The special interest in the Falls of Niagara, apart from the scenic and economic, lies in two scientific directions. One of these is connected with the researches into the remarkable physical changes, not only of the direction of the drainage of the upper lakes, but of the whole lake history and the production of the falls themselves. Although these questions are primarily American, the opportunity is better afforded here than elsewhere of studying the physico-geological problems involved, and hence the falls are of general concern. The other interest is that connected with the age of the falls, as they furnish the best measurements of the amount of geological work that has been performed in a given time, thus becoming a chronometer which, when brought into comparison with the work effected in other localities, will enable us to have definite ideas of glacial time. In this respect the subject is . . .