Vin LETTER TO THE SECRETARY. 



geologic record which too long remained blank, while the spirit of scientific 

 inquiry was moving in other lines of research with such eflective energy. 

 The lively and widespread interest manifested by the people of the United 

 States in the progress of science would ensure the favorable reception of a 

 work upon a hitherto unknown subject, even though it did not relate, as this 

 one does, to one of the most practically valuable as well as scientifically 

 remarkable geological formations of the continent. 



The study of palseo-botany acquires its highest interest when considered 

 in connection with tlie plant-life of the present time. Fossil plants are 

 records of the past, engraven on the rocks — the legible documents which 

 enable the student to discern whence and how the Flora of to-day has 

 acquired its character. The study of recent vegetation is linked with that 

 of the long past as indissolubly as are the plants themselves related by 

 descent with modification from preexisting forms; and its rational interpre- 

 tation is possible only when the subject is viewed in the reflected light of 

 geological succession. 



But the study of Fossil Floras may be brought to bear upon questions 

 of still greater magnitude and importance, even those of the origination of 

 continental land-areas as at present existing, and of their connection or sepa- 

 ration at certain periods of geologic time. To recognize, for example, that 

 the present American Flora includes types traceable back to the oldest 

 geologic formations, and that the continent has preserved certain peculiar 

 types, not found in Europe or elsewhere, through all the mutations of its 

 surface-features, would authorize the deduction that these land-areas were 

 separated for a corresponding length of time. Such studies, again, bear 

 upon the problem, whether, as some believe, the North American Flora was 

 derived by migration across intermediate land, either from Europe or Asia, 

 or whether, as others maintain, the Flora was indigenous and consequently 

 peculiar. Such considerations bring us face to face with one of the greatest 

 and gravest problems that the human intellect may aspire to solve, namely, 

 the origin and development of species. 



The value which attaches to the study of Fossil Floras as furnishing data 

 for general geological purposes has been often disputed. It is well under- 

 stood that palseontological or palaeo-botanical material is more or less valuable 

 and reliable in proportion to the abundance and state of preservation of 



