The Structure and Distribution of Coral Reefs noted the location of the different types of coral around the reef and in the lagoon. In his diary, he described, "examining the very interesting yet simple structure & origin of these islands. The water being unusually smooth, I waded in as far as the living mounds of coral on which the swell of the open sea breaks. In some of the gullies & hollows, there were beautiful green & other colored fishes, & the forms & tints of many of the Zoophites were admirable. It is excusable to grow enthusiastic over the infinite numbers of organic beings with which
Open Polar Sea had stopped previous explorers, a temperate sea would be found beyond it. Although today we know that the North Pole was covered with thick ice for much of the period, the theory of the Open Polar Sea was popular in the 16th–19th centuries and many arguments were made to justify its existence: The Open Polar Sea theory was debunked gradually by the failure of the expeditions in the 1810s through the 1880s to navigate the polar sea. Reports of open water by earlier explorers, such as Elisha Kent Kane and Isaac Israel Hayes, fueled optimism in the theory in the