A more subtle radial pattern in the ejecta can be seen where the Sun's rays shine across it, to the north and south of the crater. Most young lunar craters wider than about 40 km have flows on their rims that resemble lava flows or mud flows on Earth. Flows in the middle of the picture surged downhill off the high rim of the crater making lobes and tongues and leaving behind drained channels with levees. In the area to the right of the crater, enlarged in figure 104, are some thin lobate flows that apparently rode over small hills, as if these flows were propelled outward from the crater with sufficient velocity to climb the hills. Ejecta deposits farther than about 1 km from the rim are radially lineated and are smoother than the ground immediately surrounding the crater.
Arrows point to the lower ends of two flows.
The origin of the flow material is controversial. At sampling station 8, 3.4 km from the edge of South Ray, astronauts John Young and Charles Duke sampled some rocks from South Ray that had been deposited as ejecta along one of its numerous rays. Studies of these rocks indicate that South Ray formed about 2.5 million years ago bringing rocks 3.8 billion years old to the surface. The impact that created South Ray crater occurred when Australopithecus lived in Africa-well before contemporary man evolved. Its rim crest is much sharper than South Ray's and its rays overlie those of South Ray.