REPORT OF THE DIRECTOR I916 97 



sulated mass of marine Devonian strata known as the Perce rock, a 

 section which above the waterhne represents a sea deposit 300 feet 

 thick, 1300 feet long and about 250 feet wide; and the figures for 

 these few species run into the hundreds of milhons 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 the most closely studied 

 formations have already yielded up a large percentage of their 

 actual fauna. For some well-studied formations in limited areas 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 details with its brilliant vistas already 

 before us of learning the inchoate life of the primitive soils and first 

 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 suggestive- 

 ness 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 structures, com- 

 pare by way of simple illustration compressed into the emergencies 

 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 de- 

 velopment ; and if aught is left to become known of internal anatomy 

 or ecology, the lessons of the past are the promise of the future. 

 What was 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 num- 

 bers of living animals, their phylogeny 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 others 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 have 

 piled higher with every year. 



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

 temple : 



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