Feeling out of place at North Lake

Windows Through time, The Register Star – May 20, 2010

Updated by Robert and Johanna Titus

We are all very fortunate to have a place such as the North-South State Campground in our region. It has been a very popular draw for visitors since the early 19^th Century and for good reason. It must be one of the most picturesque landscapes east of the Mississippi. The park sits atop the Catskill Front, overlooking a 70 mile stretch of the Hudson Valley with many breathtaking views.

There is a lot of geology to be seen in the park, so you have to make up your minds on what to do. You will want to walk around North Lake at, we hope, a leisurely pace. The walk will start at the Mountain House site parking lot and head north until you circle around most of North Lake and then return.

So, what is the geological “bait?” Well, mostly it is the Ice Age history of North Lake that you will want to explore. Both North and South Lake basins were scoured out by the glaciers, probably at the very peak of the Ice Age. Glaciers filled the Hudson Valley and then rose up and streamed into the area. You will want to walk along the eastern shore of North Lake and take a good look at the bedrock evidence of this. This rock records the passage of the ice. It’s actually been ground down and polished by the advancing glaciers. But the most striking features along the lakeshore are the striations carved into the rock. The glaciers dragged rocks along with them, and these gouged the rock. It’s a lot of fun to spot these and take note of them.  Each striation has the very same compass direction as the movement of the ice. Each is thus a history of Ice Age activity at North Lake.

But what we like even better than the striations are the Ice Age features that are called “erratics.” These are boulders, often very large, which were carried here by the moving ice. Glaciers are quite capable of lifting very large rocks and sweeping them along. We have been finding erratics here in abundance. Some of them are famous; maybe you have seen the one called Alligator Rock.  It, in fact, does look like the head of an alligator. It even has a large open “mouth.” People have been putting stone teeth in that mouth for as long as they have been coming here.

Dinosaur Rock

This great rock, and probably scores of others, dot the landscapes at North Lake. We think the largest number of them are found on the point that separates North and South Lakes. But there are many more, all around the lakes. What are they and where did they come from?  Well, the history of any erratic begins when ice was passing across its home bedrock. The ice tended to stick to that rock and, as the glacier advanced, it plucked the boulders loose and dragged them off. That’s what’s erratic about these rocks; they don’t match the local bedrock. The glaciers eventually melted and when they did, they left those erratics behind, right where we see them

today.

There’s more to the story.  Erratics are clustered in the North Lake vicinity,

suggesting they all came from the same glacier. When you get to North Lake, you

should look up to North Point and see where that glacier came from. Near the top of

North Point there is great basin, just below the peak. Geologists will recognize this as

what is called a cirque. Cirques are the basins in which Alpine glaciers had formed and

from which they began their downhill journeys. We will look up at that cirque and in our

mind’s eyes we will see an Alpine glacier. We will watch as it slowly descended the

slopes of Mary’s Glen, heading toward North Lake. We won’t be able to see them, but

that glacier was ripping up our erratic boulders and carrying them along for the ride. We

will watch long enough to see the climate warm and the ice melt. It is then that those

boulders will be left behind

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

Geologist.”

Dinosaur Rock

Memories Come Flooding Back

On the Rocks/ The Woodstock Times

July 2, 1998

Updated by Robert and Johanna Titus 

A little east of the town of Delhi we found a ledge of Devonian aged river sandstone which had been a deep channel cut into a now fossil soil horizon. This sort of thing is hardly rare in the Catskills, there are, for example, many such fossil rivers in the hills above Woodstock, but this was a very good one, however, and it made us ponder the history that such ledges represent: There was a story here.

March 14th, the year 387,469,184 BC, late afternoon.– All day long, very moist air has been rising up the slopes of the Acadian Mountains to the east, and now dark banks of storm clouds tower above the tall mountain peaks. Soon three closely spaced lines of thunderstorms unload, in quick succession, upon the mountains. The rain of the first line of storms quickly waterlogged the soils and the subsequent torrents have raced off downhill in deep, fast-flowing, erosive streams. Deep gullies have been rapidly cut into the soft, blue-black earths of the upper mountain slopes. A thick ooze of dirty water (in fact, almost watery dirt) has funneled into gullies too numerous to count. Down slope, those gullies combine into several powerful cascading streams; deep channels are being widened rapidly. More dark earth is engulfed by the expanding flow, and whole slopes slide into the torrent. The rush of the confined water is being pushed and hurried along by the great torrents backed up behind.

From various compass points, similar flows combine to a point well down on the face of the Acadians. Here, today’s cascade, and many earlier ones like it, have combined to carve a great, vee-shaped cleft in the mountain range. This gap dwarfs the canyons above it. Through this cleft, on this day, flow several large Niagaras; this is a catastrophic event, a thousand year flood.

Below the narrows, the Acadian slopes level out. Vast piles of coarse sand and gravel have formed an enormous, rounded apron of sediment, draped against the slopes of the range. As it flows across this slope, the water breaks up into a number of smaller streams, which continue several miles down the gentle slope until the streams enter a broad plain, a flat morass of flooded bayous, marshes and ponds.

The morass we speak of makes up the great Catskill Delta. Now, its various glutted and disorganized channels reflect the brunt of the flood; their powerful flows cut into adjacent flood plains and carve new channels. Their banks give way and, along with whole stands of trees, collapse into the flow. The channels are soon clogged and dammed with mud and broken trees. The dammed, blue-black waters rise up and flood out across the delta plain.

Flash floods like this are violent but they don’t last long. At the bottom of the now-submerged stream channels, the flood currents eventually slow down and the sediments begin to be deposited as dark horizons of muddy sand. Many plants and animals are being buried within these sands.

As the evening advances, the main flow continues down the channels of the delta. Downstream, the flow is still rapid, but it is beginning to ebb. At the mouths of the rivers, the flood waters, dark with sand and silt, are being disgorged into the western Catskill Sea. From above, large plumes of dirty water can be seen slowly expanding out into the sea. Many tree trunks and a flotsam of broken foliage drift seaward, half hidden in the darkening skies.

By midnight the storms have long been over. The sky is clear and the stars shine, competing with a wine-colored moon. The upper slopes of the Acadian Mountains are now dark, silent silhouettes. Downstream, the churning flows of the day are still rapid and gurgling with noise, but the normal languid flow of the delta will soon return. The rivers are still dirty, but they are clearing. Offshore the plumes of sediment are settling into thick strata of sticky sand. A large number of shellfish are dying in that burial. Their shells will lie, buried as fossils, for 400 million years.

It has been a very hard day for the biota of the Catskill Delta. But nobody cares. The world of the Devonian is a soul-less one; there is no mourning, no grief, no pity or even self pity. Indeed, there is no real understanding of exactly what happened today, and by midnight, there are few living creatures who can even remember these terrible events.

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

LAKE ALBANY

On the Rocks, updated by Robert and Johanna Titus

The Woodstock Times. 1998

Geology blossomed in the last half of the 19th century. The science matured, developed its fundamental methodologies, its practitioners fanned out across the globe and wondrous discoveries came to light. Our views of world history would never be the same as we came to recognize the record of epic events carved into the landscapes and etched into their rocks. Fortunately, you do not have to go off to some exotic and distant land to appreciate this. Right here will do just fine. Plenty of great discoveries have been made here. One of them concerns the very nature of the Hudson Valley.

Much of the floor of the Hudson Valley is flat. Now that’s not much of a surprise as the floors of most great river valleys are flat. Rivers eroded these surfaces which are called floodplains. But the flatlands of the Hudson Valley floor are different. Around here the Hudson flows at an elevation of about sea level, but the river valley’s well developed flat level is much higher: About 160 feet in elevation. It cannot be a floodplain, but if not, then just what could it be?

The answer to that question came as quite a surprise to geologists back at the end of the last century. In exploring these odd flat landscapes, geologists eventually encountered pits dug into them and, remarkably, they found lake deposits. There is no mistaking the sediments of a lake. The strata are very fine grained and thinly laminated. The surprise grew even greater as geologists realized how extensive these lake deposits were. They can be found up and down almost the entire length of the Hudson Valley. This was a big lake. Of course, it had to have a name, it was soon dubbed Lake Albany.

The history of Lake Albany goes back to the end of the last ice age. As the Hudson Valley glacier was melting and retreating up the valley it provided a great deal of meltwater, more than enough to supply a large lake. But more than just water was needed; a large lake needs a large basin. The Hudson Valley glacier was so heavy that it actually depressed the crust beneath it and not just a little. Here in the Woodstock area the crust was depressed about 220 feet. That made an equal amount of volume available for the lake; it was 220 feet deep around here.

Deposition of sediment on the floor of Lake Albany was rapid, and a lot of clays accumulated. These can still be seen as the old lake floor which is that flat level of landscape we talked about above; it’s at the 160 foot elevation.

If you would like to see the floor of Lake Albany, there are many good vantage points. Take Churchland Rd. north from the Glasco Turnpike; the intersection is just west of the New York State Thruway. The road follows the shoreline of the old lake and, about three miles north of the intersection you can look to the right and see a good view of the flat old lake bottom stretching out below.

Now we need your help here. Please appreciate our problem. As writers, we are trying to write about flat landscape and make it sound interesting. Such landscapes usually aren’t. Iowa has lots of flat, but nobody has ever found that interesting. But flat here in the Hudson is different, it’s the flat of an ancient lakebed and we think that that is interesting, but we need you, the reader, to help me on this.

Go and take a good look at the view from Churchland Road. Then take a right at Churchland Lane and descend out onto the old lake bottom. Try to imagine about 60 feet of lake water above you. See the sunlight playing upon the passing waves. Watch as small blocks of ice drift by. With a little imagination you should be able to turn that kind of flat into quite an experience . . . we hope.

This really is fundamental to appreciating much of our region’s area geological history. This isn’t Iowa; flat is just not normal around here. When you are looking at flat land, here in the Hudson Valley as well as throughout the Catskill region, it almost always indicates the floor of an old glacial lake. Try to develop an eye for flat landscape. When you do see it try to imagine the lakes that likely were once present and see if that doesn’t change your concept of our landscape. Flat can be interesting, but you just have to understand it.

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

Eroding Values

On the Rocks, The Woodstock Times 1998

Updated by Robert and Johanna Titus

As historical geologists, we do not have to face very many serious ecological issues. None of the fossil species we deal with are endangered; none of the environments we study are threatened. They all disappeared about 400 million years. As writers about modern geology, things are a bit different. It’s only natural for a geologist to take a very long-term view of things, and so it has been that, in traveling about in the Catskills, we do sometimes come across some developing problems. And, surprisingly, that includes the Catskill Park, the forever wild preserve that the state began to put aside more than a hundred years ago.

Not surprisingly, the forest preserve attracts people who, for the most part, have a real sense of the value of this land. Few would deliberately do harm to this landscape. The trouble is that there are so very many of us. The most serious example is at Kaaterskill Falls. The site is blessed with a wonderful scenery and cursed by the thousands of visitors who come every year to see it. The best approach to the falls is to take the yellow trail up from Bastion Falls below. Nobody intends to do harm, and nobody does much harm, but the traffic is so heavy that the wear and tear on the Bastion Falls trail has really been showing for quite a while now and it’s getting much worse. The path is just plain beat up.

It may be worse from above. Many people choose to descend into the clove from the top of the falls. This takes them down a very steep, and erosion prone, slope. People tend to slip and slide as they struggle down the steep clay surface. The damage has been very bad there. Again, it’s not anybody’s fault, it’s a collective and cumulative effect.

There’s a conflict of values here. The land is owned by the people and open to the public. The New York State Constitution guarantees that all of us can walk anywhere we want to in the forest preserve. Nobody has the right to tell you or me where we can or can’t go. Such restrictions could never be enforced anyway. But, in exercising our rights, we harm the very land that we have chosen to save. But, in fact, throughout almost all of the preserve the damage has been minimal, and human nature being what it is, almost none of us take responsibility for the very little bit of damage that each of us does.

Few of us can see into the long-term future and appreciate the damage that is underway. but a geologist can, and there are areas where the damage has gotten so bad that something must be done. Inevitably, other locations will share the same fate. It’s best we develop strategies now so we can deal with these problems as they become manifest.

Which gets us back to Kaaterskill Falls which is certainly the place to start. The State has put up signs asking people to be careful, but that is unlikely to be of much help. After all, it’s not me who is the problem, it’s all of those other people. An obvious approach is to build a wooden staircase. Back in the hotel days there was one here and tourists had an easy time of it visiting the falls. But this is a nature preserve and, in theory, we are not supposed to be building unnatural things here.

That’s the kind of problem all preserves eventually must face. We have to choose, and we are afraid the choice is forced upon us. We can’t have a perfect preserve and allow everyone to enjoy it at the same time without a few compromises. We do hope that the day will soon come when a staircase at Kaaterskill Falls will allow people to visit the site while minimizing the damage. There is some precedent. There is a fine wooden staircase at Mine Kill Falls and it’s a nice looking one. That site is not suffering the kind of damage we lament at Kaaterskill Falls.

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

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.”