j8 GEOLOGICAL STRUCTURE OF THE 



"adventitious granitic gravel and holders throughout 

 the western states and territories. It is true, that 

 mound the Prairie du Chien, and many other places 

 along the hanks of the Mississippi, as well as those 

 of the Missouri* and even to the borders of the Ar- 

 kansa and Red Rivers, rounded debris occasionally 

 appear, sufficiently distinct from any thing which we 

 have met with either in the beds of the St. Lawrence 

 and its lakes, or along the Ohio and its tributary 

 streams ; such are the different varieties of fine cal- 

 cedony, far more resembling those of India than of 

 Europe, and which we term carnelian* sard, &c. as 

 they vary in color and texture, being either red, hya- 

 line and white, or different shades of yellow ; all 

 these varieties, and possessing every requisite beauty 

 for the lapidary, are to be met with in considerable 

 abundance along the Missouri, less plentifully on the 

 gravel bars of the Mississippi, while little more than 

 their existence is ascertainable, along the banks of 

 Red River and the Arkansa. To what class of 

 rocks or strata these were to be attributed, as they 

 appear on the Mississippi and the Missouri, I never 

 was able to ascertain ; nor am I still much better in- 

 formed on the subject, although I have had an oppor- 

 tunity of observing a singular granulated rock, in 

 which they are occasionally imbedded, bassetting out 

 from under the more recent testaceous lime-stone of 

 Red river, about one thousand miles above its entrance 

 into the Mississippi. My uncertainty as to the true lo 

 < alky of these rounded chalcedonic debris, arises from 



