 His initial impression was of a desolate and sterile volcanic island, but after visiting the town he came to a deep valley where he "first saw the glory of tropical vegetation" and had "a glorious day", finding overwhelming novelty in the sights and sounds.FitzRoy set up tents and an observatory on Quail Island to determine the exact position of the islands, while Darwin collected numerous sea animals, delighting in vivid tropical corals in tidal pools, and investigating the geology of Quail Island.Though Daubeny's book in "Beagle"'s library described the volcanic geology of the Canary Islands, it said that the structure of the Cape Verde Islands was "too imperfectly known".