FAUNA OF ORTHAULAX PUGNAX ZONE. 87 



the Tampa silex beds at Ballast Point, Tampa Bay, Florida. U. S. 

 Nat. Mus. Xo. 165099. 



This is the typical species of the genus, distinguished by its long- 

 ovate, elevated form, of which immature specimens have been figured 

 by Gabb and Guppy. 



ORTHAULAX PUGNAX Heilprin. 



Plate 15, figs. 5, 10. 



Waffneria pugnax Heilprin, Trans. Wagner Inst., vol. 1, p. 106, pi. 15, 



figs. 36, 36a, 1887. 

 Orthaulax pugnax Dall, Trans. Wagner Inst., vol. 3, pt. 1, p. 170, pi. 8, 

 figs. 5, 8, 1890. 



Middle Oligocene of the Tampa silex beds, at Ballast Point, 

 Tampa Bay, Florida, Heilprin and Dall; also at Bainbridge, 

 Georgia, the islands of Antigua and Cuba, and in the Canal Zone, 

 Panama, MacDonald. U. S. Nat. Mus. No. 165100. 



This is the commoner species of the silex beds, though usually 

 badly broken, and can be discriminated from the other two Flor- 

 idian species by its short, stout, and remarkably heavy shell. So 

 far as yet known, it also has the widest geographical range. 



ORTHAULAX GABBI Dall. 



Orthaulax gabbi Dall, Trans. Wagner Inst, vol. 3, pt. 1, p. 170, pi. 12, 

 figs. 5, 5a, 5b, 1890. 



Oligocene marl of the lower bed at Alum Bluff and the adjacent 

 marl of the Chipola River, Florida. Burns and Dall. 



I have included a reference to this species, though it is not laiown 

 yet from the silex beds, for the sake of completeness and because it 

 may at any time turn up in other Middle Oligocene beds. It is more 

 strombiform than either of the other species and has been well 

 figured. The species occur in large numbers at Alum Bluff, but the 

 expanded outer lip is almost invariably defective. 



Genus STROMBUS (Linnaeus) Lamarck. 



Strombus Linnaeus, Syst. Nat., ed. 10, p. 742, 1758. 



Strombus Lamarck, Prodrome, p. 72, 1799. Sole example, S. pugilis 

 Linnaeus. 



STROMBUS CHIPOLANUS Dall. 



Plate 9, figs. 8, 10. 



Strombus chipolanus Dall, Trans. Wagner Inst., vol. 3, pt. 1, p. 176, pi. 4. 

 fig. 1, 1890 ; pt. 2, p. 263, pi. 13, figs. 1, 3, 1892. 

 Oligocene marls of the Chipola River, West Florida, and Tampa 

 silex beds. Ballast Point, Tampa Bay, Florida. Dall and Burns. 

 U. S. Nat. Mus. No. 112227. 



This is a common species at Chipola, but so far only fragmentary 

 at Ballast Point. The S. alhiruplanus Dall, from the White lime- 



