TABLE 1: SEDIMENTARY FEATURES ASSOCIATED WITH EROSION SURFACES

Table 1: Sedimentary Features Associated with Erosion Surfaces

Feature	Ease of Recognition
Silt Lags	in outcrop, careful examination reveals thicker silt beds (>5mm) in hand specimen and on cut surfaces, beds of 1-2 mm thickness readily seen
Sand Lags	in outcrop, careful examination typically reveals coarser beds, 5-20 mm thick in hand specimen and on cut surfaces, beds of 1-2 mm thickness readily seen
Bone Beds	typically a variant of sand silt lags, with comparable ease of recognition larger bone fragments readily recognizable with hand lens on fresh surfaces
Pyritic Lags	in outcrop, thicker pyritic lags, 10 or more mm thick, may be recognized via rusty stains or crusts of secondary white and yellow hydrous ferric sulfates in handspecimen, layers as thin as 1 mm are readily seen on fresh surfaces
Conodont Lags	may form a variant of sand/silt lags, with comparable ease of recognition mostly forms almost pure layers of conodont material, 1-3 mm thick, that are best observed in handspecimen (bedding plane examination with hand lens)
Lingula Lags	in outcrop and hand specimen, easily recognized only when shale is split along bedding planes in thin section, shell cross-sections easily identified, but may be missed when Lingula shells are sparse on surface
Low-Angle Truncations	typically not recognizable in outcrop best recognized on cut/polished surfaces and in oversize thin sections
Soft Sediment Deformation	deformation on the scale of tens of cm’s (e.g. with associated ball and pilow structures) can be recognized in outcrop small scale deformation (mm’s to cm’s) best recognized on cut surfaces and in thin section
Sharp-Based Shale Beds	recognition easiest on cut and polished surfaces and in thin section very difficult and tentative in outcrop

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