simple illustration may better serve to show the true character of the conclusion urged here by the opponent of Sir Charles, than any such line of statement as that which I employ, however clear to the geologist. In the year 1817, Prince's Street, in Edinburgh, was opened up to the Calton Hill, and the Calton burying-ground cut through to the depth of many feet by the roadway. Let us suppose that when the excavation has been carried a hundred yards into the cemetery, a geologist, finding the laborers cutting on the average about a yard per day, simply intimates as his opinion that the laborers have been a hundred days at work. "No," replies a controversialist on the anti-geological side; "for the first fifty yards, so soft was the subsoil, and so shallow the covering of mould, that the laborers must have cut at the rate of two yards a day; it has been merely for the last fifty yards that they have been excavating at the present slow rate: they cannot have been more than seventy-five days at work. I marvel exceedingly at the absurdity of geological reasoners: _palpably the burying-ground of the Calton is only seventy-five days old._" Now, such, in no exaggerated, but, on the contrary, greatly modified form, is the argument that would limit the age of the earth to the period during which the St. Lawrence has been scooping out a channel for itself, from Queenston to Niagara, through an ancient Silurian burying-ground. Both arguments alike confound the age of the ancient burying-grounds with the date of the modern excavations opened up through them; but in order to render the argument of my illustration equally absurd with the other, it would be not only necessary to infer that the Calton cemetery was only seventy-five days old, but also that the rock on which it rested was no older.