TERTIARY FOSSIL PLANTS FROM COSTA RICA. 



By Edward W. Berry, 



Of the Johns Hopkins University, Baltimore, Maryland. 



The present contribution is devoted to a small florule collected from 

 the Tertiary of Costa Rica by Dr. Wendell P. Woodring in March, 

 1917, while in the employ of the Sinclair Oil Company, and now 

 deposited in the United States National Museum. 



The collection was made at the northeast border of Talamanca 

 Valley on the west fork of Sheroli Creek, about one-half mile above 

 the forks, there being a waterfall and conglomerate precipice about 

 100 feet high at the latter locality. In more general terms, the 

 locality is on the southeastern frontier of Costa Rica along the left 

 scarp of the Sixaola Valley, about 30 miles from the Caribbean. 



The section at the plant locality comprises a thick basal steeply 

 inclined series of marine fossiliferous shales with thin intercalated 

 sandstones, which have been called the Uscari shales. Overlying 

 these unconformably is a thinner series of sandstones and shales from 

 which the fossil plants were collected, and these beds are overlain 

 unconformably by a conglomerate (the Suretka conglomerate). 



The Mollusca collected from the Uscari shales have not yet been 

 studied, so that the lower limit of age of the deposit can not be 

 stated. The flora itself is too small to throw any light on this point, 

 as it is of a type that might well occur in the American Tropics at any 

 horizon between the Oligocene and the Recent. Only one of the 

 species, and that somewhat doubtfully, has been recorded from the 

 Canal Zone, namely, Hieronymia lelimanni Engelhardt, of the 

 Caimito formation, which is considered as of Upper Oligocene age. 

 This same species was described originally from Loja, Ecuador, from 

 a locality of unknown age, which I have considered as probably lower 

 Miocene. Two other of the Costa Rican fossil plants have an outside 

 distribution, having been described originally from Santa Ana in the 

 Rio Magdalena Valley, Colombia, also from an unknown, probably 

 Miocene, Tertiary horizon. The age of the Costa Rican plants is 

 undoubtedly Miocene, and I would not be surprised if future work 

 would show that it is younger rather than older Miocene. 



Proceedings U. S. National Museum, Vol. 59— No. 2367. 



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