Sir Charles Lyell (1845). “Travels in North America, in the Years 1841-2: With Geological Observations on the United States, Canada, and Nova Scotia”, p.15
William Buckland (1820). “Vindiciæ Geologicæ: The Connexion of Geology with Religion, Explained in an Inaugural Lecture Delivered Before University of Oxford, May 15, 1819, on the Endowment of Readership in Geology”, p.5
William Buckland (1820). “Vindiciæ Geologicæ: The Connexion of Geology with Religion, Explained in an Inaugural Lecture Delivered Before University of Oxford, May 15, 1819, on the Endowment of Readership in Geology”, p.6