Iloir the llixtonj of the 2\Dst la Head 



have been preserved entire, but this is where 

 they have lived at a comparatively recent date, 

 and were entombed in ice or frozen ground 

 immediately after death. A few specimens of 

 the mammoth and one or two of the woolly 

 rhinoceros are all that have been thus preserved, 

 and both these animals lived in Europe with 

 early man ; and although this was thousands of 

 years ago, from a geological standpoint it is but 

 as yesterday. 



Even the hard parts of animals have become 

 changed by the dissolving of some portions 

 particularly of the animal matter and the 

 filtering in of other substances, until through 

 this process of replacement the shell or bone 

 has become changed to stone, or, as it is often 

 termed, petrified ; and the older these objects 

 are and the deeper they lie in the rocks the 

 more complete are the changes they have 

 undergone. 



So completely, though gradually, do these 

 changes take place, that even the minute struc- 

 ture of wood or bone may be seen under the 

 microscope, the exact shape of each little cell 

 3 9 



