Night had fallen upon unchartered Pal-ul-don. A slender moon, low in the west, bathed the white faces of the chalk cliffs presented to her, in a mellow, unearthly glow. Black were the shadows in Kor-ul-JA, Gorge-of-lions, where dwelt the tribe of the same name under Es-sat, their chief. From an aperture near the summit of the lofty escarpment a hairy figure emerged--the head and shoulders first--and fierce eyes scanned the cliff side in every direction. It was Es-sat, the chief. To right and left and below he looked as though to assure himself that he was unobserved, but no other figure moved upon the cliff face, nor did another hairy body protrude from any of the numerous cave mouths from the high-flung abode of the chief to the habitations of the more lowly members of the tribe nearer the cliff's base. Then he moved outward upon the sheer face of the white chalk wall. In the half-light of the baby moon it appeared that the heavy, shaggy black figure moved across the face of the perpendicular wall in some miraculous manner, but closer examination would have revealed stout pegs, as large around as a man's wrist protruding from holes in the cliff into which they were driven. Es-sat's four handlike members and his long, sinuous tail permitted him to move with consummate ease whither he chose--a gigantic rat upon a mighty wall. As he progressed upon his way he avoided the cave mouths, passing either above or below those that lay in his path. The outward appearance of these caves was similar. An opening from eight to as much as twenty feet long by eight high and four to six feet deep was cut into the chalklike rock of the cliff, in the back of this large opening, which formed what might be described as the front veranda of the home, was an opening about three feet wide and six feet high, evidently forming the doorway to the interior apartment or apartments. On either side of this doorway were smaller openings which it were easy to assume were windows through which light and air might find their way to the inhabitants. Similar windows were also dotted over the cliff face between the entrance porches, suggesting that the entire face of the cliff was honeycombed with apartments. From many of these smaller apertures small streams of water trickled down the escarpment, and the walls above others was blackened as by smoke. Where the water ran the wall was eroded to a depth of from a few inches to as much as a foot, suggesting that some of the tiny streams had been trickling downward to the green carpet of vegetation below for ages. In this primeval setting the great pithecanthropus aroused no jarring discord for he was as much a part of it as the trees that grew upon the summit of the cliff or those that hid their feet among the dank ferns in the bottom of the gorge.