59i GEOLOGY OF CENTRAL WISCONSIN. 



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

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

 wliilst on the eastern slope of the ridge, towards the valley vritliin the qufliftzite ranges, 

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

 Lower Magnesian horizon. 



Within the qmrtzite ranges. In tho 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 iacluded appears everj'where to be un- 

 derlaid by sandstone, which is of considerable thickness. In tlie northern poitioiis of 

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

 quartzite range, and woUs pass tlurough 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. ia the town of Greenfield, the 

 high sandstone-filled country,just described as occm-ring on the south flank of the north 

 quartzite range in Caledonia, lireaks down suddenly, in a vertical cUff 135 feet high, at 

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

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

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

 quartzite range, and vrithin half a mile of this cUff, is a small Hmestone quarry. 

 Fig. 48 gives a map and section showing tlie relative positions of this hmestono and 

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

 is about 25 feet, the layers running from 1 to 6 inchfes, but much displac<jd, 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 mudi greensand 

 in coarse grains; these much more abundant in the lower layers, at tlie l)ase of 

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

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

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

 versity: lime carbonate, 51.61; magnesia carbonate, 38.51; siUca, 6.66; alumina and 

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

 a,nd casts of fossils are found throughout. The following have been identified by 

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

 H. Eaton: Stromatopora, und. sp.; Orthis Barahwnsis? ; Metoptoma, n. sp.; Mcw- 

 lurea Sivezeyi, n. sp.; Holopea, n. sp.; lUcenus antiquatus, n. sp.; Dicellocephahis 

 Barabnensis, n. sp. Immediately above the quany, the ground rises rabidly to 

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

 the quaiizite range. A short distance along the road which ascends to tlie eastwai'd, 

 are small exposures ( " " " of the map of Fig. 48, con-esponding in elevation to " a" 

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

 of the quaiTy. Down-hiU, a short distance to the westward, are ledges of fine- 

 grained, friable, hght-colored, non-calcareous, sandstone (746) coming iuimediatcly 

 below tlie quany layers, some ten feet in height; wliilst still farther west, sandstone ex- 

 posures are seen at diff'erent levels (6, c, of Fig. 48), down to 140 feet below the quaiiy 

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

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

 layers (748) are medmm-grained, very friable, brownish, banded sandstone, composed of 

 veiy 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, tlie wholo 

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



