Petrified Forest National Park, Navajo, Apache, Arizona, United States

A slightly later route along the parallel was a wagon road, built between 1857 and 1860, that involved experimental use of camels as transport. In the late 19th century, settlers and private stagecoach companies followed similar east–west routes. Homesteaders who stayed in the area developed cattle ranches on the grasslands, and cattle grazed in the Petrified Forest until the mid-20th century.
Also close to the 35th parallel was the Atlantic and Pacific Railroad. Its opening in the early 1880s led to the founding of towns like Holbrook and Adamana. Visitors could stop at the Adamana train station, book a hotel room, and take a tour of what was then called the Chalcedony Forest. Over the years, the line changed hands, becoming the Atchison, Topeka and Santa Fe Railway, and then the BNSF. More than 60 BNSF trains, mostly carrying freight, pass through the park every day. U.S. Route 66, a former transcontinental auto highway developed in 1926 from part of the National Old Trails Road, ran parallel to the railroad tracks until it was decommissioned in 1985. The park has preserved within its boundaries a small grassy section of the road. Interstate 40, which crosses the park, replaced the older highway.
Increasing tourist and commercial interest in petrified wood during the late 19th century began to alarm residents of the region. In 1895, the Arizona Territorial Legislature asked the U.S. Congress to create a petrified forest national park. Although this first attempt failed, in 1906 the Antiquities Act signed by President Theodore Roosevelt was used to create the Petrified Forest National Monument. Between 1934 and 1942, the federal Civilian Conservation Corps built road, trails, and structures in the monument, and the government acquired additional land in the Painted Desert section. The monument became a national park in 1962. Six years after the signing of the Wilderness Act in 1964 by President Lyndon B. Johnson, wilderness areas (where human activity is limited), were designated in the park. In 2004, President George W. Bush signed a bill authorizing the eventual expansion of the park from 93,353 acres (about 146 mi2 or 378 km2) to 218,533 acres (about 341 mi2 or 884 km2). Theft of petrified wood is still a problem. Despite a guard force of seven National Park Service rangers, fences, warning signs, and the threat of a $325 fine, an estimated 12 short tons (11,000 kg) of the fossil wood is stolen from the Petrified Forest every year.
Jessee Walter Fewkes, the first archeologist to visit Puerco Ruin, predicted in the late 19th century that it would yield many artifacts. Conservationist John Muir conducted the first excavations of the ruin in 1905–06. Although he did not publish his findings, he urged the federal government to preserve Petrified Forest. Professional archeological work in the park began in the early 20th century when Walter Hough conducted excavations at Puerco Ruin and other sites. In 1919, a phytosaur skull was discovered near Blue Mesa in the Petrified Forest and sent to the Museum of Paleontology in Berkeley, California. In 1921, Annie Alexander, founder of the museum, visited Blue Mesa to collect more of the phytosaur and other specimens; this led to further excavations by paleontologist Charles Camp. Since then, more than 250 fossil sites have been documented in the park. In the 1930s, the Civil Works Administration funded research in the park by archeologists H.P. Mera and C.B. Cosgrove. A National Park Service resurvey of the Petrified Forest in the early 1940s identified most of the large sites with stone ruins, and subsequent surveys since 1978 have identified a total of more than 600 artifact sites, many of them small. Research in paleontology and archeology continues at the park in the 21st century.