September 2019

A Gem, Fossil and Mineral Show
The Catskill Geologists

The Mountain Eagle

Sept. 2019
Robert and Johanna Titus

There’s an event coming up that should be of great interest to all of us, that includes the two of us and all of you, our readers. That’s the annual Mineral, Jewelry, Gem and Fossil Show at Howe Caverns. It’s sponsored by the Howe’s Cave Museum. That’s on Saturday, Sept 28 from 9 to 5 and Sunday, Sept 29, from 9 to 4. It will be held in the indoor pavilion which lies above Howe Caverns. There is a $5 admission charge. The event is sponsored by the Cave House Museum of Mining and Geology. We went last year and found it to be a very fun and educational event.

The primary attraction is a sale. There will be 25 venders set up in the indoor pavilion. You can wander the room and look at and pick among a large and very wide variety of rocks, minerals and fossils. Then, of course, there’s the jewelry It’s like going to a museum except that you can buy pretty much anything you see. We saw some very nicely made gemstone jewelry. Then there were the mineral specimens themselves. They are beautiful and fascinating to look at. The fossils were equally good, in fact we were quite surprised at the high quality of some of them. Your house really needs a good trilobite in it, doesn’t it? Or how about a nice fossil fern? Many of these have been made for placement on coffee tables or knickknack shelves. They will dress up anyone’s home. Overall, we thought the prices were quite reasonable. And here’s a thought. Christmas shopping is coming up soon. And how many birthdays will you be celebrating this coming year? How many people do you know who are impossible to find gifts for? Well the show is perfect for that sort of shopping. Give it a try.
And the dealers are such interesting people. They are mostly collectors themselves, so they are in the business to support their habits. They are fun to talk to and fountains of good information. Don’t worry about food; there will be venders.
You can make a full family day of it. Do you enjoy Antique Road Show on TV? Well the Cave House Museum will have a booth where you can get your fossils, minerals and rocks identified. The Capital District Mineral Club will be operating a sand box where kids can sift out fossils and minerals. Don’t forget to take the tour of Howe Caverns itself. Have you been there? It’s well worth the trip. Then we hope you will go over to the Cave House Museum. There will be free tours there. You can see a collection of local fossils, minerals and rocks. There is a museum rock garden, a row of fascinating boulders donated to the Museum over the years. As part of the tour you will be led into the old and original Lester Howe Cave. That was the very first Howe Caverns, open during much of the 19th century. Something we are very much looking forward to is a lecture on fluorescent minerals by Bob Ballad. If you have never seen such minerals, you will find them astonishing. The lecture will be on Sunday at 1:00. All in all, his show is a fine local tradition, a true community event. Don’t miss it.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.” They will be on WIOX 91.3 FM at 6:00 on Oct. 1st and 15th. That’s also at wioxradio.org.

Top of the Mountain
The Devonian of Greene County Part 13

The Greenville Press
Oct. 6, 2006
Updated by Robert and Johanna Titus

It was been a long time ago, November [2005], since we wrote our last installment on the geology of Greene county. We are sorry for the delay. But now it is high summer, and it is time to finish up our saga. When last we left off, we were at North/South Lake State Park, heading north on the blue trail. We had also been traveling through the great Devonian age Catskill Delta. We had been looking at gray sandstones that were deposited in the ancient delta’s rivers, and red shales that had originated as soils in between those rivers. Our trek had taken us almost to Sunset Rock. Let’s belatedly resume our hike.
The blue trail follows a course that takes hikers just west of the knob of rock that displays Sunset Rock. That stretch of the trail takes you along a shady route that has a towering cliff above it. That cliff is composed of remarkable sedimentary rocks and these tell the story of a changing Devonian landscape. This cliff is largely composed of a very coarse-grained sedimentary rock called conglomerate. The unit is called the Twilight Park Conglomerate. The grains are pebbles and cobbles. Many of them are very much rounded. Remarkably they are stream worn and that is key to understanding them.

These cobbles indeed did travel in Devonian age streams and along the way they came to be rounded. You can see this in many modern rivers. It is important to understand that it takes a powerful flow of water to carry cobbles along in a stream. That kind of current can only occur where the stream is descending a steep slope. The steep slopes we are speaking of were the lower slopes of the Acadian Mountains.
We have mentioned the Acadians before in this series. Off to the east, in what is New England today, was this great rising chain of mountains. They did not yet exist during deposition of the early Devonian limestones that we saw along Rte. 23 in Leeds. They were just coming into existence at the time of the black shales we visited north of Greenville on Rte. 32. They were getting fairly well elevated during deposition of the early Catskill sandstones that we visited as we ascended Rte. 23 going toward East Windham. But now, at the time of the Twilight Park Conglomerate, the Acadians had developed into very tall mountains. Indeed, many modern geologists suspect that the Acadian were as tall as today’s Himalayas. Look east across the Hudson and imagine that!
Great, powerful, white water streams must have descended the Acadian slopes and often these carried gravel and cobbles. That is what we see in the Twilight Park. Take a good look at these and you will not have to be a very good geologist to recognize that there are a lot of different types of rock that make up the cobbles. These are all that is left of the Acadians; you are looking at fragments of ancient mountains and those mountains were made of all sorts of different types of rock. It is just a bit awesome to realize that all of the rest of the mountain chain has weathered away to a virtual nothingness. You are looking at the last fragments of mountains.
Continue north on the blue trail and, if you want to, take a side trip down the yellow trail. It will take you to Sunset Rock with its fabulous view of North and South Lakes. Our journey, however, will take us farther along on the blue trail. We will first see the Newman’s Ledge cliff, to our left, just short of the yellow trail and it is that ledge that continues our story.

Newman’s Ledge is a massive unit of gray sandstone. It is many tens of feet thick and that is a lot of stratified rock. It is composed of river sandstones; all of the rocks you see were once the deposits of river channels. You will see most of the river features we visited last autumn. There are cross-bedded sandstones that accumulated in the fast flowing, deep parts of the channels. Then there are flat bedded sandstones that formed out in the middle of the channels. There are a few concave surfaces, and these are small, petrified channels that formed within the river complex. It can be a bit confusing, but for our purposes the simplest way to view this sandstone is as a massive complex of rivers sands.
In this sort of science, the hardest thing to see is what is not there. It takes a while but eventually you notice that the are virtually no red shales along this elevated stretch of the trail. We had seen a lot of these along Rte. 23 as we ascended towards East Windham, but we will see almost none of them for the rest of our climb at North Point. What happened?
Red shales are typical of inter-stream areas, bits of floodplain between delta river channels. Such landscapes are flat and low-lying. If these deposits are missing, then these habitats must also be missing. Our guess is that, once again, we are ascending the lower slopes of the Acadian Mountains. You can’t have low-lying, flatlands on a slope so you can’t have the red shales. Instead, we are imagining the lower Acadian slopes as being draped with great masses of sand. The rivers that flowed across those deposits were themselves glutted with sand and when they hardened into rock, they produced what we see at Newman’s ledge.
In other words, our journey across the Catskill Delta plain has ended and our ascent of the lower Acadian slopes has begun. And that will pretty much be the case for the rest of our ascent to the top of North Point. If you continue up the blue trail you will ascend Newman’s Ledge itself. Notice all of the very large cobbles that are displayed at the top of the ledge. Soon the blue trail will head into the forest and continue toward North Point. It won’t take long before you reach Bad Man’s Cave. Here you will see another massive ledge of cross-bedded sandstone. It is very much a match for Newman’s ledge. There is a little red shale here, but just a little.
The trail continues with relatively long, flat stretches and a few ascents through more sandstone ledges. Eventually, however, we reach the last incline that leads to the top of North Point. It’s a steep final climb but well worth it. The view from North Point is one of the best in all of the Catskills. Before us are North and South Lakes. Then there is South Mountain and a glimpse of Kaaterskill Clove. Best of all is the seventy-mile stretch of the Hudson Valley running from Kingston to Albany.
All around, however, is more strata of sandstone. And they continue to speak of rivers, struggling across sandy landscapes at the base of the Acadian Mountains. It is one of the ironies of Catskill geology that the climb to the top of one mountain range takes you to the bottom of another.
We have reached the highest and youngest rocks of this part of Greene County and thus our journey through Devonian time has ended. We do, however, still have one more episode to go.

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

Stories of Catskill Geology
The Devonian of Greene County Part 12
Robert Titus

Our journey through the Devonian of Greene County has slowly and gradually carried us uphill. Our first chapters were along Rte. 23 in Leeds, not much above sea level, but gradually we have worked our way up and have recently been climbing Rte. 23 towards Windham. We are getting toward the highest elevations of Greene County and that’s where our story will eventually end.
Today let’s travel to North/South Lake Campground and continue our trek. It’s late in the season now and good weather is getting hard to find, but there still may be time. The park is closed now, but you can drive to South Lake and park there. It’s only a modestly long hike to where we would like to start today. Let’s meet on the ledge at the Mountain House site. The cliff beneath us is about 30 feet of light gray sandstone. These, we have recently learned, represent Devonian age river channels. We are looking at something that geologists call the Oneonta Formation. It is a complex of river and delta plain deposits which is quite extensive. The unit is hundreds of feet thick and it extends all across the Catskills to Oneonta and beyond. It makes up a sizable portion of the Catskill Delta, the enormous deposit that, in turn, makes up much of the Catskill Mountains.
There were two dynamics going on during deposition of the Oneonta Formation. First the crust of the great Catskill Delta was subsiding. Then, as it subsided, the delta’s rivers migrated back and forth across the delta plain and they deposited all the sediment that eventually hardened into the rocks that make up the mountains today.
These wandering streams are called “meandering rivers.” They literally snake back and forth across the delta plain. One side of the river has a deep channel, with fast flowing currents. This is the erosive side of the stream. The other side is shallow with relatively slow currents. There deposition of sediment occurs. With erosion on one side and deposition on the other, you can see how rivers can migrate. That allows them to lay down great thick layers of sediment all across the delta. But, by the time they have migrated “back” and then “forth” the crust beneath them has sunk. The forth deposits thus end up being laid down on top of older back river sediments. This happens again and again, and thick sequences of sediments pile up. Each back and forth sequence runs about 50 feet thick and is called a “story.” Is that confusing? Well let’s go see. It might make more sense in the field.
Take the unmarked trail south from the Mountain House site and follow it a very short distance. You will very soon be climbing uphill. You will pass across red shales and red siltstones. These, as we have seen in recent chapters, represent the delta plain deposits. Some of them were flood sediments; some of them are delta soils. If you continue uphill, you will soon encounter a great overhanging ledge of sandstone. The thick sandstone represents another river channel complex. The Mountain House ledge and this overlying delta deposit represent the first two “stories” on our journey.
Take a look at the underside of the large ledge we have just climbed to. You are actually looking up at the bottom of an ancient river. Look around and you will see small channels cut by Devonian river currents into the floor of that stream. To realize that you are looking at the evidence of nearly 400-million-year-old currents is quite something.

  Trough cross bedding.

Turn around and find your way north past the Mountain House ledge and start up the Blue Trail towards Sunset Rock. You won’t have to go too far before you will encounter another great sandstone ledge. The climb up it is quite a scramble. Along the way we would like you to look for what we call “cross bedding.” The strata are inclined to the left here and to the right there. The two sets intersect each other. We are again looking at evidence of ancient river currents. These formed in the deepest, fastest flowing part of the river. Currents first scoured the channel sand this way and then that way; the results hardened into the sandstones that you are looking at. With some searching you may find sandstone strata all dipping in one direction; these are called “planar cross beds.” These represent what were, essentially, dunes of sand that had been migrating in a downstream direction. The beds dip in the old downstream direction. Then too, you may also pass by horizontally bedded sandstones. These formed in a quieter part of the stream; it was shallower here and the flow was much less.

  Planar cross bedded sandstone below; horizontal beds above
Again, what a marvel all this is? We are looking into the deep past and seeing the very currents of very old rivers. Each grain of sand came to rest during the Devonian and each one has not moved one bit in all the time since, and that is about 375 million years.
Our hike will take us farther north along the Blue Trail. We will pass “Artist’s Rock” and that represents another ancient stream story. Eventually we will find our way to what has been called “Sunset Rock.” (It probably should be called “Bear’s Den.”) This is one more great sandstone ledge and, of course, it represents another complex of stream channel deposits. Look for more cross bedding and horizontal laminations along the way. You may see some more of those red floodplain deposits as well. The view from this site is one of the greatest in all the Catskills. We will end today’s hike here.
We are getting towards the end of our Devonian saga, but the blue trail continues north and climbs to higher elevations. We will come back soon and continue our journey.

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

The Devonian of Greene County Part 11
The Red Delta
The Greenville Press
June 5, 2006
Updated by Robert and Johanna Titus

The year 2005 will long be long remembered as the year that the great hurricane hit New Orleans. In many parts of the city the destruction was nearly total, and rebuilding the city was a difficult, expensive and perhaps futile endeavor. Even rebuilt there is no guarantee that another, even worse, storm won’t come along. We, in Greene County, can rest easy. We shall not see that sort of flooding. But, back during the Devonian, that was not the case; back then Greene County must have suffered many such floods. It’s an interesting story and there is a lot about New Orleans that can be learned right here.
You will, we hope, remember from our last chapter that Greene County was once covered by a great delta, called the Catskill Delta. That Devonian age structure was easily as large as the Mississippi Delta and it displayed most all of today’s delta habitats. There were swamps and bayous and floodplains, but most importantly there were rivers, lots and lots of rivers. The general public has recently learned a great deal about such deltas, especially about the flood threats they are exposed to. We talked about some of them in our last chapter.
We learned that it is normal for such deltas to be subsiding. The mass of the sediment deposited on them presses down on the crust and the delta simply sags beneath its own weight. That has been going on in Louisiana for millennia. Some parts of the state are subsiding about an inch per year. That’s fast. What went wrong with all this began centuries ago. Back then the levees of New Orleans started being built to prevent floods. Those levees worked quite well and, in fact, relatively few floods have occurred. But, ironically, the absence of floods has increased the threat of bad floods. It has meant that there has been no new deposition along most of the Mississippi River, especially at and upon New Orleans. You see, normally, flood waters carry sediment onto the delta plain and the resulting sedimentation keeps up with subsidence. As the delta presses down, flood deposition maintains a constant level just above sea level. But since New Orleans came to be “protected” by levees it has sunk but no new sediment has been able to “keep up” with the sinking. Instead, as New Orleans continued to subside, people have just kept raising the levees. It was a race between man and Nature; Nature has won, she always does, and the results were very predictable.
Few people can appreciate the relentless nature of such subsidence. How can they; they just can’t see the results? Subsidence buries all the evidence of itself. Well, surprisingly, here in Greene County, we can see the evidence. Go south on Rte. 32 until you reach its intersection with Rte. 23 where that road begins its ascent towards Windham. All along the road from the bottom of the mountain to on past Point Lookout you will observe a seemingly endless sequence of mostly red shales and red sandstones.
This is, all of it, the Plattekill Formation. We learned a lot about the sandstone and shale in the last installment. The sandstone represents the channels of many ancient, Devonian Catskill Delta rivers. The sand had been carried in the stream channels. Eventually it came to be lithified into sandstone. Most of the shale formed originally as soils and flood deposits on the floodplain surfaces in between the channels.
We saw all of this in the last episode when we visited the Ashokan Formation, along Rte. 23 in Cairo. The difference here is that red color. That brick red is particularly handsome, and it is characteristic of the Catskills as a whole. We owe a lot of our region’s picturesque appearance to it. Why is it there? This red is from the mineral hematite, an iron oxide which forms mostly in well oxygenated terrestrial landscapes. Also, it is most common in tropical settings; red soils are very common in the Amazon and Congo Basins.
So, the Catskill Delta was a great red tropical Devonian landscape. But our interest is in relating it to New Orleans. Let’s get back onto Rte. 23 and head up the mountain. Just a short distance past and across the highway from the Cornwallville parking area is a fine exposure of a Catskill Delta river. You can see a cross section of the entire channel. The deep side of the stream is on the right and the shallow side is on the left. It is, in short, a “fossil” river. We are not sure if you have ever heard of such a thing as a fossil river, but they do occur, and this is a very good one. And let us tell you, you don’t see them this good just anywhere.
This outcrop sets the tone for the rest of the uphill journey. Watch as you drive along and stop along the way and look at the ledges. There are long thick sequences of red shale; these speak of great delta floodplains. Then, periodically, there are thick sandstone sequences. Those speak of other fossil rivers; none of them, however, are nearly as nicely preserved as the Cornwallville specimen. Horizons of gray and red shale are usually ancient fossil soils. When you come to understand what you are looking at you get a great sense of the time involved. Each of the layers of stratified rock that you pass represents a large amount of time. As you continue uphill you are traveling through a vastness of time, almost more than a person can comprehend. All together, from Cairo to East Windham, you are rising through a thickness of about 1,500 feet of sedimentary rock. That’s a lot of stratified rock and that’s where New Orleans comes in.
One of the critical things to remember in all this and that all of these sediments accumulated at an elevation of just a few (really, a few) feet above sea level. The Cornwallville channel formed at sea level. About 1,500 ft. uphill and across the highway from Point Lookout is another sandstone channel deposit. It also formed at sea level. You might ask “how can 1,500 ft. of sediment be deposited, all of it at just about sea level?” You might think that deposition should pile up to an elevation rising well above sea level, but you have to remember that, just like with the Mississippi Delta, as the Catskill Delta subsided more sediment was deposited. Subsidence and deposition always just keep up with each other.

 
There is nothing whatsoever unusual about this East Windham sedimentary sequence, these thicknesses are typical of large deltas. And that includes New Orleans. Beneath New Orleans there are many, thousands of feet of sediment that were all deposited at sea level. Above New Orleans there will someday be many thousands of feet more. That will take many millions of years. And after all of that sedimentation, the area will still be at about sea level. And that’s where we really come to understand what has happened to the (once great?) city. Over the centuries, as it was being built, it was being dragged downward along with the subsiding crust. Nothing can stop that process. New Orleans will continue its subsidence. And no matter how high we build the levees, Nature will eventually catch up (as it already has) . . . again, and again, and again. In the end New Orleans will be a “fossil” buried under hundreds and then thousands of feet of sedimentary rock.
Today Rte. 23 takes us to a wonderful place; there is great scenery here. On one side of the highway are beautiful red stratified rocks, on the other side is one of the best panoramic views of the northeast. To relate all this to the tragedy in New Orleans leads to some pretty somber thoughts. It is almost a sacrilege, but it is what we see as we drive up the highway towards Windham.

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