The next port to the eastward is Rosario Bay. It was named by Sarmiento "Puerto de Nuestra Señora del Rosario." The rock formation here is limestone, and of the kind above mentioned, but the effects of frequent rain in washing away the more soluble parts of the rock were not only manifested by the honeycombed appearance of exposed surfaces, but also by the prevalence of caves of most irregular shape. Soon after we had anchored, Sub-Lieutenant Beresford and I, who had gone away in the skiff, were paddling around an islet with lofty and precipitous sides, when we noticed in the face of a bare rocky cliff a suspicious-looking dark opening, partly blocked up with stones, and situated about thirty feet above the sea level. We ran the boat alongside the rocks, and Beresford kept her from bumping while I climbed up the cliff to reconnoitre. On clearing away a heap of stones and rubbish, I laid bare a sort of niche in the rock, in which were portions of a human skeleton, the long bones lying together in a compact bundle, as if they had been so placed there when in the dried state. Not many yards from this crevice we soon discovered a small cave in the rock, and partly imbedded in the soil which formed its floor were a human jaw-bone and fragments of smaller bones. On excavating the floor of the cave we found it to consist of a stiff pasty greyish-white marl-clay, abounding in small shells, amongst which were species of the genera _Patella_, _Fissurella_, _Chiton_, and _Calyptræa_. On reaching a depth of about one foot, we came upon a nearly complete human skull of immature age, an otter skull with bones of the same, and the tooth of an _Echinus_. The human bones obtained were part of the skeletons of two individuals, one of whom must have been young, for the epiphyses of the long bones were not quite cemented to the shafts. I noticed that the skull presented a completely ossified frontal suture, although, from the nature of the teeth and alveoli, the person to whom it belonged could not have lived for more than twelve years or thereabouts. A tibia found in the first depôt bore marks of having been chopped by some sharp cutting instrument. From the fact of these bones being found interbedded with marine deposits, coupled with what we know of these islands having been elevated within recent times--I here refer to the evidence afforded by raised beaches and old high-water marks in the faces of cliffs--there is reason to believe that these bones were deposited in the cave at a time when it was under water, that they thus became surrounded by and imbedded in an ordinary marine shallow water deposit, and that eventually, on the island being elevated so as to raise the cave to its present position--thirty feet above sea level--the surface deposit was reinforced by the percolation of lime-charged water from the rock above, thus resulting in the formation of the marl-clay surface-layer above mentioned.