THE 



EDINBURGH NEW 



PHILOSOPHICAL JOUENAL 



The Theory of Successive Development in the Scale of being 

 both Animal and Vegetable, from the earliest periods to our 

 own time, as deduced from Paloiontological evidence. 



The theory of successive geological development, so ge- 

 nerally adopted by geologists, is clearly stated by Professor 

 Sedgwick in his admirable Discourse on the Studies of Cam- 

 bridge. " There are traces," he says, " among the old 

 deposits of the earth of an organic progression among the 

 successive forms of life. They are to be seen in the ab- 

 sence of mammalia in the older, and their very rare appear- 

 ance in the newer secondary groups ; in the diflfusion of 

 warm-blooded quadrupeds (frequently of unknown genera) 

 in the older tertiary system, and in their great abundance 

 (and frequently of known genera) in the upper portions of 

 the same series ; and lastly, in the recent appearance of 

 man on the surface of the earth." (p. xliv.) " This historical 

 development,'* continues the same author, " of the forms and 

 functions of organic life during successive epochs seems to 

 mark a gradual evolution of creative power, manifested by a 

 gradual ascent towards a higher type of being." — Ibid. p. cliv- 

 *' But the elevation of the fauna of successive periods was 

 not made by transmutation, but by creative additions ; and 

 it is by watching these additions that we get some insight 

 into Nature's true historical progress, and learn that there 

 was a time when Cephalopoda were the highest types of 

 animal life, the primates of this world ; that Fishes next took 

 the lead, then Reptiles ; and that during the secondary period 

 they were anatomically raised far above any forms of the 



VOL. LI. NO. CI.— JULY 1851. A 



