208 



BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



UPPER OLIGOCENE. 



CULEBRA FORMATION. 



The Culebra formation and the base of the Emperador limestone 

 in the Canal Zone contain a few species that indicate close relation- 

 ship with the Antiguan horizon, but on the whole the affinities are 

 rather with the next higher fauna. Fossil corals were obtained in 

 the Culebra formation at three stations, as follows : 



Station 5863, west side of Gaillard Cut, at station 1863 of the 

 Canal Commission, between points opposite Curacha and Paraiso. 



Station 6020c, Las Cascadas, Gaillard Cut, third bed from the 

 bottom of the section. 



Station 6026, one and one-half miles south of Monte Lirio, on 

 Panama Railroad (relocated line). 



The list of species is as follows: 



Species of corals from the Culebra formation. 



Name. 



Station 

 5863. 



Station 

 6020c. 



Station 

 6026. 



Empera- 

 dor Is. 



Antigua. 



Anguilla. 





X 





X 

 X 



X 

 X 





X 











Orbicella costata (Duncan) 





X 

 X 



X 

 X 

 X 

 X 



X 











X 







X 











X 





X 













Of the 6 species in the Culebra formation, 2 also occur in the 

 Emperador limestone; 4 also occur in the Antigua formation; and 4 

 also occur in the Anguilla formation. There is only one species, 

 Astreopora antiguensis, that is elsewhere known only from the 

 Antigua horizon; while 2 species are at present known elsewhere 

 only from the Anguilla horizon. These relations indicate, but do not 

 prove, that the upper part of the Culebra formation, the part of the 

 formation in which the corals were collected, is stratigraphicaUy 

 higher than the Antigua formation, and is, therefore, referable to the 

 upper Oligocene. The foraminiferal fauna, to be discussed on pages 

 554, 555, 585, supplies stronger evidence in favor of considering the 

 upper part of the Culebra as of upper Oligocene age. 



EMPERADOR LIMESTONE. 



The principal collections from the Emperador limestone were made 

 by Doctor MacDonald and me at Station 6015 and 6016, in Empire 

 village. Dr. Ralph Arnold subsequently made a small collection in 

 Empire and obtained one species, Pocillopora arnoldi Vaughan, not 

 collected by Doctor MacDonald and me. Doctor MacDonald and 

 I also made a small collection at Station 6024&, the upper bed at 

 the lower end of the culvert where the Panama Railroad (relocated 

 line) crosses Rio Agua Salud; and he subsequently obtained some 



