582 THE POPULAR SCIENCE MONTHLY 



speakers making their approach from different fields of interest. The 

 conference was an effort to define and emphasize the common platform 

 on which the paleontologists must stand together ; even more than this, 

 it was a purpose to declare at the outset that the organization, though 

 the patron of detailed researches and patient endeavor, recognizes that 

 the sole impulse which can guarantee its usefulness and maintain its 

 integrity is its devotion to a standard which touches close on human 

 interests. 



ADEQUACY OF THE PALEONTOLOGIC RECOKD 



By Peofessoe SAMUEL CALVIN 



UNIVEESITX OF IOWA 



WHEN or how life began on our planet no one may be able to 

 tell us; but that life has been present and has been an impor- 

 tant factor in the world's geological development since before the be- 

 ginning of the Cambrian is known to the most callow of embryo geol- 

 ogists taking his first course at the village high school. So far as 

 relates to the skeleton-bearing, marine invertebrates which have lived 

 on floors of epicontinental seas, there are remarkably complete records 

 of this long history of living things, the order of their succession, their 

 migrations, their geographic distribution during any given portion of 

 geologic time, as well as of the progressive and orderly modifications 

 which resulted in the extermination of decadent or unfit types, on the 

 one hand, or resulted, on the other hand, in the advancement of certain 

 types and their adaptation to the conditions prevailing in the living 

 world to-day. 



The zoologist, confining attention to living forms, gets a view of the 

 animal creation as it exists, after ages of development and modification, 

 during a fraction of a single faunal stage. The paleontologist, while 

 unable to see the beginnings of life, gets the broader view which comes 

 from a study of the organic world as it has appeared during numberless 

 successive stages. He may trace the origin of forms and note the trend 

 and tendency of variations in ways denied the zoologist. Neither the 

 depth of the water nor the distance from the shore at the points where 

 the objects of his study lived interferes with the thoroughness of his 

 explorations. He is not limited to what he may learn by taking 

 samples of the old sea bottom, here and there, with a dredge; he 

 traces his life zones with practical continuity over areas of continental 

 extent. 



The faithfulness with which the paleontological record has been 

 kept since the beginning of the Cambrian is a matter of constant sur- 

 prise. No organism was too small for preservation, if only its soft 



