416 ^V. D. MATTHEW PROGRESS IX VERTEBRATE PALEONTOLOGY 



So far as the older and better known fields of vertebrate paleontology 

 are concerned, the progress of the past few years has been in the w^ay of 

 consolidating and confirming what had been tentatively sketched out by 

 earlier workers. In the newer fields we are reaching ont and securing' 

 the first fruits of exploration — the evidence which will confirm or dis- 

 prove hypotheses and guesses that hitherto have had free rein. 



Some Trexds of Modern Work 



In the field of paleogeography I may call attention to three publica- 

 tions treating the subject from diverse or opposite viewpoints : 



Matthew: Climate and evolution, an essay of some 318 pages; 



Arldt: Paleogeographie, a treatise of 2 ponderous tomes; 



Case: Paleogeography of the Permian, a quarto volume of moderate 

 dimensions. 



It is commonly said that paleogeographic problems should be decided 

 ojily after marshaling all the evidence in every branch of zoology, past 

 and present, as well as of geology and physiography, that can be brought 

 to bear on it. This is what Doctor Arldt has endeavored to do in his 

 great treatise. I do not hold that view, for it appears to jiie that unless 

 evidence is thoroughly understood and critically sifted as to its weight 

 and its real significance, it is of no value; and it is obviously impossible 

 for human intelligence to attain a thoroughly critical grasp of so vast a 

 field. On the other hand, the evidence in any one branch, if interpreted 

 rightly, will lead to correct conclusions, and if the conclusions drawn in 

 one field conflict with those drawn in another, it can only be because one 

 or the other is wrongly interpreted. It is not a question of balancing 

 the evidence. If it does not all point one way, then there is some mistake 

 in the interpretations placed on the facts. The problem then lies in find- 

 ing out what is the fallacy and in which field it lies ; and whether the evi- 

 dence in several fields has been vitiated by the same fallacy. It is only 

 thus that one can arrive at true conclusions in problems of this sort. To 

 attempt to decide them by the balance of evidence, as one would settle a 

 problem in taxonomy, is more likely to put one wrong than right. 



Doctor Case's volume is of interest as placing a novel and much broader 

 significance on the term paleogeography, making it almost equivalent to 

 what might be called paleoecology. He has little to say in this volume 

 as to the question of continental outlines, so commonly discussed as. 

 though it were tlie whole of the subject, but is concerned chiefly with the 

 habitat of the animals, its nature and changes, and the physical geography 

 of JVrmian Xorth America. 



