832 APPENDIX. 



In stopping at one of these caves, about twelve miles below St. 

 Peter's, we found this cause of structure verified by a lively spring 

 and pond of limpid water flowing out of it. 



Valley of the St. Croix. — This river originates in an ele- 

 vated range of the elder sand and pebble drift, which lies on the 

 summit between the Mississippi system of formations, and the 

 Lake Superior basin. It communicates with the Bruld, which is 

 "Goddard's Eiver" of Carver, and with the Mauvaise or Bad 

 Eiver of that basin. Specimens of native copper have been found 

 on Snake River, one of its tributaries.* 



Geological Monumexts. — In descending the river for the 

 distance of about one hundred miles below St. Anthony's Falls, 

 my attention was arrested, on visiting the high grounds, by a 

 species of natural monuments, which appear as if made by human 

 hands seen at a distance, but appear to be the results of the 

 degradation and wasting away, on the Huttonian theory, of all 

 but these, probably harder, portions of the strata. 



Lake Pepin. — This sheet commends itself to notice by its 

 extent and picturesque features. It is an expansion of the river, 

 about twenty-four miles long, and two or three wide. Both its 

 borders and bed reveal the drift stratum, and the observer recog- 

 nizes here, boulders of the peculiar stratification which has, in 

 ancient periods, characterized the high plateaux about the sources 

 of the river. Such are its hornblendic, sienite, quartz, trap, and 

 amygdaloid pebbles, and that variety of the quartz family which 

 assumes the form of the agate and other kindred species. Moved 

 as these materials are annually, lower and lower, by the impetus 

 of the stream, other supplies, it may be inferred, are still furnished 

 by the shifting sand and gravel bars from above. The mass must 

 submit to considerable abrasion by this change, and the diminished 

 size of the drifted masses become a sort of measure of the dis- 

 tance at which they are found from their parent beds. 



Chippewa River. — This stream is the first to bring in a vast 

 mass of moving sand. Its volume of water is large, which it 

 gathers from the high diluvial plains that spread southwest of 

 the Porcupine Mountains, and about the sources of the Wis- 



* This river was explored by me in 1831 and 1832, in two separate expeditions 

 in the public service, accounts of which have been published iu 1831 and 1832, of 

 •which abstracts are given in the preceding pages. 



