A Texas boy named George Adams was wandering along the Paluxy River near Glen Rose in 1909 when he was stopped short by huge animal tracks calcified in the stone. George's sharp-eyed discovery of what turned out to be dinosaur footprints helped open an exciting chapter in Texas and U.S. natural history.

Much later, researchers from across the country poured into the area southwest of Fort Worth, putting Glen Rose at the center of the world of paleontology. This area today is home to Dinosaur Valley State Park. At this sprawling preserve, a National Natural Landmark, visitors can see dinosaur tracks as large as three feet long by two feet wide.

This tranquil terrain along the Paluxy River, once home to the Caddo and Tonkawa tribes, today differs markedly from the era when dinosaurs roamed. The shores of the Gulf of Mexico came close to Glen Rose some 100 million years ago.

"A broad, shallow coastal lagoon allowed dinosaurs to cavort and feed in the shallow water, leaving footprints in the limey muds, a perfect physical setting for making many fossil trackways. The second ingredient needed to preserve the tracks is a gentle filling-in of the prints by sediment to keep the shape intact," writes Charles E. Finsley in his book, Discover Texas Dinosaurs.

A ranch near Glen Rose eventually yielded remains of what was thought to be the Pleurocoelus, designated in 1997 as the "State Dinosaur of Texas" by the Texas Legislature. These were plant-eating, short-necked and long-tailed animals, 30 to 50 feet in size.

But more recent research suggests the remains were actually those of a previously unrecognized dinosaur, the Paluxysaurus. The legislature might have to revisit its 1997 designation.

Remains of ancient animals have been found throughout Texas. Dinosaurs were most prevalent in Central Texas, in the plains areas including Lubbock and Amarillo, and in the Big Bend region, where remains of the great Tyrannosaurus Rex were found.

In his book Lone Star Dinosaurs, Southern Methodist University Professor Louis Jacobs marvels at the variety of Texas discoveries: "They represent a varied sampling of dinosaur diversity. They lived at three distinct intervals during the Age of Dinosaurs. And they lived in such different arrangements of the continent and oceans that they may as well have lived in different worlds."

As Professor Jacobs noted, many Texas dinosaur breakthroughs came from unlikely explorers. "The story of Texas dinosaurs is made up of a myriad of smaller tales about everyday people who make one-in-a-million discoveries." A seven-year old boy and his dad found skeletal remains in Parker County in 1988, which led to identification of a new species of dinosaur. A year later, a 12-year-old boy made an important discovery of dinosaur fossils in Fort Worth.

One site from a more recent era created substantial buzz in the scientific community. In 1978, near Waco, two local residents found skeletal remains of 25 mammoths thought to have lived "only" 68,000 years ago. Researchers believe more mammoths may have died at this one place, from the same cause, than at any other place in the world.

Fragile conditions at the site have thus far prevented public access, but the National Park Service last year determined the Waco Mammoth Site met its criteria for park system status. I am among those supporting the effort to make this site a federal park.

Texas is a young and vigorous state. We take great pride in our traditions and accomplishments of our human history. It's worth remembering that Texas's natural history is far longer, and contains many mysteries that remain to be resolved.