Feather stonhaugh^s Geological Report. 133 



will occur to every observer, that the entrance of a stream of 

 such magnitude as the Chippeway river, coming in at right 

 angles to the Mississippi, must necessarily dam up the water 

 above it. Thus, at the general subsidence of the water-level, 

 when the alluvial bottom of the other part of the valley would 

 be left dry and plants begin to grow, it would here be covered 

 up to the northwest for a certain distance, whilst the wind and 

 high waves to which this lake is now so much exposed as 

 often to make the passage a dangerous one, would keep the 

 alluvial matter in a state of suspension, and, finally wearing it 

 away, the whole breadth of this part of the valley would be 

 necessai-ily covered by water. This is the way in which I 

 would account for the origin of this lake, the only one in the 

 whole course of the river. 



The strata towards the N. W. end of the lake on the north 

 side are very cherty, and agates are frequently found amongst 

 them. Opposite to a small stream called Marchessau, on the 

 south side, an intelligent trader, well acquainted with this part 

 of the country, told me he had picked up pieces of galena. 

 There are two channels at the head of the lake ; the south- 

 west one passes between the right bank of the river and a 

 low narrow island, called Twelve-mile island, edged by lofty 

 and beautiful trees. Up this channel, and near a lofty out-lier 

 about three hundred feet high, called La Grange, is the village 

 of the Indian chief Machpayah Muzah, or the Iron cloud, 

 Dootoh,or Redwing, the celebrated old chief, being now dead. 

 Two streams, the Vermilion and Cannon river, fall into the 

 Mississippi a few miles higher up. Between them and at a 

 distance not exceeding thirty miles from the mouth of the St. 

 Peter's, there is a singular out-lier of sandstone, which shows 

 how the continuity of the strata has once existed, and how 

 much the general mineral level has been reduced. Diagram 

 No. 20 represents this curious pillar, to which the name of 

 Castle Rock has been given. It is situated on what is called 

 the Big Prairie, and can be seen for a distance of twenty 



