The history of opinions respecting the deluge of Noah is one of the most curious and instructive in the annals of man. In this field, Christians have often broken lances with infidels, and also with one another. The unbeliever has confidently maintained that the Bible history of the deluge is at war with the facts and reasonings of science. Equally confident has been the believer that nature bears strong testimony to its occurrence. Some Christians, however, have asserted, with the infidel, that no trace remains on the face of nature of such an event. And as this is a subject which men are apt to suppose themselves masters of, when they have only skimmed the surface, the contest between these different parties has been severe and protracted. Almost every geological change which the earth has undergone, from its centre to its circumference, has, at one time or another, been ascribed to this deluge. And so plain has this seemed to those who had only a partial view of the facts, that those who doubted it were often denounced as enemies of revelation. But most of these opinions and this dogmatism are now abandoned, because both Nature and Scripture are better understood. And among well-informed geologists, at least, the opinion is almost universal, that there are no facts in their science which can be clearly referred to the Noachian deluge; that is, no traces in nature of that event; and on the other hand, that there is nothing in the Mosaic account of the deluge which would necessarily lead is to expect permanent marks of such a catastrophe within or upon the earth. If such be the case, you will doubtless inquire, what connection there is between geology and the revealed history of the deluge, and why the subject should be introduced into this series of lectures. I reply, that so recently have correct views been entertained on this subject, and so little understood are they; that they need to be defined and explained. And if the distribution of animals and plants on the globe come within the province of geology, then this science has a very important point of connection with the history of the deluge, as will appear in the sequel. And finally, the history of opinions on this subject is full of instruction to those who undertake to reason on the connection between science and religion. Obviously, then, my first object should be to give a brief history of the views that have been entertained respecting the deluge of Noah, so far as they have been supposed to have any connection with geology.