March 2, 1917] 



SCIENCE 



219 



devoted to the Paleozoic; SO to the Mesozoic; 

 100 to the Cenozoic. This is in pleasing con- 

 trast to what is seen in several recent works 

 where an overweening preponderance is given 

 to the Paleozoic, apparently because it was long ! 

 or, because the author's interests were largely 

 in that era. To be sure some phases of the 

 Mesozoic are ill represented in this country, 

 and, in preparing a work for American stu- 

 dents a less complete account of this era is 

 permissible; but not so with the Cenozoic so 

 grandly recorded throughout the length and 

 breadth of this land. And again, in this era 

 were evolved the teeming hordes of modern 

 life on land, in sea and air, life of most funda- 

 mental interest to man, and man himself. 

 Imagine a work on general history descanting 

 on ancient civilizations, because they extended 

 through vast periods of time! cormnenting 

 more briefly on medieval epochs, and brushing 

 aside with a few paragraphs the fundamentally 

 important, profoundly intricate and compara- 

 tively accessible developments of modern his- 

 tory. The writer on historic geology has, how- 

 ever, greater difficulties before him than the 

 assignment of space to eras. Above all comes 

 the Herculean task of vividly portraying to 

 the beginner the events of earth history by 

 means of legitimate deductions drawn from 

 fossil forms, all of which are unknown to the 

 student. Whoever has listened to a lecture 

 on a new subject in a strange tongue will ap- 

 preciate the difficulty here referred to. The 

 average American youth may listen profitably 

 to a discourse on mountains, rivers, oceans, even 

 perhaps on volcanoes and earthquakes. With 

 animal and plant life in the form of horses, 

 cattle, trees and grasses he is more or less 

 familiar; but, in definite knowledge regard- 

 ing the life of the sea — the very type the 

 teacher wants to deal with most frequently — 

 he is found wanting. We recall the startled 

 look when he hears the common word 

 Brachiopoda for the first time; we still respect 

 the brilliancy of the student who mnemonically 

 cinched Tropidoleptus carinatus not by its 

 biological affinities but by the similarity of 

 its specific name to " Carrie Ifation." Pro- 

 fessor Miller, like Dana and others, has recog- 



nized this general lack of biological prepara- 

 tion on the part of his readers and has devoted 

 an introductory chapter to an outline classifi- 

 cation of the animal and plant kingdoms. 

 Thereafter, in orderly review, he gives under 

 each period what is happening among the 

 Echinoderms, Worms, Molluscoids, Molluscs, 

 etc., etc. Now this orderly, card-index style of 

 arrangement of facts is excellent in a book 

 for reference only; but, the bringing up of 

 each little branch of life again and again when 

 not characteristically developed leads neces- 

 sarily to the introduction of considerable un- 

 important matter ; for example : " The Pelecy- 

 pods and Gasteropods were still common, but 

 they were in no important way different from 

 those of the preceding period." Or : " Sponges 

 were common but they require no special de- 

 scription." 



It seems to the reviewer that such data 

 might be confined to the excellent " Tabular 

 Summary " at the close of each era. The 

 question arises here, as in reference to the 

 majority of texts on historic geology, would 

 it not be better for the student's mental diges- 

 tion, so to speak, if in place of this menu of 

 a vast number of short-order courses a few 

 well-balanced rations of carefully selected 

 matter were served. Schuchert in the text- 

 book already referred to has apparently acted 

 upon this principle, interlarding his chapters 

 on physical history of the periods with sub- 

 stantial essays on a few dominant types of 

 life characteristic of each great geological 

 period. Time will determine whether the 

 student profits more by being continually re- 

 minded of the progress of the various minor 

 subdivisions of life, or, by receiving once and 

 for all a thoroughgoing discussion of a few 

 great, dominant life-forms. 



Professor Miller's book seems remarkably 

 free from the small, yet sometimes ludicrous, 

 mistakes that often appear in first editions. 

 Quite probably, however, he will change the 

 wording in the following sentences somewhat 

 in the next edition of the work: (Page 106) 

 " Conformably above the Clinton beds lies 

 the Niagara, limestone, which has a still wider 

 distribution than the Clinton." 



