His speech, published as "Vindiciae Geologicae; or, The Connexion of Geology with Religion Explained", equated the last of a long series of catastrophes with the Genesis Flood, and said that "the grand fact of an universal deluge at no very remote period is proved on grounds so decisive and incontrovertible, that, had we never heard of such an event from Scripture, or any other, authority, Geology of itself must have called in the assistance of some such catastrophe, to explain the phenomena of diluvian action which are universally presented to us, and which are unintelligible without recourse to a deluge exerting its ravages at a period not more ancient than that announced in the Book of Genesis."