After 200 years and the mining of 106 million tons of iron, the Cornwall iron mine was closed. Yet, as this 10th-grader from Pennsylvania argues, the site's geologic importance is far from over.

The area surrounding the Huntington Formation is very rich in geologic history, yet it is undocumented and hasn't been mapped in detail. But that didn't stop this 11th-grader from Idaho from surveying its terrain.

About 390 million years ago, the warm, shallow Catskill Sea covered New York State. As the water retreated, it left layers of sedimentary rock and fossils, as this 12th-grader discovered.

Millions of years ago, coral and algae thrived in the shallow sea that once covered Oklahoma's rocky, tree-covered hills and grassy plains. Explore the state's geologic past with this 10th-grader.

Traverse the geologic history of Pikes Peak and the southern Rocky Mountains—from Precambrian foundation to roughly contoured summits—with this 12th-grader from Colorado.

Getting lost "somewhere between North Dakota and Montana" during a family road trip led this 11th-grader from Wisconsin to a picturesque landscape, rich with geologic discoveries.

Did you know that Long Island was once part of a chain of volcanoes? Or that it was part of the tropics—and faced south? Step back in time with this seventh-grader for a look at the forces that shaped this giant sandbar.

For three months in the early 1800s, earthquakes shook two pioneer towns in Missouri—and permanently changed the course of the Mississippi River. Relive that time with this 12th-grader from Wisconsin.

Granite rocks that resemble elephant heads, sapphires that range from the common blue-green to shapes of pink and yellow ... examine the rocks of Helena, Montana, with this ninth-grader.

The meandering stream that carved West Virginia's natural land bridge also helped create diverse layers of rock at its foundation. Tour the area's geological past with this ninth-grader.