Erratics of the Alps. 305 



English 

 feet. 



3. Near Brieg (6), . . . . . . 4988 



4. Near Martigny (d), 4757 



5. Near Great Saint Bernard (on ridge if above p), 8203 



6. Mountain of Plan-y-Beuf (p), .... 5804 



7. Above Monthey (e), .... iemo: . 3796 



8. Chalets of Playau (near k), 4010 



9. Chasseron on Mount Jura (/), .... 3444 



The traces at Nos. 5 and 6 belong to tributary or confluent gla- 

 ciers. Setting these aside, and putting the spaces from 1 to 2 and 

 2 to 3 together, the slope or inclination, from the head r y of the an- 

 cient glacier, to its north-west termination f, is given by M. de 

 Beaumont as follows :— 



Slope or Inclination. 



In degrees T r . 



, P , In feet, 



and minutes. 



From the Grimsel to Brieg (r to 6), . 1° 5' 1 foot in 51 



. . . Breig to Martigny (b to d), . 3' 1 . . . 1143 



... Martigny to Playau (d to k), . 18' 1 ... 193 



... Playau to Chasseron (k to /), . 12' 1 ... 285 



Leaving out Monthey, there is a constant fall, as the table shews, 

 from one station to another, but at rates generally varying. From 

 the Grimsel to Brieg it is 1 foot in 51, From Brieg to Martigny 

 it is extremely small ; in the two following intervals it is greater, 

 though still below the first. 



Dividing the whole space, 132 miles in length, into two sections, 

 the inclination is :— 



From the Grimsel to Martigny (r to d), 24' 1 foot in 143 



. . . Martigny to Chasseron (d to /), 1 5' 1 . . . 230 



Or taking the whole in one continuous line : — 



From the Grimsel to Chasseron (r to/), 28' 1 foot in 160 



But the glaciers which occupied the valleys at Plan-y-Beuf, and 

 of the Val de Bagne, at t r p and u, must not be overlooked. They 

 are lateral valleys indeed, but their size and elevation, and the posi- 

 tion they occupied, nearly in a line with the opening e, through 

 which the grand glacier debouched into the plain, must have ren- 

 dered them powerful auxiliaries. Descending from a great elevation 

 along a steep surface, falling perhaps 1 foot in 12, it is probable, that, 

 instead of joining the principal glacier laterally, they would override 

 it, and increase its height by many hundred feet. We know, in fact, 

 that it was from the valley of Ferrex, on the west side of Plan-y- 

 Beuf, that a large proportion of the highest blocks on Jura (those 

 at Chasseron) came. * M. de Beaumont has accordingly recognised 



