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DESCRIPTION OF THE COUNTRY 



one to four inches wide, and running in the direction of the line of strike. The 

 direction of the cleavage joints is 15° west of south, and due east and west. The 

 rock is overlaid by twenty feet of fine drift, with a thin soil of sandy loam. 



The country is gently undulating prairie, with clumps of very small pines scat- 

 tered over it. 



One mile below this we reached Du Bois's Trading-House. About five miles 

 below Du Bois's, the grayish-coloured gneissoid granite is again exposed for some 

 distance along the west bank of the river, succeeded by a very fine-grained reddish 

 granite. The rock is covered here with about ten feet of fine drift, with a thin soil, 

 supporting a small growth of oak, elm, and aspen, on the west side, while east of 

 the river a beautiful undulating prairie extends as far as the eye can reach. 



One mile above Stevens's Point there is an exposure of hornblende slate for half 

 a mile, succeeded by gneissoid granite, which extends for some distance below the 

 Village, forming rapids. The bearing of the rocks is northeast and southwest. 



The country in the vicinity of this place is undulating, with a tolerably good soil, 

 supporting a growth of oak, elm, maple, and a few pines. 



Two miles further brought us to Conant's Rapids. This point is exceedingly in- 

 teresting, not only on account of the great exposure of rock, but also in consequence 

 of the foldings and contortions which have been produced in the stratified rocks, at 

 the time of the intrusion of the igneous rocks. The prevailing rock is a very de- 

 composable amphibolic gneiss, passing into a highly ferruginous mica slate, green, 

 brown, and reddish gray, in different localities, and associated also with a very light- 

 coloured granitic gneiss. These rocks all have a vertical dip, and are compressed 

 by lateral force into almost every possible wavelike form. Between the layers of 

 gneiss, veins of felspathic granite, from six inches to twenty-five feet in width, 

 have intruded at intervals, and, at many points, overlies for a long space the ver- 

 tical edges of the gneiss. Some of the veins are porphyritic. The direction of the 

 plane of stratification is northwest and southeast. Numerous veins of quartz and of 

 felspar, from an inch to an inch and a half in width, traverse both the stratified and 

 intrusive rocks, and have a northeast and southwest direction. Camped one mile 

 below the commencement of the rapids. 



October 11. There is a fine display of gneiss on an island opposite our camp. It 

 is a gray-coloured, very fine-grained, compact rock, with a few regular crystals of 

 felspar disseminated through it, bearing east-northeast and west-southwest, with a 

 dip south-southeast of 19°. It is traversed by many granitic veins, following the 

 curvatures of the strata ; and these veins are traversed in turn by veins of quartz, 

 from half an inch to an inch wide, having a northeast and southwest direction. The 

 gneiss is overlaid for a considerable space, at many points, by a very fine-grained, 

 reddish-coloured granite. 



About two miles below Conant's Rapids, and about one-fourth of a mile below 

 the mouth of Plover River, the gneiss is again exposed, bearing northeast and south- 

 west, with a dip of 45° southeast. There is no bending of the strata at this place, 

 nor did I observe any intrusive rock. Below the mouth of Plover River, the drift 

 banks rise, on the east side of the Wisconsin, to the height of thirty and fifty feet 

 above the level of the water ; and, at the bends of the river, sand-slides occur, pre- 



