Bulletin Volume 21 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1914 Excerpt: ... the Wisconsin Eiver. He believed that workable deposits would be found in this formation. I have thus been able to trace the mineral in a series of crevices and openings from the summit of the Upper Magneslan (Galena dolomite) to the depth of 60 to 70 feet in the lower magnesian (Prairie du Chien dolomite), and have found all the beds of limestone good mineral-bearing rocks, each with one or more openings, besides vertical or pitching sheets or veins. The small depth to which mining has been extended does not allow one to trace the mineral through the whole of the extent downward in any one instance, but wherever circumstances permit of examination, the order of succession in the openings is found to be regular, and in multiplied instances vertical crevices and veins have been found passing down from one opening to another. It is then probable that the series is generally continued through the whole downward extent indicated, subject only to such interruptions as are more less common in all veins.4 The opinion expressed in my former report that the mineral was derived from beneath, is strengthened not only by the general results of my observations in the diggings, but by the appearance of disturbance in the strata, particularly along the line of the great body of mineral traversing the middle of the district, and by the relation in the bearing of that body to the extensive ranges of primary and metamorphic rocks towards the northeast, indicating that the mineral may have arisen from a mass of such rocks beneath the secondary strata. i J. D. WHITNEY Whitney showed his genius by going beyond the general views of his day and advancing a sedimentary origin for the ores, upon which practically all the later theories, including those in vogue today, are based. H...