A Long Wait for Stonybrookadactyl

The weather was right: hot and sticky. So was the terrain: swampy. The right plants -- subtropical ferns -- grew here, too.

But Jurassic Parkway won't be in theaters anytime soon because so far, there's only indirect evidence that dinosaurs lived on the place that would become Long Island.

Dinosaur bones and footprints have been unearthed nearby in New Jersey, Connecticut and the upstate Hudson River Valley. But not here. The most glamorous fossils recovered on and near Long Island have instead been teeth from mammoths and mastodons -- Ice Age elephants that lived tens of millions of years after dinosaurs disappeared from the region.

Dinosaur fossils are hard to find anywhere, and even tougher to unearth on Long Island. Except for a few exposed cliffs on the North Shore, in places like Garvies Point in Glen Cove and Roanoke Point north of Riverhead, almost all of the local rock that dinosaurs would have walked upon has since been buried beneath hundreds of feet of sand and gravel deposited by later glaciers.

Another problem is that Long Island's soil is saturated with water and rich in oxygen, which means bones tend to break down quickly before they can mineralize and become stone fossils.

``Surely there were dinosaurs around. It's just that conditions weren't right for preservation of bones,'' said Herbert Mills, curator of geology for Nassau County's division of museums.

But Mills and other local geologists haven't given up hope. On a recent trip to the Port Washington sand pits, where decades of sand mining removed newer glacial deposits and exposed the 90-million-year-old rock below, Mills noted that dinosaurs did not become extinct until 25 million years after the newly exposed rock was formed.

``You could very well be standing on a dinosaur bone,'' Mills told a visitor.

The Long Island region was often underwater when dinosaurs roamed the Earth. But at times when sea level was low enough, they probably thrived here because the climate was warmer, and swampier, than today, scientists believe. The eastern edge of North America was much closer to the equator, and included lots of marshy deltas from rivers that swept down from the newly formed Appalachian Mountains, which 200 million years ago were as tall as the Rockies are today.

Dinosaurs disappeared worldwide 65 million years ago when the climate cooled abruptly, perhaps because a giant asteroid or comet crashed into Mexico's Yucatan Peninsula and threw enormous amounts of dust into the atmosphere. On Long Island, studies of fossilized pollen show that the local vegetation suddenly switched from subtropical ferns to temperate flowering plants such as magnolia, willow and sassafras.

The richest fossil finds in the region have been in New Jersey, including the first dinosaur ever

discovered in the United States: a duck-billed Hadrosaurus unearthed in 1858 and named for Haddonfield, where it was discovered. Bones from another species, Dryptosaurus, that resembled a smaller version of Tyrannosaurus rex also have been found at several sites around New Jersey.

``I think we had as many different kinds of dinosaurs as any place on Earth,'' said David Parris, curator of natural history at the New Jersey State Museum in Trenton. ``If they're found in New Jersey, there's no reason why, theoretically, you couldn't expect to find them in New York, including Long Island.''

So far, though, the only large-animal fossils found on or near Long Island have been much newer: the teeth, and occasionally tusks, of mastodons and woolly mammoths.

The two furry elephant-like beasts lived on Long Island for several hundred thousand years before disappearing about 11,000 years ago, casualties of warmer temperatures and hunting pressure from nomadic Indians who were beginning to enter the region. Mastodons were longer but had lower shoulders than mammoths, which resembled modern elephants except for their furry coats.

On land, the fossil finds have been meager locally. Five teeth and a few bone fragments from a young mastodon were discovered by workers dredging a pond in Jamaica, Queens, in 1858 -- the same year Hadrosaurus was found in New Jersey. The only other reported finding, a mastodon jawbone recovered on a Southold beach in 1823, was later discovered to have been brought to Long Island from Kentucky by a collector.

But the waters off Long Island's South Shore have been a treasure trove of mammoth and mastodon teeth and tusks, most of them caught in fishing nets. Dozens of teeth have been found over the years, and some are now on display in the Hall of Extinct Mammals on the fourth floor of the American Museum of Natural History.

Shifting sea level explains why so many fossils have been found offshore. During parts of the Ice Age, so much ocean water was locked up in glaciers that sea level was about 350 feet lower than today and the South Shore of Long Island was 80 miles farther south, revealing a broad coastal plain, an ideal habitat for the ancient elephants.

But mastodons don't fire the imagination like dinosaurs, and local geologists are eagerly awaiting the day when someone, somewhere on Long Island, stumbles on a buried dinosaur bone -- Greatneckasaurus, perhaps, or Hicksvillatops.

``I believe such a find is possible,'' said Steve Englebright of the Museum of Long Island

Natural Sciences in Stony Brook. ``It could happen here.''

Where Beasts Roamed

Children clambering over a plastic mastodon statue in Baisley Pond Park in Queens have no way of knowing that they are playing at the only place where on Long Island where bones of the now-extinct Ice Age elephant have ever been found. No sign marks the place where in 1858, workmen excavating part of the pond uncovered five molar teeth and a few fragments of an ivory tusk belonging to a young mastodon, buried beneath four feet of muck. The only reminder of the historic find is the new mastodon statue in the park's Sutphin Boulevard playground, which was renovated last summer.

Where those mastodon bones are today is mystery. Several local geologists say one tooth was part of Adelphi University's fossil collection, but faculty members say they have no record of the tooth. All other mastodon and mammoth bones found in the Long Island region have been dredged up by fishermen trawling off the South Shore, in areas exposed during the last Ice Age, when sea level was more than 300 feet lower than today.