills, Devonian in age, something a bit less than 400 million years old.

None of this surprised us in the least. It was strictly routine stuff. But that’s where we encountered that mystery. Take a look at our photo and see what you think. The first view shows the entire ledge. Commonplace cross-bedded bluestone makes up the whole lower half of the exposure. Up top are a large number of closely spaced and very strange cavities. The close-up view shows a tightly packed cluster of these cavities in the rock. Their shapes vary considerably, but they all show a sort of boxy nature and they seem to form an interlocking network. We would like to use the term honeycomb here, but honeycombs show a consistent hexagonal shape; we don’t see that with these. The rock remaining in between these cavities is narrow. The cavities do not penetrate too far into the rock, just a few inches. And there is no reason to think that there is another horizon of these cavities under the ones that are visible. Thus, they appear to be surficial features. Nevertheless, these cavities seem to be concentrated. Many of these cavities are spaced so close together that they comprise a bigger compound cavity. Whatever it was that formed them was focused.

All in all, this is the most puzzling phenomenon that we have seen in ages. There is no trouble putting a name on what is here; it is called tafoni. Each individual cavity is a tafone; lots of them are tafoni. And the terminology keeps getting better; when tafoni occur on cliff faces, as at Phoenicia, then it is called lateral or sidewall tafoni. But, putting a name on something is not the same as understanding it.

What are these features? They seem to be weathering phenomena. Somehow, they appear on the rock surface and grow slowly into their observed shapes, but exactly how? And, also, how is it that they grow in size until they abut each other but do not grow into each other? How do they grow in size without intersecting? Those are very puzzling questions and just naming these things does not provide answers.

Tafoni have been weakly associated with poorly defined stratification on the sides of cliffs and that is the case here. But that still leaves a lot unsaid. Why does this “association” occur? What are the specifics? Salt is commonly cited as an agent in Tafoni development. They are sometimes found on coastal outcroppings, splashed by ocean waves. But there is certainly no source of salt here on a sandstone cliff in Phoenicia. And that begs the question: what exactly is different about his cliff? We have literally seen hundreds of similar cliffs, all through the Catskills and all composed of the same type of sandstone, all originally deposited in the same Catskills Delta river channels. Why don’t all of those other cliffs have tafoni? Why isn’t it that none of them do? There must be something here, right in front of us, which we have missed. This is the sort of thing that makes science so much fun.

Do you have any ideas or questions? Have you seen tafoni somewhere? Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

Buried alive, the Gilboa Forest

On The Rocks

The Woodstock Times

Oct 10, 1996

Revised 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, red sandstones of Silurian age. They formed in habitats where trees should have been common but they 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 that interval trees evolved and spread out across the Earth as the first and oldest 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. From Woodstock take Rte. 28 to Rte.42 and drive from from Shandaken to Lexington. Then take Rte. 23A west until you reach Grand Gorge. Take Rt. 30 north 2.8 miles and turn right onto Rte. 990V. Go downhill another 1.2 miles and you will reach Schoharie Creek where it passes through the village of Gilboa. Just beyond the bridge is a little park with some very fine fossil tree trunks. This humble site commemorates one of the world’s most famous fossil locations, the Gilboa forest. After looking at these fossils you can proceed a short distance to the Gilboa Museum. It’s only open on summer weekends but it displays some more very fine fossil trees.

The Gilboa forest was discovered after the terrible Schoharie Creek floods of late 1869. Extensive erosion along the river ripped through soft red 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 1920’s. Excavations for the Schoharie Reservoir revealed about 200 more fossil stumps. The trees in the little park were among these. These 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 ferns 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 very old ones are 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 Creek, 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 into the light. The irony came when so many of them were once again submerged in the waters of the Schoharie Reservoir.

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

Cycles of earthquakes?

Windows Through Time

Robert and Johanna Titus

April 14, 2016

A fun part of our job with the Columbia-Greene Newspaper chain is just going out and exploring for some fascinating locations where there is good geology. Recently we were in Saugerties to hear a lecture at the Friends of Saugerties History Group at the town library. Afterwards, we just went exploring. We found ourselves heading south on Partition Street, we crossed the bridge over Esopus Creek, and took the first left onto East Bridge Street. That took us along the Esopus on Ferry Street.

We didn’t expect to see much. You see Esopus Creek, long ago, when it began flowing into the Hudson, formed a pair of peninsulas that pushed out into the larger river. We expected that these would be composed mostly of sand and would be pretty boring stuff. Well, we were wrong.

A little less than a quarter mile down the road we were forced up and over a sizable knob of rock. When they constructed Ferry Street they had to blast through all that rock. And that gave us a beautiful exposure of bedrock.

We recognized the rock unit, immediately. It was the Normanskill Formation. That has some very important and very interesting geology. It dates back about 450 million years and it is big. Much of the middle Hudson Valley is blanketed with the Normanskill. A lot of it is west of the river, but there is more of it on the east side. It’s named after Normanskill Creek where a very large exposure is found. That‘s where Rte. 9W approaches Rte. 787.

It’s a unit that we should be writing about more often. It is composed of a mixture of thick dark gray sandstones and thinly laminated black shales. Way back during the Ordovician that sandstone was sand and the shale was mud. These sediments accumulated at the bottom of what is sometimes called marine trench or an “oceanic deep.” Deep indeed; that’s a stretch of ocean that can be 20,000 feet deep or more. The best known modern deep is the Marianas Trench in the western Pacific. It is more than 35,000 feet deep! Well, you can easily imagine those rocks caught our attention. They took us down to the deepest parts of the sea—to the very abyss.

But there is more—a lot more. Those black shales speak to us of routine moments on the floor of such deeps. They accumulated one lamination at a time. Silt and clay slowly settled to the floor of the ocean. It takes grains of silt and clay months, even years, to sink that far. So these sediments accumulated very slowly. A few inches of this sort of black shale may represent enormous amounts of time. How much time does a foot of shale represent? Well, in truth, we geologists have no idea, but it is a lot of time.

Not so with those sandstones. They are different. They are a special type of sandstone; they are called greywackes. A greywacke is not just a sandstone; it is a “dirty” sandstone. You are probably used to the clean white sands that we see along the Atlantic coast; those are almost pure quartz sands and quartz is almost white.
But these greywackes are different; there is a lot of quartz in them but they also have a large amounts of silt and clay. That’s the dirt in a “dirty” sandstone.

Greywackes are remarkable for how they form. They are often the products of submarine avalanches. Typically an earthquake strikes the deep sea floor and masses of sediment are thrown up into suspension. Such masses of sediment then, slowly at first, begin to flow down the slopes of the deep. Those avalanches are called turbidity currents and they quickly pick up speed. Soon they are thundering down the steep slopes into the abyss. Eventually they reach the bottom and begin to slow down. When they slow down enough, all that dirty sand slows to a halt and deposition occurs. Hence the greywackes we saw—and probably each one of them.

All this gets us back to the Ferry Street outcrop. It has an eye-catching feature; there are six thick horizons of greywacke and, in between them, are those expected black shales. But the shales are thin, only inches thick. That conjures up quite an image.

We walked along this outcrop and counted those six thick greywackes; we realized that we were likely counting earthquakes. And those thin shales indicated to us that those earthquakes and those turbidity currents had come in relatively short intervals. Those earthquakes were occurring in the nearby rising mountains of New England. Those mountains were in full uplift mode and we saw the results—in Saugerties.

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