PIPESTONE AND ROCK COUNTIES. 541 



Quartzytc. Conglomerate. Pipestone. ] 



from the center. Similar upheaved spots occur on the red quartzyte outcrops near New Ulm.* 

 These upheaved spots vary from five to fifteen feet in diameter, or perhaps more. They may have 

 been caused by ice, i. e., alternate freezing and thawing with the change of seasons, aided by the 

 force of vegetation and a little soil gradually getting into the openings. 



Bottomland r>" i it .;:c* rivsr. 



FIG. 40. SECTION ACROSS THE ROCK RIVER VALLEY AT THE MOUSD. 



Figures designate feet above the rivi-r. 



At "the mound,'' where this high land terminates abruptly, and faces the valley of Rock 

 river, the elevation is about 175 feet above the river. The perpendicular bluff of rock is from 

 40 to GO feet in its highest part; but owing to a dip of about 10 from the horizon, nearly west, or 

 partly northwest, and to the breaking off of the upper layers, causing a gradual slope from the 

 brow of the hill backward through several rods, the actual thickness of beds visible may be 150 

 feet. The rock here,also appears to be almost entirely a reddish or pink, heavy-bedded quartz- 

 yte. If wrought there might be some softer and thinner layers discovered in the angles of the 

 talus, but the refractory nature of the great mass of it will causj it to be used but sparingly for 

 building. Tin nviin bluff curves westwardly at both ends, and by reason of the dip and ravines 

 that enter the valley from the west, its exposed layers gradually disappear 

 under the soil in that direction, and the rock is lost in the prairie. From the 

 base of the perpendicular wall of rock, which is about a hundred feet above 

 the Rock river, a talus of blocks and fragments of quartzyte, mingled with 

 glacial drift, curves gracefully down to the bottomland. At points in this 

 slope the quartzyte beds are seen in place, and exhibit the general shape of 

 glaciation but show no striae, the surface indicating rather the action of water. t 

 FIG. 41. Conglomerate. On the tops of some of the ridges in the northwest part of 



Mound township, apparently near the top of this formation, the rock is con- 

 glomeritic. This occurs in large superficial areas, planed and smoothed down (rarely glaciated), 

 arid the colors of the pebbles, usually not larger than beans, give these spots a blotched and 

 variegated mottling. The pebbles are mainly white, but some are jasper red and some purple. 

 According to Mr. Upham, the quartzyte becomes conglomeritic about four miles southwest 

 from Pipestone City. It may be seen by the side of the road to Dell Rapids, exposed along a 

 depression for about fifteen rods, dipping at the rate of one foot in six or eight feet, or about eight 

 degrees south, thirty degrees east. It is in layers from one to two feet thick and contains a multitude 

 of pebbles of white quartz and red jasper, of sizes up to an inch in diameter. The edges of the 

 layers, exposed toward the northwest, are polished, doubtless by the dust particles swept by winds. 

 The surface in some placas is as smoothly polished as can be done artificially by the utmost skill 

 and patience. 



An outcrop of a similar conglomerate, exposing about an acre of smooth rock, is reported in 

 the west edge of Sweet township, on the southeast side of Pipestone ereek, but little east of the 

 state line. 



The pipestone, or catlinite, of the pipestone quarry, is a h'ne clay varying 

 in color from blood-red to pale red or pinkish, or even to a pale yellowish 

 red. The lighter colors fade into the darker, but sometimes the light 

 appears in the red as round spots, on a polished surface, but the red is not 

 thus distributed through the lighter shades. It has of course suffered all 

 the metamorphic influences that the quartzyte itself has. but it has not lost 



*Sec the first annual report, p. 76. 

 tit appear.-* that the Indians son 



by killing them Whim Mr Shoe __, 



found a buffalo's skeleton wedded among the huge blocks of quartzyte at its base. 



tit appear.-* that the Indians sometimes drove bnrtaloes over the rockv precipice with which the mound ends, 

 thereby killing them When Mr Sliojin ckor, who lives at the east aidi of this lonjf line of cliff, flrst explored it, he 



