GEOLOGY. 203 



ceives a fine polish, and is a highly ornamental and valuable 

 stone. There is also a soft, black, variegated marble, like 

 the Egyptian, and some other marbles in the southern por- 

 tion of Iowa, betw^een the Des Moines and low^a. In some 

 parts of this district bituminous coal has been found, and on 

 the east side of the Missisippi is an extensive bed. Further 

 north, about the Wabesipinicon, is a region of iron, then the 

 great bed of galena or sulphate of lead, and in the farther 

 north the copper district. This is probably the richest 

 mineral region in the world ; and to the geologist and mine- 

 ralogist, an extensive and profitable field of research. The 

 banks of the Missisippi contain great quantities of the pre- 

 cious stones, wdiich are washed out by rains and carried 

 down by the stream. In some places, within four or five 

 years, the writer has found some very beautiful agates and 

 cornelians in the streets of the towns ; and, in a stroll of an 

 hour on the shore, has loaded his pockets with them. 



There are several very accurate and complete descriptions 

 of the geology of this country. And, instead of attempting 

 to give my own account of it, I shall embody in this part of 

 my work the published account of Long, Owen, and Nicol- 

 let, &c., which, together, include the greater part of the 

 country w^iich is the subject of this volune. My own obser- 

 vation of the country, geologically, being very cursory and 

 partial, and the survey of these gentlemen, all scientific men, 

 furnishing a very satisfactory description of the country in 

 this respect : I transcribe their observations in extenso, Mr. 

 Nicollet's observations extended over a large portion of this 

 region, and his remarks below give us the result in several 

 different localities. He says : 



" The region comprised within my map is covered by a 

 species of deposite of the kind for a long time known by the 

 name of diluvium ; but, as this word implies a theoretic idea 



