Nature Notes: Sands of Time

I live across the street from Noyac’s Long Beach, a barely more than 100-foot-wide isthmus between Noyac Road and Route 114. The isthmus, with its county road, Long Beach Road, separates the inner Sag Harbor Cove from the outer Noyac Bay, part of the Peconic Estuary.

The upper beach, or “backshore,” is almost 100-percent stony, while the lower beach is three-quarters sand and a quarter stone. The high-tide line is marked by the usual detritus collection of slipper shells, jingle shells, parts of crabs, bivalve mollusk shells, as well as the occasional conch shell. Bay beaches contrast with ocean beaches, except for Montauk, because they are rarely 100 percent soft sand, and often as stony as sandy.

We know the stones were brought here by the last glacier some 15,000 or so years ago, but what is the origin of the quartzy sand? The stones are mostly smooth and roundish from grinding together over many millennia, but the sand grains tend to be angular when viewed under a microscope. It’s hard to believe that all the sand came from thousands of years of stones moving against stones, becoming smaller and smaller, but no doubt a large portion of it did. Yet you find few pebbles when you sift it. Are they the forerunners of sand grains? And why are they so scarce in comparison?

The beach is very active from the end of May to mid-September. Literally hundreds of pairs of feet walk up and down it paralleling the water’s edge and back and forth from the parking area to the water eight hours a day. One would think that all this tramping back and forth in the company of the coming and going of the tides and churning of the waves would grind down the exposed sand and the small stones, producing more and more sand and fewer and fewer small stones from one season to the next. Not so. When you measure the grains from year to year you find that they are largely the same size as they were 10 years ago, a quarter of a millimeter or so big.

One would think that the grains would get smaller and smaller with time and, indeed, there are smaller particles of earthen materials around, such as clays and silts and windblown soils, or loess, the stuff that makes loamy soils, such as those south of the highway in Bridgehampton and Water Mill, excellent for farming. Loess is constantly being deposited, washed away, or blown away and redeposited somewhere else. During the famous Dust Bowl era experienced by the Midwest and Southwest in the 1930s, tons and tons of soil took to the air and landed — just where has never been determined. Dust storms are not confined to Oklahoma and states north and west, but occur all over; most recently, annually in Arizona and every other year or so, right here in little ole East Hampton, especially along Long Lane northwest of the village.

If you compare the size of the sand grains in the Walking Dunes to that on the Napeague Bay shore to the north, you will find a notable size difference. The ones in the dunes are smaller, and, when walked on, seemingly softer to the unshod sole.

We take sand for granted but it covers much of the world’s surface and forms an almost continuous band at the periphery of every continent except Antarctica. One of a coastal child’s first experiences is digging in the sand with the tiniest of shovels and, perhaps, filling a pail almost as tiny. Later on, the child puts down his or her shovel and pail and begins fashioning sand castles. In the past, inland yards often accommodated a rectangular sandbox. We had one for kindergarten and early elementary grades at Mattituck School.

The sand that the glacier deposited, known as subsoil, is found in quantities just south of the moraine. Most of Long Island’s sand quarries are situated in that belt, south of either moraine.

The Italians knew, 2,000 years ago, that beach sand doesn’t make good concrete or mortar. One needs bank-run sand, the kind that you see piled up around new construction sites here and there where a foundation for a new house is being constructed. In other words, the quarried sand is much more angular than the beach sand. While it has been quietly snoozing for 10,000 years or so under the upper crust or topsoil zone, it hasn’t been jostled around as much as the stuff on the beach and in the dunes.

Without beach sand there would be no Mr. Beach. The question that I asked last time when I wrote about sand has never been adequately answered. Think about the Sahara Desert, the ones in Saudi Arabia and Mongolia, think about the Walking Dunes and the barrier beaches locally. What happens to all that sand over time? Does it continually wear away and get tinier and tinier until it is not more than a few molecules of silicon dioxide in size? Are the sands of time timeless, or do they have a finite life on earth the way we do?

Please let me know the answer before my time is up and I am covered in sand forever.

Larry Penny can be reached via email at [email protected].