TEKTIARY MOLLUSKS OF THE GENUS ORTHAULAX 

 FROM THE REPUBLIC OF HAITI, PORTO RICO, AND 

 CUBA. 



By Wendell P. Woodring 

 Of Washington, District of Columbia. 



A large number of Tertiary molliisks were collected during a 

 geologic reconnaissance of the Republic of Haiti, under the super- 

 vision of the United States Geological Survey, by J. S. Brown, 

 W. S. Burbank, and myself during the winter of 1920-21. The 

 largest collections are from beds of Miocene age in the Central Plain, 

 an interior plain in the northern part of the Republic, where a mol- 

 luscan fauna of more than 300 species was obtained from the Tho- 

 monde formation. A preliminary account of the stratigraphy of the 

 Miocene rocks of the Central Plain has been published,^ and a de- 

 tailed description of the rocks with faunal lists is now ready for 

 press.^ 



Most of the Miocene mollusks are undescribed, and as a long in- 

 terval of time may elapse before they are monographed it is planned 

 to give accounts of the most interesting species. 



Orthaulax aguadillensls Maury is the most striking and one of the 

 commonest of the mollusks in the upper faunal zone of the Thomonde 

 formation. In the Republic of Haiti it is confined to this faunal 

 zone, which embraces the uppermost 100 meters of the Thomonde 

 formation, and it was collected at every locality where collections 

 were made from this zone. 



During February, 1922, G. R. Mansfield, of the United States 

 Geological Survey, while examining a dam site for the Porto Rican 

 Government in the Province of Aguadilla, collected an interesting 

 new species of Orthaulax from beds probably of middle Oligocene 

 age on Rio Guajataca. This species is described to supplement 

 Cooke's recent summary of all the known species of the genus.^ Mr. 

 Mansfield also collected casts of Orthaulax aguadillensls Maury from 

 the Quebradillas limestone at the locality given on page 8. 



1 Woodring, W. P., Stratigraphy, structure, and possible oil resources of the Miocene 

 rocks of the Central Plain : Rep. Haiti Geol. Survey, 19 pp., map, 1922. 



' Woodring, W. P., J. S. Brown, and W. S. Burbanlc, Geology of the Republic of Haiti : 

 Rep. Haiti Geol. Survey (ready for press). 



> Cooke, C. W., Orthaulax, a Tertiary guide fossil : U. S. Geol. Survey Prof. Paper 129-K, 

 pp. 23-31, pis. 2-5, 1921. 



No. 2491.— Proceedings U. S. National Museum, Vol. 64. Art. I. 



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