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The Hills of the Seven Sisters

Continental Glaciers Cause Enormous Hills in Sachem.

Long Island is relatively flat. We don't think of ourselves as mountain dwellers because, well, we aren't. We are used to driving many hours to reach the Catskills or Adirondacks. Long Island is mostly flat and sandy, with barely a hill to ride a sled down.

But in the middle of the Island are the remnants of a great glacial event that took place tens of thousands of years ago. The most visible "monument" to this event is the Vietnam Memorial location, sitting atop Bald Hill on Route 83. Just to the west of Bald Hill, in an area of Farmingville and Selden known locally as "The Hills of the Seven Sisters" (because they resemble seven sisters lying on their backs), lies a residential area with street names like Berkshire, Highview, and Adirondack. Mountain names.

Adirondack Drive is the stuff of local legend. If you grew up anywhere within a 10-mile radius you explored these hills as soon as you got your driver's license. While a magnet for thrill-seekers, the safety concerns over the years have become very real and expressed periodically by area residents, particularly when there were accidents. Eventually, stop signs were added along the several mile stretch of road.

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In 2008, an accident at the intersection of Mooney Pond Road and Adirondack Drive, where only a stop sign regulated traffic, took the life of 14-year old Alora Williams and injured several others. Over the years the crossroads had become notoriously dangerous and the site of innumerable accidents.

Area residents were used to being jolted by the sound of metal crashing into metal. Eventually a traffic signal was added to the intersection. It was too late for Alora Williams, but hopefully just in time to save other lives. The hills themselves remain, and are now safer to navigate with the better traffic control of stop signs and traffic signals. The hills are still a wonder and still fun enough to make a detour on the way home. But why do they even exist on this flat and sandy island?

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According to J. Bret Bennington, a professor of geology at Hofstra University, these are part of a series of hills extending from Westbury all the way to Montauk Point, collectively known as the Ronkonkoma Moraine. Twenty-thousand years ago, a great continental ice sheet made it as far south as Long Island.

"Continental glaciers are like enormous conveyor belts made out of ice," Dr. Bennington said.

Back then, as ice was melting and flowing at the same rate, "at this equilibrium position, as the ice kept flowing, the margin of the glacier maintained the same position for many years, allowing a belt of gravel, sand, and mud to be deposited along the ice margin," he added.

As the glacial front retreated back north, it left massive deposits of accumulated rocky debris behind.

Professor Gilbert Hanson of SUNY Stony Brook describes this process as "similar to how a bull-dozer pushes sediments into mounds".

All that rocky mess formed the hills that make up Bald Hill and The Hills of The Seven Sisters on Adirondack Drive and the surrounding area.

Telescope Hill, at 334 feet, is the highest elevation in the area (although not the highest point on Long Island; that would be Jayne's Hill in Huntington at 401 feet). At the end of Tower Hill Avenue, Telescope Hill was the site of a fire tower from 1918 to 1959, and was a popular site for romantic locals. The tower served a useful purpose during World War II, as on several occasions Nazi u-boats were spotted from the location.

Telescope Hill, Adirondack Drive, and Seven Sisters area are still locally famous, still an adventure, still a great place to take out-of-towners to marvel at the local landscape and the view. Now much safer to travel, these hills will continue to be the place where new drivers come to test, safely, their skills.  

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