PALEONTOLOGY 401 



are different: (1) that present-day forms are the lineal descendants of 

 ancestral forms unlike themselves and that all new forms with ever in- 

 creasing complexity spring from older ones ; (2) new forms different 

 from the older ones have been created at different periods ; (3) all forms 

 were brought into existence at about the same time, but due to a great 

 world upheaval the fossiliferous strata have been so confusedly arranged 

 that while all fossils are of one age, it is our mistaken interpretation 

 which makes us believe they are of different ages ; or (4) organisms came 

 into existence which at the time of their origin had the possibility of 

 change placed within their germ-plasm, but which had to await the 

 proper conditions of food and environment before they could come forth 

 to produce present-day forms. 



If it be accepted that any present-day forms are different from their 

 ancestors, and that these new forms can produce offspring capable of 

 transmitting that change to their posterity in turn, we must speak of an 

 evolution as having taken place. 



References. 



Karl von Zittel's "History of Geology and Paleontology." 



A. Dendy, "Outlines of Evolutionary Biology." 



H. A. Nicholson, "Manual of Paleontology." 



Charles Schuchert, "Historical Geology." 



A. Morley Davies, "An Introduction to Paleontology." 



H. S. Williams, "Geological Biology." 



Articles on Geology, Paleontology, etc., in Encyclopedia Britannica. 



