OTD in 1837, Charles Darwin first presented his theory of how coral reefs are formed to the Geological Society of London. The event marked his public debut as a theorist.
L: hand-colored section of Cocos Island atoll.
R: diagram of the same from his 1842 book (Darwin Online).
๐ฑ๐๐งชโ๏ธ๐๏ธ๐ง #HistSTM