380 DESCRIPTIONS OF NEW SPECIES OF FOSSILS, 



centre. Section sub-triangular, centre of the outer side forming an obtuse angle, the 

 lower edge more acute, the inner side flat, and the upper edge acute, and finely den- 

 ticulated near the hand, gradually becoming less prominent and finally obsolete 

 on the outer half of the edge. Surface smooth and polished, showing no external 

 marks, but, through the translucent shell, a kind of reticulation, owing to inequalities 

 beneath. 



Locality and Position. — Great Bend of the Missouri. Lower part of division No. 4 

 of Section. 



LiNGULA SUBSPATULATA, «. Sp. 

 Plate I. Fig. 2, a, h. 



Shell sub-elliptical, margins regularly curved above, straight or little contracted 

 below the centre ; base sub-truncate ; surface marked by faint concentric striae, and a 

 few strong wrinkles parellel with the lateral margins. Viseral impression trifoliate. 



The only specimen we have is imperfect, and the shell is preserved only on the 

 margins. It has nearly the proportions of Lin(/ula Roidinia?ia, (D'Orbigny, Pal. 

 Frangaise, Terrains Cretads, Brach. p. 10, pi. 490, fig. 1,) but differs in having its 

 greatest width above the middle, while in the European species the greatest width is 

 below the middle. Our species is also more abruptly rounded or sub-truncate at the 

 base. The surface markings are similar. 



Locality and Position. — Xear Eed Cedar Island, thirty-five miles below Fort Pierre. 

 Di\'ision Xo. 4 of Section. 



Caprinella coraloidea, n. sp. 

 Plate II. Fig. 3, a -/. 



Our specimen is a portion of the larger valve extending about two and a half inches 

 from the apex, and partially invested with the thick, fibrous shell. From this is drawn 

 the following description. 



Inferior valve spiral, rapidly increasing from the apex towards the aperture ; when 

 divested of the outer fibrous shell, the internal septate part is seen to be spirally 

 curved, and rapidly increasing in size ; a longitudinal groove or depression extends 

 from the apex along the back of the curve to the larger extremity, crossed by numer- 

 ous irregular septa, which pass from the inner side outwards and upwards. 



This interior septate portion is enveloped in a thick, fibrous shell, Avhich, in the 



