Early in 1908, Sternberg planned an expedition to the Lance Creek area in eastern Wyoming, where the family had not worked before. In search of acquirers of potential fossil finds, he wrote to the British Museum of Natural History that he knew where in Wyoming to find a skull of the horned dinosaur "Triceratops", knowing that the museum was lacking a good specimen; the museum agreed to buy any good fossil finds if such were made. The Sternbergs left their family residence in Kansas in early spring, and arrived in the Lance Creek area in July. Sternberg's plan foresaw the exploration of an uninhabited area of approximately north to the North Platte River and south to the Cheyenne River in Converse County (today Niobrara County). The predominant badlands of this area expose sedimentary rocks of the Maastrichtian stage of the Upper Cretaceous, which today are known as the Lance Formation. The area had already been intensively explored by paleontological expeditions; before the start of his expedition, Sternberg learned that the American Museum of Natural History had been unsuccessfully working in the area for years. Although the party was enthusiastic (Sternberg's sons had never discovered dinosaur fossils before), the first weeks of search were unsuccessful. Sternberg wrote in his 1909 book "The Life of a Fossil Hunter":  At the end of August, Sternberg finally discovered a fossil horn weathering out of the rock; subsequent excavation revealed a long "Triceratops" skull. Soon after, George, the oldest son, found bones sticking out of the rock while prospecting new territory with Levi, the youngest son. Levi discovered more bones nearby, apparently belonging to the same skeleton. By then, the group had travelled from their base camp, and food was running short. Sternberg instructed George and Levi to carefully remove the sandstone above the skeleton, and Sternberg himself set off for Lusk with Charles Jr. to purchase new supplies and to initiate the shipping of the "Triceratops" skull to the British Museum. The third day after their father's departure, George and Levi recognized that they had found an apparently complete skeleton lying on its back. When removing a large piece of sandstone from the chest region of the specimen, George discovered, to his surprise, a perfectly preserved skin impression. In 1930, George remembered:  When Sternberg finally returned at the fifth day, George and Levi had run out of food, and had eaten only potatoes for the last two days.