﻿582 BULLETIN- 103, UNITED STATES NATIONAL MUSEUM. 



MIDDLE OLIGOCENE. 



As stated on page 203 in the discussion of the coral faunas, the 

 Antiguan OHgoccne must, in my opinion, be taken as the type forma- 

 tion and type locality of the middle (Rupelian) Oligocene of Am.crica. 

 I have definitely correlated with this horizon the reef-coral fauna 

 from Tonosi, Panama, station 65S7, which I consider to be the strati- 

 graphic equivalent of the lower part of the Culebra formation. 

 Lepidocycllna ■panajnensis and L. duplicata are associated For- 

 aminifera. Tlie presence of marine deposits of this age in Antigua, 

 Porto Rico, Santo Domingo, Cuba, Florida, Alabama, and eastern 

 Mexico has been mentioned on pages 199-207, 



Messrs. Roy E. Dickorson and W. S. W. Kew have recently pub- 

 lished a paper ' in which they say: "most of the localities listed below 

 appear to belong to the San Fernando formation of Dumblc." This 

 name is invahd, because it is preoccupied by the name of certain 

 formations in Trinidad, and has been renamed San Rafael formation 

 by E. T. Dumble. On page 205 of this volume I correlate it with 

 the middle Oligocono Antigua formation, the basal part of the Chatta- 

 hoochee formation, and the European Rupelian, on the basis of tho 

 corals, which possess no such heterogeneous stratigraphic affinities as 

 the fossils recorded by Messrs. Dickorson and Kew. I will not hero 

 undertake to analyze the fauna they report, but will say that it con- 

 tains names of species of upper Eocene (Jackson-Ludian), lower 

 Oligocene (Vicksburgian-Lattorfiam), upper Oligocene (upper Chatta- 

 hoochee-Tnmpa-Aquitanian), and lower Miocene (lower part of tho 

 Alum Bluff and the higher horizon represented by tho Bowden marl- 

 Burdigalian) ago. In fact their list includes nearly every horizon 

 from upper Eocene almost to middle Miocene. I will not attempt 

 to explain this surprising paleontologic assemblage as the collections 

 may represent a number of horizons, the species may be misidonti- 

 fied, or some of the species may have extraordinary stratigraphic 

 ranges; and it will be mentioned that, as in at least one instance 

 Cotteau made an error in stating the locality at which the type of 

 a species was collected, there is some confusion for which Messrs* 

 Dickorson and Kew are not responsible. An attempt will be made 

 to remove in the forthcoming memoirs on West Indian paleontology 

 as much of this kind of confusion as is possible. 



West of Alabama in Mississippi and Louisiana there are plant- 

 bearing beds of middle Oligocene age, for a considerable part of tho 

 Catahoula sandstone is certainly of that age, but that formation seems 

 to include beds of lower, middle, and probably upper Oligocene age. 

 No middle Oligocene deposits are known in Texas. There is no 



» The fauna of a medial Tertiary formation and the associated horizons of northeastern Mexico, Cali- 

 fornia Acad. Sci. Proc, vol. 7, pp. 125-156, pis. 17-26a, 1917 (date printed with title July 30, 1917; received 

 by me Oct. 16, 1917). 



