86 



SCIENCE. 



[Vol. YL, No. 130. 



THE BECENT LAND-SLIDE ON OWL'S HEAD. 



The path of the sUcle, commencing at a single 

 point, gradually increases in width till the maxi- 

 mum of a hundred and sevent3'-five feet is 

 reached in a vertical descent of three hundred 

 feet. Essentially this width is maintained for a 

 vertical descent of six hundred and fifty feet, 

 when there is a change in the direction on its 

 reaching the bed of the stream, and the width 

 is narrowed as much as thirty or forty feet. 

 Very man}^ smooth ledges were uncovered in 

 the first five hundred (vertical) feet from the 

 starting-point, and the angle of the slope has 

 lessened to about 20^ at three hundred feet 

 from the top to the bend six hundred and fifty 

 feet below the starting-point. This part of 

 the slide may be seen to excellent advantage 

 from the village of Jeflferson Hill, and other 

 elevated points in the neighborhood. The 

 lower part of the slide is obscured from most 

 points by the adjacent forest. 



1 The illustration of the slide is from a photograph by D. W. 

 Butterfield, photographer of the Boston and Lowell railroad. 



Coincident with the change in the direction 

 from N. 60° E. to nearly north is a diminu- 

 tion in the slope and a deepening of the exca- 

 vation. At first not more than a foot or 3'ard 

 in depth seems to have been removed. At the 

 bend the depth of the middle portion of the 

 excavation is as much as forty feet. The 

 distance from the bend to the extreme end of 

 the slide is about one mile. The slope falls 

 from 20° to about three hundred feet to the 

 mile below Stanley's house. The width of 

 this lower section is usuall}^ about a hundred 

 and fifty feet, being ninety-five feet at the 

 narrowest place below Boudreau's house, and 

 a hundred and seventy-five feet just above 

 Stanlej^'s. So rapid was the descent, that 

 every change in the direction, caused by bend- 

 ings of the caiion, carried the debris much 

 higher upon the bank in front. There is a 

 marked absence of large blocks of stone above 

 Boudreau's. Near his house a rather large 

 bowlder was stranded. Others appear just 



