LOGAN ON THE PACKING OF ICE IN THE ST. LAWRENCE. 429 



the cascade, where there is an accumulation of large boulders, evi- 

 dently derived from the granite further up. At this spot a mill- 

 dam across the stream occasions a fall of about fifteen feet, which 

 with a very small addition will represent the whole amount of de- 

 scent in the river from the granite hills to the lake receiving it, a 

 distance of twelve miles. 



The general course of the river is from N.W. to S.E., with, how- 

 ever, a few meanderings. Where the landslip occurred, about nine 

 miles below the cascade, the stream is from ten to twenty yards 

 wide. Flowing nearly south, it suddenly turns to the west, and 

 running in that direction for about TOO yards, it again turns direct 

 south. The valley in which it winds its way is of uniform breadth, 

 the summit of the banks being about 200 yards apart. The banks, 

 as may be inferred from what has been said, are about 120 feet 

 high, and the landslip in question took place on the right bank, in 

 the middle of the western turn mentioned. 



On the 4th of April IS^O, while the snows of winter were yet 

 upon the ground, about eight o'clock in the morning, the inmates of 

 the farm-houses on the spot were alarmed by the agitation of their 

 wooden dwellings, and looking from the windows, became aware, 

 from changes in the relative positions of the trees in the neighbour- 

 hood, that the ground on which they stood was in motion. They of 

 course quitted their houses with precipitation and fled in great ter- 

 ror to rouse the country around, and the confusion and dread which 

 the event occasioned while in progress disabled the population from 

 making very accurate observations of the phaenomena with which it 

 was accompanied ; but from an examination and survey of the spot 

 after it had happened, and such accounts as I could collect, il would 

 seem that a mass of the soft deposit, covering the solid rocks, about 

 200 yards wide and 700 yards long, but how deep is uncertain, 

 slipped out of the bank endways towards the river. This was fol- 

 lowed in quick succession, at intervals of a few minutes, by four 

 others, occupying with the first an area of about eighty-four acres, 

 of an irregular form, somewhat resembling the section of a long- 

 necked flask, the whole length of which was 1300 yards, and the 

 widest part, removed a considerable way back from the river, was 

 600. The contents of this huge trough, consisting of a marly cla}^, 

 slipped out at the long narrow spout where the movement began, 

 crossed the river, struck the opposite bank, and splitting into two 

 parts, one-half proceeded up the stream about three quarters of a 

 mile, the other an equal distance down, and thus completely blocked 

 up the valley for half a league. The whole operation was com- 

 pleted in about three hours, and for a considerable time after it be- 

 gan the surface of great patches of tlie moving mass continued un- 

 broken. More than half the amount was covered with fine sugar- 

 maple trees, and these for the most part travelled in an erect posi- 

 tion on the surface of the earthy deluge as it poured both ways 

 through the valley ; but occasionally a tree or two in diff*erent places 

 would be prostrated, and a few, caught below, were crushed and en- 

 gulfed. Two farmsteads were carried away, and though the people 



VOL. II. PART I. 2 F 



