980 PROFESSOR J. PRESTWIOH ON THE EVIDENCES OF A SUBMERGENCE 
The rubble is purely local aud contains the remains of a land surface only. That 
its accumulation was an act of short duration, and considerable force is evident from 
the general fractured condition (admitting some to have been broken by man) of the 
bones, their innumerable splinters, and the absence of wear. It was suggested by 
M. Nold""' that the bones must have been fresh at the time of entombment, as he 
found that the thick end of a humerus, which had been shattered and flattened, still 
held together, in consequence, as he supposed, of the gelatine of the bone preventing 
the dispersion of the fragments. This, of course, is open to another explanation— 
that the bone was smashed in the descent of the rubble, and, being held in place by 
the matrix, was kept there in the general cementation effected by the subsequent 
calcareous infiltration. There is, I think, reason to believe, as I hope to show when 
describing the ossiferous fissures, that the bones found in this drift are those of 
animals which sought refuge on these isolated hills from the rising waters, and 
were eventually destroyed, their remains being afterwards swept down with the 
local rubble on the subsequent upheaval of the land. 
These detrital taluses are not to be confounded with those later ones produced by 
the weathering of the rocks and the action of rain, so common on the steep slopes of 
the Jurassic valleys of Burgundy, and in the Oolite valleys of England. These, in 
the distinct we are speaking of, consist of finer debris, generally loose, and locally 
called Arene or Trasse^ They are inclined at steeper angles, and contain oifiy 
recent remains—sometimes the skeleton of an animal with the bones entire and not 
fractured. On the other hand, the older rubble is coarse, often includes large blocks, 
has prolonged slopes, is frequently cemented so as to form a hard breccia, and 
contains remains of the extinct mammalia. The action of the one still continues, 
that of the other ceased with post-glacial times. 
Mentone .—One more illustrative section of this breccia on the south coast of 
France may be mentioned. It was discovered in making the coast railway east of 
Mentone, at a spot where Jurassic limestone cliffs rise to the height of 260 feet on 
the sea-board. On the face of these escarped slopes are situated the several well- 
known ossiferous caves of Mentone]; at an average height of 100 feet abovm the 
sea-level. According to the late Mr. Moggridge, “ Below these caves a slope of 
about 180 feet descends to the edge of the sea. Through the upper part of this 
slope, at distances from the caves of from 0 to 10 feet, is a railway cutting 600 feet 
long, 54 feet deep, and 60 feet above the sea. The mass removed in making this 
* ‘ Bull. Soc. Geol. de France,’ 2nd ser., vol. 2, p. 722, 1845. 
t For further instances and details, see the work of M. Collet^ot before quoted, p. 452 et seq., and 
the elaborate work of M. Belgrand, the late eminent engineer, entitled ‘ La Seine,’ vol. 1, Chapters 
III and XVIII, 1869. 
t ‘ Report.s, Brit. Assoc.’ Edinburgh, 1871, p. 156. 1 cannot agree with Mr. Moggridge in considering 
the cave of more recent date than the breccia. On the contrary, the breccia partially masked two 
caves. 
