SCIENCE 



NEW YORK. FEBRUARY 17, 1893. 



A REMARKABLE OCCURRENCE OF SELENITE. 



BT DR. J. E. TALMAGE, SALT LAKE CITY, UTAH. 



The writer is pleased to report a deposit of selenite in southern 

 Utah, which is remarkable for the size, perfection, and ■variety of 

 the crystals there to be found. It is situated in the newly-created 



county of Wayne, in what is locally known as the South Wash, 

 which is connected with the canyon of the Fremont River, and 

 this in turn is tributary to the Colorado. 



The formation in the neighborhood of the deposit in question is 

 mostly sandstone and argillite, with a top dressing of erratic 

 boulders of lava. Innumerable fantastic forms in stone declare 

 the cutting power of water and wind; indeed, the entire region 

 has been the site of wonderful eroding action. Ripple marks in 

 great distinctness are frequent in the sandstone of this region and 

 other evidences of lake formation are common. 



The most convenient way to reach the deposit from the north 

 is by way of either the Grand Wash or the Capitol Wash, spurs 

 of the Fremont Canyon, both of which abound in scenes which 

 are terribly grand. As one leaves the deep canyons, however, 

 and enters the side washes, the scenery assumes a milder, though 

 a scarcely less diversified, character. 



Here and there along the gorges are outcroppings of gypsum, 

 varying in degrees of purity ; and seams of this material cut 

 through the country rock in all directions. In places, veins of 

 satin spar, as thin as a sheet of note-paper, or even an inch in 

 thickness, can be traced for many hundreds of yards upon the 

 surface of the ground in uninterrupted cour.se, except for inter- 

 secting planes of the same material. On the walls of the ravines 

 and canyons places are seen where spar veins cross and recross 

 each other with bewildering profusion. Here (Fig. 1) is a sketch 

 of such seams in an exposed face eight by twelve feet on the steep 

 side of a' ravine. 



Gypsum in all varieties may be found within a short radius, 

 fibrous and scaly laminas, plaster-stone or rock-gypsum in masses, 

 lumps of pure alabaster, and fragments of selenite crystals are 

 scattered along the washes and strewn upon the bench-lands, as 

 they have been left by the fierce floods which tore them loose 

 from the place of formation. These occurrences form an encour- 

 aging introduction to the superb deposit of crystals already men- 

 tioned. 



The crystals occur in a cave, and this is inclosed by a thick shell 

 forming a mound which stands in relief on the side of a hill 



bounding the Wash. Of this formation, a pood idea may be gained 

 from Fig. 3. which is reproduced from a photograph. The mound 

 is somewhat of an egg-shape, 35 feet in length east and west. 10 

 feet in breadth, and of an average height of 20 feet from the 

 ground on the lower side; all outside measurements. This selenite 

 mass seems to have been left exposed by ihe weathering of the 

 loosened friable sand and clay, of which the hill whereon the 

 mound is situated is composed. The mound consists entirely of 

 selenite, the outside having a somewhat battered and roughened 

 appearance from the action of the wind-driven sand; yet the 

 whole exterior is made up of the exposed ends and sides of crys- 

 tals, and in the sunlight the formation glistens with indescribable 

 beauty. The outer walls are generally regular, though there are 

 a few depressions and sheltered niches, within which small prisms 

 of selenite nestle snugly, in groups. 



The entrance to the cavern faces the east, and when first observed 

 by the writer it was about six fi^et in height, and three and a half 

 in width. The cave can be travered to a depth of 26 feet. Gen- 

 erally the crystals project from either side toward the central line 

 of the cavern, approaching each other within about three feet, 

 though some of the largest crystals extend entirely across the 

 cavern like huge beams. 



Fig. 3 is from a photograph of the interior of the cave, one 

 massive crystal having been sawn off to afford a better view. The 

 floor of the cavern consists mostly of sand, probably deposited by 

 water in flood times, and carried in at all seasons by winds. Pro- 

 jecting out of the sandy floor are the terminations of many superb 

 crystals. Inside the cavern, a yard from the entrance, the crys- 

 tals descend within three feet of the bottom, so that one has to 



Fig. 2. 



stoop to pass; but farther in there is room to stand erect, and near 

 the hack wall a jjerson may clamber up to a height of fifteen feet. 

 Looking upward from the bottom of the cavern, one sees a mass of 

 mammoth prisms, suggesting, but for their singular beauty, the 

 heavy timbers of a deep mine. The entire deposit is a colossal 

 group of crystals, the like of which is seldom to be seen. 



