Part A-Naming an Erosional Surface Uncordomates represent a gap in the geologic fecord. There are 3 main types of uncentermaties: 1. Oiscondormily: an uncontomity between parallel iayers (e.g. strata or lava howa) 2. Angular unconiomity: an unsenformity between two layers (or sets of layeet) that are not pasaliol. In elher words; the 2 layers forin an angie where they meet at the uncontormity 3. Noncondiemity an unconformity that seperates younger sedimontary rocks from metamorphic or igneous rocks In the below diagram, letber Z represents.