Strains thought to be associated with movement of a thrust sheet over a ramp are recorded by cleavages and syntectonic fibers within a thrust slice of the Hamburg sequence north of Reading, Pennsylvania. The three cleavages and bedding are coaxial with the regional east-northeast strike, and three related sets of fibers are found in pressure shadows on microscopic, near-spherical pyrite framboids. Viewed east-northeast at XZ sections, the oldest fiber set in the pressure shadows begins with a short segment at ∼40° to the slaty cleavage (S ₁), but smoothly reorients clockwise to parallelism with the gently dipping S ₁. A crenulation cleavage (S ₂) crudely fans a broad antiform in S ₀and S ₁, but consistent north-northwest-side-up offsets across cleavage planes throughout the fold, and localized development of an extremely stylolitic character to S ₂in the core of the fold, suggest that this cleavage preceded folding. Fibers of the first set curve sharply but continuously into fibers of the second set, which are parallel to S ₂. A third cleavage (S ₃) crenulates S ₂and exhibits consistent top-toward-south-southeast offsets. Short fibers parallel to S ₃are found on framboids in zones between S ₂lamellae, but within the S ₂lamellae, long fibers in cylindrical pressure shadows together with other features indicate a volume gain, subhorizontal extension during F ₃development. The progression through these three deformation phases fits well with the strains expected during the movement of a thrust sheet: (1) on a flat; (2) through a closing bend onto a ramp; and (3) through an opening bend onto a higher flat.