Santucci, Vincent L., Kenworthy, Jason and Kerbo, Ron. 2001. An Inventory of Paleontological Resources Associated with National Park Service Caves. Geologic Resources Division Technical Report NPS/NRGRD/GRDTR-01/02.
More than 3,600 caves and karst resources have been identified in at least 79 units of the National Park System. In 1998, the National Park Service Geologic Resources Division initiated a servicewide inventory of paleontological resources occurring in association with these caves. The inventory documented at least 35 park areas that preserved fossils within cave resources.
Cave-paleontological resources are identified in two categories: 1) fossils preserved within the cave-forming bedrock, and 2) fossils accumulated within the caverns, chambers, or other openings in karst systems.
Caves occur in both karst and non-karst areas. Karst caves, and features within them such as stalactites and stalagmites, are formed by a variety of processes. These processes include the dissolution and erosion of sedimentary and evaporitic rocks, and later deposition of mineral from the dissolution process. Within limestones, the remains of marine invertebrate and vertebrate fossils are typically preserved. Paleozoic limestones constitute the parent rock in which many cave and karst features develop in NPS administered areas. Therefore, the fossilized remains of Paleozoic fauna are often the most common types of paleontological resource associated with caves. Caves also form as the result of lava flows (lava tubes), wave action (littoral caves), and by the fracturing of rock (earth cracks).
Cave feature development is documented from the Holocene back to the Eocene. Caves, sinkholes, solution tubes, and other karst features attract and can trap animals. Pleistocene and Holocene vertebrate remains are abundant in many caves. Rich deposits of fossil bone can develop either through the accumulation of remains associated with organisms inhabiting the cave, such as Neotoma (packrats), or through a variety of transport mechanisms.