Friday, July 24, 2020

Knobology







     The things I do for science.
     I'm on a narrow rib of rock. To my left the cliff drops off a hundred feet or so. To my right I'm looking at tree tops. It's hard to tell how far down to tree bottoms. With one hand clinging to a hold I use the other hand to pull out my Peterson Field Guide to Ferns.
Then gingerly thumb thru until I get to page 136. And there it is! 
Pellaea atropurpurea. Purple-Stemmed Cliffbrake. Lance shaped leaflets with inrolled margins, purplish-brown stalk, about a foot tall. Perfect match except for one thing... 




     I'm no scientist. Not much of a rock climber either. Just curious. Just trying to solve a small mystery. What's a plant that favors dry limestone crevices doing growing out of a crack here? I was on Starks Knob after all. Composed entirely of volcanic pillow basalt. Or is it? I looked closely at the rock just inches from my face. Later I did a little more research. Slowly clues to this out of place plant began to emerge.




     The steep hill north of Schuylerville was first scientifically scrutinized in 1901 when J.B. Woodworth, a geologist with the New York State Museum recognized its uniqueness. Woodworth may also have been the first to call it Starks Knob after General John Stark who held positions here in October 1777 to block British retreat after the Battle of Saratoga. 
     Woodworth's detailed description of the rock was so good that it is still referred to today. What's even more remarkable is that the geology was largely hidden beneath trees and vegetation at the time. That was about to change. 



The Knob in 1901

     Over the next decade the construction of the Barge Canal and other road projects required large amounts of rip-rap (referred to as 'road metal' back then).The Knob was seen as a convenient local source and much of its eastern face was quarried off. Old photos reveal a remarkable change between 1901 and 1912. This gave the next geologist to study it a much cleared picture of the Knob's structure. H.P. Cushing's 'The Northumberland Volcanic Plug' is included in the 1914 State Museum Bulletin Geology of Saratoga Springs and Vicinity co-authored with R. Ruedemann.


The Knob in 1910


     Cushing noted the numerous amygdules (inclusions) and intervening veins of white calcite associated with the black 'lava rock' that makes up the bulk of the hill. So there it was...the clue needed to explain why a lime loving fern was growing here, a long way from any real limestone cliff. Apparently there is enough calcium in the cracks and inclusions to satisfy purple-stemmed cliffbrake's requirements and thus it's here, sparse and a little bedraggled, but here. 







     After examining the fern I cautiously made my way up the knife edge to the top of the Knob, passing a few lavender harebells and lots of poison ivy along the way. There's a small open area on the summit with an upright limestone slab that used to have a bronze plaque on it explaining the sites history. Many years ago some useless miscreants chiseled off the bolts securing the plaque and took it. Now there's a newer display with an interesting map of military positions during the Revolution. Note that you don't have to climb the rock to get here. There's a short steep trail that comes up from Starks Knob Road. Also note that this is a somewhat precarious spot with nothing between you and the cliff edge but more poison ivy. Drunks and people with small children and stupid dogs (or small dogs and stupid children) ... you have been warned. If you fall off the area would probably be closed, ruining it for the rest of us. 





     At one time the State Museum owned a number of unique geologic sites called 'Scientific Reservations'. Today only two remain and both are in Saratoga County. Lester Park, in the Town of Greenfield, features stromatolite fossils while Starks Knob has the pillow basalt. Credit geologist Ed Landing for revitalizing both locations in the late 1990's. Speaking of geologists, I've long suspected they take great pleasure in confusing terminology that baffles the rest of us. Case in point: I've seen the Knob deposits variously described as lava rock, pitchstone, trap, igneous extrusions and the current nom du jour ... pillow basalt.


WISH YOU WERE HERE... 






     The State Museum has put up informative signs explaining the geology of the Knob. Reading the details while standing next to the rock is definitely the way to go. For now I'll offer a brief synopsis. Woodworth and Cushing, the early investigators, weren't sure if the Knob was a volcanic neck or part of a flow, whether it developed in place or was brought here by crustal movements. Since their time the theory of plate tectonics, a clearer understanding of the Taconic Orogeny and new technology that has let us see lava extruding on the sea floor have helped in deciphering the Knob.



Web image

     Some 450 million years ago this area was in the southern hemisphere and under the ocean. As two of Earth's plates converged the crust was stressed to the point of fracture with molten rock flowing out of fissures into cold sea water. The one to two foot pillows of basalt were the result as the rock quickly cooled. It's thought by some that the limestone in and between the pillows was formed not biologically, but chemically as the red hot lava 'steamed' carbon dioxide and calcium out of the sea water. With continued plate convergence the pillows, along with the shales and mudstones they were embedded in, were pushed westward at the leading edge of what would become the Taconic Mountains. There followed hundreds of million years erosion and the work of some quarrymen to expose the Knob we see today. 



Looking across the canal at the quarried Knob (early 1900's?)  - web image




Map by W. Kidd



OVER THE TOP...







     Rock, fern, history. I lingered on top absorbing it all as a hot summer day faded into twilight. That's when things started happening. "Pop...Pop...Pop" along with little explosions of color and light in the hills across the river. When I was a kid we just called this 'The Volcano' and now the kid in me thought "Here we go! I'm standing on top of an erupting volcano!"
     Then I remembered...this was the evening of July 4th. With most of the big fireworks displays cancelled some individuals had apparently decided to enliven the holiday (and bolster the Chinese economy) by staging their own shows.
     Next came a big glowing orange floating up from the eastern horizon. Actually the full moon, of course, but boy did it look fat and juicy enough to eat. Finally I was surrounded by on and off sparklers as fireflies took the stage for their nightly performance. These little alchemists mix luciferase with luciferin to produce the flashes of light that say 'summer' like nothing else.




     Geology may get top billing at the Knob but all the other 'ologies' play strong supporting roles. The entomology of the fireflies and all the other insects one can find crawling/flying over the rock. The mycology of the indigo milky mushrooms that sometimes pop up around the base. The bryology of the mosses that cling to the basalt. The meteorology of the towering thunderheads and flashing lightening bolts that mesmerize as they dance above the Vermont mountains to the east. The archaeology that chronicles the activity of those who came before us.
     What is it about high places? Why are they such good places to think? Starks Knob isn't really that high and I'm not prone to deep thought, but I found myself pondering our relationship to science while on top. There are those with narrow minds and expansive egos who speak with beguiling certitude. The simplicity and self-assuredness of their pronouncements appeal to some. Science, on the other hand, is more circumspect. After close observation and controlled experiment, after hypothesis, data collection and peer review it may arrive at a cautious conclusion: "Given the facts and understanding we have at this point it appears that..." 
     The first scientists to investigate Starks Knob didn't have all the answers. But they were remarkably perceptive and others since then have filled in the gaps. For my part I'll continue to look to science as a way of making sense of the world. And I'm looking forward to many future visits to this little pile of rock pillows.
I'm still in knobology kindergarten with lots to learn.






***
   
     Those more attuned to the aesthetic than the scientific will still find a visit to the Knob rewarding. Greenwich author/artist James Howard Kunstler has a series of paintings done from the top of the Knob. Take a look here. I've also seen some striking photos taken from the same vantage, although I can't remember where and by whom. One suggestion: in the fall the Hudson is sometimes cloaked in a blanket of fog and mist. Catch that at sunrise from the Knob and you could get a memorable image. Also, the contrast of the purple blooms of spotted knapweed against the black rock can be eye catching. Pick any sunny summer day. Finally you'll want to check out Michelle Vara's whimsical sculpture of Henry Knox hauling cannon. It's in the pocket park Along Rt. 4 at the base of the Knob. 



Ghostly beasts below the Knob



     For history there are so many books. You might ask the Town of Saratoga's Historian for a suggestion. Contact the office here..
Thomas Wood's Around the Town of Saratoga is filled with old photos of the area. It's in the Images of America series. To learn more about General John Stark try Stark by Richard and John Polhemus. Read it from the top of the Knob for extra points.