Petrified wood scattered across the valley floor of Jasper Forest once lay encased in the surrounding bluffs until erosion removed softer rock and left the wood to tumble and accumulate below. In the late 19th and early 20th centuries, the area, once filled with fallen logs, was heavily plundered by commercial collectors and travelers seeking petrified wood for souvenirs. Easy access came with the nearby railway line completed in 1882, and many tons of petrified wood were hauled away in railway cars. Outrage over this devastation helped lead to the establishment of Petrified Forest as a National Monument in 1906. Wood thieves also carried material away by wagon, buggy, and cart, sometimes using dynamite to break larger logs into smaller pieces and expose hidden crystals. A mill to grind petrified wood for abrasives was built at the nearby railroad settlement of Adamana in 1892, but it never operated. Even after protection began, travelers continued removing petrified wood, prompting federal law to prohibit taking any petrified wood, other fossils, or artifacts from these protected lands.