Region around Fort Winnebago. 3 



trations ; nor can I obtain so perfect a section of the inequalities that 

 do exist as I desire. 



The following section is cut from a small hill of about one hun- 

 dred feet in height, called stonequarry hill, of a range E. N.E. and 



w. s.w. 



A, Stonequarry hill. — a. Limestone. — b. Sandstone. — c. Limestone. — dd, Calcare- 

 ous soil. — e. Swan lake.—/, Prairy. 



Stonequarry hill appears to be an uplifting of the earth, a peculi- 

 arity common to most if not all the elevations in this country. There 

 are some fragments of tolerably pure limestone imbedded in the sur- 

 face near the greatest elevation, but more generally they are impure 

 calcareous sandstone, and pure sandstone of a very peculiar and in- 

 teresting character, always found in place or horizontal. This sand- 

 stone is so far suitable for architectural purposes, as to bear exposure 

 to the atmosphere, where it hardens after slight disintegration. I 

 consider most kinds of wood superior to it for hydraulic purposes. 



This stone appears in laminae, three or four feet in thickness, with 

 frequent vertical fissures, as if affected by some powerful convulsion, 

 and when exposed, the surface has become hard. The predomina- 

 ting color is white, often intersected by portions which are blood-red, 

 pale-red, pink, pale-orange and black. 



The structure is very peculiar. The mass consists of an aggrega- 

 tion of pure siliceous particles, about three fourths the size of mus- 

 tard seed, devoid of every appearance of cement. I cannot conceive 

 of a more clear and beautiful illustration of cohesion.* 



The fracture is conchoidal and uneven — small fragments, after 

 exposure to a moist atmosphere, crumble between the fingers, and 

 heat renders it a very excellent sand. I do not give this as a gen- 

 eral description of sandstone of the country, but as a remarkable ex- 

 ception. I recently had an opportunity of examining its general 

 structure to such a decided advantage, that I am induced to present 

 the result of my examination, although the location is not embraced 



* Very accurately described as appears by a specimen forwarded, which greatly 

 resembles a very pure arenaceous quartz. — Ed. 



