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Reflections 2010
Series 26
December 18
The Ice Sheet & the Outer Lands (Staten Island to Cape Cod)


Outer Lands   Of all the things I found amazing when doing this research, perhaps most spectacular to me was the revelation of the Outer Lands. In short, a huge deposit of material was made between 15 and 12 millennia ago by the ice sheet along the shore of North America from Staten Island to Cape Cod. But the ice sheet giveth, and a rising sea taketh away, so much of this land was later flooded and drowned. But the result today is that we owe to this giving and partial taking back the addition to the landscape of the “new lands” of Staten Island, Long Island, Block Island, the islands of Narragansett Bay, the Elizabeth Islands, Martha’s Vineyard, Nantucket, and the lower part of Cape Cod! These additions to the continent may be referred to by the very appropriate name--given their location off the coast--of Outer Lands (Staten Island, immediately to the southwest of Long Island, should be shown on this map in green.) The Outer Lands are then essentially an archipelago of islands--plus Cape Cod--that should be considered as a single unit, at least geologically and historically, rather than the “New York islands” in the west and the “Massachusetts Islands and Cape Cod” in the east, plus the smaller Rhode Island islands in the middle (Block Island and the Narragansett Bay islands).


[Note that Manhattan Island is not included with the add-ons of the Outer Lands. Its granite bedrock (favorable for skyscrapers) is an extension of the bedrock extending from the North American mainland from Westchester County through the Bronx to Manhattan. This long narrow extension is referred to as the Manhattan Prong. It makes an interesting mental image to picture the Manhattan Prong and New Jersey existing before Staten Island, or Brooklyn, Queens, and the rest of Long Island were ever added to the scene by the ice sheet.]


Now let’s look at the development of the Outer Lands in more detail. While some continents might have almost no continental shelf (sort of a coastal plain, today underwater) at all, the average shelf extends from the mainland perhaps 80 km (50 mi) and the one off the northeastern US coast could be in places more than twice that. (That means the Manhattan Prong, for instance, was not any closer to the sea before the Outer Lands appeared, but rather even further away from the water than today.) In glacial periods water is concentrated in the ice and the shelf is exposed. In interglacial periods with much less ice, such as now, the shelf is drowned. Therefore, it must be visualized that glacial sediments were deposited on an exposed continental shelf.


TWO MORAINES Now realize that the advancing ice sheet slowly scraped off (at glacial speed [!!!]) about 20 m (65 ft) of surface material as it moved south from New England and deposited it on its southern edge on the continental shelf from off the New Jersey coast (becoming Staten Island) to off the Massachusetts coast of that time (becoming Cape Cod). (Just think--maybe Long Island was once the surface of Vermont!) But an ice sheet (glacier) stops advancing when the snow added at the northern origin balances the melting at the southern edge and equilibrium is reached. This happened about 18 millennia ago. At this point, a large amount of sediment was deposited in a terminal moraine, in this case known as the Ronkonkoma Moraine, the southernmost advance of the ice sheet. Then, with even more melting in the south than snow deposits in the north, the ice sheet started receding. Later on, another period of equilibrium occurred stalling the retreat and resulting in a second, recessional moraine, the Harbor Hill Moraine, a bit further north than the terminal moraine.


This map, just highlighting Long Island, since the moraines in this region are named after places there, is from the USGS (US Geological Survey). The moraine comes across Pennsylvania in the west, where I-80 generally follows the moraine. The moraine then crosses New Jersey and northern Staten Island (Richmond County on the map). The moraines are also associated with the highest natural points in each New York county they cross. Not only the highest point on Staten Island, but the highest natural point in all five boroughs is located on the moraine, Todt Hill (Dutch for “dead”; say “tote”), at 125 m (410 ft).


Do realize that the Narrows did not yet exist at this time and Staten Island was attached to Brooklyn, so the moraine connected right across to Brooklyn (Kings County), giving the neighborhood of Bay Ridge its name. The highest locations in Brooklyn (67 m / 220 ft) and Queens (79m / 258 ft) are on the moraine, which then splits in Nassau County, as is visible on the map.


To the south is the (terminal) Ronkonkoma Moraine, which passes near the town of Ronkonkoma and continues to Long Island’s South Fork at Montauk Point. The Harbor Hill (recessional, and therefore younger) moraine to the north is a is named after Harbor Hill in Roslyn, LI, which is the highest point in Nassau County (106 m / 348 ft). Also on this moraine is the highest point in Suffolk County and on all of Long Island, Jayne’s Hill, near Walt Whitman’s birthplace, and near Melville. It’s disputed height is either 118 m (387 ft) or 122 m (401 ft), the highest in either case. It’s also the highest on either moraine, since Bald Hill in Farmingville, the highest point on the Ronkonkoma Moraine is 101 m (331 ft).


The Harbor Hill Moraine forms Long Island’s North Fork to Orient Point, goes underwater to Fisher’s Island (in white on the map and part of New York), then crosses to the New England mainland. If you ever wondered why Long Island has two forks at its East End, you now know why.


The best map I have of the Outer Lands is this one. It’s actual purpose is to show Native American peoples, but we’ll get to that later. Otherwise, it shows the entire region we’re discussing to the best advantage. Apparently geographers are more interested in showing only state maps that include just the New York or Massachusetts segments of the Outer Lands. A map showing both, and including the “drowned” area of water in between, is hard to find. We can now continue our tracing of the two moraines.


The Ronkonkoma Moraine leaves Montauk Point and runs underwater in a large drowned area up to Massachusetts. On the way it runs south of Block Island (part of the state of Rhode Island), and then remains invisible from the surface until it reaches Martha’s Vineyard and Nantucket. Where it passes these islands is very clear on the map. It goes around Martha’s Vineyard in a clear inverted-U shape forming the north shore of the island. It then continues, forming most of the north shore of Nantucket in the shape of a regular U. It then continues eastward out to sea. I find it very revealing to now understand that these two islands are “connected” underwater in this S-shape, and that both of them are “connected” to Long Island’s Montauk Point.


The more northerly Harbor Hill Moraine, after it leaves Orient Point, crosses to Fishers Island (NY) off the Connecticut coast, and then reaches the mainland at the point where Connecticut and Rhode Island meet. It runs along the shore and along the south end of Narragansett Bay, then crosses Buzzard’s Bay to form the Elizabeth Islands (the string of islands on the map at the south end of this Bay). The Elizabeth Islands ARE nothing more than pure moraine. It then runs up Cape Cod on the east side of Buzzard’s Bay, then across the W-E portion of the Cape before continuing out to sea. (The Upper Cape was formed more recently by wave action.) And again I find it very revealing of the nature of things to realize that Long Island’s Orient Point “connects” to Cape Cod, just as Montauk Point “connects” to the islands.


OUTWASH PLAINS Most of the Outer Lands are outwash plains sloping southward from the two moraines, that is fine material sifting through the gravel and loose rock of the moraines along with glacial meltwater. Much of Cape Cod is an outwash plain, as is all of Nantucket and Martha’s Vineyard. Long Island south of the moraines is a sandy outwash plain. This is particularly noticeable, as mentioned earlier, inasmuch as the North Shore beaches are rocky from the remaining glacial debris, while the South Shore beaches are crisp, clear, outwash sand. It is important to visualize how these moraines and outwash plains formed coastal highlands along the exposed continental shelf.


GLACIAL LAKES These coastal highlands were just south of the melting ice sheet and to a large extent they impeded the copious glacial meltwater from reaching the sea. In addition, there was the matter of isostatic depression, which is the sinking of the earth due to great weight, such as from the glacier. These depressions at the foot of the retreating ice sheet formed natural lake beds, and the combination of the lake beds and the meltwater impeded by the coastal highlands ended in the formation of a string of glacial lakes located on the inland side of the Outer Lands. These glacial lakes resulted in a series of marine areas running from today’s Long Island Sound to today’s Cape Cod Bay.


The Long Island Sound basin actually had had a head start in development, since it had existed as a depression even before the glaciers, probably having been formed by the action of local streams. But then additional isostatic depression and the damming affect of the moraines and outwash plains caused glacial meltwater to form what is termed Lake Connecticut, a freshwater lake in the basin 20-18 millennia ago.


This US Geological Survey map of Lake Connecticut beautifully shows in red the two moraines on Long Island and how Lake Connecticut was dammed by the Harbor Hill Moraine running along the north fork of LI via Fishers Island (NY) to Watch Hill (RI).


We need to rely for a second time on that map of Native American peoples to understand the location of the rest of the glacial lakes. Lake Connecticut was connected to similar freshwater lakes in, sequentially, Block Island Sound (to the NW of Block Island); Rhode Island Sound (to the NE of Block Island); Narragansett Bay (“Lake Narragansett”); and Buzzards Bay, all of which are geographical extensions of Long Island Sound.


Beyond Buzzards Bay, other glacial lakes formed in the east, including Vineyard Sound (between the Elizabeth Islands and Martha’s Vineyard), Nantucket Sound (north of Nantucket to the Cape), and even Glacial Lake Cape Cod that was the predecessor of Cape Cod Bay. Glacial Lake Cape Cod drained via an outlet to the southwest into the lowland that was to become Buzzard’s Bay. When the lake eventually drained, the low, abandoned, waterless outlet remained, and became the obvious location in the early 20C to dig the Cape Cod Canal. What goes around comes around, and there is apparently nothing new under the sun: the Cape Cod Canal is essentially a reconstruction of a prehistoric river!


FLOODING The ice sheet reached its furthest extent, the Ronkonkoma Moraine, some 20 millennia ago. Then as it melted and retreated, the sea level rose. The emergent coastline (raising to the surface of the continental shelf) that had appeared at the beginning of the ice sheet now became a submergent coastline during and after the retreat. The flooding (“drowning”) covered most of the continental shelf with the exception of the coastal highlands, which were to become an archipelago of islands from Staten Island/Long Island (still attached to each other) to Cape Cod, which was the only exception to island formation, since it was the only land area that remained attached to the mainland as a peninsula rather than an island.


As the sea level rose along the continental shelf, the Ronkonkoma moraine began to be assaulted by coastal erosion and its lower portions were covered over by the sea. Today, only its highlands on remaining islands remain visible; other remnants of these moraines are submerged and are continuing to endure submarine erosion.


The sea level rose gradually, and began to flood the freshwater glacial lakes. When it reached about 25 m (80 ft) below today’s level, the Harbor Hill Moraine dam that impounded Lake Connecticut failed at a point between the North Fork of Long Island and Fishers Island, and seawater flowed into the basin and transformed it from a nontidal freshwater basin to a tidal saline arm of the sea.


Again, features of submergent coastlines are rias (drowned river valleys), fjords (drowned glaciated valleys), and estuaries (drowned mouths of rivers). In the history of the Outer Lands, there were apparently also flooded lakes, today referred to as sounds or bays. Rhode Island’s Narragansett Bay is a ria consisting of a series of flooded river valleys, with complex channels and islands, part of the Outer Lands. The system is vast compared to the three small rivers that enter it.


To experience the feel of sailing the contemporary sounds and bays that resulted from the glacial lakes located inland from the Outer Lands, I’m presenting here a video made by musician friend Carter (2008/5, Guest Essayist Carter Brey, “Pyongyang Diary”). It’s a quality video, with informative informational “balloons” and appropriate background music (no surprise). Carter sails his boat with a companion from City Island, part of the Bronx at the western end of Long Island Sound, past adjacent Hart Island. He passes Block Island (Block Island Sound), and Newport RI (Rhode Island Sound, adjacent to Narragansett Bay). He ends in the Elizabeth Islands between Buzzard’s Bay and Vineyard Sound at Cuttyhunk Island, the westernmost of the chain of islands that consist of nothing more than the Harbor Hill Moraine. He ends with a view of tiny Penikese Island in Buzzard’s Bay before returning to City Island, where he includes a view of the Throgs Neck Bridge connecting Queens with the Bronx over the East River, the first fixed crossing traversing this entire maritime route.


Long Island-Cape Cod Cultural Connections   I had never associated the two ends of the Outer Lands, that is, the New York islands and the Massachusetts islands and cape, as having anything to do with each other, which I think is common. But once I realized the geological connection millennia ago, I found a lot more in the way of cultural, historic, and political connections between them.


NATIVE AMERICANS When it comes to Native Americans who lived in the region, they all spoke languages within the Algonquian language family. But as it turns out, Long Island is split, with only the western half being culturally connected to New York while the eastern half was culturally connected to New England.


To the west were the Lenape people (LEH.na.pi), who also called themselves Lenni Lenape, and who were referred to by arriving Europeans as the Delaware. The Lenape spoke the Algonquian language called Munsee, and, as shown in this German map, inhabited the Delaware and Hudson valleys, but also the western half of Long Island.


But now looking for the third time at this map of Native American tribes, let’s see what it was meant to show. Southern New England and the eastern half of Long Island were both inhabited by peoples who spoke the Algonquian language, today extinct, known as Mohegan-Montauk-Narragansett, which we can shorten to Mohegan (not to be confused with James Fenimore Cooper’s The Last of the Mohicans, which referred to a different people in upstate New York). The distance across the sounds and bays between New England and Long Island was not an impediment to the cultural unity of these peoples. It is also ironic that the Mohegan Sun Casino in Connecticut, located in the Mohegan’s tribal area on the map, and the second largest casino in the US, built in cooperation with the Mohegan tribe, draws casino-goers from the entire New York-to-Boston region on the map. Once again, Long Island Sound is not an impediment.


We cannot leave this map without making note of a distinguishing feature of many Mohegan tribal names and place names. Notice how often one finds names ending in -et, (sometimes spelled -ett), and how they to this day, spill over from New England to Long Island. Let’s start with good old Nantucket, an island whose second town is called Siasconset, or ‘Sconset. There’s the Nauset tribe, and the Massachusett tribe, so we see that the name of the state was originally construed as a plural. There’s the Narraganset tribe, although the Bay is spelled Narragansett. A major RI city is Pawtucket. To the west is the Paugussett tribe. But on Long Island, we see that Montauk is short for the Montaukett tribe. Near Montauk is the town of Amagansett, and further east lie Syosset and Manhasset. Possibly connected with a variant spelling in -ut is the state of Connecticut, which in modern Mohegan is Kônuktukut “on the long tidal river”.


It’s a surprising cultural connection, and can also be a humorous one. You know how often limericks refer to Nantucket, and I refer you for a good laugh once again to the Travelanguist Limerick Collection (2008/17), especially the trio of limericks published in 1924 that deftly connect Nantucket MA with Pawtucket RI and Manhasset NY.


EUROPEAN SETTLEMENT One first associates Long Island--all of it--with the Dutch settlement of New Amsterdam, but that isn’t accurate. In a similar division of Long Island as that of the Native American peoples, the original Dutch settlements only affected the westernmost portions of Long Island, essentially Brooklyn and Queens. The eastern region was settled by English Puritans from New England, again because of the closer proximity of the East End to New England than to New York harbor.


The first settlement from New England involved the Hamptons. On the South Fork of Long Island, Southampton was settled on June 12, 1640 by Puritans from Lynn, Massachusetts. Some of those settlers later migrated to what is today East Hampton. Later on the same year, Puritans came from New Haven, Connecticut, settling in Southold on the North Fork of Long Island on October 21, 1640.


I was in Southampton earlier this year and read the historical marker proudly declaring Southampton to be the oldest English settlement (1640) in New York State. New Amsterdam might have been settled earlier (1624), but it was Dutch until it became English, as New York, in 1664. Put differently, English language and culture entered New York State from the east end of Long Island, out of Massachusetts and Connecticut.


COLONIAL POLITICAL DIVISIONS In 1683, the Province of New York established within its jurisdiction its first 12 counties, including four counties with royal names, Kings, Queens, Dutchess, and Dukes. At the western end of Long Island were both Kings County (today comprising Brooklyn), and Queens County (Queens). Further afield, it established to the north Dutchess County in the mid-Hudson region, on the east bank of the Hudson abutting New England, and to the east, Dukes County, which comprised Nantucket, Martha’s Vineyard, and the Elizabeth islands. Dukes County also abutted New England just off Cape Cod, but this county and these islands remained part of the Province of New York for only eight years. In 1691 Dukes County legally became a part of New England, specifically the Province of Massachusetts Bay (Massachusetts). At that point, Nantucket County was formed to encompass just Nantucket, while Martha’s Vineyard and the Elizabeth Islands retained the original name of Dukes County. I find it of great interest that these islands were a part of New York at that time, there apparently being enough of a feeling of a relationship between them and Long Island that they were essentially considered an extension of it.


HISTORIC RAIL CONNECTIONS I remember how shocked I was when I first learned that the Long Island Rail Road was established to provide rail service to Boston. It was a three-seat ride. Trains left Brooklyn to the North Fork of Long Island, then passengers took a ferry to Connecticut, then another train to Boston. Since shortly afterward, all service went, as it does today, via Connecticut in the first place on a one-seat ride, the concept of connecting Long Island to New England amazed me. Well, obviously it doesn’t amaze me any longer. The full description of this LIRR route is at 2006/11 “Off to Boston!”


Later Additions to the Outer Lands   The sea taketh away, but the sea also giveth. Long after the Outer Lands were formed and then partially drowned by the sea, the sea also provided waves and tides to add land. Here are three notable additions.


OUTER CAPE It’s well known that Cape Cod (2009/27) is shaped like a flexed arm, easily recognized in this satellite view. We’ve said, though, that the Harbor Hill Moraine and subsequent outwash plain ran here west-east, and formed only the lower “upper arm” of the Cape, just up to the “elbow”. The south-north “forearm” and “fist” of the Cape were formed much later by sand deposited by the action of tidal currents and waves moving up the coastline.


MONTAUK ISLAND It’s always struck me as odd that one fork of Long Island, the South Fork leading out to Montauk Point, was so much longer than the other, the North Fork leading out to Orient Point. During my trip to the region earlier this year, I found out that they originally were about the same length, and why one is longer.


After the flooding of the area, the South Fork ended where the village of Amagansett is today, making it the same length as the North Fork. Five millennia ago, east of Amagansett were two islands. Beyond an inlet was what first could be called Hither Hills Island (where Hither Hills State Park is today), and then beyond another inlet was what could be called Montauk Island, where the village of Montauk and Montauk Point are today. Through time, marine erosion along the Atlantic shore carved back the headlands of the glacial moraine. Longshore currents gradually built up spits that eventually connected these two islands to Long Island, giving the South Fork an additional extension.


BARRIER ISLANDS Barrier islands are narrow, long sand spits that form just off, and parallel to, coastlines. They are strikingly noticeable off the south shore of Long Island, where a series of them begins, continuing down the east and gulf coasts of North America as far as Mexico. They include the Jersey Shore, with Atlantic City, the Outer Banks of NC, Palm Beach and Miami Beach FL, Galveston and Padre Islands TX. Scientists cannot agree how barrier islands form. One theory is that they had been sandy coastal ridges that became isolated as the rising sea level flooded the area behind them. Another theory is that waves coming ashore churn up sand and deposit it in an underwater sand bar where the waves break, losing energy. These bars eventually build up through wave and tidal action above sea level forming barrier islands. To me, this latter explanation seems the more likely.


Barrier islands are separated from each other by inlets, and separated from the mainland by lagoons, that are almost always referred to as bays. This can be ascertained from this satellite map of Long Island.


While the beaches from Montauk westward through the Hamptons are located directly on the mainland of LI, the barrier islands then follow to the west. You can see the inlet into Shinnecock Bay, to the west of which starts Westhampton Beach Island. Another inlet in Moriches Bay denotes the start of the very famous Fire Island, which eventually encompasses the visibly huge Great South Bay. Overlapping then is the also famous Jones Beach Island, followed by Long Beach Island. Beyond that is a curiosity, a onetime barrier beach that has become attached to the mainland at its east end, the Rockaway Peninsula in Queens, encompassing Jamaica Bay, with Kennedy Airport on its NE side. It should be noted that the lagoon known as Jamaica Bay is therefore a coastal phenomenon related to the barrier beaches and not part of New York Harbor, either geologically, historically, or practically.


Finally, the westernmost barrier island on Long Island is Coney Island at the southernmost tip of Brooklyn, better seen in detail here. It is now physically attached to Brooklyn since the central part of the narrow strait separating it was filled in in the mid-20C. The end of the Rockaway Peninsula is seen across Rockaway Inlet leading to Jamaica Bay.


The last barrier “island” in the region of New York harbor is Sandy Hook in New Jersey. Although it’s the first of many barrier islands running down the Jersey Shore, just like the Rockaway Peninsula, it’s attached at one end, so it, too, is a “barrier peninsula”. It can be seen here how these two peninsulas mark the entrance to New York Harbor, the geological development of which--essentially, how the mouth of the Hudson moved about--will be the topic of the next posting.

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