P-34713 This Voyager image of Triton reveals two kinds of mid-latitude terrain. Near the center and the lower half of the frame is a gently rolling terrain pock-marked with a modest number of impact craters. The density of impact craters is somewhat similiar to that found on the mare surface of Earth's moon. Crossing this rolling surface are narrow rifts, one of which grades into a chain of craters that probably are of collapse origin. In the upper right part of the frame is a smooth terrain with very sparse impact craters. This terrain evidently has been formed by flooding of the surface by low-viscosity fluids rather late in geologic time. One of the vents from which these fluids erupted probably is represented by a deep, elongate crater near the middle of the right side of the image. Two slightly dark regions underlain by late eruptive material also occur in the left half of the image. Apparent vents for these eruptions are marked by shallow depressiions, which may have been formed by drain back of material at the end of the eruptive episode.