THE 



GEOLOGICAL HISTORY OF PLANTS. 



CHAPTER I. 



PRELIMINARY IDEAS OF GEOLOGICAL CHRONOLOGY AND 

 OF THE CLASSIFICATION OF PLANTS. 



The knowledge of fossil plants and of the history of 

 the vegetable kingdom has, until recently, been so frag- 

 mentary that it seemed hopeless to attempt a detailed 

 treatment of the subject of this little book. Our stores 

 of knowledge have, however, been rapidly accumulating 

 in recent years, and we have now arrived at a stage when 

 every new discovery serves to render useful and intelligi- 

 ble a vast number of facts previously fragmentary and of 

 uncertain import. 



The writer of this work, born in a district rich in 

 fossil plants, began to collect and work at these as a 

 boy, in connection with botanical and geological pursuits. 

 He has thus been engaged in the study of fossil plants 

 for nearly half a century, and, while he has published 

 much on the subject, has endeavoured carefully to keep 

 within the sphere of ascertained facts, and has made it 

 a specialty to collect, as far as possible, what has been 

 published by others. He has also enjoyed opportunities 

 of correspondence or personal intercourse with most of 



