THE FOSSIL HIGHER PLANTS FROM THE CANAL ZONE. 



By Edward W. Berry, 



Of the Johns Hopkins University, Baltimore. 



INTRODUCTION. 



It is a truism that the present floras and faunas of Central America 

 are the result of a long series of antecedent geologic changes which 

 might be amplified as geographic, climatic, and biologic. As the 

 past can only be understood by means of our knowledge of the 

 present, so, too, the present can only be understood by means of 

 our knowledge of the past. Moreover, this can never be a local prob- 

 lem, and this is particularly true of the Isthmus of Panama marking 

 as it does at times the highway of communication between the ter- 

 restrial life, both animal and plant, of North and South America; 

 at other times marking one of the paths of communication between 

 the marine life of the Atlantic and Pacific. Thus the history of the 

 Central American region is of the utmost importance in any con- 

 sideration of the extinct terrestrial faunas and floras of North Amer- 

 ica or the marine faunas that formerly flourished on the east and 

 west coasts. 



Our knowledge of the present flora of the isthmian region is based 

 upon Seemann's flora 2 and Hemsley's flora of Central America, sup- 

 plemented by the scattered papers by numerous authors on special 

 topics relating to this flora. As the results of the recent Biological 

 Survey of the Canal Zone become available, we will doubtless have 

 a secure basis for comparisons with antecedant floras both in this 

 region and the areas north and south of it. 



The present distribution of plant associations is in its broader 

 outlines governed almost entirely by the interrelations between 



1 R. T. Hill, who did some geological work on the Isthmus in 1895 for Alexander 

 Agassiz, mentions lignite and fragments of fossil plants in the Culebra clays at the base 

 of the canal cutting at Culebra station (Bull. Mus. Comp. Zool., vol. 28, No. 5, 1898), and 

 the lignitic coal at Chiriqui Lagoon was studied by Dr. John Evans in 1857, who reported 

 " that the fossil plants associated with the coal were endogenous and allied to or identical 

 with those at present growing in the vicinity." (Repts. of Expl. & Surv. for the Loca- 

 tion of Inter-oceanic ship canals, etc., by the U. S. Naval Exped., 1875, E. P. Lull, 

 U. S. N., commanding, Washington, 1879.) 



2 Seemann, Flora Panainensis, Botany of the voyage of H. M. S. Herald, pp. 57-346, 

 3 852-1857. 



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