330 APPENDIX. 



Peace Rock. This rock is sienite. It is liigblj crystalline, and 

 extends several miles. Its position must be, from the best 

 accounts, in north latitude about 41° 30'. From this point to 

 Rum River, a distance of seventy miles, no other point of the 

 intrusion of this formation above the prairie soil was observed. 



Introduction of the Pal^eontological Rocks. — After pass- 

 ing some fifty miles below this locality there are evidences that 

 the river, in its progress south, has now reached the vicinity of 

 the great carboniferous and metalliferous formations, which, for 

 so great a length, and in so striking a manner, characterize both 

 banks of the Mississippi below St. Anthony's Falls. About nine 

 or ten miles before reaching these Falls, this change of geological 

 character is developed; and on reaching the Falls the river is 

 found to be precipitated, at one leap, over strata of white sand- 

 stone, overlaid by the metalliferous limestone. The channel is 

 divided by an island, and drops in single sheets, about sixteen to 

 eighteen feet, exclusive of the swift water above the brink, or of 

 the rapids for several hundred yards below. This sandstone is 

 composed of grains of pure and nearly limpid cpartz, held to- 

 gether by the cohesion of aggregation. If my observations were 

 Avell taken it embraces, sparingly, orbicular masses of hornblende. 

 It is horizontal, and constitutes, in some places, walls of stratifica- 

 tion, which are remarkable for their whiteness and purity. This 

 sandstone is overlaid by the cliff limestone, the same in character, 

 which assumes at some points a silicious, and at others, a mag- 

 nesian character. It is manifestly the same great metalliferous 

 rock which accompanies the lead ore of Missouri and mines of 

 Peosta or Dubuque. There rests upon it the elder drift stratum 

 of boulders, pebble, and loam, which marks the entire valley. 

 This latter embraces boulders of quartz and hornblende rock, 

 along with limestones and sandstones. It is overlaid by about 

 eighteen inches of black alluvial carbonaceous mould. 



From St. Anthony's Falls the river is perpetually walled on 

 either side with those high and picturesque cliffs which give it 

 so imposing and varied an appearance, and its current flows on 

 with a majesty which seems to the imagination to make it rejoice 

 in its might, confident of a power which will enable it to reach 

 and carry its name to the ocean in its unchanged integrity. 



St. Peter's River and Valley. — The importance, fertility, 



