Description: Lines (e.g., cross-section lines) that have no real-world physical existence, such that LocationConfidenceMeters, ExistenceConfidence, and IdentityConfidence attributes are meaningless, and that are never shown as concealed beneath a covering unit.
Description: Lines that represent dikes, coal seams, ash beds, fold hinge-surface traces, isograds, and other linear features. All have these properties: (A) They do not participate in map-unit topology. (B) They correspond to features that exist within the Earth and may be concealed beneath younger, covering, material. (C) They are located with an accuracy that likely can be estimated.
Description: Contacts between map units, faults that bound map units, and associated dangling faults. Includes concealed faults and contacts, waterlines, snowfield and glacier boundaries, and cross section boundary.