FOSSIL PLANTS AS AN AID TO GEOLOGY. 38 1 



petrographer, by the examination of a mere handful of speci- 

 mens gathered hastily as a " last thought," is asking too much ! 

 There is a limit to what can legitimately be expected of paleo- 

 botany, just as there is a limit to all knowledge. 



Again, it has frequently been a practice among geologists to 

 submit a collection of fossil plants without indication of the 

 specific information desired or even of the locality whence the 

 specimens came. This is done presumably with the idea that the 

 paleobotanist, being unembarrased with previous information, 

 would be the better able to give an unbiased opinion. This 

 again is wrong, and under such circumstances the paleobotanist 

 would be amply justified in declining to express an opinion. 

 Unless he can be placed in possession of all the information known 

 to the geologist, or, what is better, have an opportunity of exam- 

 ining the relations of the horizons himself, he should hesitate 

 before passing judgment. Of course, as pointed out under the 

 discussion of principles, certain broad conclusions may be made 

 instantly, such as the presence of dicotyledons proving an upper 

 Mesozoic age, or Lepidodendra and Sigillaria arguing a Paleozoic 

 age. These, however, are not usually the problems presented, 

 but close questions of age, as, for example, the Miocene or 

 Pliocene age of the auriferous gravels of California. 



It has been argued by many, especially botanists and geolo- 

 gists, that it is undesirable to give names to fragmentary and 

 seemingly indeterminable plant remains. When a definite name 

 is given it implies, it is argued, a more exact knowledge than is 

 often times possessed; a view that in many cases is undoubtedly 

 correct. But the name is given, when the fossil cannot be made 

 out satisfactorily, for purely practical reasons. It embodies, or 

 should, the best possible judgment as to its nature and syste- 

 matic position, and serves as a convenient basis of future men- 

 tion of it without tedious circumlocution. 



The foregoing examples have been given somewhat in detail, 

 for the purpose of showing what has already been done with 

 fossil plants, and to indicate the lines along which, it is hoped, 

 increased assistance will be rendered geology in the future. These 



