124 The Ottawa Naturalist. [Jan. 



wave marks should be noted with care. The direction of these 

 features when successive beds show a degree of uniformity 

 should be noted. Particular attention should be given to ob- 

 serving the amplitude of ripple marks, and whether they are 

 symmetrical or asymmetrical. A great predominance of one or 

 the other type of ripple mark may, as I have elsewhere 

 shown,* afford conclusive evidence regarding the continental or 

 marine origin of a set of beds. Mud cracks, rain drop impres- 

 sions, and other features characteristic of the intertidal zone, 

 should be looked for with the greatest care by the collector. 



It is true that the literature treating of fossils seldom gives 

 much data of this kind. The palaeogeographer in making use 

 of fossils in drawing the boundaries of ancient seas, has had but 

 little data of this class to curb his imagination or stay his hand. 

 Structural features of comparatively recent origin have too often 

 assumed for him a significance which they did not possess. 

 while the really significant features indicating proximity to a 

 shore line were neglected because unrecorded by palaeontol- 

 ogists and geologists. 



The observation and record of the physical characters 

 which have just been enumerated are of the utmost impor- 

 tance in connection with the collection of certain classes of 

 fossils, like the eurypterids and certain fishes whose normal 

 habitat is still a subject of discussion. It is to the careful study 

 of the physical features of the beds enclosing such fossils that 

 we must look for the solution of the problems relating to the 

 character of their habitat. 



Zoology gave to the world the hypothesis of evolution, 

 but its demonstration and its actual history is the province of 

 palaeontology. It is the privilege of the collector of fossils to 

 assist in discovering the actual course wdiich the steady upward 

 trend of life has followed through the geologic ages. For the 

 study of problems relating to orthogenesis, saltation and other 

 elements in evolution, fossils offer a great advantage over living 

 animals and plants. The time element in the latter is an un- 

 determined factor, while in the geological section its vakie may 

 be determined. Zoologists are too little acquainted with the 

 excellent results which have been attained in this field through 

 the work of such men as Waagen on mutation, Hyatt on the 

 cephalopods, and Beecher on the evokition of spines. Only 

 very well preserved material can be utilized in sttidies of this 

 class. The collector q| perfectly preserved fossils derives an 

 added pleasure from hu work through knowing that it may bs 

 of vaKie in contributing to the solution of some of the most 

 fundamental problems of the organic world. 



*Recent and Fossil Ripple Marks (in Press). 



