Friday, September 29, 2017

Stark's Knob: A Rock Pile of Note

 While my son is away this week, I've been driving over to his house in Schuylerville to care for his cats.  It's only a 10-mile drive from Saratoga Springs to Schuylerville, but I don't often think of going that way for nature adventures.  But as long as I'm over here every day, I decided to look around for some interesting places to walk.  I'd noticed the sign for Stark's Knob before, so on Thursday I pulled over to see what this "knob" was all about.

It certainly looked like a fascinating pile of rock, black as coal and rising up to an impressive height.

There were a number of signs posted in the area to help visitors understand the significance of this geologic phenomenon. I found the information included on these signs to be somewhat inadequate in addressing the significance of this particular site, but I did learn how "pillow basalt" is formed, and that Stark's Knob consists of pillow basalt.

Geology is a fascinating science, but as I'm sure most of my readers know, my first love is plants instead of rocks, so of course I started exploring these bulbous rocks to see if any interesting plants might call them home.  I believe pillow basalt can be rich in calcium, so I thought I might find some calciphile plants occupying the cracks in the rocks.

And so I did! This rather spindly-looking fern was one.  I once had seen Purple Cliffbrake (Pellea atropurpurea) growing on limestone ledges at a site south of Albany, and this certainly looked similar to that calcium-loving rock fern.

Purple Cliffbrake has two forms of its fronds, with the fertile fronds bearing their pinnae (leaflets) more widely spaced than those of its infertile ones.  Both kinds of frond can be seen in the photo above. The photo below shows a fertile frond, with the inrolled pinnae widely spaced along the purplish stipe.

When I turned the frond over, there I could see the spore packets, called sori, arrayed within the inrolled margins of the pinnae. This was the clincher:  Purple Cliffbrake it was!

I'm afraid that was it, though, for interesting plants growing among the rocks.  I did see some Columbine leaves, but there were far more leaves belonging to invasive species like Spotted Knapweed.  I should come back in the spring to re-explore these rocks for calcium-loving plants.

I next took a trail that climbed through the woods to reach the top of the knob.  If you decide to climb this same trail, be warned that it is quite steep.  I had left my hiking pole behind, and it would have been very helpful, especially coming back down on a trail that was slippery with loose gravel and fallen leaves.

But the view from atop the knob was certainly worth the climb!  I have zoomed in on the view, the better to show the Green Mountains rising to the east, beyond the Hudson River immediately below. Just imagine how lovely this view will be, when the trees reach their peak of autumn color.  Or should I say, IF they reach their peak of autumn color.  Lack of rain and a long stretch of record-hot days has caused many of our maple leaves to start to shrivel.  Even the sumacs look done for.  I fear that our autumn colors this year will be dead-grass green and dusty brown.


Woody Meristem said...

Great find among the rocks. It looks like fall will be drab down here as well; our sugar maples have already dropped most of their leaves, which merely turned brown and fell. It looks like the red maples will do the same. It's been a month since we've seen any rain.

The Furry Gnome said...

Interesting geology! Those Taconic mountains are a big influence on southern Ontario's geology.

threecollie said...

Interesting rock. I too find coming down a lot harder than climbing up these days.