Preliminary Report on the Economic Geology of Hazelton District, British Columbia. GENERAL STATEMENT AND ACKNOWLEDGMENTS. The investigation of the economic geology of Hazelton district was undertaken in the summer of 1917 with a view to stimulating the mineral production from this easily accessible and promising district by determining the origin, distribution, and general occurrence of the ores, and their relations to one another, to the gangue minerals, and to the various country rocks which enclose the veins. A topographical survey of the district was carried on at the same time by F. 8. Falconer of the Topographical division, for a map on a scale of 1 mile to 1 inch with 100-foot contour intervals. The completed portion of this map is used as a base for the geological map. _ The work was greatly facilitated by the interest and assistance of all the mining men in the district, and acknowledgment is made particularly to W. G. Norrie-Lowenthal of the Silver Standard, Messrs. Harris of the Harris mines, D. W. Williams of the Rocher De Boule, H. E. Clement of the Delta, and D. B. Morkill of the Hazelton View, for their courtesy and assistance during the examination of the properties under their manage- ment. V. Dolmage, as field assistant, gave able and enthusiastic service which is being continued in the preparation of the final report, and H. J. James was a capable student assistant. PREVIOUS WORK. Geological reconnaissance work in the Hazelton district was done by W. W. Leach in 1909 and 1910 while preparing a topographic map of the region; his report is in the Summary Reports of the Geological Survey for those years. In 1911 W. Fleet Robertson made a detailed report on the mining properties in the district, and the work has been elaborated and brought up to date from time to time since then by J. D. Galloway and the results published in the annual reports of the British Columbia Bureau of Mines from 1911 to 1917. In these reports the equipment and general develop- ment of the properties, analyses of the ores and their general occurrence are described. In 1912 G. 5. Malloch made a cursory examination of the ore deposits in the vicinity of Hazelton in connexion with his work in the Groundhog region to the north, and in the same year R. G. McConnell examined a geological section along the Grand Trunk Pacific railway through the district. Reports of these examinations are published in the Summary Report of the Geological Survey for 1912.