INTERGLACIAL EPOCHS. 327 



did in the preceding period can only be conjectured. The 

 sand that clothed the flanks of the Bock, acted upon by the 

 weather, would sooner or later become "top-dressed/' so to 

 speak, and would thus form long sloping curtains or talus es, the 

 surface of which would here and there tend to become indurated 

 by the action of rain, dissolving the calcareous matter of the 

 shells, and again re-depositing it between the grains of the grit 

 and sand. By and by, however, there ensued a second cold 

 epoch, when the limestones commenced to break up under the 

 action of frost, while their fragments were carried down as 

 before to the low grounds. Large blocks and smaller fragments, 

 toppling from the lofty cliffs that face the east, fell upon the 

 sand-slopes, here and there plunging into them where the pro- 

 cess of superficial induration had not been sufficiently advanced 

 to enable the sand-rock to withstand the force of the impact. 

 Thus in time the shelly sands came to be completely buried 

 under a thick accumulation of angular blocks and debris, which, 

 having since become thoroughly indurated, presents precisely 

 the same character as the older limestone-breccia. Underneath 

 this newer breccia the shelly sands are often hardened into rock, 

 and have been quarried for building purposes. There still re- 

 mains a long talus of sand, however, sweeping down from the 

 upper part of the great cliffs that overlook Catalan Bay. This 

 sand is even yet only partially hardened, for, unlike those in 

 the neighbourhood of the Governor's Cottage, it contains very 

 little calcareous matter. The blocks discharged upon this slope, 

 therefore, merely sank into it, and are now seen projecting above 

 its surface, while many must have rolled downward to rest at 

 the base of the Bock in regions that are now submerged. It 

 is quite possible, however, that considerable masses of breccia 

 may lie concealed underneath the sand, which even to the 

 present day is blown about by the wind. 



I have not had an opportunity of examining the breccias of 

 Malta, but from the admirable descriptions given by Professor 

 Leith Adams, I strongly incline to suspect that they show indi- 

 cations of climatic changes of a nature similar to those which 



