Gold was found in Wisconsin, specifically in Ledges of diabase in Douglas County. The Chippawa mine reported some gold values. It is important to mention that the discovery of gold in the iron ores of the Emmet mine in 1879 created quite an excitement, which was, however, rather short lived. In 1902, gold was found in glacial drift at St. Croix Falls, at the head of St. Croix River. Some interesting quantities of gold were obtained from time to time.
The Keweenawen system of rocks that are silver bearing in Michigan, near Ontonagon, also occurs in Wisconsin, and traces of silver were found along the Montreal River. When silver was first reported from this locality is unknown, regarding the occurrence of silver in this locality, the state geologist of Wisconsin said that the unfavorable experience of the operations in Michigan, however, leaves little ground for expecting rich deposits in that horizon. Also, it was mentioned that while silver was very frequently unauthoritatively reported from several parts of the state, and undoubtedly was known that gave substantial grounds for expecting any valuable discoveries. At that time is was considered that experience and observation could give no reliable information about the zone.
Although gold might be expected to occur in the crystalline rocks of northern Wisconsinm yet in one instance only was it and silver found in quartz associated with pyrite and arsenopyrite in northern Clark County. Native gold and silver were found alone and in the native copper occurring in the drift from the copper region of Lake Superior, also in the Keweenawan system of rocks which silver was near Ontonagon on the Iron river in Michigan and extends westward across the Montreal River into Wisconsin. Both silver and copper were found in this formation, but owing to the lack of success in working this silver-bearing stratum in Michigan, little or no work was done. Silver occurred in the lead ores of southwestern Wisconsin, but in few quantities only.
There was a fairly large basin in the bed of the St. Croix River extending from St. Croix Falls upstream for a distance of three or four miles prior to the erosion of the intersecting trap-ridge. The river cut through this shale, forming the banks on either side, which had a covering of drift ranging from 10 to 25 feet in thickness at the river and thinning out toward the trap-ridges. The river bed is now trap upon which the concentration of the gold in the gravel took place. During periods of low water considerable gold was obtained from the cracks in the trap. The gold occurred mainly as flakes and scales.