The Con and Negus are two gold mines near Yellowknife with ore running between $30 and $40 to the ton, and containing much visible gold. The lode deposits consist of quartz-carbonate veinlets that follow zones of shearing in pre-Cambrian andesites. The mineralogy is complex. There are sulphides, arsenides, antimonides, and many uncommon minerals including gudmundite. They suggest intermediate temperature deposition. Textures and structures suggest low pressure deposition. It is concluded that the deposits may be expected to persist to a depth of several thousand feet or more, providing the structural control continues in depth. It is intimated that the shear zones should be found at great depth as they are presumably related to a neighboring tear fault with a 5-mile horizontal displacement. Structures of this magnitude suggest, further, that the Yellowknife field may become an important mining district.