STRATIGRAPHIC SIGNIFICANCE OF THE SPECIES 

 OF WEST INDIAN FOSSIL ECHINI. 



INTRODUCTION. 



In order that the geologist who is particularly concerned with 

 problems in stratigraphic geology may easily utilize the results of the 

 detailed study of Doctor Jackson, it seems desirable to have in suc- 

 cinct form what is definitely known of the stratigraphic occurrence 

 of the species of echinoids described in his paper. 



The present status of the correlation of the West Indian Tertiary for- 

 mations is indicated in the accompanying correlation table 1 (p. 109), 

 taken, with slight modifications, from a report issued in December, 1921 . 

 The Dominican Republic exhibits the most comprehensive succession of 

 Tertiary strata at present known in the West Indies, and the section 

 there exposed may appropriately be used as a reference section for 

 that region. It may also be stated that there is no possibility of error 

 in the stratigraphic succession of the Dominican formations as indi- 

 cated in the accompanying table. 



For the benefit of those who may wish to examine the recent litera- 

 ture on the correlation of West Indian and Central American Tertiary 

 formations and who may wish to know what other organisms are 

 associated with the echinoids described by Doctor Jackson, a list of 

 recent publications is here given: 



Recent Papers on Geologic Correlation of West Indian Tertiary Deposits. 



Cooke, C. Wythe. Stratigraphic significance of Orthaulax (abstract): Geol. Soc. Amer. 



Bull., vol. 31, p. 206, 1920. 

 . Geologic reconnaissance in Santo Domingo (abstract): Geol. Soc. Amer. Bull., 



vol. 31, pp. 217-219, 1920. Correlation table on p. 219. 

 . *Orthaulax, a Tertiary guide fossil: U. S. Geol. Survey Prof. Paper 129, pp. 23-37, 



pis. 2-5, 1921. 

 . Stratigraphic and structural geology and geologic history: Dom. Rep. Geol. 



Survey, Mem., vol. 1, chap. 4, pp., 50-82, pis. 8-13, 1921. 

 Hubbard, Bela. The Tertiary formations of Porto Rico: Science, n.s., vol. 51, pp. 395, 



396, 1920. 

 Maury, Carlotta J. On the correlation of Porto Rican Tertiary formations with other 



Antillean and mainland horizons: Amer. Jour. Sci.: ser. 4, vol. 48, pp. 209, 



215, 1919. 

 .* Tertiary Mollusca from Porto Rico: New York Acad. Sci.: Scientific Survey of 



Porto Rico and the Virgin Islands, vol. 3, pt. 1, pp. 1-77, 9 pis., 1920. 

 Vaughan, Thomas Wayland. Correlation of the Tertiary geologic formations of the 



southeastern United States, Central America, and the West Indies: Wash. Acad. 



Sci. Jour., vol. 8, pp. 268-276, 1918. 

 •. Geologic history of Central America and the West Indies during Cenozoic time. 



Geol. Soc. Amer. Bull., vol. 29, pp. 615-630, 1919. 



' T. W. Vaughan. C. Wythe Cooke, D. D. Condit, C. P. Ross, W. P. Woodring, and 

 F. C. Calkins, A geological reconnaissance of the Dominican Republic: Dominican Repub. Geo- 

 logical Survey, Memoirs, vol. 1, 268 pp., 23 pis., 1921. 



♦The three papers marked with asterisks in this list contain systematic descriptions of fossils, 

 but their titles aie not repeated in the next list. 



107 



