POLISHED BOULDER PAVEMENT. 



391 



veal any diatomacese. The polished pavement at the foot 

 of the cliff was observed this afternoon inclined at a high 

 angle, so much so indeed, that it was difficult to walk 

 upon it. 



Towards evening the country began to improve, and 

 the timber to include a few elm and birch. In the 

 prairie are clumps of aspen ; on the flats, which occur 

 regularly at the inside of each bend of the river opposite 

 steep clay cliffs on the outside of the curve, fine aspens 

 are common and the herbage is very luxuriant. Seventy- 

 five miles from the Grand Forks we leveled the most 

 rapid part of the river seen during the voyage thus far, 

 and found the fall to be 2*85 feet per mile. 



August 4tth. — Temperature of air at 8 a.m. 61°, of 

 the South Branch 67°. The balsam- spruce begins to 

 appear in groves. The river winds between high wooded 

 banks, with low points and wooded bottoms on one side, 

 high cliffs also wooded with aspen and spruce groves on 

 the opposite bank. The flats are covered with a rich 

 profusion of vetches, grasses, and rose bushes. There 

 are traces everywhere of a former fine aspen forest, with 

 clumps of elm and ash ; the dead trunks of these trees, 

 eighteen inches in diameter, being frequently concealed by 

 the undergrowth, offer a rude and stubborn obstacle to 

 progress on foot through the tangled mass of vegetation 

 which covers the rich flats. A view obtained from a low 

 hill coming down to the banks of the river, continues to 

 show a deep valley about three-quarters of a mile broad, 

 through which the river winds from side to side in mag- 

 nificent curves. The polished pavement on the banks 

 was frequently seen during the day scarred with ice fur- 

 rows and scratches. During the whole afternoon we 

 passed swiftly through a good country, well fitted for 

 settlement, as far as we could judge from soil and vege- 



c c 4 



