GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 21 



material from the island of Antigua, it has not previously been recog- 

 nized in the fossil state. 



The family Lauraceae, so extensively represented in the Tertiary 

 floras of the Mississippi embayment and in the Recent tropical flora 

 of South America, is represented at Panama by a single fragmentary 

 species which is referred to Mespilodaphne. The latter has numer- 

 ous modern species in the tropics of America and Africa. 



The Myrtaceae, one of the abundant families in the existing for- 

 ests of tropical America, has a fossil species of C alyptrantJies at 

 Panama. This genus has about 70 exclusively American existing 

 species ranging from Mexico and the West Indies to southern Brazil. 

 Hemsley records 7 recent species from Central America, of which 

 2 are found on the Isthmus. It is also represented in the lower 

 Eocene of the Mississippi embayment. The abundant, both Recent 

 and fossil, representatives of the allied genera Eugenia and Myrcia 

 have not been recognized in the fossil flora of the Isthmus. 



The Melastomataceae, an immense tropical family in the existing 

 flora and very abundant throughout Central America, has a single 

 fossil species in the Culebra formation. 



The family Ebenaceae, usually abundant in fossil floras from the 

 Upper Cretaceous onward, and with a large number of species in 

 tropical America, is represented on the Isthmus by the petrified 

 fruits of a species of ebony (Diospyros) known to be from an older 

 horizon (Eocene) than the balance of the known fossil flora. 



The Rubiaceae, a prominent family in the existing flora of Central 

 America, where according to Wallace (1911) it ranks fourth in size 

 with 146 species, is represented by two fossil species, both found in 

 the Gatun formation. These are referred to Rondeletia and Rubi- 

 acites. 



The former has not heretofore been found fossil. It includes 

 about 70 existing species of a variety of habitats, confined to the 

 American tropics and chiefly massed in the Antilles and Central 

 America. Rubiacites is represented by a fruit which is apparently 

 referable to the tribe Ixoreae, now confined to the tropics of both 

 hemispheres. 



TERTIARY ECOLOGY. 



The restricted variety and fragmentary condition of the fossil 

 plants thus far collected inhibits a detailed discussion of the prob- 

 able ecology of the Tertiary flora. In so far as climatic conditions 

 are concerned the Tertiary plants indicate an abundant rainfall and 

 relatively high equable temperatures such as prevail at the present 

 time in the Hill country and Coastal Plain of the Isthmus. There is 

 no indication of upland vegetation. None of the fossil plants indicate 



