This is a "bedding plane" view of the outcrop of the Vassalboro Formation seen in images 1-3, that is, the view is 90 degrees from the views in those pictures (which, in terms of this view, were taken from over to the left of this view, looking towards its right). Notice the meso-scale "ripples" on these surfaces: these ripple features are not primary sedimentary features, but features formed as these rocks were deformed. The larger fold of which this outcrop is just a part requires these smaller folds within each bed to take up the strain of deformation.

When you fold a telephone book, each page adjusts to the fold by sliding past the page above and below it. In the case of these rocks, friction does not allow the individual grains to slide past each other so easily. Not only that, in the case of the telephone book, the topmost pages grow relatively shorter while the bottommost ones grow relatively longer: a large rock unit must make the same adjustments while being folded, with the added complication of being confined frequently by other rock units above and below.