At the beginning of the nineteenth century a large part of the present territory of the United States that lies west of the Mississippi River was unexplored. By the year 1850, the main geographical features of this vast area had been revealed. This book is an attempt to reconstruct the geographical setting in which the explorers accomplished their work, and thus to estimate the influence of geographical factors on the history of the exploration of the region.
The first two chapters of the book are introductory in character. Chapter I is a brief historical summary of the exploration of North America before the nineteenth century, and shows that, in 1800, although the outline of the Pacific coast was known, inland exploration towards the west had not advanced far beyond the Mississippi River. Between that great river and the Pacific lay the Rocky Mountains and the interior basins, as yet untraversed by European explorers. The second chapter describes the purchase of Louisiana by the United States.
Part I is an analysis, in the light of modern geographical knowledge, of the region which remained unexplored in 1800. The geographical factors which influenced exploration have been emphasised. This part includes accounts of the physiography, climate, vegetation, animals, and human inhabitants of the area and correlates these geographical factors on a regional basis. The geographical conditions are illustrated by numerous extracts from the writings of the explorers themselves.
Part II is an account of the exploration of the region during the first half of the nineteenth century. This book does not attempt to give a detailed historical description of every expedition; it does attempt to draw a picture of the geographical setting of western America, as it appeared to the explorers of the time. The western America of a hundred years ago has passed away; the Africa of Livingstone exists no more. The systematic reconstruction of such geographical scenes, as they existed at given past periods of history, is the true function of historical geography.