“Upon every side it is girdled by a broad barrier of coral, about fifteen feet above the level of the ocean. There is no entrance to the lagoon, neither does it communicate with the ocean by subterranean passages, as the water inside is _fresh_ and _potable_. It is slightly brackish, but will appease thirst. The ‘ROCK’ is a ragged pile of volcanic formation, on the south end of the island, gray and splashed over with the deposit of the birds. It is cracked and split in every possible direction, here and there shooting into tottering pinnacles. As you wander through the caverns and clefts, with which it is perforated, there is an incessant splashing and dropping of water. On the very topmost pinnacle, which I reached after a hard climb, I found a little basin containing a couple of buckets full. The caverns were dreary looking places, dark and wet, and echoing to the hoarse cries of the sea-birds. The rock, on its sides, is rounded and smoothed by the action of the waves, at some long past time, and in many places ‘_the walls are crusted with coral_.’ “The highest pinnacle of the rock is about 120 feet high, and it covers, I should think, about two acres. It stands on the edge of the lagoon, or rather within it, being connected with the coral barrier only by a narrow isthmus of coral clinker. Between this rock and the sea, however, the barrier, instead of being as elsewhere, a solid platform of coral, is only a heap of fragments, piled in winrows by the waves, 250 or 300 yards in width. The lagoon is a quiet fresh water pond, two miles long and about one broad, with a long spit of mud running out into the middle of it, but elsewhere of a light green color, which seemed to indicate a considerable depth. Its shores are abrupt, the coral platform in most places projecting out over water of a considerable depth. I did not find the least sign of vegetable life upon the island. “The only plant[14] seen, grew in considerable quantities in the lagoon, which I pulled out of the water, where it was growing. There is nothing but a coral platform, coral clinker and coral sand. We found nothing to detain us and left the island on the afternoon of the day on which we landed.” Mr. Darwin, on his remarks on the geographical distribution of reef-building corals, states that he could find no evidence of their living on or near the west coast of America, and consequently discredits the statement made by Sir Edward Belcher; for after examining a Ms. chart of Clipperton Rock, at the Admiralty Office, drawn by Sir Edward, came to the conclusion that it was more of the shape of a crater. The Island is, however, a true Atoll and has been elevated at least 100 feet. It must have been closed since 1839, and the freshening of the water has probably been caused by rain.