This paper is devoted to a discussion of the auriferous gravels of the southern and northwestern parts of Seward Peninsula. Its purpose is to meet the wants of the miner and prospector by presenting the results of the reconnaissance surveys made from 1899 to 1903, so far as they bear on the distribution and origin of the placer gold. As a necessary preliminary the geology of the peninsula will be presented in outline, but as this volume must be kept to a reasonable size, much matter not directly pertinent to the discussion of the mineral wealth will perforce have to be omitted. More extended accounts of the geology will find place in future publications, to be prepared when the more detailed surveys, already begun, permit the presentation of conclusions with more confidence.Geologic and topographic surveys of the peninsula were begun in the fall of 1899 by F. C. Schrader and the writer, who spent a few weeks in examining the auriferous gravels in the immediate vicinity of Nome, while D. C. Witherspoon made a topographic survey of the same area. The increase of public interest led to the dispatching of three parties to this field in 1900. One of these, led by W. J. Peters and W. C. Mendenhall, made reconnaissance surveys of the southeastern part of the peninsula. Another party under charge of E. C. Barnard, assisted by D. L. Reaburn, H. G. Hefty, and R. B. Robertson, made a topographic survey of the southwestern part of the peninsula, including Port, Clarence to the west and Ophir Creek to the northeast. This work was materially aided by the cordial cooperation of J. F. Pratt and J. J. Gilbert, of the United States Coast and Geodetic Survey, who commanded a large force of men engaged during the same summer in charting the southern coast line of the peninsulaAt the same time the geologic work in this region was intrusted to the writer, who, assisted by G. B. Richardson and A. J. Collier, carried a reconnaissance over much of the southern half of the peninsula and extended it into the then newly discovered Kougarok district. In the fall of 1900 the writer also made a geologic and topographic reconnaissance survey of the York district at the west end of the peninsula. In 1901 W. C. Mendenhall and D. L. Reaburn made a hasty examination of part of the northern coast of the peninsula, after the completion of an exploration extending from the Yukon to Kotzebue Sound. The growth of the mining interests led to the extension of the reconnaissance survey over the northwestern part of the peninsula in 1901 by T. G. Gerdine and A. J. Collier. The northeastern quarter of the peninsula still remained to be surveyed, and this was done in 1903 by D. C. Witherspoon and F. H. Moffit.The reports on these surveys included an account of practically every gold-producing creek in the peninsula, but the rapid progress of mining not only led to the discovery of many new placers, but also revealed many new facts bearing on the occurrence and distribution of the auriferous gravels. This made it desirable to supplement these investigations, and to this task A. J. Collier, assisted by F. L. Hess, was assigned in 1903. In the fall of 1904 Mr. Collier was able to spend a few weeks in the peninsula to collect some additional data. The writer's own investigations in 1899 and 1900 have been referred to; in addition to these he has made brief examinations of some of the mining districts along the southern coast in 1903, 1904, and 1905.The results here set forth are based (1) on the studies of Mr. Collier and Mr. Hess in 1903, and (2) on the earlier work in this province. In some cases this fact is plainly brought out by direct quotations from the published reports, but in many others there has been so gradual an evolution of opinion as to make it impossible to give the proper credit.