452 JENKINS— GEOLOGY OF THE [May 29, 



The angle of the spire is about 12°. The shell has from 16 to 22 

 volutions, usually 18 or 19, ornamented with two rows of tiny knobs 

 situated at the borders of the volution, close to the suture. The 

 row on the upper side is more prominent and becomes more so the 

 nearer it approaches the top of the spire. In some of the younger 

 or smaller specimens it stands out as a knobby ridge. There is 

 another rather distinct row of knobs or points following the center 

 of the volution. The material is so poor that it is difficult to de- 

 termine anything further about the ornamentation except that it 

 varies a little among different specimens. Some of the knobs are 

 almost spines, appearing as little points, 6 or 8 on each half volution. 



This form is not Turritella elicita as given by White, found at 

 Maria Farinha and Ponta de Pedras. It differs principally in the 

 ornamentation, having rows of points instead of ridges on the 

 volutions. Also these rows are not situated in the same positions 

 as in Turritella elicita, nor is the angle of the spire nearly so great. 



The original shells were never found, so the casts were studied 

 principally from wax molds made from them. 



Associated with these fossils were Cardium soaresannm Rath- 

 bun, some Cerithiiims, and a Corhnla-Wkt form. Apparently on 

 top or interbedded with strata containing these were found casts 'of 

 plant fragments, such as palm leaves. 



Numerous casts of these Tnrritellas were found near Itapasa- 

 roca, Rio Grande do Norte, in the limestones exposed by the railway 

 cut. In most of the other limestone exposures of this region these 

 same forms occur. 



Other Fossil Remains. 

 (Plate XX., Figs. 3, 5, and 9.) 

 Other fossil remains were found in the limestones. One ap- 

 peared to be a portion of a Pholas-Vikt shell ; another, probably an 

 Ostrea (Fig. 3). A larger bivalve, Cardinni-Uke, about 25 mm. 

 long and 20 mm. high, was rather common. A small Cerithiitm-like 

 form (Fig. 5) with a sharp, smooth spire, making an angle of 40°, 

 was found and is probably different from the other Cerithiums. A 

 few specimens of a small gastropod (Fig. 9), something like Natica, 



