318 



FALL OF MONT GRENIER. 



" Mont Grenier rises very abruptly upwards of 4000 feet above 

 the plain. It is capped with an immense mass of limestone strata, 

 not less than 600 feet in thickness, which presents on every side the 

 appearance of a wall. The strata dip gently to the side which fell 

 into the plain. This mass of limestone, rests on a foundation of soft- 

 er strata, probably molasse, under which are distinctly seen thin stra- 

 ta, alternating with soft strata. The annexed cut represents the east 

 wing of the mountain, and a small part of the Abymes de Myans. 

 There can be little doubt that the catastrophe was caused by the 

 gradual erosion of the soft strata, which undermined the mass of lime- 

 stone above, and projected it into the plain. It is also probable, that 

 the part which fell, had for some time been nearly detached from the 

 mountain by a shrinking of the southern side, as there is at present a 

 rent at this end, upwards of 2000 feet deep, which seems to have cut 

 off a large section from the eastern end, that now 



' Hangs in doubt fill ruins round its base,' 



as if prepared to renew the catastrophe of 1248. The Abymes de 

 Myans are hills, or rather monticules, of a conical shape, varying in 

 height from twenty to thirty feet; they cover about nine square 

 miles : the monticules are composed of fragments of calcareous stra- 

 ta, some of which are of immense size. They consist of yellowish 

 oolitic limestone, strongly resembling the hwer oolites in Gloucester- 

 shire ; a gray limestone, harder and more crystalline than lias, which, 

 however, it may probably be ; and a thin slaty arenaceous limestone, 

 much resembling Stonesfield slate. Fragments of schistose chert 

 were interstratified with some of the limestone. 



"The largest masses have, evidently, fallen from the upper bed 

 of limestone by which Mont Grenier is capped. The velocity they 

 would acquire by falling from so great a height, making due allow- 

 ance for the resistance of the atmosphere, could not be less than 300 

 feet per second ; and the projectile force they gained by striking 

 against the base of the mountain, or against each other, has spread 

 them far into the plain. In the course of years, the rains or currents 

 of water from dissolving snows, have furrowed channels between the 

 larger masses of stone, and, washing away part of the loose earth, 

 have left the immense number of detached conical hills which are 

 seen at present. So deep and vast was the mass of ruins that cover- 

 ed the town of St. Andre and the other parishes, that nothing belong- 

 ing to them has been discovered, except a small bronze statue."— 

 Vol. i. p. 201. 



A part of a mountain near Servos, on the road to Chamouny, fell 

 down in the year 1751. The fall continued for many days, and the 

 air was darkened with immense volumes of black dust, which ex- 

 tended for twenty miles, and is still remembered by some of the old- 

 est inhabitants of Chamouny. A continued succession of reports, 

 like those of cannon, announced the successive falling of rocks, day 



