The Inner Coastal Plain province consists of lowlands and rolling hills underlain by Cretaceous deposits. Surficial geology in this region contains a number of fossils. The Monmouth County Park system, for example, includes a number of creeks where students and enthusiasts can gain real field exposure to cretaceous geology and paleontology. (Always check with the park service staff regarding permissibility before entering any field site.) The region's northwest border lies along the Piedmont Fall Line. Fertile, loamy soil makes the land ideal for agriculture and is responsible for New Jersey's nickname of the "Garden State". Its deposits of Greensand marl containing potash were used since colonial days by farmers to fertilize their fields.