English: Color image of part of the Ismenius Lacus region of Mars (MC-5 quadrangle) containing the impact crater Moreux (right center); north toward top. The scene shows heavily cratered highlands in the south on relatively smooth lowland plains in the north separated by a belt of dissected terrain, containing flat-floored valleys, mesas, and buttes. This image is a composite of Viking medium-resolution images in black and white and low-resolution images in color. The image extends from latitude 36 degrees N. to 50 degrees N. and from longitude 310 degrees to 340 degrees; Lambert conformal conic projection. The dissected terrain along the highlands/lowlands boundary consists of the flat-floored valleys of Deuteronilus Mensae (on left) and Prontonilus Mensae (on right) and farther north the small, rounded hills of knobby terrain. Flows on the mensae floors contain striae that run parallel to valley walls; where valleys meet, the striae merge, similar to medial moraines on glaciers. Terraces within the valley hills have been interpreted as either layered rocks or wave terraces. The knobby terrain has been interpreted as remnants of the old, densely cratered highland terrain perhaps eroded by mass wasting.