CONTRIBUTION TO THE PALEONTOLOGY OF TRINIDAD. 95 



rather large specimen even shows the typical characteristic of the ridge above the 

 row of headings becoming obsolete on the lower whorls. 



Height of shell figured 20, greatest diameter 9 mm. Greatest diameter of 

 largest specimen found at Soldado 12 mm. 



In 1887 Dr. White described a shell with very similar form and ornamentation 

 from the Maria Farinha beds, Province of Pernambuco, Brazil, under the name 

 of Nerinea buarquiana. 76 



As Professor Harris has already pointed out, 77 this species has much in common 

 with T. nerinexa. 



Locality. — Bed No. 2, Soldado Rock, Gulf of Paria. 



Geological horizon. — Basal (Midway) Eocene. Equivalent to the Midway 

 of Alabama and of the Maria Farinha beds, Brazil. 



Turritella mortoni Conrad. Plate XII, Figure 23. 



Turritella mortoni Conrad, Jour. Acad. Nat. Sci. Phila., vol. VI, pt. 1, p. 221, pi. 10, fig. 2, 1829. 

 Turritella mortoni Conrad, Fossil Shells of the Tertiary Formation of North America, vol. I, 



No. 3, p. 40 (96), pi. XV, fig. 11, 1835. 

 Turritella mortoni H. C. Lea, Proc. Acad. Nat. Sci. Phila., vol. IV, p. 107, 1848. 

 Turritella mortoni Conrad, Am. Jour. Conch., vol. 1, p. 32, 1865. 

 Turritella mortoni Heilprin, Proc. Acad. Nat. Sci. Phila., vol. 31, p. 219, 1879. 

 Turritella sylviana (Hartt) White, C. A., Arch, do Museu Nac. do Rio de Janeiro, vol. VII, pp. 



161-162, pi. XVIII, fig. 10, 1887. 

 Turritella mortoni Smith and Johnson, U. S. Geol. Surv., Bull. 43, pp. 30, 33. 1887. 

 Turritella mortoni de Gregorio (ex parte), Am., Geol. et Pal., p. 122, pi. 11, fig, 7, 1890. 

 Turritella mortoni Kennedy, Proc. Acad. Nat. Sci. Phila., vol. 47, p. 147, 1895. 

 Turritella mortoni Clark, W. B., U. S. Geol. Surv., Bull. No. 141, pp. 40, 44, 45, 46, pi. XIII, figs. 



la-le, 1896. 

 Turritella mortoni Harris, Bull. Am. Pal., vol. I, p. 224, 1896; Geol. Surv. Louisiana, p. 229, pi. 



52, fig. 9, p. 308, pi. LV, fig. 4, 1899; Bull. Am. Pal., vol. Ill, pp. 74-75, pi. X, figs. 3, 4, 1899. 

 Turritella mortoni Clark and Martin, Eocene, Md. Geol. Surv., pp. 147-148, pi. XXVI, figs. 1-5, 



1901. 



Conrad's original description. — " Shell turreted, conical, thick, with revolving 

 distant, and finer intervening striae; whorls with an elevated acute carina near 

 the base of each; volutions about 11 ; the striae are largest on the elevations of the 

 whorls, which are slightly concave above, and abruptly terminate at the sutures; 

 the lines of growth on the last whorl are strong and much undulated." 



Type locality, Maryland. 



Remarks. — This Turritella, which is a rather common species at Soldado Rock 

 in the Bed No. 2 fauna, is one of the most important and characteristic fossils 

 of the Lower Eocene deposits of the Atlantic and Gulf coasts of the United States. 

 It was first described by Conrad in the Maryland Eocene where it is exceedingly 

 abundant. Dr. Clark 78 shows a photograph of blocks of the Aquia Creek forma- 

 tion made up almost wholly of T. mortoni. And great masses of this Turritella 

 rock strew the shore at the base of the Aquia Creek and the Potomac Creek bluffs. 



Professor Harris 79 remarks that this species occurs in the form of casts in 

 great abundance, large size and of most typical form in a soft layer in the Midway 



76 Arch, do Museu Nac. do Rio de Janeiro, pp. 142-144, pi. XIV, figs. 8, 9, 10, 11. 



77 Bull. Am. Pal., I, p. 225, 1896. 



78 Eocene Md., 1901, pi. Ill, fig. 2. 



79 Bull. Am. Pal., vol. I, p. 224. 





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