594 GEOLOGY OF CENTRAL WISCONSIN. 



of 80 feet above the Mendota in the quarry above named. From this point, sandstone 

 continues in place as the road ascends through the N. W. qr. of Sec. 14 to the center of 

 that section, and beyond, reaching an elevation of 250 feet above the Mendota base. 

 The same thing is to be observed on the road ascending through sections 2, 3 and 11 j 

 whilst on the eastern slope of the ridge, towards the valley within the quartzite ranges, 

 sandstone is constantly seen with a great total thickness, lying within and above tho 

 Lower Magnesian horizon. 



Within ilw quartzite ranges. In the town of Caledonia, Columbia county, more or 

 less of Sees. 27, 28, 29, 30, 31, 32 and 33, T. 12, R. 8 E., lie between the converging 

 ranges, which unite on Sec. 27. The area thus included appears everywhere to be un- 

 derlaid by sandstone, which is of considerable thickness. In the northern portions of 

 Sees. 28, 29 and 30, the altitude is 500 to 550 feet, as great as that of the northern 

 quartzite range, and wells pass through many feet of sandstone, one near the north 

 line of Sec. 30 penetrating 170 feet of that rock. 



Along the east line of Sec. 25, T. 12, R. 7 E. in the town of Greenfield, the 

 high sandstone-filled countryjust described as occurring on the south flank of the north 

 quartzite range in Caledonia, breaks down suddenly, in a vertical cliff 135 feet high, at 

 the foot of which a slope continues the descent to the Baraboo river, through an 

 additional vertical distance of 275 feet, and a horizontal distance of two miles. In 

 the northern part of Sec. 25, T. 12, R. 7 E. on the south flank of the northern 

 quartzite range, and within half a mile of tins cliff, is a small limestone quarry. 

 Fig. 48 gives a map and section showing the relative positions of this limestone and 

 the other rock exposures in the vicinity. The whole thickness of limestone exposed 

 is about 25 feet, the layers running from 1 to 6 inches, but much displaced, and cov- 

 ered by debris. The rock (1251) is rough-textured, brownish-yellow, and non-arena- 

 ceous, carrying many small cavities lined with calcite crystals, as also much greensand 

 in coarse grains; these much more abundant in the lower layers, at the base of 

 which is a regular greensand layer such as is often to be seen at the base of the 

 Lower Magnesian. The composition of the limestone is indicated by the following 

 analysis, made gratuitously for the survey by Mr W. A. Hover at the State Uni- 

 versity: lime carbonate, 51.61; magnesia carbonate, 38.51; silica, 5.66; alumina and 

 iron oxide, 2.26; water, 0.40. The uppermost layer in the quarry is finely glaciated, 

 and casts of fossils are found throughout. The following have been identified by 

 Mr. R. P. Whitfield, from a collection made at this place by the late Prof. James 

 H. Eaton: Stromatopor'a, und. sp.; Orthis Barabuensis? ; Metoptoma, n. sp.; Mac- 

 lurea Sivezeyi, n. sp.; Holopea, n. sp.; lllcenus antiquatus, n. sp.; Dicellocephalus 

 Barabnetisis, n. sp. Immediately above the quarry, the ground rises rapidly to 

 the northward for 60 feet, without exposure; becoming then nearly level on top of 

 the quartzite range. A short distance along the road which ascends to the eastward, 

 are small exposures ( " a" of the map of Fig. 48, corresponding in elevation to "a 11 

 of the section) of brownish, non-calcareous, sandstone, 20 feet higher than the top 

 of the quarry. Down-hill, a short distance to the westward, are ledges of fine- 

 grained, friable, light-colored, non-calcareous, sandstone (746) coming immediately 

 below the quarry layers, some ten feet in height; whilst still farther west, sandstone ex- 

 posures are seen at different levels (b, c, of Fig. 48), down to 140 feet below the quarry 

 base, but not continuously. The base of the sandstone cliff lying half a mile southeast 

 across the intervening valley, is 75 feet above the top of the quarry layers. Its lower 

 layers (748) are medium-grained, veiy friable, brownish, banded sandstone, composed of 

 very much rolled quartz grains; further up, some bands of bright red sandstone are in- 

 cluded, whilst near the summit (740, 750) are a number of rapidly alternating, red, 

 white, and yellow bands of quite fine-grained and saccharoidal sandstone, the whole 

 thickness being 135 feet. The determination of the true stratigraphical position of tho 



