17 [ 237 J 



not yielding: to the nail ; not scratched by selenite, but easily by calcareous 

 spar; specific gravity 2.90. The acids have no action upon it; before the 

 blowpipe it is infusible ;jer se, but with borax gives a green glass. 



According to Professor Jackson, of Boston, who has analysed it, and ap- 

 plied to it the name of cathnite, after Mr. Catlin, it is composed of — 



Water ....--.. 8.4 



Silica --.---.. 48.2 



Alumina --.---.- ^S.'i 



Magnesia -------- 6.0 



Peroxide of iron ------- 5.0 



Oxide of manganese -.-... o.g 



Carbonate of hme ...... 2.6 



Loss (probably magnesia) ------ 1.0 



100 



But Professor Jackson assimilates it to the agalmatolite, from which it 

 differs, however, very materially by its general aspect, its conduct before 

 the blow-pipe, and its total insolubility in sulphuric acid.* 



Another feature of the Red Pipestone valley is the occurrence of granitic 

 boulders of larger size than any I had previously met. One of them meas« 

 sured about 6U feet in circumference, and was from 10 to 12 feet thick. 

 They are strewed over the valley, in which it is remarkable that there are 

 no pebbles. 



1 shall now proceed to give a short account of some of the regions of 

 country adjoining the Coteau des Prairies, omitting those which have al- 

 ready found a place in the geography of the United States, so as to be more 

 particular concerning such as are but little or not at all known. 



Among these, that which appeared to me the most favorable, is the one 

 Undine re- watered by the Bold Mankato, or Blue Earth river, and to which 



sion. I have given the name of Undine Region. 



The great number of the navigable tributaries of the Mankato, spreading 

 themselves out in the shape of a fan; the group of lakes surrounded by 

 well-wooded hills ; some wide-spreading prairies with a fertile soil ; others 

 apparently less favored, but open to improvement ; — the whole together be- 

 stow upon this region a most picturesque appearance. It was while on a 

 visit to lakes Okamanpidan and Tchanhassan, (Little Heron and Maple- 

 wood lakes, that it occurred to me to give it the name I have adopted, de- 

 rived from that of an interesting and romantic German tale, the heroine of 

 which belonged to the extensive race of water spirits living in the brooks, 

 and rivers, and lakes, whose father was a mighty prince. She was, more- 

 over, the niece of a great brook (the Mankato) who lived in the midst of 

 forests, and was beloved by all the many great streams of the surround- 

 ing country, &c., (fcc. 



I do not know why I fancied an analogy between the ideal country do- 

 scribed in the tale, and that of the one before me ; but I involuntarily, as it 

 were, adopted the name. 



The limit of this region is the NE. prong of the Coteau des Prairies, 



♦ The red pipe stone is also found on the upper part of the Mishkwa§;okag, or Red Cedar 

 river, which fills into the Chippeway river, that empties itself into the Mississippi below lake 

 Pepin. 



2 



