. Bulletin of the University of Wisconsin. Science. 124 BULLETIN OF THE UNIVERSITY OF WISCONSIN. often as much as three inches in length. A specimen from Benton presents interesting skeleton growths, which out- line the half of an octahedron truncated by a cube. This probably represents one phase of the Galena referred to as reticulated galena in the report of the state geologist.' The more beautiful feather-like skeleton growths have been figured in that Fig. 5.—Aggregate of Galena from Mineral Point. At Mineral Point have been found large quite symmet- rical cubes resembling those f
. Bulletin of the University of Wisconsin. Science. 124 BULLETIN OF THE UNIVERSITY OF WISCONSIN. often as much as three inches in length. A specimen from Benton presents interesting skeleton growths, which out- line the half of an octahedron truncated by a cube. This probably represents one phase of the Galena referred to as reticulated galena in the report of the state geologist.' The more beautiful feather-like skeleton growths have been figured in that Fig. 5.—Aggregate of Galena from Mineral Point. At Mineral Point have been found large quite symmet- rical cubes resembling those found at Highland. On some specimens the faces of the galenas are studded with octa- hedrons of pyrite which are superficially altered to limon- nite. On the crystals of other specimens are found gray cerussite crystals from 5-7 '"™ in diameter. Still another series of specimens from Mineral Point presents very beau- tiful aggregations of sub-individuals on which the octahe- dron has a large development, forming hopper faced aggre- gate individuals of the same habit (see figure 5). The average size of the component individuals is only a few millimeters and they are nearly perfect carbo-octahedrons, but at the ends of each of the principal axes of the aggre- gate crystal are large crystals with cubic habit, whose cubic face determines the size of the cube face on the ag- gregate crystal. The aggregate crystals have quite uni- formly a diameter of about three to six centimeters and 1 ChamberliD, Geol. of Wis., Vol. IV. p. 385. (1882.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original University of Wisconsin. Madison, Wis. : The University
Size: 1601px × 1560px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectscience
