LECTURE IX. 235 



considered as errors^ and everthing relating to fossil man 

 was set aside. WTien, however^ latterly, there were found 

 products of art, stone liatchets in beds containing bones of 

 extinct animals, the attention was again directed to the results 

 formerly obtained in the exploration of grottoes and fissures. 

 The methodical examination of such spots was now carried on 

 Avith renewed zeal, and though but a comparatively short 

 period has elapsed since these studies were recommenced, the 

 results obtained are great. But before touching upon the 

 discovery of human remains in caverns, grottoes, and fissures, 

 I must offer some few observations on certain geological phe- 

 nomena and important facts pertaining- to this inquiry. 



It has been repeatedly and justly observed that, there is 

 scarcely any solid rock upon the earth which is not somehow 

 torn or split; it has even, with some exaggeration perhaps, 

 been maintained, that there is not a block found of the size of 

 one cubic meter which does not show some fissure. These 

 fissures are generally very fine, and frequently newly cemented 

 by trickling water. Thus, in dark-coloured chalks, we frequently 

 find a network of white calcareous veins representing the 

 original fissures. The lodes which are sterile or filled with 

 ore, are but large fissures of this kind, which have gradually 

 been fiUed with the deposit of mineral matter. In these 

 deposits, again, are found cavities not filled up. Fissures quite 

 empty are also frequently seen. In other instances, it may be 

 seen how the trickling water not only furnished crystalline 

 deposits, but that clay, earth, sandstone, and pebbles have been 

 introduced into the fissures. Nothing is more frequent than 

 to find such deposits in the fissures, so that the margins of 

 the crevices do not exactly correspond, and, if the fissure be 

 not perpendicular, there are alternate contractions and expan- 

 sions. Neither is it rare to find fragments of the surrounding 

 rocks fiUing the fissures ; and there are even mountains and 

 hills presenting the aspect of heaps of irregular superposed 

 blocks with intermediate fissures, whose form and size is con- 

 stantly changing under the infiuence of atmospheric action. 



Whilst, on the one hand, the trickling waters form in most 

 stones crystalline deposits, it is undoubted that they also 



