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A Real-World Geology Lesson
A Real-World Geology Lesson
by Marcia Amidon Lusted
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It’s more than a mile deep, home to pink rattlesnakes and blue-green waterfalls, and one of the seven natural wonders of the world. You can ride a mule down into it to visit the most remote settlement in the United States. You can also stand above it on a clear horseshoe-shaped viewing platform that makes you feel like you’re walking on air. Where are you? Chances are you already know: the Grand Canyon.
A Golden Oldie
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Located in Arizona, the Grand Canyon is a real-world geology lesson. It was formed over millions of years by the Colorado River as it slowly eroded layers of sandstone, limestone, and shale. Dirt and rocks carried by the river worked like sandpaper on the stone. Gradually the river cut a groove through the rock and created the cliff walls of the mile-deep canyon. This means that the rocks at the rim of the canyon are about 270 million years old, while those at the bottom of the canyon are more than 1.8 billion years old. The different types of stone also give the cliffs of the Grand Canyon its amazing colors—from brown and cream to deep red, purple, and white.
Home Sweet Canyon
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The Grand Canyon may be millions of years old, but people have only inhabited it for a few thousand years. The first canyon dwellers were Native Americans who built settlements inside the canyon and its caves. Later, Pueblo tribes considered the canyon a holy place and made pilgrimages to it. The Havasupai tribe still lives in a settlement at the bottom of a branch of the Grand Canyon. The first Europeans to see the canyon were Spanish explorers in 1540.
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In 1869, a Civil War veteran named John Wesley Powell set out to explore and map the length of the Colorado River. He traveled through the Grand Canyon and also studied the cultures of some of the Native Americans he met. Powell was also the first person to name the canyon the Grand Canyon (before that it had simply been called “the Big Canyon”). United States President Theodore Roosevelt visited the canyon in 1903. Through Roosevelt’s efforts, the Grand Canyon became a National Park in 1919.
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The Native American tribes who live in the Grand Canyon today include the Havasupai. Their settlement is 3,000 feet down, in a part of the canyon not reachable by car. Visitors must make an eight-hour hike down a very steep trail to reach the tiny town. Even the mail must be delivered by mule.
Do Look Down
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The Hualapai tribe has a reservation in the canyon, too. In March 2007, the Hualapai opened one of the Grand Canyon’s newest attractions: the Grand Canyon Skywalk. The horseshoe-shaped viewing platform has a clear floor. This allows visitors to stand 70 feet out from the canyon rim and see 2,000 feet down to the floor of the canyon. That’s like looking straight down from a skyscraper.
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The tribe was divided over building the attraction. Some members thought it disturbed a place that was holy to the Hualapai people. Others hoped the attraction would bring jobs and income to the tribe. The Skywalk has only been somewhat popular, due to its remote location (10 miles down a dirt road), the cost ($85), and the fact that cameras are not allowed.
Who Owns the Canyon?
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In November 2012, Arizona citizens voted to keep the Grand Canyon under federal jurisdiction. Some Arizona lawmakers had wanted the canyon turned over to state ownership, a move some said would create jobs for people in Arizona. Opponents feared that state ownership of the canyon would undermine the federal government’s environmental protections for the area. With a 2:1 margin, voters decided that the land would remain under federal jurisdiction and would be protected from mining, drilling, and logging industries.
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The Grand Canyon is one of Arizona’s—and the country’s—most famous and recognizable attractions. After all, where else can you descend on the back of a mule through billions of years of Earth’s history? This descent could be the most exciting geology lesson you could ever have.
Adapted from “A Real World Geology Lesson” by Marcia Amidon Lusted from Faces Magazine Based on the information in the passage, select all the statements that are most likely true about John Wesley Powell.

He enjoyed being in the wilderness.

He was a good soldier in the Civil War.

He valued learning about other people groups.

He thought the Grand Canyon was fascinating.

GPT-4o mini · Answer

Based on the information in the passage, the statements that are most likely true about John Wesley Powell are:

He enjoyed being in the wilderness. - This is likely true, as he set out to explore and map the length of the Colorado River, which suggests an appreciation for wilderness and exploration.
He was a good soldier in the Civil War. - While the passage states that he was a Civil War veteran, it does not provide evidence or details about his performance as a soldier, so we cannot definitively say this is true.
He valued learning about other people groups. - This is likely true, as the passage mentions that he studied the cultures of some of the Native Americans he met during his exploration.
He thought the Grand Canyon was fascinating. - This is likely true as well, given that he explored and mapped the canyon, indicating he found it worthy of his attention and study.

Therefore, the statements that are most likely true about John Wesley Powell are:

He enjoyed being in the wilderness.
He valued learning about other people groups.
He thought the Grand Canyon was fascinating.

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