Photomicrograph of a sheared Ordovician black shale from the footwall of the Champlain Thrust fault in Vermont. A large calcite vein can be seen in the bottom of the photo, and a smaller one stretches diagonally across the field of view. The darker, finer-grained bands that run roughly horizontally across the field of view represent a spaced shear fabric. The thinner calcite vein can be seen to predate these discrete, fine-grained shear surfaces, as observed by the offset in the vein visible near the center of the field of view. This rock could be classified as a cataclasite. This picture was taken under a magnification of 25x, under plane light.