THE LIVING WORLD. 
17 
It is interesting to note some of the curious forms, of which pictures are 
herewith given, and observe how closely allied to these extinct species are 
many of the salt water creatures of our time. It is important that this analogy 
should be kept in mind in order that the connecting links between succeeding 
orders may be more clearly perceived. 
HOW NEW FORMS CAME INTO EXISTENCE. 
The fossil remains spoken of were not found in indiscriminate deposition 
through the secondary and tertiary stratas; on the other hand, some were 
obtained from the lowest beds, others from the intermediate, while several were 
found in the superior strata. But all, of whatever description they may be, 
which occur in the secondary strata , belong to species now wholly extinct. 
By far the greatest proportion of those found in the tertiary strata belong like¬ 
wise to extinct species. It is only in the uppermost beds that there is any 
very considerable number of individuals which are identical with animals now 
in existence, and there they preponderate over the others. 
The bones of man are not more liable to decay than those of other animals; 
but in no part of the earth to which the researches of geologists have extended, 
has there been found a single fragment of bone, belonging to the human 
species, incased in stone, or in any of those accumulations of gravel and loose 
materials which form the upper part of the series of the strata. Human bones 
have been occasionally met with in stones formed by petrifying processes now 
going on, and in caves, associated with the bones of other animals; but 
these are deposits possessing characteristics which prove them to have been of 
recent origin, as compared with even the most modern of the tertiary strata. 
All the solid strata which abound in animal remains are either limestones, 
or contain a large proportion of lime in their composition. Many thick beds 
of • clay also abound in them; but in that case limestone in some form or other 
2 
