THE MAGNIFICENT KAMES OF MOUNT SINAI

 GLACIAL ICE PERFORATION FEATURES ON LONG ISLAND, NY, 

“Those funny conical hills are so steep, they look so different, than others we see on Long Island. Why is that?  What are they?’ ANSWER:  They are 17,000 year old “ kames” or ‘glacial ice perforations features. 

As a result of our last winter’s storms, and its significant snow cover, the topography of our local Long Island area can be so much better discerned and appreciated.

The dense vegetation of summer is gone and, the hills, valleys, high and low places are exposed.  And yes too, sadly, our neighbor’s, untidy back yard is now there to see clearly.  What our unique island has to offer is an almost textbook example of its glacial past.  And one of these is.the well preserved. magnificent kames of Mount Sinai-Miller Place.

At the eastern boundary of the sleepy little north shore village of Mount Sinai, on LI’s north shore,  one can find a wooded tract, along (interestingly named) Pipe Stave Hollow Road.*.  (See Notes) The land is  now a  parkland. But it’s entire extent is comprised of  a cluster of at least  nine conical hills produced by glacial action and known as “kames” or “ice perforation deposits”. The word “kame” is of perhaps Celtic origin meaning the crest of a hill.

These glacial features are beautifully formed, cone shaped hills rising from a glacial drainage channel to a height of about 140  feet above mean sea level (MSL). They are clearly visible if one walks along Pipe Stave Hollow Road, beginning at a point at its intersection with North Country Road (40. 954371 N and -70.014856 W).   At most times of the year these are simply lovely wooded hills, but in the early spring or fall,  or with a carpet of snow the unique conical, structure of each one can be easily seen.

To try and understand how these features were formed one must imagine Long Island of nearly 20,000 years ago when the entire region was covered with a sheet of ice nearly 2000 feet thick. 

About 17,000 years ago the Earth began to warm up (and has continued to do so).  The massive Laurentian Ice Sheet which carpeted much of eastern USA began to melt and retreat.   As it did,  it left behind at its terminal ends two sets of low knobby hills which comprise the “forks” of  Long Island’s north and south shores. But it’s melting left other deposits too. In some places it left features that were actually formed below the thick sheet of ice.  

In the area where the kames were formed a prominent lobe of the ice sheet, part of a bulge of ice occupying Mount Sinai Harbor, advanced south,  along (present day) Pipe Stave Hollow Road during the very last advance of the ice sheet. This  “Pipe Stave Hollow ice lobe” (perhaps as much as 1500 to 2000 feet thick)  flowed  south as far as Millard Road in Miller Place, where it deposited terminal moraine or ice front deposits rising to an elevation of 225 feet above mean sea level.  It was below this lobe that the kames formed.

As the warming period continued the dominant process of this now stagnant or “rotting ice” was melting and releasing the vast quantities of sand, gravel, pebbles and larger rock encased in the ice which the glacier carried.  Also at this stage of ice melting the upper brittle layer of the ice sheet was marked by multiple crevasses, some intersecting to form deep chasms. It was into these deep cracks in the ice where surface melt-waters mixed with sand, pebbles and coarser rock debris drained.     

Kames are features which form below a stagnant glacier.  They occur where glacial melt water carries sand and gravel, as well as coarser rock material down though a crevasse or crevasse complex.  The sand, gravel, pebbles and larger rocks carried by the melt water, pour down through the crevasse like a pebbly waterfall. The flow creates a void where deposits of  sand and gravel accumulate. The result of this “ice perforatin feature” is a deposit  of coarse, water-washed layers of sand, gravel and coarse rock found below the ice at the base of the glacier.  When the glacier melts away, these accumulations of sand and gravel are left behind as unaltered conical hills maintaing much of the shape they had when they formed under the ice.  

Why do they take on a cone shape?  Coarse materials falling from a height, like sand pouring out of a child’s beach bucket, fall to earth and assumes a stable slope depending on the characteristics of the material which make up the deposit ( termed the “angle of repose”).  Dry sand and gravel  assume an angle of repose of about 25 to 30 degrees.  Glacially generated kames have relatively steep slopes since they are composed of materials that have been somewhat sorted and washed of finer materials, and were deposited by flowing water. As a result, they look very different than other glacial features around them.

This was the process which formed those oddly conical hills in Mount Sinai. They are a testament to the Ice Age and to how our unique and beautiful Island was formed. Fascinating!

Note: Pipestave Hollow    A “pipe” is a small wood barrel.  The “stave” is the individual wood components which make up the tight fitting sides. The staves are generally made of white oak (Quercus alba) which today still grows abundantly in the hollow. The tightly fitted staves were bound together by wood or metal barrel hoops. In the 19th Century Mount Sinai was a source of fish and shell fish which were sent off to Connecticut or New York.  In this area pipes of oysters, clams or salted fish were packed and transported by wagon or coastal schooners away from the Harbor. Based on the name of the road, the hollow was likely a good place to collect the white oak wood needed to make the pipe staves for the barrels.