224 



ox THE TOPOGRAPHY AND GEOLOGY 



AMAURA. MGller. " ' 



A. Guppyi. Gabb, a. s. ' ■ , ■ 



N(Ukiv phaskmelloidest, Guppy, (not d'Orb.) Quart. Jour., Vol. XXII., p. 219, pi. 47, fig. 1. 



Shell subglobular, spire liigli, tw o thirds as long as the mouth ; whorls rounded, neither llattened nor channeled 

 near the suture. Aperture broad, regularly rounded in advance ; inner lip thinly encrusted, thickened and bordered 

 by a carina in advance of the umbilical region. This carina forms a flattened margin to the mouth and unites in 

 advance with tlie outer lip. 



Guppy's figure is a little smaller than the average of the full grown Dominican 

 specimens, but the shell never attains a quarter of the size of the Cuban shell. It is 

 quite common in Santo Domingo. 



SCALARIA. Lam. ' 

 S. denticulata. Sby. ■ - 



One or two imperfect specimens of this species were found. 



S. ra i n u t i s s i m a . Gabb, n. s. 



Shell elongate, slender, spire Iiigh ; whorls nine, convex, suture deep ; surface marked by prominent plates, 

 about twelve to a volution, denticulated on the upper angle. Between these plates are minute revolving lines. 

 Aperture subcircular with a continuous thickened lip. Length .2 inch. 



This species differs from 8. imcmaticosta, d'Orb., La Sagra's Hist, of Cuba, pi. 11, 

 fig. 25, 27, in having a more slender form and in the interspaces between the ribs 

 being marked by smaller and more numerous revolving lines. 



S. a m p 1 a . Gabb, n. s. 



Shell short, broad, robust ; spire a little higher than the body whorl ; whorls about seven (apex broken\ very 

 convex, and having about ten larger, I'obust sub-squamose plates, angulated, or sub-denticulated above : body whorl 

 with a few faint impressed lines and a ridge at the lower angle. Mouth circular, bordered by a heavy lip. Length 

 .6 inch, width .45 inch. 



Characterized by its short, very broad form and by the varices which are built up 

 of numerous la^^ers and are so thick that they unite at the base. I found but a 

 single specimen weathered out of the brown shale east of Guayubin. It is of the 

 same type as S. expansa Con., of the Maryland Miocene, but is hardly a thii'd as 

 long as that species. 



TEREBRA. Brug, . , • . - 



T. robust a. Hds. Proc. Zool. Soc, 1843, p. 149. 

 Id. Rve. Icon. sp. 10. 



T. sulcifcra, Sby., Quart. .Tour., Vol. VI., p. 47. 



I can find no difierence, on a critical comparison, between the fossils and i-ecent 

 Panama specimens. 



T. in;equalis. Sby., Quart. Jour., Vol. VL, p. 47. 



Id. Guppy, loc. cit., Voh XXII., p. 290. ■ ' ■ ' ! ' ' ' 



Very similar to the preceding in its young state, this shell continues slender at all 

 ages and retains its sculpture, while T. robusta widens more ra])idly as its grows 

 oldei', and the sculpture becomes olisolete. 



