National Geographic : 1969 Oct
had not also come out of the voyage) would have brought him enduring fame. Formed by countless millions of tiny polyps, the coral atolls were surrounded by almost unfathomable depths. The polyp could flourish only in the upper layers of the sea, no farther down than 20 or 30 fathoms. Yet the reefs they built often rose from tremendous depths. How could this be? Darwin reasoned that the reefs hadn't risen; full of homesick heroes," Darwin wrote, still "Th many months from home. His English pride Ron swelled when he reached prosperous Australia. hav they had sunk. The volcanic upthrusts on which the reefs first formed had subsided. It was the same instability of the earth's crust that he had seen demonstrated so clearly in the Andes. As the mountaintops on which the polyp colonies lived slowly sank, the myriad coral skeletons sank with them. More and ever more lived and died on top of them, steadily renewing the atoll. The Beagle, after 10 days at Mauritius, is is really a wonderful Colony; ancient ne, in her Imperial grandeur, would not e been ashamed of such an offspring." 493 EKTACHROME BY WINFIELDPARKS( N.G.S.