THE HISTORY OF PLANT LIFE. 27 





 of stone, marble, and all solid fossils discovered taken up into 



the water and there sustained together with seashells and 

 other animal and vegetable bodies ; and that the present earth 

 consists and was formed out of sand, earth, shells, and the rest 

 falling down again and subsiding from the water." 



We are also informed that " The Deluge came forth at the 

 end of May when nuts are not ripe," because of the occurrence 

 of imperfectly formed hazel nuts in certain moss beds. Even 

 half a century later the idea that such remains were proof of a 

 deluge had in no way lost its force, since da Costa, who first 

 pointed out that Sigillarias and Stigmarias represented un- 

 known forms of life, and was, therefore, the first to indicate 

 the extinction of former types, firmly believed cones to be of 

 vegetable origin buried in the strata of the earth at the time 

 of the universal deluge recorded by Moses. 



In these views we, no doubt, have an expression of the sur- 

 vival of primitive beliefs which are still current among certain 

 aboriginal people of eastern Asia. 



And so for fully a century and a quarter the remains of 

 plants buried in the crust of the earth for millions of years 

 were matters of speculation without any adequate conception 

 of their real significance. Since the time of Witham, Sprengel, 

 and Goeppert there has been a constantly increasing interest in 

 the scientific study of plant remains and a correspondingly 

 greater appreciation of their true bearing upon the history of 

 plant life. Of the pioneers in this work, among English-speak- 

 ing people, probably no one has done more than Williamson in 

 England and Sir William Dawson in Canada to emphasize the 

 primary importance of the internal structure as a true guide to 

 relationship. 



Our present knowledge of living forms leads us to the con- 

 clusion that there has been a more or less regular succession 

 of types from the most simple to the most complex ; and this 

 has been brought about, not by acts of special creation, but 

 by the gradual evolution or unfolding of continually higher 

 types in direct response to changed conditions of environment. 

 What those conditions were we are unable to say, but from our 

 present knowledge of plants in respect to their environment 



