SECOND LECTURE. 



THE NATURE OF THE EVIDENCE EXHIBITED 



BY FOSSIL PLANTS, AND ITS BEARING 



UPON OUR KNOWLEDGE OF THE 



HISTORY OF PLANT LIFE. 



D. P. PENHALLOW. 



In directing attention to some of the more recent results in 

 the study of those strange forms of plant life which flourished 

 in past ages, and which are now known to us only through 

 their fossilized and very fragmentary remains, it is my purpose 

 to discuss some of the fundamental aspects of the question and 

 endeavor to indicate the direction along which palaeobotanists 

 are working in their efforts to discover those facts which at 

 present constitute the missing links in a phyiogenetic chain, as 

 we know it through a study of existing species; and in so doing 

 I shall present a few typical cases in illustration of the nature 

 of the evidence it is possible to secure from organisms long 

 since extinct, and the remains of which have not only been 

 broken up and the parts widely scattered, but which, during 

 their entombment in the crust of the earth for enormous 

 periods of time, have been subjected to the destructive influ- 

 ences of decay, usually supplemented by the infiltration of 

 mineral matter, and those multiform alterations which follow 

 from heat and pressure, consequent upon the great and varied 

 changes in the material surrounding them. 



Until recently the study of fossil plants has possessed few 



attractions for the rising botanist of the new school, very prob- 



,. ably because he saw little opportunity for the development of 



the philosophical faculty and no great probability of discoveries 



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