RELATION OF NAT I RE TO THE INDIVIDUAL 239 



number of individuals of a few of the species occurring in one insulated 

 mass of marine Devonian strata known as the Perce Eock, a section which 

 above the water line represents a sea deposit 300 feet thick, 1,300 feet 

 long, and about 250 feet wide, and the figures for these few species run 

 into the hundreds of millions of individuals — and yet the rock is not 

 richly fossiliferous, in the customary use of that expression. 



It seems to be my experience, too, that tlie most closely studied forma- 

 tions have already yielded up a large percentage of their actual fauna. 

 For some well studied formations in limited ai'eas the known fauna is, 

 approximately speaking, a true and fairly full expression of the actual 

 fauna. I can not of course pursue this matter here into its further de- 

 tails with its brilliant vistas already before us of learning the inchoate 

 life of the primitive soils and impounded waters, but I think I shall 

 venture to enter the lists on call, to contend that for plant and animal 

 life alike the records of the rocks, where unaltered, are unimpeachable 

 for adequate suggestiveness of the designs which the threads of life have 

 woven. And when the imputation is too often made of imperfection 

 through loss of anatomical detail, or the destruction of essential struc- 

 tures, compare by way of simple illustration compressed into the emer- 

 gencies of this occasion the growth of knowledge of fossil anatomy within 

 the fragment of the lifetime of one man. Fifty years ago all that was 

 known of the ventral organization of the trilobite was a mere suggestion 

 embedded in a nest of speculations ; of its ontogeny a few discrete facts. 

 So far has knowledge advanced that today we seem to know these animals 

 in all their essential details and development; and if aught is left to 

 ))ecome known of internal anatomy or ecology, the lessons of the past are 

 the promise of the future. What Avas known of the Eurypterida fifty 

 years ago was little but their outline and their grosser form. Today their 

 ontogeny is understood almost from birth onward, their anatomy almost 

 to ultimate details, their habits at least as well as those of vast numbers 

 of living animals, their phytogeny as well as or better than the phylogeny 

 of any living race subjected to this speculative treatment. Supplement 

 these illustrations, which are nearest to me, with the scores of otiiers 

 known to you, and with the tremendous strides made in this same period 

 of time among the extinct vertebrates, and within the realm of lost floras 

 where sheaves of knowledge are piled higher with every year. 



These are the theses I should wish to nail on the doors of our temples: 



jSTature makes for the individual. This truth is registered on the 



tablets of the earth; it lies also in human observation and in human 



experience. Its recognition is of paramount importance ; its acceptance 



