Counties and parts of Hampshire, Hardy, Tucker and Pendleton Counties). The Supreme Court rejected these claims in two separate decisions in 1910. Development of natural resources After Reconstruction, the new 35th state benefited from the development of its mineral resources more than any other single economic activity. Saltpeter caves had been employed throughout Appalachia for munitions; the border between West Virginia and Virginia includes the "Saltpeter Trail", a string of limestone caverns containing rich deposits of calcium nitrate which were rendered and sold to the government. The trail stretched from Pendleton County to the western terminus of the route in the town of Union, Monroe County. Nearly half of these caves are on the West Virginia side, including Organ Cave and Haynes Cave. In the late 18th century, saltpeter miners in Haynes Cave found large animal bones in the deposits. These were sent by a local historian and frontier soldier Colonel John Stuart to Thomas Jefferson. The bones were named Megalonyx jeffersonii, or great-claw, and became known as Jefferson's three-toed sloth. It was declared the official state fossil of West Virginia in 2008. The West Virginia official state rock is bituminous coal, and the official state gemstone is silicified Mississippian fossil Lithostrotionella coral. The limestone also produced a useful quarry industry. Usually small, and softer, high-calcium seams were burned to produce industrial lime. This lime was used for agricultural and construction purposes; for many years a specific portion of the C & O Railroad carried limestone rock to Clifton Forge, Virginia as an industrial flux. Salt mining had been underway since the 18th century, though it had largely played out by the time of the American Civil War, when the red salt of Kanawha County was a valued commodity of first Confederate, and later Union, forces. In the years following, more sophisticated mining methods would restore West Virginia's role as a major producer of salt. However, in the second half of the 19th century, there was an even greater treasure not yet developed: bituminous coal. It would fuel much of the Industrial Revolution in the U.S. and the steamships of many of the world's navies. The residents (both Native Americans and early European settlers) had long known of the underlying coal, and that it could be used for heating and fuel. However, for a long time, "personal" or artisanal mining was the only practical development. After the War, with the