3. Preface

In presenting the following pages to the public, I am actuated by the conviction that the views hitherto had of the ancient great glacier of North America, by scientific men as well as by geological readers generally, have not come up to the magnitude of the mass, nor to the gigantic work which it has performed upon the floor of our continent. It is indeed extremely difficult, even for an intelligent man more or less conversant with the phenomena attendant upon the superficial drift covering the country, to imagine that New England and the northern states have been essentially changed in aspect since the latter part of the Tertiary ages. But the great facts everywhere before our eyes when properly generalized, assure us that this has been the case to a most extraordinary degree. The peculiar shape of the mountains of the north, the multiplicity and symmetry of its lakes, the deep indentation of its coast line into the crystalline formations, all assure us that some great change has passed over the country in a time geologically not very remote. But this mutation has not occurred since man came to occupy it. Of this event his intellect has treasured no recollection whatever.