§ 62.5 — Natural Landmark Criteria

(a) Introduction. (1) National significance describes an area that is one of the best examples of a biological or geological feature known to be characteristic of a given natural region. Such features include terrestrial and aquatic ecosystems; geologic structures, exposures and landforms that record active geologic processes or portions of earth history; and fossil evidence of biological evolution. Because the general character of natural diversity is regionally distinct and correlated with broad patterns of physiography, many types of natural features are entirely inside one of the 33 physiographic provinces of the nation, as defined by Fenneman (Physiographic Divisions of the United States, 1928) and modified as needed by the NPS.

(2) Because no uniform, nationally applicable classification scheme for biological communities or geological features is accepted and used by the majority of organizations involved in natural-area inventories, a classification system for each inventory of a natural region was developed to identify the types of regionally characteristic natural features sought for representation on the National Registry of Natural Landmarks. Most types represent the scale of distinct biological communities or individual geological, paleontological, or physiographic features, most of which can be mapped at the Earth's surface at 1:24,000 scale or are traceable in the subsurface. In some cases, the NPS may further evaluate only a significant segment of a given natural feature, where the segment is biologically or geologically representative and where the entire feature is so large as to be impracticable for natural landmark consideration (e.g., a mountain range). Almost two-thirds of all national natural landmarks range from about 10 to 5,000 acres, but some are larger or smaller because of the wide variety of natural features recognized by the National Natural Landmarks Program.

(b) Criteria. NPS uses the following criteria to evaluate the relative quality of areas as examples of regionally characteristic natural features:

(1) Primary criteria. Primary criteria for a specific type of natural feature are the main basis for selection and are described in the following table:

(2) Secondary criteria. Secondary criteria are provided for additional consideration, if two or more similar area cannot be ranked using the primary criteria. Secondary criteria are described in the following table: