LECTURE IX. 239 



organic matter they contained at first. In most cases, how- 

 ever, the bones have lost the greater portion of it, and adhere 

 to the tongue — a quahty which formerly, but erroneously, 

 was considered as the characteristic mark of a fossil. In the 

 fissures fiUed with bones which are found in the Mediter- 

 ranean region, the red clay, as well as the bones, is frequently 

 so impregnated with lime as to form a true breccia, which 

 must be blasted with gunpowder, and whence the bones are 

 only hewn out with considerable force. 



The clue to the period in which the deposits in the fissures 

 and caves took place, must be furnished by the bones and 

 other remains. Animals of the same species lived in the same 

 geological epochs, which no doubt lasted for an incalculable 

 series of years ; animals of the same species belong, therefore, 

 to the same geological chronology. It can, however, be easily 

 shewn, that similar conditions may prevail in different geological 

 epochs, and produce the same effects. When the small tunnel 

 between Merges and Iverdun was commenced, there were 

 found in the yellow limestone, which belongs to the lower chalk 

 system, crevices filled up with brown-red osseous clay, the 

 traces of which are still visible at the southern entrance of the 

 tunnel. The bones contained therein belonged to pachyder- 

 mata of the tertiary period, and were mostly identical with the 

 species found in the gypsum of Montmartre near Paris. These 

 bones were .consequently much older than those usually found 

 in ossiferous caves. On the other hand, in 1860, on the Stoss 

 in the Muotta valley in Canton Schwytz, near a place called 

 " Barentross," 5,042 feet above the level of the sea, a cave was 

 discovered in which a whole bear family, consisting of six 

 animals old and young, lay buried in a bed of clay two feet 

 thick covered with a crust of lime tufa half an inch in thickness. 

 " The bones themselves," says Eiitimeyer, " are also covered 

 with a thin tufa crust, and are in excellent preservation. Some 

 are in possession of the College of Schwytz, others in that of 

 Landamman^w/ clerMauer in Brunnen. The largest skeleton lay 

 in an outstretched position, the two anterior extremities seem- 

 ingly broken off" by a fragment of rock which fell from the roof. 

 The largest skull which I saw in Brunnen measured 285 milli- 



