STRATIGRAPHIC SIGNIFICANCE OF THE SPECIES. 113 



The names of 19 species, 15 of which are reported from Antigua, 

 occur in the foregoing list. Records of three species are from Lambert. 

 The names of two species are preceded by queries, indicating that 

 their occurrence in the Antigua formation is doubtful. The strati- 

 graphic position of Eupatagus depressus Jackson, one of the questioned 

 species, is not known, but it is probably the Juana Diaz shale; 7 of 

 the 17 unquestioned species range upward to the younger Anguillan 

 horizon or its equivalent, the Emperador limestone of the Panama 

 Canal Zone. It is probable that Clypeaster cotteaui, which is also 

 found at Guantanamo and Matanzas, Cuba, and Jamaica, and Cly- 

 peaster parvus, also found at Havana, Cuba, range upward to the 

 Anguillan horizon. If correct, 9 of the Antiguan species are also found 

 at the Anguillan horizon, and only 8 seem to be confined to the Anti- 

 guan horizon. The echinoids of the two horizons appear more similar 

 than do the members of other groups of organisms. 1 It is possible that 

 some of the echinoids reported on by Lambert came from a horizon in 

 Antigua higher than the Antigua formation. 



Clypeaster lanceolatus Cotteau, doubtfully present in the Miocene 

 La Cruz marl at Santiago, Cuba, is discussed on page 116. 



UPPER OLIGOCENE. 



The names of 21 species occur in the following list, two of which may 

 not occur at this horizon, as is indicated by queries. As the type 

 locality of this division of the Oligocene is the Anguilla formation, 

 island of Anguilla, the species from that formation must be the basis 

 of correlation with other localities. The number of species from the 

 Anguilla formation is 17, and another species, Clypeaster lanceolatus, 

 occurs in its stratigraphically equivalent formation, the Emperador 

 limestone, in the Panama Canal Zone. Because of identity of other 

 echinoid species found in Havana with Anguillan species, it seems 

 probable that Clypeaster platygaster Jackson also belongs at this 

 horizon, but it will be left out of further consideration. Of the 18 

 species that may safely be considered as occurring at the horizon of 

 the Anguilla formation, 7 are also reported from the Antigua formation ; 

 1 also occurs and another species may occur in the Miocene of Trinidad, 

 and 2 others may range upward into the Miocene proper. After 

 deducting the species also found in the Antigua formation and those 

 that may also be of Miocene age, there are left only 7 species from the 

 Anguillan horizon, and it is mostly on these that correlation by means 

 of echinoids with that horizon must be based. 



1 See p. 108 for references to papers on other fossils. 



