Confining myself strictly to the description of material remains, I have omitted, or reserved for another volume, all traditions and speculations of a general nature respecting their origin and the people whose handiwork they are, giving, however, in some instances, such definite traditions as seem unlikely to come up in connection with ancient history. This is in accordance with the general plan which I adopt in treating of the Native Races of this western half of North America, proceeding from the known to the unknown, from the near to the remote; dealing first with the observed phenomena of aboriginal savagism and civilization when first brought within the knowledge of Europeans, as I have done in the three volumes already before the public; then entering the labyrinthine field of antiquity from its least obstructed side, I devote this volume to material relics exclusively, thus preparing the way for a final volume on traditional and written archæology, to terminate with what most authors have given at the start,--the vaguest and most hopelessly complicated department of the whole subject,--speculations respecting the origin of the American people and of the western civilization. In the descriptions which follow I proceed geographically from south to north for no reason more cogent than that of convenience. From the same motive, much more weighty however in this case, I follow the same order in my comparisons between remains in different parts of the continent, comparing invariably each ruin with others farther south and consequently familiar to the reader, rather than with more northern structures to be described later. It is claimed by some writers that the term antiquities is properly used only to designate the works of a people extinct or only traditionally known. This restriction of the term would exclude most of the monumental remains of the Pacific States, since a large majority of the objects described in the following pages are known to have been the work of the peoples found by Europeans in possession of the country, or of their immediate ancestors. I employ the term, however, in its more common application, including in it all the works of aboriginal hands presumably executed before native intercourse with Europeans, at dates varying consequently with that of the discovery of different localities. * * * * * [Sidenote: REALITY OF MATERIAL RELICS.]