14G 



CHAPTER IX. 



THEORY OF THE PROGRESSIVE DEVELOPMENT OF ORGANIC 



LIFE AT SUCCESSIVE GEOLOGICAL PERIODS. 



! 



THEORY OF THE PROGRESSIVE DEVELOPMENT OF ORGANIC LIFE EVIDENCE IN 



ITS SUPPORT DERIVED FROM FOSSIL PLANTS FOSSIL ANIMALS MOLLUSCA — 



WHETHER 



THEY HAVE ADVANCED IN GRADE SINCE THE EARLIEST ROCKS 



WERE FORMED HIGH ANTIQUITY OF CEPHALOPODA SLIGHT INDICATIONS OF 



PROGRESS AFFORDED BY FOSSIL FISH ADVANCE AND RETROGRADATION OF 



FOSSIL REPTILES LAND ANIMALS OF REMOTE PERIODS WHY RARE— FOSSIL 



BIRDS MAMMALIA STONESFIELD MARSUPIALS — ABSENCE OF CETACEA IN 



SECONDARY ROCKS — SUCCESSIVE APPEARANCE OF THE GREAT SUB-CLASSES OF 

 MAMMALIA OF ADVANCING GRADE IN CHRONOLOGICAL ORDER — MODERN 



ORIGIN OF MAN INTRODUCTION OF MAN, TO WHAT EXTENT A CHANGE IN 



THE SYSTEM. 



Iisr the last chapter we considered whether the doctrine of 

 the greater intensity of the igneous and aqueous causes in 

 remote ages has any foundation in fact, and whether the 



many 



i 



ocks favours 



the opinion that the former changes in the earth's crust, of 

 which geology treats, were governed by other than ordinary 

 causes. We may now discuss the arguments derived from 

 the organic creation in support of the notion that there is a 

 want of analogy and continuity between the past and present 

 course of events in the natural world. The objections on 

 this head were formally stated in 1830, by the late Sir 



H 



affirms 



the proposition, that the present order of things is 



the 



mo 



ing laws : in those strata which are deepest, and which must, 

 consequently, be supposed to be the earliest deposited, forms 

 even of vegetable life are rare ; shells and vegetable remains 

 are found in the next order ; the bones of fishes and ovip - 

 rous reptiles exist in the following class ; the remains 





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