The object of my communication to-night is simply to lay briefly before the Society the relationships which have been made out, or which we may hope to establish, between the Silurian rocks of the north of England and those which occupy the ‶Southern Highlands″ of Scotland. And, in the first place, let me point out to you a fact which ought to be very cheering to all of us. The Silurian districts of the north of England and the south of Scotland, as you all know, may be very favourably compared with the classical Silurian regions first described by that eminent geologist, Sir Roderick Murchison, both in point of actual thickness and as regards the superficial area which they occupy. There was one point of view, however, in which ‶Siluria″ might be said to stand unrivalled, in this country at any rate, and that was in the abundance and beautiful preservation of its organic remains. Now, I think I may safely say, there are few of us, however ardent geologists, who do not prefer to find our work in the field assisted by the occurrence of those ‶medals of creation″ which we know as fossils; and there are many of us who in addition have an intelligent interest in these, as working palaeontologists. There can, therefore, be very little doubt but that the investigation of the Silurian deposits of the north of England and the south of Scotland has suffered much retardation, and even in some cases has been erroneously