590 GEOLOGY OF CENTRAL WISCONSIN. 



parent dip southward, or away from the quartzite. This flanking sandstone is well ex- 

 posed at Dorvrard's Glen, on the north side of Sec. 18, where it is seen overlying the 

 quartzite, as heretofore described and illustrated in Fig. 27, which is a section along the 

 wall of the glen. This wall shows the following succession of layers, the numbers of 

 the layers being the same as in Fig. 27 : 



Ft. In. 



VI. Yellowish, fine-grained, friable and heavily bedded sandstone 14 8 



V. Pink, fine-grained and thinly bedded sandstone 4 8 



IV. Whitish and brownish, very coarse, heavily bedded sandstone, the con- 

 stituent grains much rolled translucent quartz 10 



III. Similar to the last, but yellowish and finer grained 17 4 



II. Very coarse, like IV. 5 10 



I. Bowlder-conglomerate, almost without matrix, made up of bowlders 



mostly angular, up to 1 foot in diameter; forms the stream bed 4 2 



Height of cliff 58 8 



In the town of Merrimac, Sauk county, sandstone at high levels continues to flank 

 the quartzite. This sandstone may be seen at Parphrey's Glen, on the N. E. qr. of Sec. 

 22, T. 11, R. 7 E.. where 20 feet of friable, brownish, Scottthus-beaxwg, regular-bedded 

 sandstone is exposed, including thin layers of a conglomerate of red quartzite pebbles; 

 on the N. E. qr. of Sec. 28, in a high, narrow bluff, wliich is partly detached from the 

 quartzite; and again, lying directly against the quartzite, on the N. E. qr. of the S. E. 

 qr. of Sec. 20, T. 11, R. 7 E., where it forms a perpendicular cliff directly north of, and 

 across the valley from, the Devil's Nose. The rock at this place is medium to fine- 

 grained, friable, red-and-white-banded, purely silicious, and superficially vitrified, and 

 contains throughout small pebbles of red quartzite, which are, however, aggregated 

 more numerously into two bands, the upper one 2 feet thick, and 25 feet below the 

 summit, the lower one 10 feet thick and 59 feet below the summit. The whole height 

 of the vertical cliff is 210 feet, the whole thickness of sandstone seen, 227 feet. The top 

 of the sandstone has an altitude of 622 feet; its base, one of 397 feet, so that the cliff 

 rises entirely across the horizon of the Lower Magnesian, as indicated by the occur- 

 rences of that formation in the country to the south east and west. The sections of 

 Plates XIX and XX show the structure and stratigraphical relations of this cliff. 



The isolated knob rising from the west bank of Otter creek, near the center of Sec. 

 15, T. 10, R. 6 E., Snmpter, shows the following section: 



Fc,:t. 

 I. Madison sandstone in small separated exposures; upper portions very highly 



ferruginous and firm; near the middle (1227) very fine-grained, lighter 

 colored and slightly calcareous; at the base white, fine-grained, much 



indurated 25 



II. Unexposed 20 



III. Mendota limestone; yellow, shaly, in small quarry-opening 5 



IV. Unexposed 10 



V. Grecnsand layer 1 



VI. Unexposed . 15 



VII. Potsdam sandstone, upper layers fine, white, friable, banded with calcareous 



layers, lower portions rising in an abrupt cliff from the bank of Otter 

 creek; heavily bedded, non-calcareous, alternating brown and white 140 



Height of knob 216 



Altitude of summit .' 415 



