950 PROFESSOR J. PRESTWICK ON THE EVIDENCES OF A SUBMERGENCE 
clusively that they had not been devoured by the Carnivora—could have inhabited 
the E,ock at the same time. When, however, the submergence took place, the 
animals living on the surrounding plains sought refuge on the Eock in face of this 
unprecedented danger, and there shared in the common doom. Such of theii’ remains 
as fell on the submerged surface of the Eock were subsequently carried down 
with the local detritus and their fragments incorporated, as the Rock emerged from 
the waters, here and there in the general mass of breccia. 
The highest point on the west side of the Eock which the breccia is shown 
to reach is about 500 feet, and on the east side about 700 feet. But, considering 
the volume of detritus and the denuded state of the upper portion of the Eock, we 
may presume that the greater part, if not the whole of the Eock, was submerged. 
On its upheaval divergent currents swept down, in the manner I have described in 
speaking of the “head” at Brighton and Sangatte, the great body of limestone 
debris disintegrated by the cold of the earlier glacial period, and propelled it en masse 
over the flatter ground at the base of the long slopes. With the necessary velocity 
blocks of 12 or more feet in diameter would be easily moved under such a volume of 
water, while the friction would be comparatively small. Raised above the sea level 
the surface waters, after percolation through the calcareous rocks and debris, would 
rapidly effect the consolidation of the brecciated rubble, as on the slopes of Mont 
Genay, the coast of Mentone, and in the fissures of Nice and Cette, of which this 
deposit at Gibraltar is a counterpart on a larger scale. After the final rise of the 
land the caves and open spaces left in the fissures became the resort of the more 
recent wild animals and of Neolithic Man. 
On this view the superficial deposits would be comprised in three stages or epochs. 
First and oldest, that of the later Raised Beaches and Quaternary Bone-caves. 
Second, that of the Breccia on the slopes and in the Ossiferous fissures (or Bubble- 
drifts). Third, and latest, that of the Neolithic caves. 
I have dwelt thus long on Gibraltar not only on account of the extensive scale on 
which the phenomena are exhibited, but also because the other explanations of the 
facts being by geologists of high authority and of competent local experience, I did 
not deem it prudent to advance further on what is still debateable ground, and leave, 
without an attempt to capture, so important a position in the rear. We can pass 
more rapidly over Italy and some of the Mediterranean Islands. 
Corsica .—It would seem that there are here several Raised Beaches some of which 
attain a considerable height.* I'he lowest of them is from 15 to 20 feet above the 
sea-level, and contains species of shells now living on the coast. To the north of 
Bastia stretches the promontory of Cape Corso, formed by a mountain range 
from 2000 to 3000 feet high and intersected by transverse valleys. Fringing this 
promontory on the eastern side, are numerous quarries of limestone of Cretaceous 
* M. D. Hollande, ‘ Bull. Soc. Geol. de France,’ .3me ser., toI. 4, p. 86, 1875. 
