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“Hurricane Dorian” hits the Catskills?

The Catskill Geologists; The Mountain Eagle; Oct 4, 20

Robert and Johanna Titus                                                                         

Like so many others, the two of us watched with awe, horror and fascination as Hurricane Dorian passed across the Bahamas (2019). We have spent time in the Bahamas, and we know what a low-lying landscape it is. There is so little to stand in the way of such storms. So, as geologists, we know exactly how devastating a powerful hurricane can be in a place like that. Winds of 120 miles per hour swept across lightweight homes, broke them into pieces and swept them away in large numbers. We expected to see that; we feared seeing that and we did see that.

The power of this storm was so great that you might guess that it could leave an imprint in the fossil record, and we are guessing that it did just that. Will Bahamian geologists of the very distant future find a record of Dorian? We think they will. But what about our Catskills geological past: does it present us with evidence of such storms? That’s something the two of us are always on the lookout for, and we would like to tell you about one example that we have found.

Let’s take you down to Rte. 9W in the Town of Glasco.  That’s a little north of Kingston. There you will find a very nice road outcropping which displays something called the Glasco Limestone. The rocks there are stratified. Like almost all limestones, these strata represent the floor of an ancient and shallow tropical sea, much like the Bahamas of today. Each stratum represents a moment in geological time. Some are thicker than others; the thick ones sometimes record more exciting moments.

We found one that was very exciting indeed. Take a look at our photo. It shows a five-inch-thick stratum of the Glasco Limestone which is packed with coarse sediment and fossil shells. Notice how there are so many fossils down at the bottom of the stratum; they are relatively big ones too. Notice too, that as you look upwards, the fossils become fewer and smaller. That tells the story.

Back during the early Devonian time period, about 400 million years ago, this was the bottom of the shallow, tropical Glasco sea. It was approached by and overwhelmed by a powerful storm, perhaps a hurricane. In the space of hours, the currents picked up great masses of shells and sediment, and then carried them in the direction the storm was moving. Imagine a mass of watery sediment actually moving across the shallow sea floor. All storms end, and as this one passed, its currents slowed down. Coarse sediments and large shells dropped out of the flow first. They formed the bottom of our stratum. The storm continued to slow down and finer grained sediments with smaller shells settled out of the flow. When the storm was finally gone, it left behind the stratum that we found, coarse grained at the bottom, fine grained above. With time it hardened into what might be fairly called a petrified storm deposit. Geologists sometimes call them tempestites.

This was a truly devastating event, and many shellfish and seaweeds died because of it. But there were no creatures who understood what happened on that day and certainly none who would go on to even remember it. There never was any record or memory of this storm until hundreds of millions of years passed, when unusually bright primates came along and took a good look at these rocks.

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

“Twenty-one trees”

The Catskill Geologists

Robert and Johanna Titus

We belong to and are active with a large number of local civic groups. Such memberships are rewarding things to do, and they involve us directly with our community in very special ways. We work actively with the Mountaintop Historical Society, the Green County Historical Society, Cedar Grove — the Thomas Cole National Historical Site, Olana, the Woodstock Land Conservancy, WIOX FM and numerous others. Each serves the needs of the broader community (mostly) on a volunteer basis, that’s something that makes the Catskills and the Hudson Valley great places to live. As active scientists, we bring something special to each of these groups; we plug them into their natural histories. It’s a privilege and even an honor to do so. These are interesting and fun endeavors. We urge you to join some of these groups yourself.

Let’s talk about one of the projects that we have been working on recently. That involves the Mountain Top Arboretum, the only public garden/arboretum in all of the Catskills Park. It’s been around since 1977 and has been dedicated to displaying and managing a forest ecology native to our portion of the Northeast. During this time the Arboretum grounds have grown from 7 to 178 acres of forest and meadow. As any arboretum does, it maintains a host of tree species, most of them are native but some are special exotics. We will describe some of these special ones in future columns.

Recently the Arboretum has built and opened a new Education Center. In association with that event, they have sponsored a general survey of the natural history of the Arboretum grounds. They enlisted a number of specialists to study the Arboretum landscapes’ forest history, animals, birds, insects, geology and much more. They approached us to do the geological part and we gladly agreed. It involved a fair amount of work and attendance at a number of planning sessions, but it was all for a good cause. One of the results was a voluminous natural resource inventory which came out last April. Currently, that isn’t for sale to the general public.

But, more recently, a second volume was issued and that is the one we would like to highlight today. It’s entitled “TWENTY-ONE TREES” and it is available for you, the general reader. It’s beautiful book with many fine photographs by Rob Cardillo. The book title refers to the 21 species of native trees that provided the lumber for the Education Center. We wrote an early chapter where we introduce our readers to the geological history of the Arboretum as it can be seen when walking around the grounds, we take people to some of the best bedrock exposures and from there we journey into the Devonian past. We visit the Catskill Delta and some of the streams that flowed by way back then. Then we skip through about 375 million years and visit the Arboretum during the Ice Age. Again, we walk the grounds again and point out the landscape features produced by the ice.

Forest historian Dr, Michel Kudish then takes over and leads readers through the area’s forest history. Mike describes a forest that is gradually recovering from a history of 19^th Century damage done by the tanning industry and farming. Then he describes some of the Catskills oldest peat bogs, dating all the way back to the very end of the Ice Age.

The bulk of the book is devoted to well-illustrated descriptions of the mostly native species of trees found at the Arboretum. Ron Cardillo’s unforgettable year-round photography is the highlight of the book. We recommend it strongly for all of you fascinated by the natural history of our Catskills. Don’t forget, Christmas is coming up and you can only get the book at the Arboretum. It’s a good excuse for a visit. Bring the kids.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Learn more about the Mountain Top arboretum at mtarboretum.org.

An outcrop near Prattsville

The Catskill Geologists; The Mountain Eagle; Nov. 8, 2019

Robert and Johanna Titus

We are guessing that, almost every day, you drive past roadside outcroppings on your routine travels. And we are guessing that you rarely take much notice of them. They are, after all, just rocks. Well, we are in the business of noticing outcrops and sometimes they are quite interesting. We saw one recently on our way home from an event in Prattsville and it was very stimulating. You take Rte. 23 east from Prattsville and turn left where the highway heads toward Windham. Go north about ¾’s of a mile and there it is.

The upper reaches of the strata are fairly run of the mill Catskill sandstones. We didn’t find them all that interesting; it was what we saw below that caught our attention. There, we found about ten feet of poorly stratified, shaley rocks. We are just a little bit uncomfortable in using the word “shaley.” Proper shales are horizontal strata which are also thinly laminated. These were horizontal enough but gently crinkled. Most shales are also usually black or dark gray; these strata were brick red. One of us tugged on his beard; the other furrowed her brow. Both of us were puzzled.

Then it all got worse; at the very bottom of the outcrop the strata were green, not a bright green but a strong enough hue. We could not help but to take special notice of this seemingly out of place color. Green is a rare tint in Catskills strata. But, no matter, red and green it was; there had to be an explanation for these perplexing colors. There was.

Geologists, all around the world look at red strata and reflexively react by uttering the word “terrestrial.” Brick red is the typical color of terrestrial sediments, especially in tropical landscapes. We knew that all these deposits had formed on something called the Catskill Delta. And we also knew that way back then, during the Devonian time period, that delta had lain about 20 degrees south of the Equator in a definitely tropical setting. This outcrop was a partial cross section of that delta, but could we be a little more specific?

We at first wanted to call these red strata paleosols – that word means fossil soils. But we were uncomfortable with that term, fossil soils are usually a good bit more structured than these were. They often display the kinds of A, B and C horizons of typical soils. Ours didn’t, so what was it? Once again beards were tugged, and brows were furrowed. Our final answer involved just the least bit of waffling; we called all this an overbank deposit, not a soil. These fine-grained strata had been deposited as some sort of floodplain sediments and then only just a few soil forming processes began.

All this led to our final story which took us back to a time of drought on the Devonian Catskill Delta. Those floodplain deposits had dried out, exposing them to a lot of oxygen. That oxygen combined with iron to form an iron oxide mineral called hematite which is brick red. That colored the future rocks. But, even during a bad drought, there would still be some water deep in these soils. The water table had been about eight feet deep and down there, without much oxygen, the soils turned green.

So, we have what scientists call a hypothesis to explain what we see along the road. A hypothesis makes sense and is consistent with the evidence. But we are not absolutely sure that we are right and that is why we can’t yet call it a scientific theory. Hypothesis or theory: there is a difference. We don’t know which but still, it is a nice story.

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

A glacier at Pratt Rock

The Catskill Geologists

Robert and Johanna Titus

We were happy to read in the Mountain Eagle of plans for the upcoming restoration of Pratt’s Rock. It’s quite an unusual location; it’s been there a long time and does need an upgrade. We look forward to seeing what will happen, and we hope, when things are done, there will be some appreciation for the geological heritage of this fascinating rock.

Had all gone to plan then Zadock Pratt would have had quite the Mausoleum up there, but that did not happen. Nevertheless, Pratt does have an impressive monument. Probably most all of you have visited it. Many of you have climbed up and seen closeup the carvings that are there. There is still a chamber where Pratt planned to be buried. Then there is the poignant image of Pratt’s son George who died at the Civil War’s Second Battle of Bull Run.

None of this would have or could have been if there had not been such a steep slope there to begin within. Take a look at our first illustration; it shows a topographic map of Pratt’s Rock. Can you “read” contour lines? Then you will recognize the steep Pratt Rock slope from the closely spaced contours. It’s nearly a cliff and it faces the valley of Schoharie Creek which flows through Prattsville. Ledges of Catskill sandstone tower above the valley. A ledge is just a ledge, isn’t it? Well, not where we come from; we are geologists, and we know there is a deeper story here

We hike up to the carvings and then continue onwards to a ledge that offers a fine view of the valley. See our second illustration, a photo of that ledge. Notice the smooth surface and the sharp drop-off of the ledge; there is a cliff there. Less obvious, but quite important, are the scratches on that surface. There is a lot of ice age history here. We look and we see what is called the Schoharie Creek glacier passing by. It has flowed south, swelled up to fill the valley and passed across this sandstone. The ice carried a lot of sand with it, mostly concentrated at its dirty bottom. That sand acted as sandpaper and produced the flat surface. There was more, the glacier carried cobbles and boulders along with the sand. They were dragged across this surface and that produced those scratches which geologists call striations. Knowing this, now you can see that they parallel the glacier’s movement down the valley.

What about that cliff? That’s all part of the same story. Glaciers can be sticky. A glacier, when it passes across a mass of rock such as this, forms a tight bond with it. The glacier continues its journey south, it exerts a tug upon that rock. It is quite possible that the tug will break loose a mass of rock and yank it loose. That’s what happened here. There is nothing unusual about this; we geologists see such things frequently. It has a name; we call it glacial plucking. We stand at the top of this cliff, look down the valley and know that somewhere down there is all that missing rock, buried in the floodplain.

Well, the story we have just related, goes a long way to explain how it was that Pratt’s Rock came to be. It started out as an ice age feature. But there is a lot more to this story. Let’s continue next week.

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

Geology of a plowed field?

The Catskill Geologists; The Mountain Eagle – Oct 25, 2019

Robert and Johanna Titus

We are not farmers, so we don’t know why farmers plow their fields at this time of the year. But, as geologists, we do know what to look for when they do. In fact, it is not unusual for us to slow down and take a good look at a newly plowed field; Whatever are we looking for? Well, not surprisingly, we are exercising our trained eyes. And today, we would like to help you do the same.

Recently we were driving south, down Rte. 9G toward Hyde Park, when we saw the freshly plowed field in our first photo. Take a look; what do you see? Or, rather, what do you not see? We always like to say “the hardest thing to see in science is that which is not there. Take another look at our photo: what is not there? You are probably going to kick yourself when you miss this.

The answer is that there are no rocks lying on the ground. Isn’t that just a little strange? What happened the last time you did some digging? You probably hit “two rocks for every dirt,” right? So, what happened to those two rocks? Actually, they were never there. It turns out we had been driving along an old glacial lake. Lake deposits are almost all silt and clay. There are no rocks. That glacial lake has a name; it was Glacial Lake Albany and, back at the end of the Ice Age, it flooded much of the Hudson Valley, including our location along Rte. 9G. Its waters are long gone; they drained away. But the old silts and clays are all still there. One way to identify them is to wait for plowing and watch for that absence of cobbles. We like to pull over, get out and, in our mind’s eyes, gaze at the lake that we and perhaps only we, can envision.

Let’s take you to another location along the highway, Rte. 9, just south of Rhinebeck. Now your newly trained eyes probably won’t have much trouble in seeing what is there: rocks, and lots of them. What happened here? Why is this so different? This is another wide flat landscape, and you might be tempted to interpret it as another old lake bottom. But, don’t forget all those silts and clays of lake bottoms. This flat surface is quite likely a floodplain. Flood plains often are stony like this one. Floodplain deposits are generally deposited by flowing river waters. There are a lot more floodplains on his planet than glacial lakes so there is no surprise here.

So, why are we talking about sediments east of the Hudson; that’s pretty far away. Well. don’t forget we are here to train your eyes. We would like it very much if you began paying attention to flat landscapes, especially when they are plowed fields. There will be a lot of them come next spring, and that likely includes places around where you live.

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

A Family Fun Fest at Cathedral Gorge

The Catskills Geologists; The Mountain Eagle; Oct. 2019.

Robert and Johanna Titus

Our grandchildren are getting older now and they live so far away. We don’t do as many things with them as in the past. It’s been a pleasure to watch them grow up, but we do miss past activities. One of those was going to the Fall Family Fun Fest at the Ashokan Center in the town of Olivebridge, adjacent to the Ashokan Reservoir. The Center is an outdoor education organization run by famed musicians Jay Unger and Molly Mason. You might remember them for the music they composed and played for several of Ken Burns’ programs on PBS. The Center has a 385-acre campus and schedules frequent residential and day programs about the natural sciences along with equally frequent music and dance camps, concerts and art exhibitions. We sometimes find ourselves down there even without grandchildren.

This year’s (2019) Fun Fest will be on Sunday, Oct. 20. Family fun is just exactly that: There will be food, crafts, apple cider making, pumpkin painting, face painting and of course music by Jay and Molly and friends. There will also be nature hikes and that is where the geology comes in. We have known Jay and Molly for years and they, long ago, encouraged us to explore Cathedral Gorge, the scenic centerpiece of the Ashokan Center. Cathedral Gorge is just as scenic as its name implies. It witnesses the flow of the Esopus Creek through a rock walled canyon for quite a downstream distance. And you even have to cross an old covered bridge to get there.

We were invited to come down there last summer and lead their team of outdoor educators through the gorge. They wanted to learn its geological history so they would be able to include that when they lead groups on their own. And that will include Family Fun Fest. You can go for a guided tour down the gorge at 11:00 or at 3:00.

We don’t want to spoil anything but let’s talk just a little about what you are going to see. You won’t go far before you are likely to notice that Cathedral Gorge is called a gorge for a good reason. Esopus Creek, right there, is indeed squeezed into a steep rock walled canyon. It’s so easy to dismiss such a thing as just being a pretty landscape. But our columns have, all along, been aimed at training your geological eyes. When we look at such a landscape, we also look into its past. We know a thing or two about Esopus Creek. That creek has had its moments in time–geologic time.

Once, perhaps about 14,000 years ago, there was a great ice age lake filing most of the Schoharie Creek Valley. The lake rose up so high that it began draining through Stony Clove and down Stony Clove Creek and on into the Esopus Creek. As the glaciers were melting, that flow accelerated to become a huge torrent. Pause on your tour of Cathedral Gorge and look upstream. Imagine how much water was cascading down this canyon at just that moment. It’s quite an image. Powerful flows must have nearly filled the canyon. And it provides us with an explanation of how Cathedral Gorge got to be there. It was eroded by this flow.

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

Geology of a plowed field?

The Catskill Geologists; The Mountain Eagle – Oct. 25, 2018

Robert and Johanna Titus

We are not farmers, so we don’t know why farmers plow their fields at this time of the year. But, as geologists, we do know what to look for when they do. In fact, it is not unusual for us to slow down and take a good look at a newly plowed field; Whatever are we looking for? Well, not surprisingly, we are exercising our trained eyes. And today, we would like to help you do the same.

Recently we were driving south, down Rte. 9G toward Hyde Park, when we saw the freshly plowed field in our first photo. Take a look; what do you see? Or, rather, what do you not see? We always like to say “the hardest thing to see in science is that which is not there. Take another look at our photo: what is not there? You are probably going to kick yourself when you miss this.

The answer is that there are no rocks lying on the ground. Isn’t that just a little strange? What happened the last time you did some digging? You probably hit “two rocks for every dirt,” right? So, what happened to those two rocks? Actually, they were never there. It turns out we had been driving along an old glacial lake. Lake deposits are almost all silt and clay. There are no rocks. That glacial lake has a name; it was Glacial Lake Albany and, back at the end of the Ice Age, it flooded much of the Hudson Valley, including our location along Rte. 9G. Its waters are long gone; they drained away. But the old silts and clays are all still there. One way to identify them is to wait for plowing and watch for that absence of cobbles. We like to pull over, get out and, in our mind’s eyes, gaze at the lake that we and perhaps only we, can envision.

Let’s take you to another location along the highway, Rte. 9, just south of Rhinebeck. Now your newly trained eyes probably won’t have much trouble in seeing what is there: rocks, and lots of them. What happened here? Why is this so different? This is another wide flat landscape, and you might be tempted to interpret it as another old lake bottom. But, don’t forget all those silts and clays of lake bottoms. This flat surface is quite likely a floodplain. Flood plains often are stony like this one. Floodplain deposits are generally deposited by flowing river waters. There are a lot more floodplains on his planet than glacial lakes so there is no surprise here.

So, why are we talking about sediments east of the Hudson; that’s pretty far away. Well. don’t forget we are here to train your eyes. We would like it very much if you began paying attention to flat landscapes, especially when they are plowed fields. There will be a lot of them come next spring, and that likely includes places around where you live.

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

Ecology in the Anthropocene

Robert and Johanna Titus; The Catskill Geologists; The Mountain Eagle

Sep. 19, 2019

The frontiers of science are always exciting places to be. There can be so much creativity going on, sometimes even a frenzy of fast paced deep thinking. Our field, geology, is a very old and a very mature science so you might think that little of this occurs anymore. Maybe, maybe not.

In recent times our science has been debating something called the “Anthropocene.” That’s a, so far, hypothetical unit of time that may have only recently begun. The question is “has mankind altered the world so much that the fossil and stratigraphic record will record and recall the impact of this alteration?” Will geologists of the distant future find stratified rocks that record dramatic and worldwide changes that date back to our times? Late at night in geology bars we, today’s geologists, debate all this.

Well, the two of us think that this notion of an Anthropocene just might be legit. We think that there are two trends going on currently that will dramatically alter the future fossil record. First, there seem to be reasons to foresee a general decline in worldwide biodiversity. That’s because of, more than anything else, habitat reduction. Our human species numbers about 7 1/2 billion individuals today and that will quite possibly continue increasing until leveling off at about 11 billion by the end of this century. There were only two billion of us as late as 1930 so you can see that a dramatic population growth has been underway.

Along the way we have also been expanding into habitats where we had been, not long ago, few in numbers. Currently our accelerating expansion into the Amazon Basin is the most striking example of this. All this has led to worldwide habitat reduction which has been literally squeezing out one species after another. We have, for example, real fears for the near future fate of the Amazon Basin. The rapid reduction of elephants is also another cause for concern. We can only guess that the future fossil record will see a depletion of species diversity, recorded in the stratified rocks of our age. That would mark the beginning of the Anthropocene’s new and very different fossil record.

  Japanese knot weed

But there is something else. Our expansion throughout the world has facilitated the appearance of abundant invasive species. Where we live, in Greene County, there has been an increasing abundance of Japanese knot weed. Throughout the American South there are massive infestations of kudzu. Both are invasives that were transported from Japan with the help of human intervention. Among other things, invasives have the potential of reducing or eliminating native species. The invasive chestnut blight fungus has, for example, all but eliminated the chestnut. Our images of the Anthropocene ecologies are thus not just depleted in species but far more homogenous as well. Future geologists will likely see depleted and homogenized Anthropocene fossil records. That will help define the new time unit.

We want to make a few more points. First, none of this has anything to do with global climate change. If we could push a button and carbon dioxide emissions would come to a complete halt, that might stabilize the climate, but it would hardly stop or even slow human population growth. So too, it would not end habitat reduction. Nor would it even slow species invasions. Second, we do not recall seeing a lot of discussion of these issues. We suspect they have been overshadowed by talk of climate change. These are altogether different ecological problems. That’s troubling.

Are these changes enough to define a new epoch of geologic time? Others think the appearance of radioactive wastes is important. And how does human driven climate change fit into this scenario? Late at night in geology bars…

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

“Cabin Rock” in Windham; Robert and Johanna Titus

The Catskill Geologists; The Mountain eagle; Aug. 23, 2019

Have you been reading us in Kaatskill Life magazine? This current issue, Summer 2019, has an article by us that includes a visit to Windham. We went there while researching an article about large boulders that are called “standing stones.” Standing stones are great flat boulders that should, of course, be lying flat on their sides. They aren’t. Instead, standing stones are, as the name implies, standing upright. We were told that there was a good one in Windham, so we went to see for ourselves. And there it was, just west of the Windham Fire Department. It has a name; it’s called Cabin Rock.

But standing stones seem so unlikely; how could such things be? Well, one obvious explanation is that they were hoisted into place by people, perhaps people of a prehistoric stone culture. These things do exist, but mostly in Europe and Asia. Such standing stones are suggested to have served religious or astronomical purposes. This would make our local examples the Stonehenge stones of the Catskills and that would be pretty exciting. Who wouldn’t want this to be true?

Well, as scientists, we are always skeptical of such claims. The late astronomer Carl Sagan said it so well: “Extraordinary claims require extraordinary evidence.” It’s one thing to conjure up an ancient stone age culture but is another to back that claim up with evidence. Suppose any of these standing stones had actually been of cultural significance? That extraordinary claim should be, we think, easily supported by conventional archeology. A society that valued such stones should have left behind the flotsam and jetsam of their culture: flints, pottery shards or whatever. But, in America, such archeology is hardly, if ever, found with standing stones. These extraordinary claims are not even backed up ordinary evidences.

So, are we skeptics right? Well, not yet; there is still a real problem here. It is, after all, an equally extraordinary claim that standing stones were not lifted by people. Now, we skeptics are the ones who need extraordinary evidence. We think we have found it in the work by renowned glacial geologist John Lyon Rich. Rich did extensive research on the ice age history of the Catskills during the first half of the 20^th century. He mapped the Windham area and found something called a glacial moraine in western part of town. A moraine is an ice age feature formed when an advancing glacier bulldozes forward a heap of earth. Rich found that a valley glacier had advanced westward through Windham and ground to a halt in the western part of town.

Glaciers have no trouble shoving boulders around, even very big ones. The earth of a moraine is a jumble of sediments, so there is no reason that boulders can’t end up lying at any inclination, including vertical. We conclude that Cabin Rock is simply an ice age boulder which, by accident, was left in a vertical position. No stone age culture need be expected to have had anything to do with this.

The next time you pass through Windham, watch for this rock. And see if you can find another one on your own. But we ask you to respect the right of the landowners here. Take a good look but there is no need to trespass.

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

Some Devonian fossils

The Catskill Geologists; The Mountain Eagle; Aug 16, 2019

Robert and Johanna Titus

Have you joined our social media page yet? It’s on facebook at “The Catskill Geologist.” We post our upcoming events and publications there. But there is more; our page has over 6,000 members and many of them post things about what they are doing. It can get pretty interesting sometimes and it’s not unusual for us to be inspired to write one of our columns from one of those postings. That’s what happened this week.

One of our members, Stash Rusin, posted a photo of some Devonian marine fossils, that a friend found in the town of Morris, west of the Catskills. The rock is especially rich in fossils. Take a look at our first photo; you might think this is something remarkable, but it’s actually not. We see things like this all the time, but that’s, if anything, what makes it all the more worthy of some discussion. Let’s do just that.

First, there are a lot of fossils in this rock, but almost all of them belong to only one group. They all seem to be creatures that are called brachiopods. These invertebrate shellfish resemble clams. Like clams, brachiopods lived inside two articulating shells. But that is where resemblance ends. “Brachs” are not common today, but some do still live in modern seas. And biologists have found that their internal anatomy is entirely different from what is found in clams. They belong to entirely different forms of life. In short, brachiopods ain’t clams!

Back during the Devonian time period, and this rock is about 380 million years old, brachiopods were the most common forms of marine life. This rock is a petrifaction from one of those Devonian sea floors. But why is there such a dense jumble of brachiopods in this rock? We can never know for sure, but we can hypothesize. We have seen a lot of similar rocks in the Morris region, so we know a good bit about such sea floors. And “jumbles,” like this one, are common.

We know that this was a relatively shallow sea. From time to time it must have been wave and current swept. When that happens, the currents pick up and carry away the smaller sedimentary grains. The shells, being heavier, are left behind in increasingly dense accumulations (jumbles). Take a look at our second photo; it shows one of these that we found in Oneonta.

Knowing all this is valuable to a geologist who is interested on deducing what it was like around here all those hundreds of millions of years ago. The more common the shell hashes are then the shallower the water was likely to have been. But, more than that, these transport us through time and let us visit these sea floors.

August 16, 380,765,954 BC — We see a dark, quiet sea bottom — at first. But a storm approaches. The currents pick up quickly. Soon, powerful flows sweep the sea floor. The water becomes brown with dense quantities of silt and clay. Now, a number of shells are uncovered from the eroding sediment. With time, the currents slow down. We look down and see that a dense litter of brachiopod shells has been left lying on that sea bottom. It will, with time, come to be buried by more sediment. That will all harden into rock and wait 380 million years until one of our curious readers encounters it.

Do you have an interesting geological photo? Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”