^96 Observations on the Nature and Importance of Geology. 



rocks of the earliest formations are the simplest, while the 

 newer are more and more compound ; on the contrary, the 

 oldest appear to be the most compound. In complete opposi- 

 tion to this, the organic world, in each of its two principal divi- 

 sions, exhibits a series of formations from simple to compound ; 

 the simplest being the oldest. Thus we observe animal life 

 commencing in infusory animals, without any discernible organs. 

 Simple digestive organs are first visible in the polypi ; in the 

 echinodermata the organ of respiration first appears ; in insects 

 a system of nerves and muscles ; in crustaceous animals circula- 

 tion ; and in the last two, simple organs of sense make their 

 appearance. At the same time, generation preserves the pe- 

 culiar character of organic beings ; and after having accom- 

 plished its purpose, by mere division and dissolution, the particu- 

 lar generative organs develop themselves in distinct sexes. With 

 the avertebral animals are conjoined the series of the vertebral, 

 in which every system appears more perfect, and more close- 

 ly connected. New organs of sense are unfolded, and the 

 brain becomes the centre of feeling, perception and life, till 

 in man it attains the highest state of perfection, and endows him 

 with consciousness and rationality. Long ago, celebrated natu- 

 ralists, relying upon these observations, attempted, with more or 

 less success, to arrange the species of animals, sometimes accord- 

 ing to a scale of gradation, and sometimes according to a reticu- 

 lated form, without giving any distinct account of the meaning 

 of such an arrangement. Should it, like the piling up of a col- 

 lection of books, merely serve for a more convenient survey of 

 innumerable creatures, without any reference to their origin ? Or, 

 do they intend, by means of such an arrangement, to express the 

 design that hovered in the mind of Omnipotence, before he cal- 

 led these creatures into being ? Or, have they originated in the 

 way in which they appear in the scale of gradation, as if the 

 hand of the Creator, like that of a human artist, perhaps, must 

 first be exercised on simple formations, before it was capable of 

 producing such as were compound ? 



Upon these questions, whose answer might contain no less 

 than a key to the profoundest secrets of nature, Mr Lamarck, 

 one of the most sagacious naturalists of pur day, has expressed 



