Robert Titus - page 23

The Shores of an old river

The Catskill Geologists

Robert and Johanna Titus

We have, in recent columns, been looking into our Catskills sandstones. Most of them were deposited in the channels of Devonian rivers. There is a pattern here: the various structures we have been looking at are arranged within the old river channels. Geologists have determined that these were meandering streams; they wandered back and forth across their old floodplains. Take a look at our first illustration.

Meandering streams have symmetrical channels; they have a deep side where the fastest flow is and they have a shallow side where the slowest flow is. That fast side is also erosive so the stream meanders in that direction. We have been, these past weeks, describing trough cross beds, planar cross beds and flat lying strata. These are typically arranged from the deep side to the shallow one. Again, see our first illustration.

Well our main point is that, if you look at our Catskills sandstones and recognize these structures, then you will find yourselves understanding our Catskill geology so much better. You can transport yourselves back through time and place yourselves in one of those streams. These, so long ago, were real environments, real habitats, just like those of modern rivers. Now you can experience those habitats. You can place yourselves into those channels.

Let’s finish our trip across these rivers. When we arrive at the shallow side of these streams, we are likely to see waves washing onto the old river’s shore. They are making a lap-lap sound. But, more importantly, they are doing what waves are very good at: they are sculpting the river sands into what geologists call ripples. Take a look at our second illustration. An experienced geologist looks at these and sees that they are symmetrical; that means that the slopes of each side are of similar steepness. That’s the mark of wave ripples. Current ripples are asymmetric, always steepest on the downstream sides.

As we wash ashore on the shallow side of our stream, we have completed the crossing of a 385-million-year-old river and have become so much more knowledgeable of Catskill geology. Reread our latest four columns and then take what you have learned on to your next hike into our mountains. It’s time for you to actually see those ancient streams/

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

Crack Me Up

On the Rocks – The Woodstock Times 1998

Updated by Robert and Johanna Titus

Middle and late summer often brings the dry season of the year to the Catskills. The streams run dry or nearly so. The cobbles and boulders become light with a coating of dry and bleached algae. Nervous fish circle in the remaining pools of unhealthy, stagnant water. Along the stream banks, dry weeds have a lifeless look to them. If the plants are thirsty, then it’s at least partly their own fault: They have drawn so much water out of the ground.

It’s not a pleasant time of the year for those plants and animals that depend on lot’s of water. And it never has been. Our August cycle is just this year’s edition of something that always has been, and probably always will be. It’s hot in August and when it’s hot things dry out. If I said that it was like this back in the Devonian time period when the Catskills were a great delta complex, I think that you might believe me. But if I said that you can go and still see some of the damage done during Devonian droughts, I’d expect at least some skepticism. And yet it is so.

Sedimentary rocks, take sandstones for instance, are records of conditions as they were when the sediments were being deposited. Our Catskill sandstones were deposited in a multitude of delta environments, but one thing was certain. When there were droughts, pretty nearly the whole delta dried out. And that is reflected in the sedimentary rocks.

Sediment is generally deposited in some sort of watery environments. Catskill sediments were deposited in streams, ponds, pools, marshes and all sorts of watery settings. So they were very nearly always wet upon deposition. But that didn’t mean that they would stay wet. Back in the Devonian there were dry seasons and dry years. Ponds and pools evaporated, shrank and dried up. Even rivers could run dry in the worst cases. Similarly soils and sediments dried up as well, although we geologists like to say they “desiccated.” At any rate, the last thing to happen was that the still wet muds at the bottom of any body of water were exposed to the sun and began to dry out. The clays within them would begin to shrink and so too would the whole mass of sediment.

Mud does not just dry out; it begins to divide into many small individual masses. Each of these continues to dry out and shrink towards it’s own center. The result is a maze of interlocking polygonal blocks. We call these “mud cracks.”

All this kind of explanation works better if you can go outside and see some of these features. Drive up to Kaaterskill Clove and find a place to park near the clove’s first fine water fall, Fawn’s Leap. There is a bridge below the falls and below that bridge you will find a prominent ledge of very red sandstone. Climb down and look carefully. It shouldn’t be long before you see some green mud crack polygons, standing in sharp contrast to the red sandstones. That’s them.

It’s very kind of nature to give me those color contrasts, but there is nothing magical about it. Mud cracks tend to fill with quartz sand while the surrounding muds were rich in certain clay minerals. These clays tend to oxidize in the presence of air and that turns them red. The mud cracks, being of a different mineralogy and maybe being a little more waterlogged, don’t turn red, they turn green. Presto! Sharp contrast.

A mud cracked surface can be a lot of fun to crawl around on and study carefully. You can sometimes find insect tracks or bits of plant fossils. Raindrops prints are found where the rocks record a brief shower that interrupted the drought. Once I found a complete fish skeleton. The poor animal had died as its pond slowly dried up. As I said these are bad times for plants and animals. That’s the wonder of it; the rocks are records of the past. They speak to us of awful, killing droughts of long ago. Animals suffered in the heat and died painful deaths alone in the dust or dried out pools. But that was back in the Devonian and nobody cared, nobody mourned, nobody pitied. And, in the end, only the rocks remember.

Contact the authors at randjtitus@prodigy.net

Crack Me Up

On the Rocks -The Woodstock Times

1998

Updated by Robert and Johanna Titus

Middle and late summer often brings the dry season of the year to the Catskills. The streams run dry or nearly so. The cobbles and boulders become light with a coating of dry and bleached algae. Nervous fish circle in the remaining pools of unhealthy, stagnant water. Along the stream banks, dry weeds have a lifeless look to them. If the plants are thirsty, then it’s at least partly their own fault: They have drawn so much water out of the ground.

It’s not a pleasant time of the year for those plants and animals that depend on lot’s of water. And, it never has been. Our August cycle is just this year’s edition of something that always has been, and probably always will be. It’s hot in August and when it’s hot things dry out. If we said that it was like this back in the Devonian time period when the Catskills were a great delta complex, we think that you might believe us. But if we said that you can go and still see some of the damage done during Devonian droughts, we would expect at least some skepticism. And yet it is so.

Sedimentary rocks, take sandstones for instance, are records of conditions as they were when the sediments were being deposited. Our Catskill sandstones were deposited in a multitude of delta environments, but one thing was certain. When there were droughts, pretty nearly the whole delta dried out. And that is reflected in the sedimentary rocks.

Sediment is generally deposited in some sort of watery environments. Catskill sediments were deposited in streams, ponds, pools, marshes and all sorts of watery settings. So they were very nearly always wet upon deposition. But that didn’t mean that they would stay wet. Back in the Devonian there were dry seasons and dry years. Ponds and pools evaporated, shrank and dried up. Even rivers could run dry in the worst cases. Similarly soils and sediments dried up as well, although we geologists like to say they “desiccated.” At any rate, the last thing to happen was that the still wet muds at the bottom of any body of water were exposed to the sun and began to dry out. The clays within them would begin to shrink and so too would the whole mass of sediment.

Mud does not just dry out; it begins to divide into many small individual masses. Each of these continues to dry out and shrink towards its own center. The result is a maze of interlocking polygonal blocks. We call these “mud cracks.”

All this kind of explanation works better if you can go outside and see some of these features. Drive to Kaaterskill Clove early on a weekday. There should be a fw parking spaces. You have to walk up the road to the clove’s first fine water fall, Fawn’s Leap. There is a bridge below the falls and below that bridge you will find a prominent ledge of very red sandstone. Climb down and look carefully. It shouldn’t be long before you see some green mud crack polygons, standing in sharp contrast to the red sandstones. That’s them.

It’s very kind of nature to give me those color contrasts, but there is nothing magical about it. Mud cracks tend to fill with quartz sand while the surrounding muds were rich in certain clay minerals. These clays tend to oxidize in the presence of air and that turns them red. The mud cracks, being of a different mineralogy and maybe being a little more waterlogged, don’t turn red, they turn green. Presto! Sharp contrast.

A mud cracked surface can be a lot of fun to crawl around on and study carefully. You can sometimes find insect tracks or bits of plant fossils. Raindrops prints are found where the rocks record a brief shower that interrupted the drought. Once we found a complete fish skeleton. The poor animal had died as its pond slowly dried up. As I said these are bad times for plants and animals. That’s the wonder of it; the rocks are records of the past. They speak to us of awful, killing droughts of long ago. Animals suffered in the heat and died painful deaths alone in the dust or dried out pools. But that was back in the Devonian and nobody cared, nobody mourned, nobody pitied. And, in the end, only the rocks remember.

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

Journey to the Center of.the Earth.

On the Rocks

The Woodstock Times, Nov. 12, 1998

Updated by Robert and Johanna Titus

The recent list of the top 100 movies has been rounded criticized for all sorts of reasons; such lists always are. We were not terribly surprised to see one of our favorites omitted. That was “Journey to the Center of the Earth.” Maybe you remember it. If not, we are not too disappointed, it really wasn’t that good. James Mason, as the geologist, might have been the movie’s highlight. Then too, Pat Boone probably never acted better. But the story was a silly one: Our heroes courageously entered the earth and descended all the way to its center. They found an ocean down there and the remains of a classical civilization. Then they rode a volcanic eruption back to the surface. A pretty good field trip, if you ask us.

But you just can’t do that. There are certainly no caves leading all the way to the Earth’s center. The weight of the Earth’s rocks creates enormous pressures, and any cave would be crushed by those great weights. And it gets very hot down there too. The world’s deepest mines go down a mile or so and even at those relatively shallow depths it is plenty hot, any deeper and it is too hot. Volcanoes don’t begin at the Earth’s center either. Still, the movie wasn’t really meant to be believed, just watched. Hollywood’s motto is often “suspend belief and enjoy.” Too bad about that though. It certainly would be quite an adventure. And wouldn’t geologists enjoy the chance to see rocks at such great depths? But we can’t. Or can we?

Even if we can’t go all the way to the center, there are indirect ways of traveling quite deeply into the Earth’s interior, and best of all, you can make the journey yourself. You just need to know where to go and what to look for. Our journey will take us into the core of the Appalachian Mountains to depths of probably more than a few miles beneath the surface.

Travel north to Rte. 23 as it descends out of the Catskills and heads toward the town of Catskill itself. The highway crosses Catskill Creek and then the New York Thruway. In this vicinity the highway department has cut several deep canyons into the rocks and exposed some very nice cross sections of bedrock. The rocks here are mostly gray limestones; they belong to something called the Helderberg Group. That means they are Devonian in age, nearly 400 million years old. The Helderberg Limestone was originally sediment deposited as flat sheets on the floor of a shallow, tropical sea. Those strata then hardened into hard, brittle rock. But if you pull over and walk up and down the highway, you will soon see that the rocks are no longer flat-lying. They have come to be contorted into quite a few folds. The strata fold up and down into structures we sometimes call anticlines and synclines. Our photo shows some of the most extreme folding that we have found there.

Pause and think about what has happened here. Rock is sturdy, brittle stuff, not easily deformed. If you want to, you can slam it with a hammer and break it up, but bend it? That’s a different matter. Geologists have come to understand that such rocks were once buried under incredible thicknesses of strata, long since eroded away. The folded strata that you are looking at were once maybe 15,000 feet beneath the surface. At that depth there is an enormous amount of pressure, plenty to cause brittle rock to fold. It gets worse. At that depth the temperatures are very high, hundreds of degrees at least. In that kind of heat and pressure the rock becomes pliant so it’s no surprise that rock will fold quickly and easily.

And the rocks had a lot of “motivation” as well. During the Devonian time period this area was buckling under the influences of the great Acadian mountain building event. All of what is now western New England and part of eastern New York State were involved in this regional uplift. It was part of the process that created the Appalachian chain.

But let’s return to our main point. As you pass down Rte. 23 through this highway canyon of limestone, you are in reality traveling thousands of feet beneath the surface through the core of a very large mountain range. Not quite a journey to the center of the Earth, but not bad.

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

Some Leeds on Where to Find Fossils

On the Rocks The Woodstock Times

Updated by Robert and Johanna Titus

The old stone bridge at Leeds must have been something of a marvel when it was completed in 1792. It really is something to look at, a grand old three-span stone bridge. We imagine it must have attracted many visitors during its first century. Mind you, even in 1792 it was nothing new, the Romans were building better bridges thousands of years ago, but in 18th Century upstate New York it must have been one of the biggest and best around. Once there were a number of similar stone-arch bridges; We have seen several of them up in the Mohawk Valley region. Mostly they were a lot smaller and few of them still operate. This one is big; it must have been planned for a long future. It was rebuilt in the 1930’s and easily accommodates modern traffic. It’s very wide and it’s not only used but still very busy.

The bridge has been the subject of a lot of post cards and, in fact, that’s where we first became aware of it. Recently we decided to go find it and take a look; it was certainly worth the effort. we didn’t have any trouble finding it; it’s on Rte. 23B right at the western access to the Leeds business district. We parked just beyond the bridge and slowly walked across it. We weren’t too surprised at what we found. In fact, we very much anticipated it.

The men who built these bridges very often took a great deal of pride in their work. They didn’t just want to build bridges, they wanted to create works of art. That is certainly reflected in the beautiful curves of the arches, but it is also reflected in the stone itself. If you go there, take a good look; it is made of limestone, which was a good choice for its density and durability. But it’s more; the stone is rich in fossils.

We had little difficulty recognizing the rock unit; it is the Helderberg Limestone, which is common all up and down the Hudson Valley. We have talked about the Helderberg before; it’s from the early Devonian time period, dating back a little more than 400 million years. It’s a sedimentary rock, first formed as deposits of white or pink sand, not silica sand as we have in the north, but a softer calcium carbonate sand as in Florida. It accumulated in a clear, shallow, aqua, tropical sea. There are many units within the Helderberg and two of them are represented here, they are called the Coeymans and the Becraft Limestones.

The Coeymans makes up most of the bridge’s stone. It’s a thick-bedded limestone which probably means that it was deposited by very agitated water, perhaps wave or current swept. Many animals lived in this rugged but hospitable ecology. They were well-adapted to the rough water in that they had thick, heavy shells, good sturdy protection from being batted about. The most common forms are called brachiopods. These were bivalved shellfish, similar in many ways to clams, but of an entirely different group of animals. Most of the other fossils were crinoids, called sea lilies by their common name. We have written about them several times before, they are colorful and beautiful stemmed animals, each with five delicate lacy arms. Beyond that we found a number of other forms, including trilobites, corals, bryozoans and others.

The second unit, the Becraft Limestone, has a fair amount of the mineral hematite in it, and that gives the unit a distinctive red hue. It was also very fossiliferous and the most abundant forms here were remarkably large crinoids. It’s red hue and abundant fossils made this a popular stone, not just for bridges, but, more often, for 19th Century “marble” table tops.

As we said, we saw the handiwork of an able craftsman at work here. This would not just be a functional bridge, but a pleasing and interesting bridge. We have seen a lot of Helderberg Limestone and, while it is a very fossiliferous unit of rock, it is rarely as nice as this. Our bridge maker spent a lot of time looking for and selecting the best slabs. Look, especially, at the capstone that makes up the sidewalk walls east of the bridge and on the bridge itself.

As geologists, we are used to reading and hearing messages from the rocks. Usually, they are sent across hundreds of millions of years and the messages come from ancient ecologies and their long-dead plants and animals. This is one of the few times we have gotten a message from a man of the past. we wonder who he was.

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

Muddying the Record

On the Rocks – The Woodstock Times Dec. 31, 1998

Updated by Robert and Johanna Titus

We scientists see hurricanes as lifeless, soul-less entities, and we are right. But there are other viewpoints. Some Animist religions might see them as having souls, the souls of evil spirits of course. In a primitive culture, living on the edge of nature, that can be easy to believe because hurricanes can behave as mean spirits. Few were ever worse than this autumn’s Hurricane Mitch which brought not just catastrophe to central America, but a form of slow, seemingly premeditated catastrophe befitting an evil spirit.

Mitch approached the Coast of Honduras and stalled offshore for three days. That allowed time for the waves and tides to build up on the coasts of that poor nation. It was like a military invasion. After softening up the coasts, Mitch assaulted. For five agonizingly long days the storm meandered across central America, first Honduras, then Guatemala and finally southern Mexico. That ugly hurricane was in no hurry, in fact it was incredibly slow. During its journey, about 50 inches of rain came down, more rain in five days than we get in a year and a half. With its heavy rains and strong winds, this storm’s “mean spirit” was that of a predator, catlike in its killing. Like a cat it slowly, methodically, almost lovingly obliterated some of the poorest communities of the region.

In the highlands Hurricane Mitch’s waters were extremely erosive, scouring out canyons and washing away villages and bridges. Great masses of mud quickly glutted local stream channels. Downstream those many gluts of mud coalesced and advanced as enormous terrifying and killing mudflows. The cold, wet masses rushed down canyons at the speed of an automobile.

No area was worse than the slopes of the Casitas Volcano in Nicaragua. This long extinct Volcano, with its rich soils, had supported agricultural communities for ages. Many villages dotted its slopes, especially along the small stream that flowed south from the summit. At the volcano’s peak there was a large crater. With the heavy rains, the crater filled up and eventually overflowed as a flood. The flood waters rushed down the small canyon and picked up great masses of mud. Soon there was muddy water, then there was watery mud.

From the air, pilots reported that the Casitas mudflow looked like a brown lava flow. It flowed down the canyon and was soon 1500 feet across and eventually ten or more miles long. It flowed across two high mountain villages, one more village farther downslope, and several smaller habitations. Burial was in a matter of a minute or so. In the end about 30 square miles of Nicaragua were under thick layers of mud. In the end, also, about 2,000 people died.

Mudflows are horrible killers. They advance at speeds no one can escape. They engulf villages with little or no warning. Death in a mudflow must be an awful fate. The speeding currents of cold mud strip still-living humans of their clothing and then smother them. Some bodies are contemptuously spit back naked to the surface; most are left buried forever. There is talk of marking the Casitas location as a national cemetery.

These awful events are not confined to far-away places, they have happened here, but only in the very distant past. High in the Catskills you can climb and see what is left. Travel to the Central Escarpment of the Catskills and hike the slopes of Indian Head, Twin, or Sugarloaf Mountains. Below 2,800 feet in elevation, the strata are a mix of red shales and brown sandstones. These are old fossil floodplain soils and river channel deposits. Above 2,800 feet the strata are different. There the strata are thick masses of coarse gray sandstone. Within the sands are many bits of gravel. Not all, but many of these thick strata are old mudflow deposits. Those flows descended the slopes of the old Acadian Mountains of nearly 400 million years ago. The old muds have hardened into fine ledges of rock with magnificent vistas of the wild central Catskills landscape. It is ironic that such awful events of the past should give us such beautiful views today.

We geologists are not Animists, we know that our rocks do not have spirits, but if we are wrong and they do, then there are many evil spirits up there in the higher Catskills.

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

Stony Clove

On the Rocks. The Woodstock Time

Updated by Robert and Johanna Titus

It can often be difficult to teach a science, even one as interesting as geology. Many people are averse to the sciences. One problem is that a lot of people really would rather not know the technical details behind some remarkable phenomenon. They believe it 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 to the ice Age.

When you get a chance, travel to Stony Clove. As you approach the top of the clove, there is a lake to your left. Beyond is the narrow gap in the mountain. Drive to the crest of the hill and stop; 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. 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 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 foaming white water racing down the valley. The strength of the flow is manifest in the cracking sound of tumbling, colliding cobbles. Competing currents of water criss cross around boulders and collide with each other sending white fountains into the air. The hissing spray catches the sunlight and forms rainbows.

Many of the powerful currents abut the stream bank. Where this occurs, muddy gravels collapse into the flow and the sediment is rushed away. Beneath the white surface the water is brown with erosion. It’s this erosion 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.

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

The Uplift of the Catskills?

The Catskill Geologists

Robert and Johanna Titus

Late at night in geology bars we get into all sorts of tussles with people over various geological subjects. Recently we were debating the issue of whether or not the Catskill Mountains had ever suffered from the tectonic effects of folding and uplift. Most mountain ranges have endured both and often to a very great extent. So too have our Catskills but these events have been far more subtle and to properly understand them, they need some careful explanation.

Let’s do folding first; that’s the easy part. There is folding in the Catskills but only in its easternmost areas. All Catskills stratified rocks within the Hudson Valley were folded during the Acadian Mountain building event, a little less than 400 million years ago. We think that the Catskill Mountain House ledge has a gentle westward slope to it which brings it down to the shores of South Lake .Beyond that, there is a gentle southwest tilting of the strata throughout much of the rest of our mountains. It’s virtually impossible to see. None of this deformation is all that impressive, especially compared to the Rocky Mountains but it did occur, and it occurred during an important mountain building event.

The uplifting is far more difficult to explain. We are going to have to summon up our clearest writing skills and you are going have to be very perceptive readers. Ready? It all began as the Acadian mountains were rising above today’s western New England. Visit the Mountain House site; look east and you can easily imagine this mountainous uplift on the eastern horizon. Those rising mountains weathered and then eroded. Vast quantities of sediment, most of it being sand, poured onto our Catskills region. Over millions of years, the weight of that sediment pressed down into the crust, causing it to be depressed thousands of feet into the depths. Great thicknesses of sediment that had been deposited at the sea level elevation of a delta, came to lie thousands of feet beneath the earth’s surface.

As long as the Acadian Mountains were rising this process continued and even got worse. Thicker and thicker sedimentary sequences were pressed deeper and deeper into the Earth’s crust. All of it hardened into rock, mostly sandstone. But eventually the mountain building ended in New England. And with this the Catskills stopped being a depositional vicinity and, with more time, became erosional. Over the course of tens of millions of years Catskill sandstones eroded away. This triggered what geologists call a rebound. As erosion stripped rock away, the loss of all that weight resulted in an uplift or rebound from below. Stratified rock, that had long been deeply buried literally rose toward the surface and, in its turn, came to be eroded away. Last week we described the Mountain House Hotel ledge as having been a river channel deposit that had formed at sea level. Now it lies at an elevation of about 2,200 feet. It is a typical example of what we are talking of today. Stand there sometime and look down. These rocks had once been thousands of feet lower and now they are slowly rebounding.

In the end, our main points are that the Catskill mountains were deformed by folding, just not a lot of it. And those same rocks have, indeed been uplifted, just not in the same manner as is seen on other mountains.

Time for another pitcher of beer and another topic to “discuss.”

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

The Mountain House Ledge

The Catskill Geologists

Robert and Johanna Titus

We always like to say that there is a spiritual heart to the Catskill Mountains and that heart is a field called Pine Orchard, lying atop the Catskill Front near North-South Lake Campground. There is a fine ledge of sandstone there and it offers a 75-mile sweeping view of the Hudson Valley. Not surprisingly it became the site of a hotel and that was the famous Catskill Mountain House, first opened in 1824. We frequently find ourselves visiting and we like to sit upon that ledge and gaze into the valley below. Behind us is the image of the old hotel, crowded with its many guests. Back in the 19^th Century anyone who was anyone stayed in the hotel. Three presidents visited along the most prominent businessmen, industrialists, artists, writers and so many other celebrities of those times. Now the hotel is gone, but its presence can still be felt here; it was an important place; it still is.

We put our hands upon that sandstone bedrock; it is important too. Human history fills the empty space above the ground but everything below the surface is geological history, and that’s all ours. We can touch it and we can see it. There are miles of sedimentary rock beneath the surface right here and that is a lot of history. That sandstone ledge, for example, is a petrified river deposit. Those sandstones were once sands and they filled a sizable river channel, flowing from out of New England and into the west.

That river flowed across something called the Catskill Delta. It’s an ancient bit of history, well-known and perhaps even well-loved by geologists, and it conjures up quite a story. We look east and see the profile of a rising mountain range out there. Those are the Acadian Mountains and we are looking about 380 million years into the past. Those mountains are in their prime and are very actively rising. They are also actively weathering. Chemical processes are destroying the bedrock of those mountains, turning it into sediment, mostly sand, which is traveling down mountain streams. Where those streams are entering the Catskill Sea, which lies west of the mountains, they are depositing the Catskill Delta.

And, at the Mountain House site, we are sitting in the middle of just one of those streams. It’s not unusual for hundreds of them to make up a large delta complex. But suddenly we realize something important about this river: in its day, it must have been lying exactly at sea level. Such deltas always form at sea level. We, again, gaze into the valley below. The Hudson River flows at today’s sea level and that lies about 2,200 feet below us. Suddenly we have an “aha” moment. This ancient river had once flowed by at a level 2,200 feet lower than where it is today. It has been uplifted all that much. There has to be a story here, a story of tectonic uplift. Let’s continue with this next week.

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

The Abyss at Olana

Robert and Johanna Titus

The great tourist attraction in the middle Hudson Valley is Olana. We went there and stood on the bank in front of the south-facing porch of the old mansion and gazed at its fine view of the Hudson Valley and Catskill Mountain. This is one of the great vantage points from which to see the Catskills. There are days when the atmospheric conditions are just right, and the mountains seem to reach out to you. It’s not just a view; this is also a genuine work of art. Frederic Church intended the porch should have this vista; it is, among many others, one of his “planned views.” For thirty year he was able to enjoy the scene and we envy him that.

But as geologists, we are privileged to see some other views at Olana. On that wonderful site our minds drifted back into deep time. We were at the bottom of the oceanic abyss that was once here. The waters were cold and black, but more than anything else they were still and silent. This was a dead seafloor. Nothing crawled across the mud and nothing swam in the waters. We scooped up some of the mud; it was soft and sticky. It was foul with the remains of dead microbes that constantly rained in from above.

With time the avalanches came. The stillness was abruptly interrupted as the seafloor was jolted by seismic shocks. Shortly thereafter great masses of sediment began tumbling down the slopes. For long minutes there was the rush of dirty water. The torrent boiled as murky clouds billowed upwards all around us. Then the current slowed and gradually the water cleared. The Olana seafloor returned to it silent dead, stillness.

Our mind’s eyes rose through tens of thousand of feet of quiet water until they reached the surface of the sea. We gazed eastward and saw dense black clouds rising above the horizon. The blackness drifted my way and soon it rained volcanic dust into the water all around. Then we looked back eastward again and now a rising landmass had replaced the black clouds on the horizon. The stark profile of volcanic mountains defined this new horizon

The passage of time accelerated. As we watched, this landmass grew taller and its shores swelled out toward us. We were soon lifted out of the sea by the rising gray crust. Occasional, the earth beneath us shook with powerful quakes as the land rose higher and higher. Eventually, we found our imaginary selves high atop a still rising Taconic Mountain range. To the north and south, volcanoes erupted in violent spasms. Below, to the west, what was left of that deep sea retreated away from the rising mountains.

There should have been a great deal of green in this image but there was none. This was a fine range of mountains, but it was a dead landscape that had replaced a dead seafloor. We were in the Late Ordovician time period, and life, especially plants, had not yet managed to colonize the lands. All around us was a bleak, blue-gray landscape. There were not even proper soils, just a litter of gray gravel lying upon bare rocks. Only the dry channels of gullies and ravines broke the monotony of the desolation.

We realized that we had come to the very spot where, 450 million year later, Frederic Church would stand. But we were not seeing what he would see. No, below us and stretching off to the west, a large river delta had formed adjacent to the rising Taconic Mountains. A complex of murky streams crossed the dark gray of that delta. Farther away we could see the retreating waters of the sea. It was bleak and lifeless vista, but there was grandeur in this, Olana’s great unplanned. view.

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