PIPESTONE AND ROCK COUNTIES. 539 



Quartzyte. Pipestone quarry.] 



ward the east fifteen degrees south, so that the rock soon disappears under 

 the prairie in that direction, but presents a nearly perpendicular escarp- 

 ment toward the west, formed by the broken oft' heavy layers of the rock; 

 though its greatest hight, which is not more than 25 feet, is a little north 

 of the present pipestone quarry. It also gradually disappears under the 

 prairie both toward the north and toward the south, the lower ground on 

 the west of the escarpment slowly rising in these directions like the sides 

 of a basin, and coalescing with that on the east of the ledge. A small 

 stream, dry some parts of the year, known as Pipestone creek, works north- 

 westwardly and passes over the ledge from the upper prairie to the lower 

 with a perpendicular fall of about 18 feet. In the vicinity of this fall, and 

 also at one or two places farther south, are dwarfed bur oaks and shrubs, 

 but the country in all directions for many miles is a prairie, which has a 

 great monotony of surface. It is not on the top of the Coteau des Prairies, 

 as supposed by Catlin, that range of hills being 10 or 12 miles farther 

 northeast. Mr. Catlin seems to have correctly described the eastern as- 

 cent of the Coteau as rising with almost imperceptible swells above the 

 prairie farther east, but failed to observe when he passed down the west- 

 ein slopes, that the real Coteau dies out still more insensibly in the 

 prairies on the western side. 



The little stream which crosses the rock at the pipestone quarry (fig- 

 ure 33) widens out into a lake just before passing the ledge, making Pipe- 

 stone lake, and again, after passing it, it forms Crooked, Duck and White- 

 head lakes in the same way. In these lakes water stands constantly. 



The rock itself in general is exceedingly hard, in heavy layei*s of one 

 foot, or of two or three feet, and is separated by jointage planes into huge 

 blocks of angular shape that lie often somewhat displaced or even thrown 

 over entirely by the action of the frost through many winters. Thus there 

 is a rough talus along the foot of the escarpment where grow a few bushes 

 and small oaks, protected from the prairie fires by surrounding masses of 

 fallen quartzyte. The rock is sometimes pinkish and massive; when blood- 

 red it is more apt to be thin-bedded. 



The real " pipestone quarry" is situated about a quarter of a mile west 

 of this ledge and in the low land of the lower prairie. Earlier diggings 

 seem to have been opened in the superficial outcropping of the pipestone 



