PREFACE. 



Questions as to the origin and history of life are not at the 

 present time limited to mere philosophical speculation and 

 poetical imagining. The solutions of these questions are 

 now supposed to be based on the facts of Biology and 

 Palaeontology; and, establishing themselves on these facts, 

 the bolder speculators suppose that they can scale heaven, 

 dethrone God, ar ^ sweep away all belief in the spiritual 

 nature and higher destinies of man. 



No portion of our modern acquisitions in science is more 

 closely connected with these daring speculations than that 

 which relates to the succession of forms of life in geological 

 time ; and none is more unfairly dealt with by the more 

 extreme theorists. On the one hand, they parade carefully 

 selected series of fossil species as demonstrating the reality 

 of continuous derivation. On the other hand, when this 

 process fails to meet the requirements of the facts, they 

 affirm that the imperfection of the record, or of our know- 

 ledge of it, invalidates any testimony of Palaeontology on. 

 the subject. 



