The Gilboa Forest

Flash floods are hardly unheard of in the Catskills. Our mountains commonly stand in the way of weather patterns, forcing rising air masses to generate sudden thunderstorms. A heavy downpour, in the upper, narrower valleys of the higher Catskills, can quickly overwhelm the drainage system and raise the levels of the streams. Schoharie Creek has had as occasional flash flood in its upper reaches which stretch eastward from the village of Gilboa. North of Gilboa (which is downstream), the creek is generally wide and flat-bottomed, but south and east (upstream) of Gilboa the valley is considerably narrowed and flood-prone.

Flash floods can be extremely dangerous to life and property and they are one of the major hazards of life along a river. But, to a paleontologist, the flash flood offers the hope of discovery. The floods are erosive and it is not unusual for them to expose previously buried rocks and, sometimes, to reveal fine fossils. So it was in 1869.

The flood of the fall of 1869 was an especially bad one. Many Schoharie bridges and roads were washed out and flood erosion was most severe in the vicinity of Gilboa. After the flood was over, a small forest of fossil trees was found, freshly uncovered along a riverbank swept clean by the flood. Mind you these were not whole trees; they were only the stumps; but by the standards of paleontology, that’s not bad. The trees were found in late Devonian age sedimentary rocks and are about 370 million years old. At the time of their discovery, they made up the oldest known forest in the world, quite a distinction for a small Catskill village!

At the time this was a very important discovery and the excitement was considerable. James Hall, the New York state paleontologist was the first to describe the find in a report of the New York State Museum. He thought so well of this discovery that he even traveled all the way to England to report about it at the annual meeting of the British Association for the Advancement of Science. That’s a long trip in the 1870’s. The upper reaches of the Schoharie Creek were scoured for more discoveries, but with little luck. In 1897, Charles Prosser, of the New York State Museum, found a few small tree stumps at Manorkill Falls and then nothing more was to be found for quarter of a century.

Good luck returned in the early 1920’s when New York City began work on the Gilboa Reservoir. The reservoir, after it was completed, submerged the original collecting site, but quarry work for the reservoir revealed still other fossil trees. One site, called the Riverside Quarry, yielded 18 stumps. All told, it is thought that several hundred trees have been found in the upper reaches of the Schoharie Creek.

How did the Gilboa Forest come to be preserved? The rocks that they are found in tell that story. Below the trees are dark shales in which marine fossils are sometimes found. These trees must have lived near the shores of an ancient ocean which stretched westward from the Catskill region. The stumps are generally found planted in a red shale which was a red clay soil of long ago, much like those for which Georgia is famous. Red clays are typical of warm and usually tropical climates. The stumps themselves are buried in lighter colored, thinly laminated sandstones. In an earlier article (Kaatskill Life, Summer, 1992), I wrote about laminated sandstones. These are river flood deposits. The sands were deposited from subsiding floodwaters of the rivers which once formed the great Catskill Delta of the late Devonian Period. The Gilboa Forest was thus a coastal forest on the shores of a tropical ocean which exists no more. All of this conjures up an image of an ancient river bank. During flood seasons the river waters rose, flooded the Gilboa Forest, and then deposited several feet of sand which buried the lower reaches of the tree trunks. The sand compacted tightly around the trunks to form molds of them; then these sand molds emptied with the decay of the wood. Later, more sand filled in the molds to form the fossils of today. The fossils are casts of the original trees.

The trees of the Gilboa Forest are not the same types that live in the Catskills today. By the late Devonian, land plants had only been around for a relatively short period of time but they had been evolving rapidly. These trees are thought to belong to a group of plants called the progymnosperms. What that means, in common terms, is that they were essentially big ferns with woody stems whose descendants would later evolve into cone-bearing, evergreen trees.

Back then, Gilboa was a state-of-the-art forest, but its trees were quite primitive land plants by today’s standards. Gilboa trees lacked true roots. The bottom of the trunk is like the bottom of a mushroom, another primitive land dweller. Gilboa trees did not have roots but they were very poorly developed. The upper reaches of the trees may have had large fronds instead of individual leaves, but we are not sure of that because no fronds were ever found attached to the trunks. For a long time these trees were thought to have had seeds but we know better know; they, like all primitive land plants, produced tiny reproductive spores.

James Hall was the first to describe these trees in the scientific literature, but it was left to a paleobotanist of a later generation to bring them into the imagination of the general public. That was Winifred Goldring. During the 1920’s she went to work on the newly discovered specimens from the reservoir site. Under her supervision, the New York State Museum put together a reconstruction of the Gilboa sites which became its most famous display. If a scientist can be said to produce a “masterpiece,” then this one was Goldring’s.

The figure above shows a photograph of that exhibit. The background shows the Manorkill Falls vicinity as it was before being partly submerged beneath the Gilboa Reservoir. To the right and left are plaster reproductions of the ledges of strata in which the trees were found. On three horizons of these ledges were actual fossil stumps from Gilboa. Painted in the background are several species of fossil trees found in the Catskills. Winifred Goldring unveiled this display in 1924 and it was viewed by the public for more than four decades.

Time has been unkind to the old display. The Goldring exhibit was in the old state museum, on the top floor of the Education Building. When the state museum relocated to its present location the Gilboa reconstruction was not brought along. It’s been broken down and there are no immediate plans to set it up again. To make things worse, today’s generation of paleobotanists have come to disagree with Goldring’s reconstruction. Evidently she placed the fronds of one type of tree upon the trunk of another. That sounds like an awful error, but actually it’s the kind of mistake we paleontologists make all the time when we deal with very old and poorly preserved fossil remains.

Quarries and building excavation sites have, in recent decades, yielded more fossil trees but, as far as I know, no one has found any more sites as good as the Gilboa Forest. There may be more and that’s where you come in. Paleontology is one of the few sciences where the amateur can make a real contribution. A lot of fine fossils are found every year by amateur fossil hunters. Take a good look at the pictures I have included here and if you find any more fossil tree trunks, let me know, or bring a photo to the New York State Museum.

You certainly should see some of the ones which are on display. There are none currently on display at the museum in Albany, but I think it is better, anyway, for you to see the fossils where they were found. Fortunately, you can. Travel on Route 23 to Grand Gorge, in the western Catskills. Head north and go 2.8 miles on Route 30; turn right and travel another 1.2 miles. This takes you downhill and toward Schoharie Creek where you will reach a small parking area just before the bridge across Schoharie Creek. There is a small park nearby with a display of seven fine fossil tree trunks.

These trees are time travelers and their journey has been an odyssey. It was floods which buried and preserved them long ago and it was a flood which brought them back to the surface in 1869. Ironically, today they sleep beneath the sediments once again, buried beneath the muds of the Gilboa Reservoir. Once they were revered fossils, subjects of a world famous museum display. Now they are largely forgotten, mere asterisks in the chronicles of science. Such are the histories of fossils through time.

What you have in your mind?