108 Esmark 07i the Geological History of' the Earth. 

 9,. That they are not all of the same sort. * 



3. That they have not all been deposited at the same time, 

 but at periods far remote from one another. 



4. That those which belong to the earliest periods have a less 

 perfect organization, the farther back the less perfect ; that those 

 on the contrary which have been found in mountains of a later 

 formation, have a more perfectly developed organization. 



5. That we find a multitude of petrifactions of different ani- 

 mals which are now totally extinct, and that we find others 

 which have some resemblance to animals now existing ; but 

 with differences which prove them to be of another species. 



6. That we likewise find a great multitude of plants incorpo- 

 rated with the solid strata, of which some are different from 

 those which now exist, while a great many seem to resemble 

 them. The most remarkable circumstance connected with this 

 fact is, that the climate of those places where these plants are 

 found inclosed in the solid rocks, is not at all like the climate 

 where they are now found growing. We find, for example, a mul- 

 titude of plants in a state of petrifaction in the most northerly re- 

 gions of Europe, which are now found growing in the torrid 

 zone. As they are found with stalks and leaves, and sometimes 

 even with fruit upon them, they must necessarily have grown in 

 the places where they are now found, and could not have been 

 wafted on the surface of the sea from regions lying far distant. 



7. That of the human race, we find, with certainty, no re- 

 mains inclosed in the earth, with the exception of a few which 

 have been found partly in tuffaceous limestone, partly in clefts of 

 older mountains which have since been filled up with sand, 

 clay, and rubbish, and which must be considered as remains of 

 the latest revolutionary changes in the earth. 



We find a variety of theories formed in later times on this sub- 

 ject, by Burnet, Whiston, Woodward, Fontanelle, De Luc, 

 Ray, Hutton, &c. They have each their own peculiar notions ; 

 and though it cannot be said that any one of them is right, this 

 will be a matter of no surprise, when we consider how far be- 

 hind they were in many of the sciences which have made such 

 progress during the last century. Though from this progress in 

 mineralogy, chemistry, physical, mathematical, and astronomi- 

 cal science, we stand on much higher ground than they did, 



